New Study Finds that Present CO2 Levels are Capable of Melting Large Portions of East and West Antarctica

If you’re a regular reader of this blog and its comments section, you’re probably more than a little worried about two bits of climate science in particular:

Our understanding of past climates (paleoclimate) and 5-6 C long term climate sensitivity.

And if you’re a frequent returner, you’ve probably figured out by now that the two go hand in glove.

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Looking back to a period of time called the Pliocene climate epoch of 2.6 to 5.3 million years ago, we find that atmospheric carbon dioxide levels were somewhat lower than they are at present — ranging from 390 to 400 parts per million. We also find that global temperatures were between 2 to 3 degrees Celsius warmer than 1880s ranges, that glaciers in Antarctica and Greenland were significantly reduced, and that sea levels were about 25 meters (82 feet) higher than they are today.

(The Totten Glacier is one of many Antarctic land ice systems that are under threat of melt due to human-forced warming. A new paleoclimate study has recently found that levels of atmospheric greenhouse gasses that are below those presently in our atmosphere caused substantial Antarctic melt 4.23 million years ago. Image source: antarctica.gov.)

Given that atmospheric CO2 levels during 2017 will average around 407 parts per million, given that these levels are above those when sea levels were considerably higher than today, and given that these levels of heat trapping gasses are rapidly rising due to continued fossil fuel burning, both the present level of greenhouse gasses in the Earth’s atmosphere and our understanding of past climates should give us substantial cause for concern.

This past week, even more fuel was thrown onto the fire as a paleoclimate-based model study led by Nick Golledge has found that under 400 parts per million CO2 heat forcing during the Pliocene, substantial portions of Antarctica melted over a rather brief period of decades and centuries.

Notably, the model found that the West Antarctic Ice Sheet collapsed in just 100-300 years under the steady 400 ppm CO2 forcing at 4.23 million years ago. In addition, the Wilkes Basin section of Antarctica collapsed within 1-2 thousand years under a similar heat forcing. In total, the study found that Antarctica contributed to 8.6 meters of sea level rise at the time due to the loss of these large formations of land ice.

From the study:

We conclude that the Antarctic ice sheet contributed 8.6 ± 2.8 m to global sea level at this time, under an atmospheric CO2concentration identical to present (400 ppm). Warmer-than-present ocean temperatures led to the collapse of West Antarctica over centuries, whereas higher air temperatures initiated surface melting in parts of East Antarctica that over one to two millennia led to lowering of the ice-sheet surface, flotation of grounded margins in some areas, and retreat of the ice sheet into the Wilkes Subglacial Basin. The results show that regional variations in climate, ice-sheet geometry, and topography produce long-term sea-level contributions that are non-linear with respect to the applied forcings, and which under certain conditions exhibit threshold behaviour associated with behavioural tipping points (emphasis added).

This study began the publication process in 2016 when year-end atmospheric CO2 averages hit around 405 parts per million. By end 2017, those averages will be in the range of 407 parts per million. Even more worrying is the fact that CO2 equivalent forcing from all the various greenhouse gasses that fossil fuel burning and related industrial activity has pumped into the atmosphere (methane, nitrogen oxides, CFCs and others) will, by end 2017 hit around 492 ppm.

As a result, though conditions in Antarctica are presently cooler than during 4.23 million years ago, the considerably higher atmospheric greenhouse gas loading implies that there’s quite a lot more warming in store for both Antarctica and the rest of the world. A warming that, even if atmospheric greenhouse gasses remain at present highly elevated levels and do not continue to rise, could bring about a substantially more significant and rapid melt than during the Pliocene.

Links:

Antarctic Climate and Ice Sheet Configuration During Early Pliocene Interglacial at 4.23 Ma

NOAA ESRL CO2 Trends

NOAA’s Greenhouse Gas Index

East Antarctic Ice Sheet More Vulnerable to Melting than We Thought

Pliocene Climate

antarctica.gov

Hat tip to Spike

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Tottering Totten and the Coming Multi-Meter Sea Level Rise

A new scientific study has found that the Totten Glacier is fundamentally unstable and could significantly contribute to a possible multi-meter sea level rise this Century under mid-range and worst case warming scenarios.

