Let’s be Very Clear — 100 Percent (or More) of Recent Warming was Caused By Humans

“We actually have high confidence that the warming that is happening now is not natural cycle. If anything, over the past few decades, nature has tried to cool us off a little bit… The sun has dimmed just a little bit. We have blocked the sun with particles from our smokestacks just a little bit. And yet it has warmed. If you were to ask how much of the warming that we see recently has been caused by our greenhouse gasses, it’s a little more than all of it (emphasis added).” — Dr Richard Alley


To say that scientists, as a group, tend to be cautious is probably the understatement of the Century. In most cases, this caution is beneficial — preventing outrageous assertions regarding key issues and providing a stable basis for developing rational policy.

(Dr. Richard Alley, Dr Michael Mann, and Dr Johnathan Brockopp discuss the extent of the global warming crisis without false equivalency given to climate change deniers. Video source: Conversations — Live Climate Change.)

But when it comes to confronting climate change deniers, such caution and reticence has often been exploited by the fossil fuel interests and their political backers who tend to make intentionally deceptive arguments aimed at casting doubt on scientific findings. Just as Scott Pruitt, a man who has fought helpful emissions regulations by EPA at the behest of the fossil fuel industry for most of his legal career, did last week on CNBC’s Squawk Box when he said:

“I think that measuring with precision human activity on the climate is something very challenging to do and there’s tremendous disagreement about the degree of impact, so no, I would not agree that it’s [CO2] a primary contributor to the global warming that we see.”

Playing Disingenuous and Intentionally Deceptive Word Games

Pruitt’s statement was made with a pretty obvious intent to cast fallacious doubt on established scientific findings. It was deceptive. And it aimed at highlighting perceived, but not actual, uncertainties in the science. It ultimately perpetrated a logical fallacy of consistency (argument based on false equivalency). Such fallacies tend to exploit seeming gray areas in established understanding in order to cast doubt on solid evidence. In this case, to create a false sense that counter arguments against the scientific basis for CO2 as a heat trapping gas have equal weight to the actual science.

In the end, the perception of uncertainty is what false and fallacious arguments like Pruitt’s seek to generate. And these arguments often aim to exploit the fact that overarching scientific consensus statements seldom claim 100 percent certainty, even though findings, especially in the case of climate change, are highly accurate.

In one example, more than 97 percent of scientists agree that global warming is caused by humans. This consensus is among the strongest for any scientific finding. However, the most recent IPCC report found that:

“It is extremely likely [defined as 95-100% certainty] that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic [human-caused] increase in greenhouse gas concentrations and other anthropogenic forcings together.”

This statement, at its face value is a strong validation for the human warming consensus. However, it provides a bit of a linguistic loop-hole in the phrase — ‘more than half’ — which seems to imply that almost half of the warming Earth has experienced was caused by something other than human activity. This apparent but false uncertainty is the kind of statement that people like Pruitt, who use deceptive argumentation, tend to latch onto. And if a person were to make the conclusion that nearly 50 percent of warming was not caused by humans and that the ultimate cause of warming is therefore in doubt, then it would be a false one.

More Than 100 Percent of Recent Warming Caused By Humans, CO2 Earth’s Primary Temperature Control Knob

(Most recent warming attribution studies find that more than 100 percent of the atmospheric heat gain we’ve seen during the past 50-65 years was caused by human activity such as fossil fuel burning. Image source: Skeptical Science.)

The truth is that IPCC made a very cautious statement. It has 95 to 100 percent confidence that more than 50 percent of warming has been caused by human activity. And the basis for this statement is that most studies find that while natural factors like solar activity are pushing the world to cool, the human forcing is strong enough to overcome that natural cooling trend and to set in place a very strong and unnatural warming trend instead. The science finds that without the greenhouse gas emissions coming chiefly from fossil fuel burning, the Earth would have seen slowly falling temperatures over the past 50-150 years.

Moreover, studies for the past 50-65 years almost universally attribute 100 percent or more of warming to human produced heat forcing. The above graphic, by Skeptical Science, shows a sample of new studies in which 99 to 170 percent of recent warming was attributed to human causes.

(According to IPCC, carbon dioxide is the primary heat trapping gas emitted by humans and is responsible for the majority of atmospheric warming. Meanwhile, NASA scientists find that this gas is the chief control knob governing Earth’s temperature.)

In addition, the lion’s share of the heat trapping, according to the science, can be attributed to one greenhouse gas — CO2. For NASA, along with pretty much every other major scientific body studying climate, finds that CO2 is Earth’s primary temperature control knob.

So when Scott Pruitt, a climate change denier and Trump’s pick for head of the EPA says that there’s a lot of uncertainty about CO2 and it’s not the primary source of warming and that it’s uncertain whether humans are a factor — he’s telling a lie. The science is very clear that warming is human caused, that probably more than 100 percent of warming has been driven by human activity, and that CO2 from fossil fuel emissions has been the cause of the majority of that warming.

But in addition to telling a lie Pruitt, as head of EPA, is committing malfeasance. For he is the head of the agency responsible for regulating harmful gasses like CO2 and for preventing the severe damage that will surely be inflicted upon the American public if these gasses continue to be released into Earth’s atmosphere.


CNBC’s Squawk Box

Skeptical Science

IPCC Fifth Assessment

CO2: Principal Control Knob Governing Earth’s Temperature

Hat tip to Erik

Hat tip to Cate


For 2016, Atmospheric CO2 Concentrations are Rising at the Fastest Rate Ever Seen

“The MMCO [Middle Miocene Climate Optimum] was ushered in by CO2 levels jumping abruptly from around 400ppm to 500 ppm, with global temperatures warming by about 4°C  and sea levels rising about 40m (130 feet) as the Antarctic ice sheet declined substantially and suddenly. ” — Skeptical Science


(Fossil fuel carbon emissions are about 100 times that of volcanoes during any given year. And so much heat trapping carbon dumped into the atmosphere is forcing the world’s climate to rapidly change. Image source: The Union of Concerned Scientists.)

Human beings have never seen atmospheric CO2 values that are so high as they are today. They significantly predate our species — even preceding our distant relative Australopithecus by about 7 million years. And weather and climate conditions to which we are not adapted — either as individuals or as a civilizations — are well on the way as atmospheric CO2 levels are ramping up into the lower range of those last seen during the Middle Miocene of 14-16 million years ago at 404 parts per million during 2016.

Record Rate of CO2 Increase for 2016

As we reported in November, 2016 is on track to see a record rate of atmospheric carbon dioxide (CO2) increase. A key heat-trapping gas, CO2 is the primary driver of the big temperature increases seen around the world recently. And with new figures out from NOAA for the month of November, we have a clearer picture than ever of just how unprecedented the jump will be.

For the first 11 months of the year, 2016 atmospheric carbon dioxide concentrations exceeded those of 2015 by an average of 3.45 parts per million. With no sign evident that the pace of increase has slackened — despite a transition to La Nina during the fall — it now appears that the world is set to experience a 3.3 to 3.5 part per million jump in the atmospheric CO2 measure for this year.

Carbon Dioxide Trend Mauna Loa

(Atmospheric carbon dioxide concentrations will rise by a record rate during 2016 to an annual average of around 404 parts per million. Levels during 2017 could peak at around 410 to 411 parts per million in April and May before averaging between 406 and 407 parts per million. Image source: NOAA.)

The past two record jumps were 2015 — with a 3.05 ppm annual increase and 1998 with a 2.93 ppm annual increase. But 2016 now appears set to exceed these two values by a pretty hefty margin.

More and More Toward the Middle Miocene Range of 400 to 500 Parts Per Million CO2

Such rapid rates of atmospheric carbon dioxide increase are primarily caused by global fossil fuel burning — which now produces an emission that is more than 100 times greater than all the volcanoes that erupt across the Earth during any given year. And recent reports have found that US automobile emissions alone equal the amount of carbon dioxide emitted by the Mount St. Helens eruption every three days. This is a heavy insult to the Earth’s climate system. One that is unprecedented for millions of years.

All this fossil fuel burning has largely helped to push atmospheric CO2 values for 2016 into an average range of 404 parts per million. This is 124 parts per million higher than the pre-industrial value of 280 parts per million. Meanwhile, peak monthly values during April-May of 2017 could strike as high as 410 to 411 parts per million.


(15 million years ago, atmospheric CO2 levels in the range of 400-500 parts per million produced Antarctic melt resulting in substantial sea level rise. The above image shows the estimated location of the U.S. eastern coastline at the time. Image source: Colorado Geosystems.)

These atmospheric concentrations are now roughly equivalent to the lower range CO2 levels of the Middle Miocene climate epoch of 14-16 million years ago. Meanwhile, atmospheric CO2 equivalent concentrations, which include other greenhouse gasses like methane, averaged 485 parts per million in 2015 and likely were around 490 parts per million during 2016. These CO2e values approach the upper Middle Miocene range.

During the Miocene of 14-16 million years ago, atmospheric CO2 levels, which had hovered around 400 parts per million for about 10 million years jumped higher due to volcanic activity. Global temperatures rose from about 2-3 C hotter than Holocene values to around 4 C hotter. Antarctic ice melted and seas which were around 60 feet higher than today lifted to around 130 feet above present day levels.

By continuing to burn fossil fuels, this is the climate context we enter more and more. It is why, for example, we are seeing so many impacts from expanding droughts, to declining ocean health, to more extreme weather, to rapidly destabilizing glaciers in Antarctica. And it is this burning along with a related warming of the Earth System that is causing atmospheric carbon values to jump so rapidly into ranges to which we are unaccustomed.


NOAA Earth Systems Research Laboratory

Skeptical Science

2016 to See Record Rate of Atmospheric CO2 Increase

The Union of Concerned Scientists

US Auto Emissions Comparable to Mt. St. Helens Eruption Every Three Days

2016 on Track for Record Rate of Atmospheric CO2 Increase

During 2016, the annual rate of atmospheric carbon dioxide increase will have hit a record 3.2 to 3.55 parts per million (ppm). By 2017, the amount of carbon dioxide in the Earth’s atmosphere will be roughly equivalent to concentrations last seen during the Middle Miocene climate epoch (404 to 410 ppm average). In other words, atmospheric CO2 is rising at a record rate and we are hitting levels of this heat-trapping gas that have not been seen in about 15 million years.

Record Rates of CO2 Increase

The world is struggling to make the necessary turn toward reducing fossil fuel-based carbon emissions. Global emissions have plateaued at or near new record highs during the past three years. Conflicts over fossil fuel cuts and transitioning to renewable energy embroil numerous countries. Climate change deniers hold significant power in places like the United States, the United Kingdom, Canada, and Australia. And facing off against those who would defend the harmful interests of what could well be called the most destructive industry to ever inhabit the planet, are a broad group of environmentalists, scientists, concerned citizens, and renewable energy advocates.


(Global carbon dioxide is approaching a level not seen since the Middle Miocene period around 15 million years ago when atmospheric concentrations typically averaged above 405 ppm and global temperatures were 3-4 degrees Celsius hotter than 19th-century averages. Record annual rates of CO2 increase in excess of 3 ppm each year for 2015 and 2016 are swiftly propelling us into a climate state that is more similar to this ancient epoch — a shift that is producing increasingly harmful global consequences. Image source: The Copernicus Observatory.)

As the political turmoil ramps up, it appears that the Earth’s oceans and biosphere are straining to draw in the massive volumes of these gasses that we’ve been pumping out. Annual atmospheric CO2 growth rates for 2015 were a record 3.05 ppm. 2016 appears to be on track to beat that high mark, being likely to see a new annual increase of between 3.2 and 3.55 ppm.

Hot Lands and Oceans Tend to Produce a Carbon Feedback

The previous most rapid annual rate of atmospheric CO2 increase was 2.93 ppm during the strong El Niño year of 1998. Back then, high ocean surface temperatures combined with warming-related wildfires and droughts which spanned the globe to reduce the Earth’s capacity to take in carbon. More carbon was squeezed out of hot soils, burning forests, and warming oceans. Less was drawn down. New record rates of atmospheric CO2 increase were breached.


(Except for a couple of days, all of 2016 saw atmospheric CO2 levels above 400 ppm. Peak values as measured at the Mauna Loa Observatory in May were 407.7 ppm. By May 2017, atmospheric CO2 levels are likely to hit near 410 ppm — a level not seen in about 15 million years. Image source: The Keeling Curve/Scripps Institution of Oceanography.)

Even during the period of heightened heat stress that occurred in 1998, we did not see a year in which annual rates of CO2 increase exceeded 3 ppm. We have never, until 2015-2016, seen a time when there were two back-to-back years of such rapid rates of increase. Similar but worsening heat stress impacts have likely flagged what at first appeared to be an increased rate of carbon uptake from the biosphere during the late 2000s. Ocean heat content is now dramatically greater than during 1998 and this significant warming is likely having at least a periodic impact on the ocean’s rate of carbon uptake. Wildfires are now far more prolific, generating more atmospheric carbon. Droughts are more widespread and these tend to squeeze carbon from the soil. The Arctic is the warmest it’s been in 115,000 years and, as a result, some new Earth system carbon sources are starting to pop up.

Record High Rates of Fossil Fuel Emissions Hitting a Plateau

In the intervening years since 1998, global carbon emissions from fossil fuels have also jumped dramatically. During 1998, yearly CO2 emissions were in the range of 26 billion tons per year. By 2014-2015, these greenhouse gas releases had soared to around 35.8 billion tons per year. Through this period, average annual rates of CO2 increase continued to climb during the 2000s and 2010s.


(Global carbon emission increases stalled during 2013, 2014, and 2015 according to The Global Carbon Project. But despite this recent pause, atmospheric rates of carbon dioxide increase have continued to ramp up. Due to a number of factors, including atmospheric and ocean inertia as well as temperature and saturation stress to global carbon stores, it is likely that significant reductions in carbon emissions from fossil fuels will be necessary to have a marked impact on annual rates of atmospheric CO2 increase.)

According to NOAA, the 1980s and 1990s saw yearly jumps in CO2 at the rate of about 1.5 ppm each year. By the 2000s, this average rate of increase had leaped to about 2 ppm per year. For the first six years of the 2010s, the average rate will likely be around 2.5 ppm per year.

New Records Provide Urgency For Rapid Emissions Cuts

This rate of increase roughly matches the overall rate of increase in emissions. As yet, there is no major global trend sign in the atmospheric CO2 data showing that carbon uptake from the oceans and the biosphere has been significantly curtailed, at least not to the point that it has shown up in the long term global trend. There are, however, widespread signs of stress to the Earth’s carbon storage system, and two years of 3 ppm-plus increase back-to-back is a warning blip on the climate radar.

In other words, these new record rates of CO2 increase are disturbing. If the annual increases do not fall back into the low 2-ppm per year range in 2017 and 2018, it will be an indication that some of the Earth’s ability to draw down carbon has been significantly hampered. If that is the case, then the urgency to draw down emissions is considerably greater.



Middle Miocene

The Global Carbon Project

The Copernicus Observatory

The Keeling Curve

Doubling Down on Our Faustian Bargain

Hat tip to SmallblueMike

(Note: This post focuses primarily on CO2 as an indicator. Overall CO2e levels will be covered in a separate exploration.)

Key Hothouse Gas to Rise at Record Rate, Hit Near 408 Parts Per Million in 2016

For 2016 it appears that monthly concentrations of atmospheric carbon dioxide (CO2) will hit a new peak near 408 parts per million at the Mauna Loa Observatory in April or May. Not only is this the highest concentration of this key heat-trapping gas ever recorded at Mauna Loa, but it is also the high water mark of what is likely to be the most rapid rate of annual CO2 increase ever seen.

Atmospheric CO2 407-408 ppm

(Atmospheric CO2 keeps being pushed into record ranges by a massive ongoing fossil fuel emission. Global hothouse gas levels are now high enough to begin resulting in various catastrophic changes such as rapid sea level rise, glacial destabilization, increasing instances of droughts, floods and wildfires, and declining ocean health. Image source: The Keeling Curve.)

By 2014, a Century and a half of global fossil fuel burning had dumped an egregious amount of carbon into the world’s airs — forcing atmospheric CO2 levels to rise from about 275 parts per million in the mid 19th Century to a peak of around 401.5 parts per million during that year. By May of 2015, atmospheric CO2 levels peaked at around 403.8 parts per million. And by April of 2016, the monthly average concentrations of this heat-trapping gas had rocketed to near 407.6 parts per million. As atmospheric CO2 readings typically peak in May, we can expect a final top monthly average this year to range between 407.6 to 408 ppm — or 3.8 to 4.2 parts per million higher than during the same time in 2015. A total overall increase of around 133 parts per million since the 19th Century. A level of atmospheric carbon that — if it is maintained — is enough to increase global temperatures by nearly 3 degrees Celsius over the coming decades and centuries.

On the Edge of 1.5 C

(Atmospheric CO2 levels now approaching 410 parts per million are pushing global temperatures dangerously close to the 1.5 C threshold identified by scientists as marking a the first series of civilization-endangering climate tipping points. Maintaining CO2 levels near 410 parts per million risks 3 C warming long term. Continuing carbon emissions makes an already bad situation dramatically worse. Image source: Climate Central.)

These are now the highest atmospheric CO2 levels seen in the last 23 million years. And an annual rate of CO2 increase approaching 4 parts per million is unheard of for any time period in any geological record — even during the Permian hothouse extinction event which wiped out about 90 percent of life in the oceans and 75 percent of life on land. This very rapid rate of atmospheric CO2 increase is being spurred on by a fossil fuel based carbon emission now in the range of 13 billion tons each year (of which CO2 is the vast majority). That’s a rate of carbon addition more than ten times faster than the carbon spike that set off the Paleocene-Eocene hothouse mass extinction about 55 million years ago. A very dangerous rate of carbon accumulation that will generate increasingly severe and harmful geophysical changes over the coming years, decades and centuries. An event that, if it continues, could well be termed the mother of all carbon spikes.

New Record Rate of Increase For Hothouse Gas Concentrations as CO2 Emissions Level Off

Peak-to-peak rates of increase do not capture the full annual average accumulation, but it is an indicator. And for 2016, it appears the annual measure will jump by at least 3.5 parts per million. Previous record rises occurred last year (in 2015) and in 1998 when atmospheric carbon dioxide jumped by about 3 parts per million. Over the past decade, carbon dioxide has accumulated by about 2.2 parts per million each year. So, by any context, 2016 is looking pretty bad in that we’ll almost certainly see a new record pace of greenhouse gas accumulation.

Totten Glacier Plug in Antarctic Bathtub

(A recent study in Nature Geoscience found that continued fossil fuel burning and accumulation of atmospheric greenhouse gasses like carbon dioxide risks the irreversible destabilization of Totten Glacier which would result in rapid sea level rise this Century. In total, the Totten Glacier covers an area the size of the southeastern US, is more than a mile thick and, if melted, would raise sea levels by 11 feet. Researchers found that the mouth of the Totten Glacier — holding back this gigantic pile of ice — is rapidly melting now. Image source: Nature Geoscience and The Washington Post.)

The causes of this amazing and dangerous jump in atmospheric CO2 rest entirely at the feet of the global fossil fuel industry — which continues to push through its various political allies and media agencies for expanded and extended burning of coal, oil, and gas. But despite numerous attempts by that destructive industry to stifle the pace of renewable energy adoption and to stymie efforts to increase energy efficiency, both efficiency and renewables have advanced and rates of carbon emission leveled off during 2014 and 2015.

What the industry has achieved, however, is continued delay of a more rapid rate of renewable energy adoption which has resulted in global carbon emissions maintaining at current record high ranges. And such a huge dump of carbon into the atmosphere and oceans would have inevitably resulted in new record rates of atmospheric CO2 increase being hit eventually.

IEA global carbon emissions

(Global CO2 emissions leveled off in a record range near 32 billion tons per year during 2014 and 2015. Increasing rates of renewable energy adoption and improvements in energy efficiency helped to drive this trend. However, 32 billion tons of CO2 each year [approximately 8 billion tons of the total 13 billion tons of carbon hitting the air each year when the molecular weight of non-carbon atoms such as oxygen is removed] is likely the most rapid pace of atmospheric CO2 accumulation in all of the deep history of the Earth. A stark statistic that lends urgency to rapidly drawing such a high annual emission rate down. Image source: International Energy Agency — Decoupling of Global Emissions and Economic Growth Confirmed.)

This year, a strong El Nino reduced the ability of oceans to uptake such a massive volume of pollution belching from the world’s smokestack and tailpipes. A variable warming of waters that put a lid on what is an already fading ocean carbon sink. In addition, comparatively small but significant carbon contributions in the form of increasing global wildfires, ramping permafrost thaw and burning, and increasing methane seeps now provide a visible amplifying feedback to the massive and unprecedented human greenhouse gas emission. A feedback that is bound to rapidly worsen if the literally insane human fossil fuel emission does not stop soon.


The Keeling Curve

Entering the Middle Miocene

Ten Times Faster Than a Hothouse Extinction

Decoupling of Global Emissions and Economic Growth Confirmed

Climate Central

Hat tip to Meteorology Meg

Hat tip to DT Lange

Atmospheric CO2 Rocketed to 405.6 ppm Yesterday — A Level not Seen in 15 Million Years

As CO2 levels hit a new record global high of 405.66 ppm yesterday, I couldn’t help but think that HG Wells could not have imagined a more perilous mechanism for exploring the world’s past.

For when it comes to testing the range of new climate extremes, the present mass burning of fossil fuels is like stepping into a dark time machine. As all that carbon hits the airs and waters, the climate dial spins backward through hundreds of thousands and millions of years. Speeding us on toward the hothouse extinction eras of Earth’s deep history. Now, not only is it driving us on through extreme weather and temperature events not seen in 100, 1,000, 5,000 or even 10,000 years, it is also propelling us toward climate states that haven’t occurred on Earth for ages and ages.


Ever since 1990, the world has experienced atmospheric CO2 levels in a range that hasn’t been seen since the Pliocene geological epoch. A period of time 2.6 – 5.3 million years ago hosting carbon dioxide levels ranging from 350 to 405 parts per million and global average temperatures that were 2-3 degrees Celsius hotter than 1880s levels. Overall, global sea levels towered about 80 feet higher than those humankind has grown accustomed to.

Annual mean CO2 Growth Rate

(Never has the Earth seen a CO2 build-up so rapid as the one produced by the human fossil fuel energy era. Rates of CO2 increase just keep ramping higher ever as the world’s climate sinks appear to be filling up. In this context, 2015 saw the swiftest pace of CO2 rise yet. Warming ocean surface waters can’t absorb as much CO2 as cooler oceans. And a record hot ocean during 2015 contributed to this extreme atmospheric CO2 accumulation. For the whole of the past year, CO2 built up in the atmosphere at a rate of 3.2 parts per million per annum. That’s well above the already raging pace of 2 parts per million average annual accumulation during the decade of the 2000s. Image source: NOAA ESRL.)

If global atmospheric CO2 levels had stabilized in this range, it’s likely that we would have eventually seen climates, temperatures, and sea levels that became more and more like those experienced 2-5 million years ago. A process that would have likely taken centuries to reach a final, far warmer climate state. One in which little to no ice remained upon Greenland or West Antarctica, and one hosting a substantial retreat of coastlines.

From 1990 through 2015, that was our climate context. The new world that was steadily settling into place. One that would eventually assert itself unless atmospheric CO2 levels were somehow drawn down to below 350 parts per million. It was kind of a big deal. Unfortunately, few experts really talked about it.

Exiting the Pliocene

But starting in 2015 and continuing on into 2016 the fossil fuel burning time machine again cranked us back toward hotter, more dangerous times. For during the past two years we began to exceed the maximum CO2 threshold of the Pliocene and we started to enter CO2 ranges that were more typical to those of the Middle Miocene climate epoch of 15 to 17 million years ago.


Rocketing on past the Pliocene

(Rocketing on past the Pliocene. On February 4 of 2016, a record daily atmospheric CO2 level of 405.66 was recorded at the Mauna Loa Observatory. The Earth hasn’t experienced CO2 levels this high in 15-17 million years. Image source: NOAA ESRL.)

By late April of 2015, as CO2 approached its typical May high point, daily readings had hit a range of 404.9 parts per million — propelling us toward the outside boundary of the Pliocene climate context. For a brief period of 9 months, CO2 retreated back from the Pliocene boundary as spring and summer-time plants in the Northern Hemisphere respired. However, average atmospheric CO2 levels were still ramping higher as a rampant burning of fossil fuels around the world continued. By yesterday, February 4, 2016, daily CO2 levels at the Mauna Loa Observatory had rocketed to 405.66 parts per million. A level well outside the upper range for the Pliocene climate epoch. One more typical for periods seen during the Miocene of 15-17 million years ago.

Entering the Middle Miocene

Unfortunately, this daily Februay peak at 405.66 parts per million is not the end to the current year’s ramp up. Typical atmospheric peaks occur during May. And this year, we are likely to see atmospheric levels hit near a range of 407-409 (estimate revised in March of 2016) parts per million in the weekly and monthly averages over the next few months. Such a range thrusts us solidly out of the Pliocene climate context and well into that of the Miocene.

Though the Middle Miocene was not a hothouse extinction climate, it was one much more foreign to humankind. Back then, only the great apes existed. Our most ancient ancestor, Australopithecus, was still at least 9 million years in the future. It’s fair to say that no human being, or even our closer offshoot relatives, have ever breathed air with the composition that is now entering our lungs. Never lived under the oppressive and intensifying dome of such a great global atmospheric heat forcing.


(We said farewell to the Holocene climate context when CO2 levels rose above 280 parts per million back during the 19th Century. By around 1990, we had begun to enter the Pliocene context, a period occurring 2-5 million years ago. As of 2015, we had begun to exit the Pliocene climate context and enter the Middle Miocene. If current rates of fossil fuel burning or business as usual rates of fossil fuel build-up continue, we will be entering the Ogliocene climate context in about 25 to 50 years. Image source: NOAA ESRL.)

We are now entering a period in which atmospheres are more similar to those seen during the Middle Miocene Climate Optimum — the last time CO2 measures exceeded a threshold of roughly 405 parts per million (see here and here).

The Middle Miocene Climate Optimum of 15-17 million years ago was a radically different world. It hosted an atmosphere in which carbon dioxide levels varied wildly from 300 parts per million to 500 parts per million. Temperatures were between 3 to 5 degrees Celsius hotter than the 19th Century. And sea levels were about 120 to 190 feet higher. During this period, the world was still cooling down from the heat of the Paleocene and Eocene epochs. Carbon was being sequestered. And it was the first time the world broke significantly below a 500 part per million CO2 plateau that had been established during the Oligocene 24 to 33 million years ago.

If CO2 levels remain in this range, these are the temperatures, sea levels, and climate conditions we will transition to and ultimately experience. But time, and fossil fuel burning, is not on our side. For under business as usual fossil fuel burning rates of increase, we could hit the Oligocene threshold within as little as 25-30 years. And even if the current rate of increase were maintained, the Oligocene boundary sits about 5 decades away.


NOAA ESRL (Please support public, non-special interest based, science like the fantastic and essential work produced by the experts at NOAA.)

The Keeling Curve

Pliocene Climate

Entering the Middle Miocene

Hat tip to Kevin Jones


Humankind’s Last Days Below 400 PPM CO2?

Another ominous milestone fades away in the smog behind us…

By mid November of 2015, atmospheric carbon dioxide levels as measured at the Mauna Loa Observatory had again risen above 400 parts per million. Over the past two weeks, these levels maintained. And even though we may see a few days during which CO2 levels drop below that key threshold during late November and, perhaps, early December, those days could well be the last.

The last days of below 400 parts per million CO2 may then be behind us. It’s likely that none of us now living will ever see such ‘low’ levels of this critical atmospheric greenhouse gas. And it’s possible that humankind itself will never again see a day in which CO2 levels fall into this range (please see Is This the Last Year Below 400 PPM CO2?).