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408 Parts per million CO2. 490 parts per million CO2e. This is the amount of heat-trapping CO2 and total CO2 equivalent for all heat-trapping gasses now in the Earth’s atmosphere. Two measures representing numerous grave potential consequences.

We’re Locking in 120-190 Feet of Sea Level Rise Long Term

Looking at the first number — 408 parts per million CO2 — we find that the last time global levels of this potent heat-trapping gas were so high was during the Middle Miocene Climate Optimum of 15-17 million years ago. During this time, the Greenland Ice Sheet did not exist. East Antarctic glacial ice was similarly scarce. And the towering glaciers of West Antarctica were greatly reduced. Overall, global sea levels were 120 to 190 feet higher than they are today. Meanwhile, atmospheric temperatures were between 3 and 5 degrees Celsius hotter than those experienced during the late 19th Century.

Antarctica Below Sea Level

(Large sections of Antarctica rest below sea level. A physical feature that renders substantial portions of Antarctica’s glaciers very vulnerable to rising ocean temperatures. Since the latent heat content of water is substantially higher than that of air, even comparatively small ocean temperature increases can cause significant melt in sea-facing glaciers and in below sea level glacial basins. Image source: Potential Antarctic Ice Sheet Retreat Driven by Hydrofracturing and Ice Cliff Failure.)

Hitting the 408 ppm CO2 threshold this year catapults the current push for global climate transitions outside of the Pliocene context of 3 to 5 million years ago (topping out at 405 parts per million CO2) and places it in the bottom to mid-range of the Middle Miocene context (300 to 500 parts per million CO2). The 490 ppm CO2e number — due to added atmospheric heating contributions from human-emitted gasses like methane, chlorofluorocarbons, NOx compounds, and others — is enough to catapult our current climate context into the upper Middle Miocene range.

If global greenhouse gasses were to stabilize in this range long-term (for a period of hundreds of years), we would expect the Earth’s climate and ocean states to become more and more like those experienced 15-17 million years ago. Unfortunately, atmospheric concentrations of heat trapping gasses are still rapidly rising due to an increasingly dangerous emission coming from global fossil fuel burning. In addition, risks are rising that the Earth System will begin to contribute its own substantial amounts of carbon — possibly enough to raise the CO2e number by around 50 to 150 ppm over the next few centuries. Two contributions — one we control and another we do not — that risk swiftly pushing the global climate context into a 550 to 650 ppm CO2e range that is enough to eventually melt all the glacial ice on the planet.

Glacial Inertia vs Lightning Rates of Warming

It’s a tough climate state. A context that many scientists are still having difficulty coming to grips with. First, the global glacier research community is still looking at the world’s potential future ice melt in Pliocene and Eemian contexts. This makes some sense given the fact that current atmospheric warming in the range of 0.9 to 1.3 C above 1880s values is more in line with those two climate epochs (the Eemian saw seas 10-20 feet higher than today and the Pliocene saw seas at 25-75 feet higher). But it doesn’t take into account the underlying heat forcing and the likely climate end-state.

Second, we don’t really have a good grasp on how fast or slow glaciers will respond to the added heat we’re putting into the Earth System. We do know that at the end of the last ice age, melting glaciers contributed as much as 10 feet of sea level rise per Century. But this was during a time of comparatively slow global temperature increase at the rate of about 0.05 C per Century — not the current rate in the range of 1.5 to 2 C per Century, which is 30 to 40 times faster.

10 Feet of Sea Level Rise South Florida

(What 10 feet of sea level rise would do to South Florida. Given the increasing vulnerability of glaciers around the world to human-forced warming, there’s a rising risk that seas could rise by 10 feet before the end of this Century. Image source: Climate Central.)