(By November 13 of 2015, atmospheric CO2 levels at the Mauna Loa Observatory had risen above the 400 ppm CO2 threshold. During 2015, just four months of the year have been below that level. For 2016, it’s possible that no month will average below 400 ppm CO2. And after that time, we’ll likely never see below 400 ppm CO2 levels again. Image source: The Keeling Curve.)

Dr. Ralph Keeling, in a blog over at the Keeling Curve site back in October clearly explained why 2015 may be the last year with monthly readings below 400 ppm CO2. In short, the added global heat from El Nino tends to squeeze more carbon out of the Earth’s lands and oceans. As a result, strong El Nino years have tended to show higher rates of atmospheric CO2 increase when these Earth System feedbacks are added in to the carbon coming from an insane global rate of fossil fuel burning. The last time a strong El Nino emerged during 1998, global CO2 levels rose by 3.7 parts per million during a single year. Since the rate of human fossil fuel burning has substantially increased over the 1998 to 2015 period and as the current El Nino is peaking at or above 1997-1998 intensities, it’s possible that the annual increase in CO2 could match or exceed that seen during 1998. We could see annual CO2 levels rise by 3.5, 3.75, or even 4 parts per million or more during the 2015 to 2016 interval.

If CO2 levels rise so rapidly, 2015 will be the last year seeing any significant period below 400 ppm.


(During 2016, CO2 levels as measured at Mauna Loa will peak at between 405 and 408 parts per million CO2. These levels are the highest seen at any time during the last 3-15 million years and are more typical to the early Pliocene or Middle Miocene climate epochs. Such amazingly high levels of CO2 beg equally amazing and harmful geophysical changes to follow. Image source: The Keeling Curve.)

Unfortunately, due to CO2’s long residence time in the atmosphere and also due to the fact that the added heat provided by that CO2 tends to generate long-lasting carbon feedbacks from the global environment, it is likely that this period of above 400 parts per million CO2 will last for a very, very long time. With a single molecule of CO2 having a warming impact period of at least 500 years so long as the oceans can eventually draw the net carbon increase down (a dubious proposition in the context of warming world), even if human fossil fuel emissions halted after just one or two additional decades, it would mean that above 400 parts per million CO2 levels last for centuries to come. On the other hand, if human fossil fuel burning and related carbon emissions continue even into the middle of this Century, then it’s possible that such heightened CO2 levels could last for millennia — possibly outlasting the human race itself. In such an event, the only hope for bringing CO2 back to levels below 400 parts per million is a very significant change in land use, farming, and technological practices to directly draw carbon out of the atmosphere.

Atmospheric CO2 levels remaining at 400 parts per million for any significant period will push the Earth climate to warm by between 2 and 3 degrees Celsius. It will push for sea levels to rise by at least 75 feet. In other words, a world at 400 parts per million is a world radically changed. A world that human beings have never seen before. And as a cautionary note, the total forcing from all greenhouse gasses currently emitted by humans is now in the range of 485 parts per million of CO2 equivalent. A level well beyond the current 400 parts per million threshold and one that likely equates to around 4 degrees Celsius worth of long term warming.

These are the stark consequences of fossil fuel burning. A burning, that if it continues, will almost certainly ensure that human beings living after 2015 or 2016 never again see CO2 levels below 400 parts per million.


The Keeling Curve

Is This the Last Year Below 400?

Pliocene Climate

Miocene Climate

Skeptical Science on CO2 Residence Times






A Fearful Glance at the Global Carbon Stores — Weekly CO2 Values Hit 404 Parts Per Million a Little Too Soon

mlo two years April 15

(Big jump in weekly CO2 averages during second week of April bring 2015 concentrations into the range of 404 parts per million a month earlier than expected. Image source: The Keeling Curve.)

Over the past decade, annual rates of atmospheric CO2 increase have remained in a range of around 2.2 parts per million (ppm) each year. It’s a geologically blinding pace of increase driven by a human carbon emission on the order of around 11 billion tons each and every year. Primarily driven by fossil fuel burning, this massive dumping of carbon into the atmosphere is steadily filling up a number of the world’s key carbon stores.

The oceans are brimming full with carbon — as we see in a rapidly rising rate of acidification.  The oceans are warming, steadily losing their ability to keep a higher fraction of greenhouse gasses stored in solution. The trees are lagging in their ability to draw carbon from the atmosphere — a symptom of a combined deforestation, wildfire proliferation, and endemic outbreaks of invasive species that prey on key trees. And the carbon store in the Arctic is showing signs that it may be actively venting higher volumes of greenhouse gasses back into the atmosphere and oceans.

As a leading indicator that some of these carbon stores are starting to fill up, or worse, dump a significant portion of their sequestered carbon back into the atmosphere, we would expect to see spiking levels of CO2 and CH4 in the global measures. Which is why when, starting on April 5 of 2015, Mauna Loa CO2 values shot up to around 404 to 405 parts per million in some of the hourly records, a few eyebrows were raised.

Implications of Hitting Expected Peak Values a Bit too Soon

Typically, atmospheric CO2 peaks around mid-May. And, for this year, following the 2.2 ppm increase trajectory, we would expect a May monthly value of around 404 parts per million. So readings in the range of 404 to 405 parts per million in early April are a significant jump well ahead of the expected marks. If this increase remained consistent and showed continued seasonal rise on through mid-May, it could skew April and May readings upward — well beyond a 2.2 ppm annual increase at peak.


(Consistently High CO2 values show up at the end of the monthly measure. Note the frequent hourly departures above 405 ppm. Image source: The Keeling Curve.)

Typically, the difference between April and May monthly values is in the range of 0.5 to 1 ppm CO2. So an April Average near 404 ppm could yield a May average of 404.5 to 405 ppm or a 2.7 to 3.2 ppm increase over 2014 peak values. A significant high departure that could be a leading indicator of a bad response from the global carbon stores. This possibility was raised as daily Mauna Loa CO2 values ranged from 403.2 ppm through 404.9 ppm from April 5 to 14 and as weekly values for April 8-14 hit 403.9 ppm.

Signal or Noise?

Of course, these admittedly worrisome spikes could well be noise in the overall carbon system. CO2 values have tended to vary more wildly in the Mauna Loa measure recently. And average rates of increase from peak to peak could still fall into the standard range.

It is also worth noting that any major disruption in the global carbon system as it relates to CO2 would also show up as a trailing indicator in the CO2 airborne fraction measure. A higher level of emitted CO2 would remain in the atmosphere as sinks began to fail and as stores became sources. Such a carbon sink failure would eventually show up as a higher airborne CO2 fraction.

Overall, the airborne fraction measure is an indicator of how much of the carbon human beings emit into the atmosphere is being taken up by the global environment:

CO2 Airborne Fraction

(Airborne CO2 fraction showing global carbon dioxide emissions [as gigatons of carbon without oxygen molecular weight added] since 1960 through 2012 and amount of emitted CO2 that has remained in the atmosphere. Image source: James Hansen and The University of Columbia.)

Currently, the amount of carbon from CO2 remaining in the atmosphere is in the range of 45% of the human emission — or around 5 gigatons.

If carbon sinks are retaining their ability to uptake CO2, then the fraction will remain relatively low. If carbon sinks are over-topping and bleeding substantial volumes of their carbon back into the atmosphere, then the airborne fraction measure will tend to rise as a trailing indicator.

During recent decades, the airborne fraction has actually fallen as emissions ramped up — probably due to a combined increase in ocean surface exposure to CO2 and to an initial bump in the rate of CO2 respiratory uptake by photosynthetic life. But considering the very high volume of carbon being dumped into the global system coordinate with a wide variety of stresses to carbon stores resulting from both added heat and chemistry changes, these carbon sinks are under ever-increasing stress. A number of scientific studies have indicated a likely rise in CO2 airborne fraction, under business as usual fossil fuel emissions, to as much as 80 percent through 2100 — with start of carbon store failures during the current decade.

If carbon stores do begin to fail, we would first see atmospheric spikes in the global CO2 and CH4 measures. Then, as a trailing indicator, the CO2 airborne fraction measure would begin to ramp up. In this context, weekly CO2 spikes at Mauna Loa are some cause for concern, but we can’t make any strong calls of a larger carbon system response without a more consistent spike and, eventually, a jump in the airborne fraction.

To this final point, I’ll leave you with the somewhat related Mauna Loa CH4 measure which has, lately, also been showing an increasing rate of accumulation for that greenhouse gas:

Mauna Loa Methane Measure 2004 to 2015

(Mauna Loa Methane measure shows ramping up of atmospheric CH4 readings at that station. Image source: NOAA ESRL.)


The Keeling Curve

Doubling Down on Our Faustian Bargain

Modeling The Atmospheric Airborne Fraction in a Simple Carbon Cycle Model


Scientific Hat tip to Dr. James Hansen

Hat tip to Wili

Hat tip to Kevin Jones

Entering the Middle Miocene — CO2 Likely to Hit 404 Parts Per Million by May

The Pliocene. A period of time 2-5 million years ago hosting carbon dioxide levels ranging from 350 to 405 parts per million and global average temperatures that were 2-3 degrees Celsius hotter than 1880s levels. The great ice sheets of Greenland and West Antarctica were feeble, if they existed at all. And seas were about 25-80 feet higher than today.


(CO2 hit above 401.84 parts per million on March 9, 2015, and above 403 parts per million on March 10 — levels that test the upper boundary of CO2 last seen during the Pliocene and entering a range more similar to the Miocene. Image source: The Keeling Curve.)

In the context of human warming, the amount of heat forcing we’ve added to the global atmosphere from carbon dioxide emissions alone has been hovering in the range of the Pliocene for the past two decades. A heat forcing that, if it remained steady over a substantial period of time, would almost certainly revert the world to a climate state last seen during that time.

But by 2015, the global human heat forcing from carbon dioxide emissions had begun to exit the period of the Pliocene. Now we are entering a period in which atmospheres are more similar to those seen during the Middle Miocene Climate Optimum — the last time CO2 measures exceeded a threshold of roughly 405 parts per million (see here and here)

The Middle Miocene Climate Optimum occurred between about 15 and 17 million years ago. It hosted an atmosphere in which carbon dioxide levels varied wildly from 300 parts per million to 500 parts per million. Temperatures were between 3 to 5 degrees Celsius hotter than the 19th Century. And sea levels were about 120 to 190 feet higher. During this period, the world was still cooling down from the heat of the Paleocene and Eocene epocs. Carbon was being sequestered. And it was the first time the world broke significantly below a 500 part per million CO2 plateau that had been established during the Oligocene 24 to 33 million years ago.

The great glaciers in East Antarctica were mostly well established, even though their scope was a mere shadow of what we see today. The Greenland and West Antarctic glaciers did not exist. They would have to wait for about another 5-10 million years for the Earth to cool further.


(Glaciation since PETM. Image source: Dr James Hansen.)

As of March 9, 2015, atmospheric CO2 levels had reached 401.84 parts per million. Already a level testing the Pliocene-Miocene boundary, this measure will continue to increase through the rest of March, on into April, and keep rising until middle or late May. At that point, global CO2 levels will have reached around 404 parts per million. At least the highest levels seen in the last 3 million years and possibly the highest levels seen in 15 to 18 million years.

If the greater portion of this range is correct, then we are now breathing air that none among our species or even our hominid relatives have ever breathed since their setting foot on this world.

But CO2 alone doesn’t tell the whole story. Equivalent CO2 levels (CO2e) including all human emitted greenhouse gasses — methane and a host of industrial gasses — will reach about 484 ppm CO2e this year (see here and here). And that forcing puts us easily within the range of the warmest periods of the Miocene. A brew of heat trapping gasses including exotic chemicals that no creature has likely ever breathed while living on the Earth.


The Pliocene

Middle Miocene Climate Instability Associated With CO2 Variability

CO2 and Climate Closely Linked During Middle Miocene

Sea Level and Ice Volume Variations

IPCC 2007 Chapter 6 — Paleoclimate

Dr James Hansen

The Keeling Curve


CO2 Levels for February Eclipsed Prehistoric Highs

A Faustian Bargain on the Short Road to Hell — Living in a world at 480 CO2e

400 PPM CO2? Add in All other Gasses and it’s 478 CO2e

Hat tip to Aldous

Unsettling CO2 Spike: Hourly Levels Hit Near 404 PPM on January 13, 2015

CO2 Spike

Yesterday, at about the same time I was penning this article describing how CO2 levels were likely to exceed 400 PPM for most of 2015, a rather significant and abrupt CO2 spike was taking place at the Mauna Loa Observatory.

For on the evening of January 13, 2015, CO2 levels suddenly rocketed to nearly 404 parts per million.

The sudden upswing was certainly unexpected and rather significant — mimicking only the highest levels during 2014. These spikes came fully four months ahead of typical atmospheric CO2 peaks and seem rather ominous in the graph.

CO2 levels can be variable in the hourly measure. But this inflection was particularly strong — following a very high daily reading of 401.23 PPM on the 12th. Somewhat odd and rather early CO2 increases for 2015. A trend we will have to continue to watch.


The Keeling Curve

Late October Sees Strong Polar Amplification, Mangled Jet Stream Impacting Much of Antarctica

Globally speaking, it’s a rather hot day.

According to GFS model runs and observational data, the past 24 hour period has shown temperatures in the range of +0.72 C above the already hotter than normal 1979 to 2000 average. A hot day in a hot month that is likely to be among the hottest on record, if not an all-time record-breaker itself.

A couple of days ago, hourly CO2 levels rocketed from 396 ppm to 399.5 ppm. A rather odd and somewhat ominous jump back toward the 400 ppm level at a time of year when atmospheric CO2 should be just starting a slow rebound from lowest ebb. A bottom that this year hit about 395 ppm during mid September. A measure already more than 2.2 ppm above last year’s low. To say the least, an hourly upward swing of 3.5 ppm isn’t exactly normal, especially when one considers the fact that the world hasn’t seen near 400 ppm CO2 levels for about three million years (this year peaked near 403 ppm during late spring).

And all that extra CO2, when combined with other greenhouse gasses, is having an increasingly obvious impact on climate. We see it in the record global average temperatures. We see it in the rising oceans which have come more and more to threaten the cities, lands and isles upon which so many of us reside. We see it in increasing instances of extreme weather around the globe — in the extraordinary and often persistent droughts, floods, storms and wildfires. And we see it in the form of a rather strong temperature amplification at both poles.

Antarctic Amplification

(Global temperature anomaly maps provided by GFS and the University of Maine shows no regions of the world cooler than average with the highest abnormal warm temperature departures concentrated, as usual, at the poles.)

Greenhouse Gasses as Primary Driver of Polar Amplification

Today, the Arctic is 1.60 C above the already hotter than normal 1979 to 2000 average. Meanwhile, the Antarctic boasts the highest departures for any global region at +2.09 C. Taking a closer look at the Antarctic Continent, we find an angry red splotch featuring temperature anomalies in the range of +12 to +20 C above average. A region associated with a tropics-to-pole transfer of airs we’ll discuss more in depth later.

What causes such a powerful and visible polar amplification? In short, it can best be described as the general impact of added greenhouse gasses on the global climate system.

Because most of the sun’s radiation falls on the equatorial regions, temperatures there are governed to a greater degree by direct solar insolation. But move toward the poles where sunlight hits the earth at a much lower angle, if at all, then the impact of the greenhouse effect holds greater sway. There, the ability of a gas like CO2 to trap and re-radiate long wave solar heat radiation can have a rather extraordinary impact.

On an Earth with no atmosphere, the temperature differential between poles and equator, between night and day, would be even more extreme than the variance we see today. But as the atmosphere thickens and the greenhouse gas overburden intensifies, the temperature difference grows less. For Earth’s present climate the temperature difference between the Equator and the Arctic averages about 42 degrees C. For the Antarctic, the average is about 71 degrees C.

On a world like Venus, where a kind of super greenhouse is in force and much of the atmosphere is composed of CO2, there is practically no difference in temperature between the equator and the poles. The reason for this is that greenhouse gasses trap the sun’s long wave radiation and recirculate it around a planetary system. And on Venus, a ray of long wave sunlight that comes in has very little chance to get out. So its heat recirculates many times within Venus’s atmosphere before it finally escapes.

On a place like Earth, where greenhouse gas levels are increasing, we would expect the temperature difference between the equator and the poles to drop as the poles warm faster due to the added impact of the increased greenhouse gasses. And since about the mid 20th Century, this is exactly what we’ve seen.

North Pole to Equator Temperature Difference

South Pole to Equator temperature difference

(Top frame shows North Pole to Equator temperature difference since 1948. Bottom frame shows South Pole to Equator temperature difference from 1948 to 2011. Note the approximate 3 C temperature swing indicating a faster warming at the poles in both graphs. Data is from the NCAR-NCEP reanalysis model.)

Lowering differences in Equator to polar temperature on a warming world also denotes a much faster warming of the polar zones. Hence the term polar amplification.

Now, for the Arctic, polar amplification has also become synonymous with loss of sea ice, loss of snow cover, increased land darkening due to changes in vegetation, and local release of greenhouse gasses via feedbacks from the Arctic environment. Each of these changes has the potential to add increased warming on top of the warming already being driven by global greenhouse gas increase even as such changes likely also drive changes to local and Northern Hemisphere weather. But as important as these additional changes may be, the larger driver remains an increase in global greenhouse gases driven by human emissions.

How Polar Amplification Drives Changes to the Jet Stream

In the end, such a polar amplification is a strong driver for changes to the world’s weather. Primarily, by reducing the difference in temperature between the poles and the Equator, we tend to see weaknesses forming in the circumpolar wind field known as the Jet Stream. At times, the Jet will slow and meander, allowing for the formation of ridges that extend far into polar zones and for troughs that dip deep into the middle and lower latitudes. Rather than a west-to-east flow of wind and weather, such a shift generates more of an Equator-to-pole flow:


(Triple tendrils — meridional flows converge on Antarctica. Note the massive highs sitting in the ridge systems driving the poleward wind flows. Image source: Earth Nullschool.)

And today we see two large north to south flows issuing from the 20 degree south latitude region, traversing thousands of miles of ocean in a poleward flood and terminating at the great ice sheets of Antarctica in the region of 70 to 75 south latitude.

Note that the flow originating off the west coast of South America terminates at the vulnerable West Antarctic Ice Sheet — a region that has been warming at an extraordinary pace of 0.25 to 0.5 C each decade. The second flow, originating from the South Atlantic and terminating over East Antarctica is heavily involved in the +12-20 degree C temperature anomalies ongoing there today.

Looking at these massive flows of air and the related spikes in temperature anomalies, it is easy to become confused over the issue of cause and effect. But it is simple to recall if you understand that first, added greenhouse gasses warmed the pole which in turn weakened the Jet Stream, which in turn allowed an amplification of the north-south meridional flow transporting yet more heat into this southern polar region.

For the southern polar region, today, we see some extraordinary high temperature departures for mid-to-late spring. At this time, polar amplification should be fading as more sunlight streams in. And yet we have a still strong positive temperature anomaly.

And as for the northern polar zone with its numerous additional polar amplification vectors, we shall see to what degree, if any, a potentially emerging El Nino tamps down the extraordinary meridional flows and polar vortex disruptions seen during just this past year’s freakish winter of 2013-2014.


University of Maine

NCAR-NCEP reanalysis model

Earth Nullschool

The Keeling Curve

Polar Amplification

Rapid Arctic Warming and Wacky Weather — Are They Linked?

Global CO2 to Reach Extremely Dangerous Peak Near 402 PPM for 2014, Methane Levels Ramp Ominously Higher

During 2014, human CO2 forcing continued its long march toward ever-more dangerous and climate-damaging levels. By the peak month of May, global CO2 had ranged well above the 400 parts per million threshold, catapulting Earth at raging velocity toward climate and atmospheric states not seen in at least 3 million years.

According to May readings from the Mauna Loa Observatory, the more volatile hourly measures jumped as high as 404 parts per million while daily and weekly averages tended to settle between 401.4 and 402.3 parts per million. Given these trends, overall CO2 levels for May of 2014 are likely to peak at near or just below the astronomical 402 ppm threshold.

Atmospheric CO2 Late May 2014

(Atmospheric CO2 levels measured by the Mauna Loa Observatory over the past two years. Peak values for 2012 hit near 397 ppm, peak for 2013 hit near 400 ppm, and peak for 2014 is likely to hit near 402 ppm. Image source: The Keeling Curve.)

CO2 levels near 400 parts per million are enough, according to our developed understanding of paleoclimates, to increase global temperatures by between 2 and 3 degrees Celsius, to melt Greenland, West Antarctica and a portion of East Antarctica, and to raise sea levels by 75 feet if sustained over a long term. According to recent glacial research, these very high levels, when combined with additional greenhouse gas forcing and concurrent ocean and atmospheric warming have already been enough to destabilize or push large portions of these major ice systems into irreversible collapse.

(A history of atmospheric carbon dioxide through early this year provided by CIRES and compared to the entire ice core record of the past 800,000 years. Video source: CIRES.)

36 Billion Tons of CO2 Emission per Year and Counting

Measured from peak to peak, the rate of atmospheric increase is likely near 2.5 to 3.0 parts per million per year over the two year period. Averages over the whole range of the past two years show increases on the order of 2.4 parts per million per year — a challenge to recent rates of increase near 2.2 parts per million a year since 2000.

Steadily ramping rates of atmospheric CO2 accumulation are driven by extreme global industrial, agricultural, and land-use emissions. According to the Global Carbon Project, 2013 saw total global CO2 emissions in the range of 36 billion metric tons. This emission was 2.1 percent higher than the 2012 level and about 60 percent higher than the 1990 level at around 22 billion metric tons of CO2. Such an extraordinary pace of emissions puts severe strain on both atmospheric carbon levels and on carbon sinks around the globe. The resulting risk of such a strong continued emission is that global sinks and stores may soon become sources (see methane monster below). An issue of amplifying feedbacks that grows ever more perilous with each passing year.

Rapidly Increasing CO2 Acting in Concert With Ramping Methane, other Greenhouse Gasses

Unfortunately, CO2 is not the only human emission forcing global temperatures rapidly higher. In addition, methane, nitrous oxide, and numerous other greenhouse gasses also make their way into the atmosphere each year through industrial sources. If we combine all these other greenhouse gasses, the total CO2 equivalent carbon emission is now at around 50 billion metric tons each year. A veritable mountain of greenhouse gasses dumped at a pace more than 150 times that of volcanic emissions each and every year.

Overall, the total greenhouse gas forcing from all these sources is now likely in the range of 481 parts per million of CO2 equivalent. This immense heat forcing, were it to remain in the atmosphere long-term, is enough to raise global temperatures by 3-4 C and to melt enough ice to raise sea levels by at least 120 feet. It is also enough, with only two more years of current emissions, to likely lock in an inevitable, irreversible and extraordinarily disruptive increase of 2 C in global temperatures for this century alone.

First Glimpses of the Methane Monster

The most potent and troubling of these additional greenhouse gasses is methane. Over the course of 20 years, methane is about 80 times as powerful a heat trapping gas as CO2 by volume. And though atmospheric methane levels are far less than comparable CO2 levels (at around 1.8 parts per million, or 1/3 the total atmospheric heat forcing of CO2), there is cause for serious concern.

For not only is the industrial emission of methane increasing, primarily through the use of very damaging hydraulic fracturing technologies (fracking), the global emission of methane from the Earth System also appears to be ramping higher. Over recent years, rapidly thawing permafrost and warming oceans both around the world and, particularly, in the Arctic show signs of venting an increasing volume of methane into the atmosphere from terrestrial sources. Though annual official tracking of total Arctic methane emissions at this point is practically non-existent, recent research allows for rational estimation.

Taking into account known emissions from permafrost and the East Siberian Arctic Shelf, and adding in expected emissions from the rest of the thawing Arctic, methane emissions for the entire region are likely around 40 teragrams per year, or about 7% of the global total. This emission is equivalent to that of a major industrial nation and initial indications are that it is growing.

Mauna Loa Methane 2007 to 2014

(Atmospheric methane increase since 2007 as measured at the Mauna Loa Observatory. Note the more rapid pace of increase from 2013 through the first quarter of 2014. Image source: NOAA/ESRL.)

The result of combined increases in the human methane emission and in the Earth System emission has been enough to continue to push global levels higher with Mauna Loa readings breaching the 1840 part per billion average by early 2014. What is even more troubling is that the Earth System methane store, composed of both permafrost methane and methane hydrate at the bottom of the world ocean system, is immense.

In total, more than 3,000 gigatons of carbon in the form of methane may be at risk to eventually hit the atmosphere as the Earth continues to warm under the current human forcing. A very large store that could easily multiply the current rate of Earth System methane release many times over. One that represents a clear and present danger for a potentially very powerful amplifying heat feedback to an equally extraordinary initial human forcing.


The Keeling Curve


What Does a World at 400 PPM CO2 Look Like Long-term?

Grim News From NASA: West Antarctica’s Entire Flank is Collapsing Toward the Southern Ocean

Global Carbon Budget 2013

A Faustian Bargain on the Short Road to Hell: Living in a World at 480 CO2e

Far Worse Than Being Beaten With a Hockey Stick: Michael Mann and Our Terrifying Greenhouse Gas Overburden

Beneath the Cracking, Melting Ice, Arctic Methane Monster Continues its Ominous Rumblings





World CO2 Averages Touch 402.2 PPM Daily Values in Early April, 102 PPM Higher Than at Any Time in Last 800,000 Years

There’s a tale in the ice. A record of past atmospheres locked away as snowfall trapped air bubbles and then compressed them into thin layers age after age over tens of thousands of years. Over the last few decades, scientists have been drilling holes in the great ice packs of Greenland and Antarctica. Their quest? To unlock this tale and reveal a direct record of global greenhouse gas levels through the deep past.

What their drilling uncovered was both quite informative and rather chilling. First, it showed that, for more than 800,000 years, global CO2 levels had been relatively stable in a range of 180 to 300 parts per million. As the levels of heat trapping CO2 rose, temperatures peaked during brief interglacials. And as levels fell, temperatures plunged back into ice age conditions.

Global temperature flux during these swings from ice age to interglacial were just 4 degrees Celsius. A 100 ppm CO2 rise correlated roughly to a 250 foot rise in sea level and much warmer average conditions globally. A corresponding fall of about the same amount brought temperatures back down and piled ice two miles high over today’s temperate regions such as New York.

What the ice cores also revealed was that human CO2 emissions had pushed global levels of this potent greenhouse gas far out of any climate reckoning comparable to the context of human beings, who have only existed in current form for about 200,000 years.

In fact, what scientists found was that atmospheric CO2 levels were pushing more than 100 parts per million higher than at any time during this vast epochal span:

Ice Core CO2 record 800,000 years

(Antarctic ice core CO2 record and comparable temperature swings. Note that the difference between ice age and interglacial is about 8 C of local temperature and about 100 ppm of CO2. It is worth considering that, due to polar amplification, Antarctic temperature changes were about double the global average. Current CO2 levels are more than 100 parts per million higher than even the peak value over this 800,000 year period. If an average peak interglacial CO2 average of 275 ppm is considered, then current values are around 127 parts per million higher. Image credit: Havard/Jeremy Shakun.)

This record was a key contribution to climate science. One, it revealed how past CO2 levels compared to past temperatures. And since the data was directly derived from air bubbles trapped beneath hundreds of feet of ice, it also provided us with an exact measure for past atmospheres.

Secondly, and perhaps much more ominously, it showed us how very far beyond any climate comparable to that great span of time we’d already come.

102 ppm higher than at any time in the last 800,000 years

Humans have now pushed the CO2 boundary 102 parts per million higher than the context provided by the last 800,000 years. It’s kind of a big deal when you consider that a mere fluctuation of about 100 parts per million CO2 was enough, when combined with changes in orbital forcing, to set off feedbacks resulting in a 4 C temperature change globally (8 C change for the Antarctic environment) as ice age proceeded to interglacial and back.