In early studies, much weight has been given to glacial inertia. And older climate models did not include dynamic ice sheet vulnerabilities — like high latent-heat ocean water coming into contact with the submerged faces of sea-fronting glaciers, the ability of surface melt water to break up glaciers by pooling into cracks and forcing them apart (hydrofracturing), or the innate rigidity and frailty of steep ice cliffs which render them susceptible to rapid toppling. But now, new studies are starting to take these physical melt-amplifying processes into account and the emerging picture is one in which glacial melt and sea level rise may end up coming on at rates far more rapid than previously feared.

Overall, when taking a look at these newly realized ice-sheet weaknesses, it’s worth noting that the total heat forcing impacting the world’s ocean, air, and glacial systems is now rising into a range that is much more in line with Middle Miocene values. And that global temperatures are now increasing at a lightning rate that appears to be unprecedented in at least the past 60 million years.

Tottering Totten

It’s in this dynamic, rapidly changing, and arguably quite dangerous climate context that new revelations about the stability of one of East Antarctica’s largest glaciers have begun to emerge. In size, the Totten Glacier is immense — covering an area the size of California in mountains of ice stretching as high as two and a half miles. If all of Totten were to melt, it would be enough to raise seas by around 11 to 13 feet — or about as much as if half of the entire Greenland Ice Sheet went down.

Edge of the Totten Glacier

(The Totten Glacier, at lower edge of frame, faces a warming Southern Ocean. How rapidly this great mass of ice melts will, along with the destabilization of numerous other glaciers around the world due to a human-forced warming, determine the fates of numerous coastal cities and island nations during this Century and on into the future. Image source: LANCE-MODIS.)

Last year, a study found that warm, deep circumpolar water was beginning to approach ice faces of the Totten Glacier plunging 1 mile below the surface of the Southern Ocean. The study observed a rapid thinning that appeared to have been driven by this new influx of warmer ocean water near the glacier base:

Totten Glacier… has the largest thinning rate in East Antarctica. Thinning may be driven by enhanced basal meltingWarm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the nearby continental shelf beneath 400 to 500 m of cool Antarctic Surface Water…We identify entrances to the ice-shelf cavity below depths of 400 to 500 m that could allow intrusions of warm water if the vertical structure of inflow is similar to nearby observations. Radar sounding reveals a previously unknown inland trough that connects the main ice-shelf cavity to the ocean. If thinning trends continue, a larger water body over the trough could potentially allow more warm water into the cavity, which may, eventually, lead to destabilization of the low-lying region between Totten Glacier and the similarly deep glacier flowing into the Reynolds Trough (emphasis added).

Observed increasing melt rates for such a huge slab of ice in Eastern Antarctica was generally seen as a pretty big deal among glacial scientists and a flurry of additional research soon followed. By last week, a model study had found that Totten alone could produce nearly a meter of sea level rise before the end of this Century if global warming forces ocean waters to heat up by 2 C or more near the Totten Glacier. The study also found that 5 C worth of local ocean warming would be enough to force nearly 3 meters worth of sea level rise from this single large glacier over a relatively short time-frame.

Donald D. Blankenship, lead principal investigator for the new ICECAP study noted:

“Totten Glacier’s catchment is covered by nearly 2½ miles of ice, filling a California-sized sub-ice basin that reaches depths of over one mile below sea level. This study shows that this system could have a large impact on sea level in a short period of time.”

Like many large glaciers around the world, a huge portion of Totten’s ice sits below sea level. This feature makes the glacier very vulnerable to ocean warming. Water carries far more latent heat than air and just a slight rise in local ocean water temperature can contribute to rapid ice loss. Totten itself rests in three large below sea level basins. And study authors found that 2 C to 5 C warming of local ocean waters with somewhat greater local air temperature increases was capable of flooding these basins in stages — forcing Totten’s glacial ice to flow out into the Southern Ocean and provide significant contributions to sea level rise.

Unfortunately, Totten is just one of many large glacial systems that are now destabilizing across Antarctica. And researchers are now beginning to identify significant potential sea level rise contributions from Antarctica alone (ranging from two feet to nearly two meters) before the end of this Century. In New Scientist, during March, Antarctic researcher Rob Deconto notes:

“Today we’re measuring global sea level rise in millimetres per year. We’re talking about the potential for centimetres per year just from [ice loss in] Antarctica.”

Centimeters per year sea level rise is about ten times faster than current rates and implies 100 year increases — once it gets going — in the range of 2 to 3 meters. Such increased melt does not include Greenland’s own potential sea level rise contribution. Nor does it include sea level rise from other glacial melt and ocean thermal expansion. As such, it appears that multi-meter sea level rise is becoming a more and more distinct possibility this Century. Furthermore, the paleoclimate context is now pointing toward catastrophic levels of overall melt and sea level rise if global greenhouse gasses aren’t somehow stabilized and then swiftly reduced.

Links:

Repeated Large-Scale Retreat and Advance of Totten Glacier Indicated by Inland Bed Erosion

The Totten Glacier

The Human-Warmed Southern Ocean Threatens Major Melt for East Antarctica

Fundamentally Unstable — Scientists Confirm Their Fears About East Antarctica’s Biggest Glacier

Potential Antarctic Ice Sheet Retreat Driven by Hydrofracturing and Ice Cliff Failure

Unstable East Antarctic Glacier Has Contributed to Sea Level Rise in the Past

Sea Levels Set to Rise Far More Rapidly Than Expected

Unexpected Antarctic Melt Could Trigger 2 Meter Sea Level Rise

Entering the Middle Miocene

The Middle Miocene

LANCE MODIS

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.

mlo_two_years

(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

(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.

Links:

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

NOAA ESRL CO2 Measure

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

Worldwide CO2 Levels at 394.4 ppm in Early November, Likely to Hit 402 ppm by May, 2014

CO2 November 2013, Six Month

(Global CO2 measurements over the past six months. Small dots – daily values. Large dots – weekly values. Blue line – smoothed trend. Image source: The Keeling Curve)

After hitting a new record high above 400 ppm during the latter weeks of May, 2013, CO2 followed seasonal trends by falling to a new record high low of around 393.5 ppm in early October. By early November of 2013, CO2 had rocketed back to 394.4 ppm and, if current trends continue, will likely touch 402 ppm or higher by May of 2014.

Over the past few years, worldwide CO2 values have risen by an average of around 2 parts per million each year. But in 2013, the trend line steepened, with values increasing by about 3 ppm between 2012 and 2013. Should the new, more rapid, pace hold through 2014, maximum CO2 values for that year will reach between 402 and 403 parts per million by late May.

In context with the known geological record, the current pace of CO2 increase is far faster than anything previously observed. Past major warming events, at most, hosted a yearly CO2 increase of around .35 ppm. The most recent rate of 2 ppm per year, on average, is about six times as fast. A yearly increase of 3 ppm is nearly eight times this total.

It’s worth considering this amazing fact: human emissions are more rapid now than anytime in the geological past. Nothing, not the PETM, not the great flood basalts of the Permian, exceeded the current rate of human burning. And those great past events, many coinciding with the worst mass extinctions, were 1/6th to 1/8th the pace of what humans are doing now. Our CO2 injection machinery is more powerful, by far, than even the most terrible forces ever produced by nature.

This screaming pace of CO2 increase is leading to a series of unprecedented and damaging climate, weather, and Earth systems changes. Changes we are just beginning to understand. At the very least, we have projected ourselves into climate territory not seen in the last 3.6 million years — the last time CO2 levels were as high as they are bound to be over the next ten years. And that’s if we are somehow able to halt global CO2 emissions soon. If human emissions continue to increase as they have over the past decades, by mid century, we could be looking at atmospheric CO2 levels not seen in the past 15 to 30 million years. By the end of this century, we could achieve an atmospheric state not seen in at least 55 million years.