Current human forcings through CO2 and other emissions have now entirely over-ridden the natural cycle, eliminating the possibility for future ice ages and putting us on a trajectory for catastrophe. With annual global carbon emissions now exceeding 12 gigatons, not only have we forced ourselves well outside of any past bounds to which we can easily relate, we have also generated an unprecedented velocity of change. For the current human carbon emission now exceeds, by at least six times, the most rapid past level of natural carbon emission.

No vast flood basalt could ever rival the volume and pace at which humans currently emit greenhouse gasses.

This enormous emission continues to have severe effect through an ever-higher ratcheting of global CO2 levels.

As of the past week, global daily CO2 values had rocketed to 402.2 parts per million, well outside anything seen in the ice core record:


(Mauna Loa Observatory CO2 measure for the last six months. Note that daily and weekly values have been mostly above 400 ppm since early March. Image source: The Keeling Curve.)

This an extraordinary measure. One that has no context in direct records such as those available to us through ice core data. But paleoclimate proxy data does provide some corollary. According to isotopic carbon measures found through seabed samples, we can determine that the last time CO2 levels were above 400 parts per million was during the mid-Plieocene between 3 and 3.3 million years ago.

And during that time global average temperatures were 2 to 3 degrees Celsius warmer than they are today (with Antarctic values at least twice that). Both Greenland and West Antarctica were mostly ice free and sea levels were between 15-75 feet higher. These are, likely, the potential low end of the changes we’ve locked in due to human global greenhouse gas forcing long term, even if, somehow, global CO2 levels are brought to a plateau.

Mid-Pliocene Antarctica

(An graphic extrapolation of Antarctica’s ice cover and elevation based on paleoclimate data. Note that the Antarctic ice sheet is greatly diminished at a time when CO2 values remained constant around 400 ppm. Image source: Commons.)

480 CO2e…

Unfortunately, the global CO2 measure doesn’t tell quite the entire story. For atmospheric levels of gasses like methane, nitrous oxide, and a host of less common industrial chemicals have also all been on the rise in Earth’s atmosphere due to human emissions. As a result, according to research by the Advanced Global Atmospheric Gasses Center at MIT, total heat forcing equal to CO2 when all the other gasses were added in was about 478 ppm CO2e during the spring of 2013. Adding in the high-velocity human greenhouse gas contributions since that time gets us to around 480 ppm CO2e value. In the context of past climates and of near and long term climate changes due to human interference, 480 ppm CO2e is nothing short of fearsome.

The last time the world saw such a measure of comparable atmospheric greenhouse gas heat forcing was during the Miocene around 15-20 million years ago. At that time, global temperatures were 3-4 C warmer, the Antarctic ice sheet was even further diminished, and sea levels were 80-120 higher than today.

This combined forcing is enough to result in a state of current climate emergency. In just a few years, according to the recent work of climate scientist Michael Mann, we will likely lock in a 2 C short term warming this century and a probable 4 C warming long-term. If the current, high-velocity pace of emission continues, we will likely hit 2 C warming by 2036, setting off extraordinary and severe global changes over a very short period.

These are very dangerous and, likely, catastrophic levels. In such a context, the inexorably rising rate of atmospheric CO2 and other greenhouse gas forcings simply adds further insult to a very high risk situation.


Havard/Jeremy Shakun

The Keeling Curve

Advanced Global Atmospheric Gasses Center at MIT

Far Worse Than Being Beaten With a Hockey Stick: Michael Mann, Our Terrifying Greenhouse Gas Overburden, and 2 C Warming by 2036


Pliocene Climate

Miocene Climate and CO2 Flux With Related Ecosystem Impacts


Far Worse than Being Beaten with a Hockey Stick: Michael Mann, Our Terrifying Greenhouse Gas Overburden and Heating the Earth by + 2 C by 2036

I’m going to say something that will probably seem completely outrageous. But I want you to think about it, because it’s true.

You, where-ever you are now, are living through the first stages of a disaster in which there is nowhere to run, nowhere to hide, and no safe place on Earth for you to go to avoid it. The disaster you are now living through is a greenhouse emergency and with each ounce of CO2, methane and other greenhouse gasses you, I, or the rest of us, pump into the air, that emergency grows in the vast potential of damage and harm that it will inflict over the coming years, decades and centuries. The emergency is now unavoidable and the only thing we can hope to do through rational action is to reduce the degree of harm both short and long term, to rapidly stop making the problem worse, and to put human ingenuity toward solving the problem rather than continuing to intensify it.

But damage, severe, deadly and terrifying is unleashed, in effect and already happening, with more on the way.

*    *    *    *    *


(Michael Mann’s famous Hockey Stick graph showing Northern Hemisphere temperatures over the past 1,000 years. The influences of human warming become readily apparent from the late 19th to early 21rst centuries. But human greenhouse gas forcing has much greater degrees of warming in store.)

This week, Michael Mann wrote an excellent piece describing the immediacy of our current emergency in the Scientific American. In typical, just the facts, fashion, he laid out a series of truths relevant to the current greenhouse catastrophe. These facts were told in a plain manner and, yet, in a way that laid out the problem but didn’t even begin to open the book on what that problem meant in broader context.

Michael Mann is an amazing scientist who has his hand on the pulse of human-caused climate change. He is a kind of modern Galileo of climate science in that he has born the brunt of some of the most severe and asinine attacks for simply telling the truth and for revealing the nature of our world as it stands. But though Mann’s facts are both brutal and hard-hitting for those of us who constantly read the climate science, who wade through the literature and analyze each new report. By simply stating the facts and not telling us what they mean he is hitting us with a somewhat nerfed version of his ground-breaking Hockey Stick. A pounding that may seem brutal when compared to the comfortable nonsense put out by climate change deniers and fossil fuel apologists but one that is still not yet a full revelation.

I will caveat what is a passionate interjection by simply saying that Michael Mann is one of my most beloved heroes. And so I will do my best to help him out by attempting to lend more potency to his already powerful message.

2 C by 2036 — Digging through the Ugly Guts of it

All that said, Michael Mann laid out some brutal, brutal facts in his Scientific American piece. Ones, that if you only take a few moments to think about are simply terrifying. For the simple truth is that the world has only a very, very slim hope of preventing a rapid warming to at least 2 C above 1880s levels in the near future and almost zero hope altogether of stopping such warming in the longer term.

The first set of figures Mann provides involves the current greenhouse gas forcing. Current CO2 levels are now at the very dangerous 400 parts per million threshold. Long term, and all by itself, this forcing is enough to raise global temperatures by between 2 and 3 degrees Celsius. But hold that thought you were just about to have, because we haven’t yet included all the other greenhouse gasses in that forcing.

Mann, in the supplemental material to his Scientific American paper, notes that the total forcing of all other greenhouse gasses currently in the atmosphere is about 20% of the total CO2 forcing. This gives us a total CO2 equivalent forcing of 480 ppm CO2e, which uncannily mirrors my own analysis here (the science may have under-counted a bit on the methane forcing, but this value is likely quite close to current reality for both the short and long term).

480 ppm CO2e is one hell of a forcing. It is nearly a 75% greater forcing than 1880s values and, all by itself, is enough to raise temperatures long-term by between 3.5 and 4.5 degrees Celsius.

And it is at this point that it becomes worthwhile talking a bit about different climate sensitivity measures. The measure I am using to determine this number is what is called the Earth Systems Sensitivity measure (ESS). It is the measure that describes long term warming once all the so called slow feedbacks like ice sheet response (think the giant glaciers of Greenland and West Antarctica) and environmental carbon release (think methane release from thawing tundra and sea bed clathrates) come into the equation. Mann, uses a shorter term estimate called Equilibrium Climate Sensitivity (ECS). It’s a measure that tracks the fast warming response time once the fast feedbacks such as water vapor response and sea ice response are taken into account. ECS warming, therefore, is about half of ESS warming. But the catch is that ECS hits you much sooner.

At 480 ppm CO2e, we can expect between 1.75 and 2.25 degrees C of warming from ECS. In essence, we’ve locked about 2 C worth of short term warming in now. And this is kind of a big deal. I’d call it a BFD, but that would be swearing. And if there is ever an occasion for swearing then it would be now. So deal with it.

Mann, in his article, takes note of the immediacy of the problem by simply stating that we hit 2 C of shorter term ECS warming once we hit 405 ppm CO2 (485 CO2e), in about two to three years. And it’s important for us to know that this is the kind of heat forcing that is now hanging over our heads. That there’s enough greenhouse gas loading in the atmosphere to push warming 2 C higher almost immediately and 4 C higher long term. And that, all by itself, is a disaster unlike anything humans have ever encountered.

Global Fossil Fuel Emission

(Global annual fossil fuel emission is currently tracking faster than the worst-case IPCC scenario. Aerosols mask some of the heating effect of this enormous emission, what James Hansen calls ‘a Faustian Bargain.’ Image source: Hansen Paper.)

But there is a wrinkle to this equation. One that Dr. James Hansen likes to call the Faustian Bargain. And that wrinkle involves human produced aerosols. For by burning coal, humans pump fine particles into the atmosphere that reflect sunlight thereby masking the total effect of the greenhouse gasses we have already put into the atmosphere. The nasty little trick here is that if you stop burning coal, the aerosols fall out in only a few years and you then end up with the full heat forcing. Even worse, continuing to burn coal produces prodigious volumes of CO2 while mining coal pumps volatile methane into the atmosphere. It’s like taking a kind of poison that will eventually kill you but makes you feel better as you’re taking it. Kind of like the greenhouse gas version of heroin.

So the ghg heroin/coal has injected particles into the air that mask the total warming. And as a result we end up with a delayed effect with an extraordinarily severe hit at the end when we finally stop burning coal. Never stop burning coal and you end up reaching the same place eventually anyway. So it’s a rigged game that you either lose now or you lose in a far worse way later.

Mann wraps coal and other human aerosol emissions into his equation and, under business as usual, finds that we hit 2 C of ECS warming by 2036 as global CO2 levels approach 450 ppmv and global CO2e values approach 540 ppmv. At that point, were the aerosols to fall out we end up with an actual short term warming (ECS) response of 2.5 to 3 C and a long term response (ESS) of about 5 to 6 C. (Don’t believe me? Plug in the numbers for yourself in Mann’s climate model here.)

So ripping the bandaid off and looking at the nasty thing underneath, we find that even my earlier estimates were probably a bit too conservative and Mann, though we didn’t quite realize it at first, is hitting us very hard with his hockey stick.

What does a World That Warms So Rapidly to 2 C Look Like?

OK. That was rough. But what I am about to do is much worse. I’m going to take a look at actual effects of what, to this point, has simply been a clinical analysis of the numbers. I’m going to do my best to answer the question — what does a world rapidly warming by 2 C over the next 22 years look like?

Ugly. Even more ugly than the numbers, in fact.

First, let’s take a look at rates of evaporation and precipitation. We know that, based on past research, the hydrological cycle increases by about 6% for each degree Celsius of temperature increase. So far, with about .8 C worth of warming, we’ve had about a 5% increase in the hydrological cycle. What this means is that evaporation rates increase by 5% and precipitation events, on average, increase by about 5%. But because weather is uneven, what this does is radically increase the frequency and amplitude of extreme weather. Droughts are more frequent and more severe. Deluges are more frequent and more severe.

(Program in which top climate scientists explain how global warming increases the intensity of evaporation and precipitation all while causing dangerous changes to the Jet Stream.)

At 2 C warming we can change this loading from a 5% increase in the hydrological cycle of evaporation and precipitation to a 12% increase. You think the droughts and deluges are bad now? Just imagine what would happen if the driver of that intensity more than doubled. What do you end up with then?

Now let’s look at something that is directly related to extreme weather — sea ice loss. In the current world, about .8 C worth of warming has resulted in about 3.2 C worth of warming in the polar regions. And this warming has resulted in a massive and visible decline of sea ice in which end summer volume values are up to 80% less than those seen during the late 1970s. This loss of sea ice has had severe effects on the Northern Hemisphere Jet Stream, both pulling it more toward the pole and resulting in high amplitude Jet Stream waves and local severe intensification of storm tracks. At 2 C worth of global warming, the Arctic heats up by around 7 C and the result is extended periods of ice free conditions during the summer and fall that last for weeks and months.


(Actual rate of sea ice loss vs IPCC model predictions. The most recent record low value achieved in 2012 is indicated by the dot. Image source: Assessment of Arctic Sea Ice/UCAR Report.)

The impacts to the Northern Hemisphere Jet Stream are ever more severe as are the impacts to Greenland ice sheet melt. Under such a situation we rapidly get into a weather scenario where screaming temperature differentials between the North Atlantic near Greenland and the warming tropics generate storms the likes of which we have never seen. Add in a 12% boost to the hydrological cycle and we get the potential for what Dr. James Hansen describes as “frontal storms the size of continents with the intensity of hurricanes.”

Greenland melt itself is much faster under 2 C of added heat and the ice sheets are in dangerous and rapid destabilization. It’s possible that the kick will be enough to double, triple, quadruple or more the current pace of sea level rise. Half foot or more per decade sea level rise rapidly becomes possible.

All this severe weather, the intense rain, the powerful wind storms and the intense droughts aren’t kind to crops. IPCC projects a 2% net loss in crop yields each decade going forward. But this is likely to be the lower bound of a more realistic 2-10 percent figure. Modern agriculture is hit very, very hard in the context of a rapidly changing climate, increasing rates of moisture loss from soil and moisture delivery through brief and epically intense storms.

The rapid jump to 2 C is also enough to put at risk a growing list of horrors including rapid ocean stratification and anoxia (essentially initiating a mass die off in the oceans), large methane and additional CO2 release from carbon stores in the Arctic, and the unlocking of dangerous ancient microbes from thawing ice, microbes for which current plants and animals do not have adequate immune defenses.

How do we avoid this?

In short, it might not be possible to avoid some or even all of these effects. But we may as well try. And this is what trying would look like.