A Little Heat Age Every Six Years

It is not just the scale of the change, creating levels of CO2 not seen since ages in the Earth’s deep past, it is the pace of this change which is so immense and dangerous. According to the most recent IPCC draft report, the current increase in CO2 levels is causing an increased heat forcing of .16 watts per meter squared at the top of the atmosphere every six years. By comparison, the grand solar minimum experienced during the Little Ice Age had a negative forcing of around .15 watts per meter squared. So we now have the equivalent to a Little Ice Age, but on the side of hot, being pumped into the Earth’s atmosphere every six years. And should the sun cool to another grand minimum, it would take only about six years of current human emissions to overwhelm its cooling effect.

Should we hope to see a continued progress of human civilizations this extraordinarily rapid and dangerous pace of human CO2 emissions is an issue that must be addressed immediately. We have likely already created a serious and devastating string of events that will continue to unfold and worsen over the coming decades and centuries. Some, we have already seen, but these are the earlier, more mild, outliers, the events we locked in 20, 30, 50 years ago. So the force of events 20 years, 30 years, 50 years from now will be proportionately worse.

Continued emissions and further increases, under such a scenario, is not a survivable option. If we are to continue, to have any hope for future progress, we need to halt this mad pace of emissions as soon as possible.

Links:

The Keeling Curve

IPCC Working Group 1 Draft Report

 

New Study Finds Arctic Experiencing Hottest Temps in Nearly 120,000 Years; Lead Author: All Baffin Ice Caps Set to ‘Eventually Disappear’

“All of Baffin Island is melting, and we expect all the ice caps to eventually disappear, even if there is no additional warming.” Gifford Miller, University of Colorado climate scientist and co-author of a recent scientific study entitled: Unprecedented recent summer warmth in Arctic Canada.

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Baffin Island September, 2013

(Satellite shot of Baffin Island and surrounding Arctic environs in September of 2013. Image source: NASA)

Baffin Island is a frozen archipelago situated to the west of Greenland and to the north and east of Hudson Bay. Like Greenland, it straddles the 70th parallel as well as the Arctic Circle. And like Greenland it is showing increasing signs of unprecedented warmth and melting. Though Baffin does not boast the massive ice caps of Greenland, large glaciers still cover much of its lands and fjords. The remaining areas are littered with small brown and green grasses and shrubs struggling up from rocky outcrops or from wide ranges of the now thawing tundra.

Like so many other places in our world, Baffin Island is a place where the deep past is coming into collision with a rapid and radical transition. A transition caused by humans and their endlessly increasing use of carbon-based fuels.

Over the past 150 years humans have released enough carbon dioxide into the atmosphere to achieve a global concentration of this gas that, by spring of 2013, exceeded 400 parts per million. This unprecedented high level, a level nearly 50% higher than the global concentration 150 years ago, was last seen on the Earth around 3.6 million years ago. And if past climate states are any true guide, then the vast volumes of greenhouse gasses already released into the atmosphere by humans are enough to melt all the ice on Baffin and at least half the ice on Greenland. It is this understanding of the effects of greenhouse gasses on past climates and ice states that prompted Miller to claim we’ve already released enough CO2 to melt the remaining ice on an isle that has been locked in freezing conditions since the dawn of humankind.

A Message From Earth’s Thawing Tundra

On Baffin and all over the high Arctic, vast swaths of the world’s tundra are rapidly being liberated from an eons-old ice cap. Scientists Gifford H. Miller, Scott J. Lehman, Kurt A. Refsnider, John R. Southon, and Yafang Zhong journeyed to Baffin’s thawing ice with a key question in mind: ‘When was the last time this region of the far north thawed?’ They came armed with the latest scientific tools and measures — tools that provided radio-carbon dating to determine the age of the most recently thawed plants. What the study found was chilling. Many of the plants newly liberated by the thawing ice were at least 44,000 years old. Others were possibly as old as 120,000 years.

This new evidence shows that the heat wave the Arctic is now experiencing, a heat wave that has driven sea ice deeper and deeper into the high Arctic, a heat wave that is melting, on average, about 500 gigatons of ice from Greenland each year (and about 25 gigatons of ice from Baffin), a heat wave that is turning millions of square miles of tundra into a melting, carbon-rich soup is hotter than even the hottest period during the last 11,000 years. And it shows that the Arctic probably hasn’t experienced this much melting since the last inter-glacial period — the Eemian.

The more recent time marking a space from the end of the last ice age to the present day is known as the Holocene. It marks the most recent geological epoc. During the early and middle years of the Holocene, solar insolation — or the measured amount of radiation coming from the sun — was as much as 9% stronger. But, according to the recent paper, human greenhouse gas emissions have been enough to completely overwhelm even the peak Holocene heat effect of a 9% stronger Arctic sun experienced centuries and centuries ago:

“The key piece here is just how unprecedented the warming of Arctic Canada is,” Gifford Miller, a researcher at the University of Colorado, Boulder, said in a joint statement from the school and the publisher of the journal Geophysical Research Letters. “This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gasses in the atmosphere.”

It’s amazing to think that humans have already set in effect levels of warmth unsurpassed in 44,000 years and, possibly, 120,000 years. This new information, in itself, is unprecedented. But don’t make the mistake of falling into the false and relative comfort of thinking we only need to worry about the climates of 120,000 years ago. We’re already passing that marker now. As mentioned above, we’ve already released enough greenhouse gasses to at least return Earth to climates not seen in 3.6 million years. In this respect, the Baffin Island study adds to research conducted at Lake El’gygytgyn showing that levels of CO2 comparable to those seen today resulted in Arctic temperatures 8 degrees Celsius hotter during the deep past.

Rapidly Changing Arctic to Liberate More Greenhouse Gasses

Sadly, it is Miller’s final statement, the one stating that all the ice on Baffin is bound to melt, no matter what, which bears the most weight in our current day. With coal plants still being constructed at a break-neck pace in India and China, and with human greenhouse gas emissions rising above 45 gigatons of CO2 equivalent each year, we would be lucky if the end level of melt only included the ice on Baffin combined with a large section of the ice over Greenland. Instead, we are rapidly forging along toward a CO2 level of 550 to 600 ppm which will almost certainly ensure a dangerous and rapid melting of all the remaining ice on Earth.

In addition, billions of tons of carbon in the form of methane and CO2 lay locked within the millions of square miles of thawing permafrost. Some of this methane and CO2 is already out-gassing, adding to the already dangerously high levels of human greenhouse gasses.

Over the past month, the Arctic saw major methane spikes in which atmospheric concentrations of this potent greenhouse gas reached nearly 2500 parts per billion, more than 650 parts per billion above the global average. And should the Arctic continue to warm we are more likely to see even larger spikes of both methane and CO2 further amplifying already unprecedented Arctic warmth.

Most likely, we are headed to at least the temperatures last seen during the Pliocene, in which global averages ranged 2-3 degrees Celsius hotter than the present and during which oceans were 25-75 feet higher. Unfortunately, these are the long-term consequences we have probably already locked in. But without rapid reductions in carbon emissions to near zero over the coming decades, we can expect far, far worse outcomes.

Links:

Unprecedented Recent Summer Warmth in Arctic Canada

Arctic Temperatures at 44,000 year High

NASA/Lance-Modis

The Eemian Interglacial

Latest Methane Data Provided by USGS and Methane Tracker

Accelerated Contributions of Canada’s Baffin and Byot Island Glaciers to Sea Level Rise Over The Past Half Century

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