First, we would rapidly reduce human greenhouse gas emissions to near zero. As this happens, we would probably want a global fleet of aircraft that spray sulfate particles into the lower atmosphere to make up for the loss of aerosols once produced by coal plants. Finally, we would need an array of atmospheric carbon capture techniques including forest growth and cutting, then sequestration of the carbon stored by wood in lakes or in underground repositories, chemical atmospheric carbon capture, and carbon capture of biomass emissions.

For safety, we would need to eventually reduce CO2 to less than 350 ppm, methane to less than 1,000 ppb, and eliminate emissions from other greenhouse gasses. A very tall order that would require the sharing of resources, heroic sacrifices by every human being on this Earth, and a global coordination and cooperation of nations not yet before seen. Something that is possible in theory but has not yet been witnessed in practice. A test to see if humankind is mature enough to ensure its own survival and the continuation of life and diversity on the only world we know. A tall order, indeed, but one we must at least attempt.


Earth Will Cross Climate Danger Threshold by 2036

What does a World at 400 Parts per Million CO2 Look Like Long-Term?

One Scientist Argues 2036 Could be Point of No Return for Climate Disaster

A Faustian Bargain on the Short Road to Hell

Doubling Down on our Faustian Bargain

Dr. Jennifer Francis, Top Climate Scientists Explain How Global Warming Aps the Hydrological Cycle and Wrecks the Jet Stream to Unleash Extreme Weather

Assessment of Arctic Sea Ice/UCAR Report


CO2, Earth’s Global Thermostat, Dials Up to Record 401.6 ppm Daily Value on March 12

NASA GISS, likely the world’s premier Earth atmospheric monitoring agency has dubbed CO2 “The Thermostat that Control’s Earth’s Temperature.” So when human fossil fuel emissions keep cranking that thermostat ever higher, it’s important sit up and take note. For, inexorably, we keep forcing atmospheric values of this critical heat-trapping gas up and up.

According to reports from The Mauna Loa Observatory and The Keeling Curve, daily CO2 values for March 12 rocketed to a record 401.6 parts per million. Hourly values rose briefly higher, touching 402 parts per million. Levels fell back to around 400 ppm on March 13. But the overall trend will continue upward through March, April and much of May when the height of annual atmospheric CO2 readings is typically reached.

By comparison, during May of last year, daily and weekly values hit just slightly higher than 400 parts per million while measures for the month hovered just below this number. We are now about two months away from the 2014 peak. So it appears possible that daily values could rise to 404 ppm or greater with highs for the month potentially exceeding 402 ppm (you can view a comparison graph for May 2013 here).

March CO2 401.6

(Daily and hourly atmospheric CO2 values from March 7 to 13. Image source: The Keeling Curve.)

Such high levels of this gas have not been seen on Earth in over 3 million years. A time when temperatures were 2-3 degrees Celsius warmer and sea levels were 15-75 feet higher than today. And should CO2 levels merely remain at the level currently achieved, we can probably expect at least the same amount of warming long-term.

CO2 in Context

Annually, the average rate of CO2 increase now is an extraordinary 2.2 parts per million each year. This rate is about 6-7 times faster than at any time in geological history. None of the vast flood basalts of the ancient past, no period of natural vulcanism, can now rival the constant and massive injection of this powerful and long-lasting greenhouse gas by humans into the atmosphere.

Last year, the rate of increase spiked to around 2.5 parts per million and we can view this as mere prelude under a continuation of business as usual. For if human fossil fuel emissions are not radically brought into check, the ongoing economic inertia of existing fossil fuel based infrastructure and planned new projects will likely shove this rate of increase to 3, 4 even 7 parts per million each year by the end of this century. As a result, CO2 levels alone have the potential to reach catastrophic values of 550 parts per million by around 2050-2060 that, long term and without any of the added effects of other greenhouse gasses, would be enough to eventually melt all the ice on Earth and raise global temperatures to around 5-6 degrees Celsius above current levels. A level that, through acidification alone and not including damage through stratification and anoxia, could drive up to 1/3 of ocean species to extinction.

CO2 accounts for much of the greenhouse forcing when taking into account the feedbacks it produces on water vapor and clouds. NASA notes:

Because carbon dioxide accounts for 80% of the non-condensing GHG forcing in the current climate atmosphere, atmospheric carbon dioxide therefore qualifies as the principal control knob that governs the temperature of Earth.

All other greenhouse gasses pale in comparison to both its total effect and its current rate of increase. Methane, the next most potent greenhouse gas, accounts for about 15% of the forcing and is rising at a rate of 4 parts per billion (1/550 that of CO2), generating a net effect equal to, in the worst case, an additional .4 parts per million CO2 each year (.29 when aerosols drop out). A troubling and dangerous increase itself. But still a mere shadow compared to the overall rate of CO2 increase.

Only in the most catastrophic of scenarios, when added atmospheric heat, primarily generated through added CO2 and other greenhouse gas forcing, triggers methane emissions equal to 2 gigatons each year in the Arctic (a rate 25 times the current release), would the total methane forcing approach the predicted value for CO2 by the end of this century under current fossil fuel emissions scenarios. More likely, paleoclimate scenarios tend to suggest that the natural methane feedback, long-term, is roughly equal to 50% of the CO2 forcing and is largely governed by it. A dangerous amplifying feedback driven by a devastating and long-lasting CO2 forcing.

CO2 is also the longest lived of the major greenhouse gasses with one molecule of CO2 providing effective atmospheric warming for at least 500 years. By comparison, the oxidation time for a single molecule of methane is around 8 years. What this means is that it takes an ever increasing methane emission just to keep values constant while atmospheric CO2 takes much longer to level off given even a constant rate of emission.

The result is that heat forcing from CO2 tends to remain constant over long periods while methane heat forcing values have a tendency to spike due to rapid oxidation.


(Radiative forcing from a 10 gigaton release of methane in red compared to expected end century CO2 values of 750 ppm. Note how the methane heat forcing spikes and then rapidly falls off. Image source: RealClimate.)

Current rates of CO2 increase, therefore, should be viewed as catastrophic to climates that are both livable and benevolent to humans. A rate of increase that puts at risk severe changes to Earth environments and which provides a trigger for setting off a series of powerful amplifying feedbacks through the medium and long term. These include both loss of ice albedo and the potential for spiking methane emissions from the widespread natural store.


Most recent daily values from March 12 onward in relationship to the six month trend. Note the sharp spike upward at the end of the period as well as the overall volatility of the trend line. High volatility may well be an indication that the typical carbon cycle is suffering disruption with sinks, stores and sources experiencing larger than typical fluxes.


(Mauna Loa Observatory six month trend. Image source: The Keeling Curve.)

Dr. Ralph Keeling today noted:

“We’re already seeing values over 400. Probably we’ll see values dwelling over 400 in April and May. It’s just a matter of time before it stays over 400 forever.”


The Keeling Curve

May 2013: CO2 Touches 400 ppm

The Thermostat that Control’s Earth’s Temperature

Atmospheric Composition, Radiative Forcing, and Climate Change as a Consequence from the Massive Release of Gas Hydrates


Hat Tip to Climate State

Kudos to Mark Archambault for Looking Sharp

A Faustian Bargain on the Short Road to Hell: Living in a World at 480 CO2e

On the highway to a smokestack hell, Faust met a devil who said to him:

“Give me all your tomorrows, all your children and all your children’s children, and I will make this one day, for you, a paradise.”

*    *    *    *    *

Understanding how much warming may be in store from all the CO2, methane, N2O and other greenhouse gasses humans have pumped into the atmosphere can be a bit problematic. First, definitions have tended to be confused due to the fact that equilibrium climate sensitivity measures (Charney) used to project warming for this century by the IPCC only take into account about half of long-term (slow feedback) warming should CO2 and other greenhouse gas levels remain high.

For example, equilibrium climate sensitivity measures show an effective rate of warming by about 3 degrees Celsius (C) for every doubling of CO2 from 1880 onward. By this measure, we get about 3 C worth of warming over this century once we hit 550 ppm CO2 and about 6 C worth of warming at levels around 1100 ppm. It is important to stress that these short term warming projections do not take into account long-term ‘slow’ feedbacks to a given rise of CO2 that are strong enough to double the ultimate temperature increase. This larger Earth Systems Sensitivity (ESS) measure is both observable in paleoclimate and in the various model runs that project a given level of atmospheric CO2 out through the centuries.

Fast Feedback vs Slow Feedback Climate Sensitivity

(Fast feedback equilibrium climate sensitivity over one century vs long term sensitivity over multiple centuries to a given greenhouse gas forcing. Note that approximately double the amount of warming occurs after ‘slow feedbacks’ like ice sheet response and environmental ghg emissions are taken into account. Image source: Leeds.)

So both paleoclimate and most model runs end up with a long term warming of about 6 C at 550 ppm CO2 and of about 12 C at 1100 ppm CO2.

It is here that we run into an additional difficulty. We don’t ultimately know how long, long-term will really be. We hope, and our climate models seem to support this hope, that such ‘long term’ warming from the so-called slow feedbacks like ice sheet albedo response and natural carbon emissions won’t appear in force this century. But given the stunning pace of human greenhouse gas build-up combined with a number of observed ‘slow feedback’ responses going on now, we don’t really know for certain. And there is some reason to believe that the ‘slow feedbacks’ might not be so slow after all.

In this context, the current level of CO2, at around 400 ppm, results in a warming this century of around 1 to 1.5 degrees Celsius (if the slow feedbacks are as slow as expected) and a long-term warming of about 2-3 degrees Celsius. And it is at this point where an already complex dynamic begins to break down, taking on a number of, yet more complex, factors.

A Host of Extra Gasses No-One Really Talks About

At issue is the fact that humans have emitted a massive volume of additional greenhouse gas into the atmosphere. These gasses have grown in proportion and heating effect alongside the, admittedly larger and more significant, CO2 emission. And each has made their own additional contribution to human warming.

Some of these gasses, like methane, have been a typical part of natural atmospheres for millions of years. At times, methane concentrations are observed to have spiked to levels even higher than those seen today. But the periods during which such levels were apparent were also times of global crisis — the hothouse mass extinction events.

Methane Since 1984 MLO

(Atmospheric methane concentrations since 1984 as observed at the Mauna Loa Observatory. Image source: NOAA ESRL.)

But the other gasses: nitrous oxide, CFCs, HFCs, nitrogen triflouride, and a host of nearly 50 other industrial chemicals that contribute to warming were either never in the atmosphere before or were present at much lower levels than what is seen today. The result of this added pollution is yet more potential warming, in addition to a number of other difficult to deal with impacts. A pollution impact that is outside the context of past global crises and that puts current day greenhouse gas forcing at a critical and unstable level.

Methane levels alone have more than doubled since the start of the Industrial Revolution, rising from about 750 parts per billion to about 1835 parts per billion today. This value, depending on how it’s calculated over time, is equivalent to an additional CO2 forcing of between 22 and 110 parts per million. And though methane is the strongest non-CO2 warming agent, adding them all together can result in a value that is quite a bit higher than the base CO2 level would indicate.

Nitrous Oxide MLO

(Atmospheric nitrous oxide levels since 1997 as observed at the Mauna Loa Observatory. Image source: NOAA ESRL.)

In addition, on the negative side of the ledger, human fossil fuel burning (primarily coal) burning emits sulfur dioxide, other sulfates and various aerosols which, overall, create strong negative feedbacks in the climate system by reflecting incoming sunlight. The net result is a temporary suppression of a portion of human-caused warming. The reason this suppression is temporary is due to the fact that the sulfur dioxide and related sulfates rapidly wash out of the atmosphere. So if coal burning ceases, the reflective particles rapidly fall away and we readily come to witness the full strength of the human greenhouse gas emission.

Which brings us to the question — what is the full strength of the current human emission and how long will it last? There’s a term for this number: CO2e. In other words — the equivalent CO2 forcing of all greenhouse gasses added together.

Fortunately for our exploration, there’s been a bit of work done on just this subject. Last year, MIT’s Advanced Global Atmospheric Gasses Experiment issued a report describing model data that determined the current CO2 equivalent forcing from all of the more than 50 greenhouse contributing trace gasses in the atmosphere. And the results were somewhat disconcerting. As of June of 2013, that amount was equal to 478 parts per million CO2. Or a CO2e of 478 parts per million when all the other greenhouse gasses were added to the already high and rapidly rising levels of CO2. Adding in the current rate of CO2 rise, we end up with about 480 parts per million of CO2e from all greenhouse gasses by this year. So if we’re talking about the total burden of all greenhouse gasses and the one that will be with us through the long term, 480 is, unfortunately, the number we should be dealing with and not 400.

Aerosols and the Faustian Bargain

Unfortunately, to determine the current forcing one has to also take into account those pesky aerosols we mentioned above. And, luckily, we also have a reliable measure that provides the negative forcing or relative cooling effect of sulfur dioxide in the current atmosphere. As of 2013, the IPCC had found that sulfates and other effects due to aerosols provided a net negative forcing of about .8 Watts per meter squared or about 1/2 the positive forcing of CO2 which was, then, at around 390 ppmv (2011), about 1.68 Watts per meter squared. This approximate 1/2 value, when divided by the then observed rise in CO2 since 1880 gives us a rough equivalent negative forcing value of minus 55 parts per million CO2e.


(IPCC AR5 Radiative Forcing Assessment. Image source: IPCC)

So subtracting out the net effect of sulfates and other aerosols brings us to a total net forcing from all factors related to human changes to the atmosphere of about 425 ppm CO2e. A rather disturbing final number both due to its departure over the current 400 ppm CO2 value and due to the fact that though most greenhouse gasses have atmospheric residence times of decades to centuries, the cooling sulfates would likely last for 1-2 years before falling out entirely. This means that once fossil emissions stop, we may as well just add +55 ppm CO2e to the current total.

This warmth masking factor of human coal emissions was described by James Hansen as a kind of Faustian bargain in which current burning of the dirty fuel provides temporary respite to warming at the cost of even more rapid future temperature increases. And it is just this devil’s deal in which we are now entangled.

425 CO2e: A Dangerous Interim

So it is likely that current atmospheric forcing, including all greenhouse gasses and all human sulfates, is probably at around 425 ppm CO2e. And since the residence times of these gasses are decades to millennium, while Earth Systems feedbacks appear to be enough to maintain high methane levels indefinitely, we should probably view this as an interim figure when considering how much short and long-term warming is likely locked in.

In the short term, using equilibrium climate sensitivity measures, we are likely to end up with between 1.2 and 1.8 C warming over the course of this century even if all greenhouse gas levels, along with sulfate levels, were to remain stable and if the slow feedbacks move along at the expected pace. Meanwhile, long-term warming of between 2.4 and 3.6 C would be expected if all atmospheric gas levels were to stabilize.

But unless an ongoing regime of sulfate aerosol spraying of the stratosphere were put into place, the sulfates would, predictably, fall out once human emissions stopped. And that rapidly brings us back to the 480 ppm CO2e number.

480 CO2e: What is Probably Locked in Long-Term

Looking at the more permanent 480 CO2e value, the fact begins to sink in that we are already well on the way to extreme climate difficulties. For 480 CO2e, without the reflective aerosols, means that the world probably ends up warming by between 1.8 and 2.3 C before the slow feedbacks kick in and between 3.5 and 4.5 C long-term. At these levels, major ice sheet destabilization and melt is eventually likely to result in between 50 and 140 feet of sea level rise with the only remaining glaciers in the end confined to central and eastern Antarctica.

The only saving grace to a cold turkey cessation of emissions now is that most of the worst amplifying feedbacks are likely to be kept in check and thus prevent rapidly accelerated warming and climate destabilization. The extra 1.7 to 2.2 C worth of long-term warming likely comes from a combination of albedo loss, permafrost thaw and related ghg release keeping currently high levels high long-term, and, perhaps, a methane belch in the 1-50 gigaton range that spikes atmospheric levels.

I say likely to be kept in check… but we have to also consider that there is a low, but not out of the question, risk of setting off a kind of mini-runaway that generates warming far beyond the expected range and pushes climates to a hothouse state not seen since the PETM or Permian extinction events. There is little evidence for such an event in response to current climate forcings in the models at this time, but we have a number of scientists, including Peter Wadhams, Natalia Shakhova, and Igor Simeletov, who have raised the possibility, based on their observations of Arctic sea ice and carbon stores, that just such an event could be in the offing. Unfortunately, without more in-depth research into the potential pace of release of current carbon stores (permafrost, forest, clathrate, ocean) we don’t have a scientific oracle that provides a comfortable certainty on this key issue.

It’s worth noting that this best possible future, where the risk of a mini-runaway in warming to PETM or Permian levels remains low, probably won’t happen as business as usual fossil fuel emissions continue unabated with no sign of being rationally held in check. Under the current regime, a CO2e of about 550 ppm, enough to warm the Earth between 5-6 C long term, is locked in within 25-30 years. A climate state that pushes the risk of a mini-runaway to moderate. Meanwhile, levels that would almost certainly set off a Permian or PETM type, anoxic ocean, extinction event, at around 800 ppm CO2e, become possible under BAU by 2060-2080.

The situation is, therefore, once again worse than expected…


400 PPM CO2? Add in Other Gasses and It’s 478 CO2e

Earth Systems Sensitivity

Leeds Climate Sensitivity

Jules Charney (bio)


Radiative Forcing Links:

Real Climate: Radiative Forcing

The Advanced Global Atmospheric Gasses Experiment

NOAA: Radiative Forcing of Non-Greenhouse Gasses

IPCC: Initial Radiative Forcing Assessment

Non-CO2 Greenhouse Gasses: Scientific Understanding, Control and Implementation

CDIAC: Recent Greenhouse Gas Concentrations and Analysis

IPCC AR4 Appendix/Glossary

Nitrous Oxide and Climate Change

CO2 Continues Dangerous Rise, Hits 400.2 Parts Per Million in Late February


(Daily and hourly CO2 readings at the Mauna Loa Observatory from February 20 to 26. Image source: The Keeling Curve.)

More than two months before typical annual maximum in late May or early June, global average CO2 levels have again breached the dangerous 400 part per million threshold.

On February 26th, Mauna Loa’s CO2 observatory recorded three hourly readings at or above 400 parts per million with a peak value of 400.2 ppm. The reading comes just ten months after weekly CO2 values exceeded 400 parts per million during May of 2013, the first time in more than 3 million years that atmospheric levels have been so high.

At the current annual rate of increase, we can expect CO2 levels to peak around 401.5 to 403 parts per million sometime in late May of this year. Last year’s average annual rate of increase was 2.6 parts per million over 2012. If 2014 were to match this, abnormally rapid, pace, daily and hourly measures could exceed peak values of 403 parts per million over the next two months.

A Steepening Rise of Concentration

From the early 1960s the pace of atmospheric CO2 increase was about 1 part per million each year. As human population, fossil fuel consumption, and industrialized agriculture expanded, annual rates of CO2 increase up-ticked to about 1.5 parts per million from 1980 to 2000 and again to slightly above 2 parts per million each year from 2000 to the present. Due to a number of factors including an expected continued increase in fossil fuel burning, the exhaustion of various carbon sinks around the globe, expected changes to ocean and land based photosynthetic life, and the release of various global carbon stores due to amplifying feedbacks related to human-caused warming, rates of CO2 increase are expected to be as much as 7 parts per million or more each year by the middle of this century.


(An ever-steepening curve. CO2 levels from 1700 to the present. Image source: The Keeling Curve.)

Current Pace of Emission Without Precedent

The current pace of emission has no corollary in the geological record. Based on best observations, the fastest CO2 increases in the past were during either the PETM extinction event of 55 million years ago or the Permian Extinction, or Great Dying, of 250 million years ago. During these periods, rapid rates of CO2 increase were observed at about .35 parts per million each year. The current pace is now six or seven times that seen during these dangerous geological epochs and expected rates of CO2 increase during this century could exceed 20 times that seen in the record.

It is worth noting that more than 32 billion tons of CO2 now go into the atmosphere each year and that this rate of emission alone is about 160 times that of volcanic emissions the world over. Total human carbon emissions in CO2 equivalence for all greenhouse gasses is now over 50 billion tons, or more than 200 times global volcanic emissions. Even an epic flood basalt on the order of that which appeared during the Permian Extinction couldn’t match the current pace of human emission.

CO2 emissions sks

(CO2 emissions through 2012 with related IPCC scenarios overlaid. Image source: The Conversation.)

The very rapid pace of increase also drives an exceedingly rapid pace of climate and geophysical change. Among the impacts include very rapidly rising temperatures, potentially very rapid ice melt and global sea level rise, potentially very rapid pace of ocean stratification and anoxia, rapid and chaotic reordering of climate and ecological zones, and a pace of ocean acidification that has no corollary during any past geological age. This combination of rapid-fire impacts presents very severe hazards to all life and ecological systems that are likely to result in stresses never before seen on Earth over the next century under business as usual fossil fuel emissions.

What Does the World Look Like at 400 Parts Per Million CO2, Long-Term?

Considering that we are already passing the dangerous 400 ppm CO2 threshold, it is important to think about what a world with a near constant level of CO2 in this range looks like over the long haul. This is important because, in the current political climate, it appears highly unlikely that fossil fuel emissions will ever be brought into a range that results in a potential for atmospheric CO2 decline (approaching zero fossil fuel emissions). In addition, a number of heat-driven amplifying feedbacks are already in place that are pushing some of Earth’s large carbon stores to release. These include, but are not limited to, major Arctic carbon store releases and major tropical forest carbon store releases that are now likely on the order of human CO2 emissions during the middle of the 20th Century.

In addition, the human and feedback methane release, human nitrous oxide release, and other human greenhouse gas release counters all the global cooling resulting from human aerosol release (sulfur dioxide etc). And while the human aerosol release will eventually draw down with the cessation of coal use (either through laissez faire depletion or through an attempt at rational political action), these other greenhouse gasses will remain in the atmosphere for years, decades and centuries.

The result of these combined factors is that the world is likely to remain in the range of 390-405 parts per million CO2 even if rapid mitigation were to begin today. And so it is worthwhile to think about what such a world looks like, considering that to be our rational, best case scenario, and not to put too much faith in the entirely too conservative equilibrium-based scenarios posed by the IPCC.

For a corollary to our absolute best case, we should therefore look to the Pliocene climate of 3.0 to 3.3 million years ago when CO2 levels stabilized at around the current range of 390 to 405 ppm CO2. And Pliocene during this time was 2 to 3 degrees warmer than the 1880s average. It was a climate in which sea levels were at least 15 to 75 feet higher than today (some studies show up to 110 feet higher). And it was a climate in which the Greenland and West Antarctica were entirely bereft of glaciers.

This climate vision of the past if probably the absolute best we can hope for under current systems and a very rapid mitigation. Wait just a few more years and we push above the 405 parts per million threshold as we begin entering a rough corollary to the Miocene climate of 15 million years ago. Wait another few decades and we get to the 500-600 part per million threshold that puts all ice on Earth at risk of melt and sets in place conditions, according to paleoclimate, where a 4-6 C temperature increase is locked in.

Rapidly Moving Into an Ever More Dangerous Future


(Alberta Tar Sands. Just one major unconventional fuels project rapidly pushing the world toward climate change game over. Image source: Water Defense.)

That the current pace of change in unprecedented is probably an understatement. Human beings and governments need to come to grips with the ever-more-dangerous world they are creating for themselves, their children and grandchildren. Focus should now be put on preventing as much harm as possible. And all government action should be aimed at that result.

There is no greater threat presented by another nation or set of circumstances that supersedes what we are now brazenly doing to our environment and the Earth System as a whole. And the rate at which we are causing the end level of damage to increase is practically unthinkable. Each further year of inaction pushes us deeper into that dangerous future.


The Keeling Curve

Tropics Found to Release Two Gigatons of Carbon Each Year

Arctic Sea Ice Melt, Methane Release Shows Amplifying Feedbacks to Human Caused Climate Change

What Does a World at 400 Parts Per Million CO2 Look Like Long Term?

The Emissions Gap Report

The Conversation

Water Defense

Stop The War to Silence Science, End Egregious Cuts To Greenhouse Gas Monitoring Now

Here we stand at the cusp. At the brink. At the precipice of the crisis that will certainly define this century. An extraordinarily dangerous human alteration of the climate that, at its end, could be far more destructive and deadly than any war. A growing and emerging monstrosity created by us. One which, should we continue to feed it, would plunge us into the heart of one of the blackest climatological eras ever experienced on this planet.

We know there is danger. And we have known it for some time due to the clarity and accuracy of our vision. A vision provided to us by a scientific understanding of our world that is the pinnacle of human progress. For if there is one thing that we should be proud of, that we could all share in as a great victory for our race, it would be the knowledge and understanding that we have gained in our long and tempestuous rise from darkness.

Global CO2 levels since 1700

Global temperatures since 1880

(Upper graph: Global CO2 concentrations since 1700. Lower graph: Global temperatures since 1880 as measured at the world’s meteorological stations. Image sources: The Keeling Curve and NASA GISS.)

And yet now, at the brink of crisis, we are at risk of having the new senses provided to us by science, senses we depend upon so much for that knowledge, that vision we need most desperately, begin to fade, to dim, to wink out. For the monitors we use to track the crisis are steadily being de-funded and are at risk of going dark.

Just this past Christmas Eve, Dr. Ralph Keeling, son of the renowned Dr. Charles David Keeling, made a public appeal for increased funding of the critical Mauna Loa Observatory’s CO2 Monitor. The funds, you see, after more than 40 years of cuts to critical scientific research, research often labeled by political opponents to be ‘wasteful government spending,’ were at risk of short-fall. So Dr. Keeling, a scientist in the crucial and much-needed field of atmospheric monitoring, was forced, by the most greedy and heartless among us, who only see the gift beyond price that is human science as a tax burden equivalent to ‘wasteful government spending,’ to pan handle for the continued funding of his, all-too-necessary and growing ever more important with each passing day, mission.

Dr Keeling’s appeal was the very modicum of dignity and candor. And it contained hardly a jot of the outrage which he, and the rest of us, should justifiably feel. Instead, he simply and candidly reminded us of the importance of his ongoing mission:


I am writing as the director of the Scripps CO2 and O2 programs, which keep track of how these vital gases are changing in the atmosphere over time.  The CO2 measurements include the iconic Mauna Loa record, now commonly known as the “Keeling Curve”, which was started by my father in the late 1950s.

The O2 measurements, carried out on samples from Mauna Loa and many other stations, also provide critical information about how the planet is changing.  The measurements show that the world’s O2 supply is slowly decreasing, and have helped prove that the CO2 increase is caused by fossil fuel burning, but offset by natural sinks of CO2 in the land and oceans.

The need to continue these measurements has not diminished. The planet is undergoing dramatic changes, unprecedented for millions of years.  This past year, our group reported that CO2 topped 400 parts per million at Mauna Loa for the first time…

The Scripps CO2 and O2 measurements now face severe funding challenges.  The situation is most urgent for the O2 measurements.  These measurements have been supported for decades through proposals submitted every few years to the federal agencies.  The value of these measurements is not questioned, but federal funding for these programs has never been so tenuous.  This is the basis for this unusual to the public at large…

I have struggled throughout my career to cope with [funding challenges], and I will continue the struggle.  The quest for continued federal support will not end.

For now, I ask for your support so that we can keep up these activities and sustain our watch on the planet in this time of unprecedented global change.


Ralph F. Keeling

(I’ve abbreviated Dr. Keeling’s appeal for this post. That said, I fully urge you to read the entire appeal at his blog The Keeling Curve, to help spread word of his appeal far and wide, and to donate generously.)

Now, as Dr. Keeling knows all too well, 400 ppm CO2 is a big deal. If the world were to remain at this level for an extended period, global temperatures would eventually stabilize between 2-3 degrees hotter than the 20th Century Average. Analysis of the dramatic changes, including a 15-75 foot sea level rise, massive expansion of deserts, a reduced productivity of lands and oceans, and dangerous changes to the world’s weather as it undergoes this temperature transition would put most if not all human civilizations at risk of collapse. Failure to heed this warning and rapidly stabilize and then reduce CO2 levels would risk these and far worse consequences. Yet despite this danger, we are rapidly heading on toward 450, 550, 650 ppm CO2 or more.

NASA has rightly labeled atmospheric CO2 concentration ‘the global thermostat’ and if you want to get a good idea of where the temperature is heading, you need to keep an eye on the thermostat needle. Dr. Keeling’s research gives us that needle. And without the measure his research provides, we are flying blindly into a world of worsening and ever more dangerous weather.

Methane Monitoring Cut as Well

Sadly, Dr. Keeling’s essential monitoring is not the only measure at risk of funding cuts. According to a recent report in Live Science, monitoring of another essential greenhouse gas, methane, has fallen by 25% due to ongoing cuts and is now at serious risk of collapsing. Ed Dlugokencky, an atmospheric chemist with NOAA’s Earth Sciences Research Laboratory in Boulder, Colorado noted:

“We’ve had about a 25 percent decrease in the number of air samples measured from the global cooperative network. If we want to understand what is happening [with methane], we’re going in the wrong direction to do that.”

While CO2 is the primary driver of current warming, methane is, increasingly, an indicator of one of the worst amplifying feedbacks due to human caused change. Massive volumes of methane lay stored in tundra and on the sea bed. Should these stores, which are sensitive to heating, be released into the atmosphere, they could add substantial additional warming on top of the warming already set in play by CO2 increases.


(Global Methane Distribution Indicative of Large Arctic Emissions. Image source: NASA)

Recent reports and studies have found evidence of an increasing Arctic emission of methane, one that has possibly exceeded 90 megatons annually. Though not yet catastrophic, this increasing emission is a serious concern and we would be very unwise to stop taking measures of this very volatile and potentially dangerous atmospheric gas.

As is the case with Dr. Keeling, cuts in funding to scientific monitoring of these gases are as egregious as they are short sighted. The scientists and the research efforts they provide go to benefit us all. They work diligently to serve our interest and to give us the best information along with the means to make sound decisions, should we choose to. They are not wealthy and could have probably earned far more using their considerable intellects to game the stock market, for example, or to aid CEOs in determining how best to off shore US jobs to cheap, easily exploitable foreign labor.

There is no tax cut for the top 1 percent, no foreign oil war, no subsidy to the fossil fuel industry that is more important than funding this scientific effort and these selfless public servants who work so diligently on our behalf. So we should do everything necessary — increase taxes on the wealthy, stop fighting wasteful wars, and stop subsidizing dirty and dangerous industries — in order to provide the support needed to continue this vital service to humankind.

And as for those dark political and social forces that, as they did in Canada with the dismemberment, looting, and dissolution of scientific libraries, seek to suppress the accumulation of knowledge about how our world operates and, yes, responds to the harm we’ve inflicted upon it — they should be banished back to the dark ages from which they arose. They have no place here. Not at this time of clear and present danger. They are traitors to human progress, to our civilizations and, ultimately, to the vitality of life on this world. And they should be swept aside lest, one by one, we all, and not just the scientists, be silenced.


The Keeling Curve


NASA’s Earth Observatory

NASA: CO2 Acts as Global Thermostat

Live Science

In Book-buring Like Episode, Conservatives in Canada Destroy Scientific Libraries

Hat tip to Colorado Bob

World CO2 Levels Dangerously High: January Sees 399.5 ppm in First Week, Could Crack 400 Before Month-End

In speeding toward a climate cliff unlike anything seen in geological history, we continue to slam the accelerator through the floor-boards of our metaphorical ‘world civilization’ automobile… One hopes we should apply the breaks, but, in the same thought, wonders if they have already started to give out…

*    *    *    *    *    *

From 2012 to 2013 worldwide annual CO2 levels, as measured by the Mauna Loa Observatory, raced ahead by nearly 3 ppm. This break-neck pace was more than seven times faster than at any period in the observed geological record spanning hundreds of millions of years. As 2013 transitioned to 2014, the unprecedented pace of increase showed little sign of slackening with hourly average CO2 levels reaching 399.5 PPM on January 7th of this year.

Mauna Loa Early January

(Daily and hourly CO2 average readings as recorded at the Mauna Loa Observatory from January 1 to January 7. Image source: The Keeling Curve.)

These levels are similar to those seen last year during late April, near the peak of the annual atmospheric CO2 cycle that typically occurs during late May to early June. If this year’s pace of atmospheric CO2 increase continues, it is entirely possible that hourly, daily, or even weakly averages will exceed 403 ppm CO2 come late spring. Meanwhile, it appears possible that hourly CO2 averages will exceed 400 ppm before the end of this month.

Increasing Environmental Feedbacks Driving Higher Rate of CO2 Increase?

Though it is too early to conclude that the rate of CO2 increase has quickened, observations show rising contributions of both CO2 and methane from Earth Systems in addition to the inexorably increasing human emission. Thawing Arctic tundra, increasingly wide-spread forest fires, expanding drought zones, and ocean zones that appear to be reaching CO2 saturation points all hint at an Earth System that is both less able to absorb human CO2 emissions and more likely to release carbon (CO2 and methane) on its own.

The Arctic alone, in recent years, has been placed on the map as a major emitter of both CO2 and methane contributing enough volumes of these gasses to make it one of the world’s largest emission sources. If the Arctic were a country, it would probably rank around 4th in total global carbon emissions when compared to the world’s industrialized nations. And, unfortunately, the Arctic is likely just starting to ramp up as a carbon source (see Amplifying Feedbacks and Arctic Methane Monster Stirs).

With the human forcing so strong and the pace of Arctic warming so great, it is only a matter of time before the emissions signal coming from the Arctic becomes irrefutable to the rational observer. The question, at this point, is: has it already started to happen?

Racing Toward a Very Dangerous World

Both the quickening pace of global average CO2 increase and the observed increasing emission from the Arctic are cause for serious concern. A world that remains stable at 400 ppm is a world about 2-3 C hotter than today. Its seas are 15 to 75 feet higher. And its ability to support the kind of environments that humans are used to is radically reduced. But world CO2 levels are not stable at 400 ppm. They are racing higher at between 2.2 and, in recent years, close to 3 ppm (official average increase of 2.65 ppm for 2013) — six to seven times faster than ever before.

The Earth System has yet to fully respond to this rapid and very powerful insult.

Which brings me to this final thought as was so creatively illustrated over at the Arctic News blog:


(Image source: Arctic News)


The Keeling Curve

Arctic News


CO2 Levels Rose 6 Parts Per Million in Two Years. Are the Earth’s Carbon Sinks Starting to Fill Up?


(Image source: Keeling Curve)

In May of 2011, worldwide CO2 levels hit a yearly maximum of 394 parts per million. At the most recent average rate of CO2 increase (about 2 parts per million each year), the world would have hit 400 parts per million by 2014. Instead, that number was reached 1 year sooner.

It was a faster rate of atmospheric carbon increase — about 3 parts per million rise each year — that resulted in the world rocketing to the new milestone sooner than expected.

Pace of Rise Accelerating

The pace of atmospheric CO2 increase, at the time measurements began in the late 1950s, was about 1 part per million each year. This pace of increase steadily rose to an average of 2 parts per million each year during the late 1990s. By the end of the first decade of the 21rst Century, average rates of increase were about 2.2 parts per million.

This accelerating pace of CO2 accumulation has been driven, largely, by a vast increase in the amount of CO2 released into the atmosphere. In the late 1950s, the world dumped about 8 gigatons of CO2 into the atmosphere each year. By 2012, that number had nearly quadrupled to 31.6 gigatons.

IEA World Carbon Emissions

(Image Source: IEA Report: Re-Drawing the Energy/Climate Map) (And a Hat-Tip to Climate Progress for digging it up)

But Carbon Sinks Keep Pace with Rising Emissions

You’ll notice that though carbon emissions nearly quadrupled, the average pace of atmospheric carbon increases only slightly more than doubled. The reason for this is that as global emissions rose, the amount of carbon absorbed by the oceans and the land also dramatically increased. So both the oceans and land together continued to absorb about 50% of all the carbon our factories and automobiles spat out.

The remaining fraction still ended up in the atmosphere. And so we still saw a rapid increase in global CO2 levels. But not so rapid as we would have if carbon sinks weren’t helping us by drawing down half of the CO2 we were dumping.

CO2 Sinks Graph

(Image source: NOAA)

…Until They Become Exhausted

Unfortunately, carbon sinks are a finite resource. As such, scientists expect them to eventually lag in their ability to uptake ever greater volumes of our greenhouse gas emissions. This is especially true with the oceans which a number of scientific reports show are starting to reach their saturation point.

According to a recent NOAA report:

“The uptake of carbon dioxide by the oceans and by ecosystems is expected to slow down gradually,” Tans [one of the report’s authors] said. Oceans, for example, are already becoming more acidic as they absorb about a quarter of the carbon dioxide pumped into the air by human activities. “As the oceans acidify, we know it becomes harder to stuff even more CO2 into the oceans,” Tans said. “We just don’t see a letup, globally, yet.”

In fact, a related research paper found that a large swath of the southern ocean, which absorbs 15% of the world’s CO2 emissions, had become completely saturated and could no longer absorb CO2 from the atmosphere.

A New, Very Dangerous Pace of Increase Going Forward?

So all this begs the question: are the world’s CO2 sinks starting to become exhausted?

A six parts per million CO2 increase over two years is a much more rapid rate than the world is used to. At such a rate, we reach 450 parts per million by 2030. And if the world’s carbon sinks are, indeed, starting to exhaust even as world CO2 emissions remain high or continue to climb, then we may see annual increases of 4 parts per million or more over the coming decades.

We won’t know if the 3 parts per million annual increase is established for a few years yet. But if it is, it is yet one more sign that the world is starting to reach a number of very dangerous tipping points and we should do our best to reduce the potential harm by as much as possible.


Keeling Curve

IEA Report: Re-Drawing the Energy/Climate Map


The Southern Ocean is CO2 Saturated

CO2 Breaks 400 PPM Daily Average on May 13, Exceeding An Extraordinarily Dangerous Level

Mauna Loa 400 ppm Daily

(Image source: Keeling Curve)

Back in early March we began to warn that CO2 levels could break 400 PPM in 2013. In April, the Mauna Loa Observatory recorded hourly CO2 levels above 400 PPM for the first time in more than 4 million years. Then, two days ago, daily averages for 400 PPM CO2 were breached.

Whether May averages just below or slightly above 400 PPM CO2 remains to be seen. But it is certainly possible that weekly and even monthly averages of CO2 break this severely high threshold this year. Almost certainly, a month or two of 2014 will see CO2 averages over 400 PPM. By 2015 or 2016, yearly averages for CO2 will exceed that extraordinarily dangerous level.

This massive jump to 400 PPM CO2 from pre-industrial averages is disturbing and alarming for many reasons. The first of which is the heating impact CO2 has on the Earth’s atmosphere. According to Paleoclimate data, a world at 400 PPM CO2 is, on average, between 3 and 4 degrees Celsius hotter. Even worse, temperatures in the Arctic average about 14 degrees Fahrenheit hotter. This increase in temperatures results in radical alterations to the world’s climate, pushes major sea level rises, and results in massive volumes of ice melted. It is doubtful that most of the world’s glaciers and ice sheets could survive such a long-term assault of extreme high temperatures. And it is worth noting that human beings as we know them have never occupied a world without ice.

But even as bad as maintaining CO2 levels at 400 parts per million may sound, worse are the potential feedbacks such a high initial spike of atmospheric carbon may kick off. Vast stores of methane lay locked in the world’s tundra and oceans. Even a small fraction of these gasses liberated by human-caused warming would serve to add more greenhouse gasses to the atmosphere, further increasing the warming already in store. In addition, as the ice sheets recede, more dark ocean and land features are exposed to sunlight. This loss of albedo results in increased solar heat absorption, further increasing global temperatures. So past climate may not be a perfect analogue to what we may be setting in place. Instead, it may be the launching point for even worse changes.

At 400 parts per million there is the danger that such terrible consequences may well become permanent features of the world in the coming decades and centuries. The current danger is somewhat low due to the fact that, if we were to rapidly reduce emissions now, we might be able to secure a livable climate and let the Earth’s natural processes reduce CO2 levels to 350 PPM or lower over the course of about a century. However, there is risk that the current human forcing is enough, even now, to generate a powerful response from the Earth’s climate and environment. One strong enough to result in CO2 levels stabilizing at the current level or even increasing somewhat due to these natural feedbacks. In order for this to happen, global climate would have to be much more sensitive than scientists currently estimate. But the fact is that, at current CO2 levels, such a dangerous feedback is possible, if not likely.

What is even more maddening, though, is the fact that human CO2 emissions and global CO2 levels are rising at a break-neck pace. Just last year, May CO2 levels peaked at an average of 396.8 PPM. This year’s levels are likely to be 3 PPM+ higher than last year. Global averages have been rising at a rate of 2.2 PPM per year or more. So at the current rate of CO2 rise and factoring in the rate of increased CO2 emissions, it is likely that 450 PPM could be breached in about 20 years. This pace of increase is faster than at any time visible in the geological past by at least a factor of 5. In short, it is likely that Earth has never undergone such a radically rapid increase of CO2.

At 450 PPM CO2, the world is far more likely to experience the kind of powerful global feedbacks noted above. And with world CO2 emissions continuing to increase, it is fair to say that we are in the era of this dangerous climate change now. Which it is why it is very important to recognize that with each passing year of CO2 emission increases and failure to reduce overall world carbon emissions, we pass deeper and deeper into an extraordinarily dangerous territory. Pushes to reduce atmospheric CO2 levels to the ‘safe range’ of 350 PPM must be pursued with great speed and effort if we are to preserve hope of a livable climate for human beings beyond the first half of this century.



Keeling Curve

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