At Least 20-75 Feet of Sea Level Rise Already Locked In? Putting Climate Central’s Surging Seas Into Context

“There are some recent modeling efforts that now show you could get a section of the Antarctic ice sheet, several meters worth of sea level rise, to go in a decade. We used to think it was centuries.” — Andrea Dutton Geochemist at the University of Florida.

*  *  *  *  *

Recent reports out from Climate Central and supported by the work of experts show that a sea level rise of at least 6 meters could already be locked in. And as bad as that sounds, a six meter sea level rise from the warming already set in motion by high atmospheric greenhouse gas levels and likely to come from further human emissions could be a best-case or even unrealistic scenario.

To get an understanding as to why so much water may be heading toward the coastal cities of the world, enough water in a 6 meter rise to set off a mass migration of hundreds of millions away from the world’s coasts (just 1.1 meters is enough to flood out 150 million people), it helps to take a good, hard look at paleoclimate. In studying past, warmer, climate states, we can get an idea how much additional sea level rise might be in store. When looking at these past climates for comparison, the key readings to keep in mind are — temperature, greenhouse gas level, and related sea level.

A Question of Whether We Lock in Greenhouse Gas Levels Comparable to Past Climates

Starting with the current climate that is now being rapidly warmed by human fossil fuel burning, we find that this year peak monthly CO2 levels hit near 404 parts per million. It’s a value fast approaching the top of this key greenhouse gas’s range during the Pliocene around 3.5 million years ago. A time when temperatures were 2-3 degrees Celsius hotter and sea levels were between 25 and 75 feet higher than they are today.

Virginia Beach 6 meter sea level rise

(What Virginia Beach looks like after 6 meters of sea level rise. Notably, about everyone I knew as a child or who still lives in VB now is under water in this scenario. Image source: Climate Central.)

Looking at the climate situation in this way tends to elicit a bit of an ‘oh crap’ response. And it should. For all other things being equal, if CO2 levels were to remain so high over the course of a few Centuries, that’s where we’re headed. Toward a world with 2-3 C hotter temperature and 25 to 75 foot higher seas.

But the atmosphere of today is only a rough allegory to that of Pliocene times. In addition to CO2, our airs now host expanding volumes of other greenhouse gasses — exotic and common. A vast majority of which are emitted as a result of fossil fuel burning, extraction, and industrial processes. So to compare our atmosphere to that of the period around 3.5 million years ago and expect the same results with regards to temperature and sea level would be unrealistic. Current methane readings alone — in excess of 1800 parts per billion — now hit levels likely twice that of the Pliocene. And methane is a greenhouse gas with a global warming potential equal to 20 to 120 times that of CO2 over timescales relevant to current human civilization.

As a result of this additional accumulation of methane and other gasses, this year’s atmosphere is a closer allegory to past atmospheres containing an equivalent of about 484 parts per million CO2 (CO2e). Such times, occurring 15-25 million years ago, hosted sea levels that were more than 100 feet (and possibly as much as 200 feet) higher than today.

It is for this reason that we should view Climate Central’s recent and excellent report on sea level rise — based on Paleoclimate and predicting that at least 20 feet of sea level rise could already be locked in — with a bit of concern. At issue with the report are two factors. The first is that the study bases its findings on predicted temperature increases for the 21st Century only. A process established by IPCC-based studies in which it is assumed that 2 degrees Celsius warming over the course of this Century is, perhaps, the best possible target we can hit through a pretty rapid transition to a zero or near-zero carbon civilization. Implied in this IPCC approach is limiting global CO2 accumulation to 450 parts per million or less. A level that also implies a 530 to 550 parts per million CO2e when other gasses are added in unless all the methane overburden falls out due to its short atmospheric lifetime (about 8 years). A dicey assumption at best considering that at least some and possibly all of that overburden could be maintained by feedbacks now at play in the Arctic and in the world’s land and ocean systems.

Miami submerged 6 meters

(At six meters of sea level rise, Miami is completely submerged. Image source: Climate Central.)

In worse cases, we could see the methane overburden expand in the event that the Arctic carbon stores are less stable than we’d hoped. So while 450 parts per million CO2 might limit us to between 2 and 2.3 C warming this Century, 530 to 550 parts per million CO2e gets us to 2.2 to 2.9 C.

The second issue is that we are only looking at warming for the 21st Century. Due to the long term warming impact of CO2 and other greenhouse gasses on the climate system in total, each 1 C worth of warming this Century implies about 2 C worth of warming long term (ESS sensitivity). So hitting the 2 C target by 2100 gets you to 4 C after many Centuries. And hitting a 550 parts per million CO2e threshold means about 2.7 to 2.9 C 21st Century warming and 5.5 to 5.8 C long term warming. An upper range that is nearly enough to melt all the land ice on Earth and raise sea levels by nearly 240 feet.

How Fast Could Sea Levels Rise?

At least 6 meters indeed! In the 550 parts per million CO2e case, we have one of the better global human carbon emissions scenarios meeting with one of the somewhat more pessimistic Earth Systems response scenarios (but not the worst case) for an absolutely terribly catastrophic outcome. An outcome made even more terrifying by the fact that it is in the mid-to-low range of overall projected greenhouse gas forcings for this Century. In other words, 2 C warming this Century can start to look like a pretty bad outcome for the long haul and we’d probably best be trying to hit well below the implied 450 ppm CO2 target (as Hansen and others have warned). And to this point, we had better move very fast on emissions reductions, because the longer even current greenhouse gas levels are maintained the more likely we hit ice sheet destabilizations that push world ocean levels closer and closer to the Pliocene’s or Miocene’s swollen seas.

Post-Glacial_Sea_LevelTemperature Change End of Last Ice Age

(Just 1 C worth of global warming from 22,000 years BP to 15,000 years BP was enough to set off rapid sea level rise during the end of the last ice age. We are fast approaching the 1 C warmer than 1880s thresholds now. Image source: Commons and Livescience.)

Which brings us to a final question hinted at in the header — how fast could sea levels rise if human forced warming approaches 2 C or more this Century? The modelling efforts Dutton hinted at shows that West Antarctica alone can contribute meters of sea level rise over the course of just decades. And going back to paleoclimate studies of the end of the last ice age we find hints that somewhere between 1 and 2 C worth of warming can trigger very large and rapid glacial outbursts (that then increased sea levels by as much as 16 feet per Century). Finally, recent glacier surveys from Antarctica to Greenland have found extensive and expanding destabilization. Efforts and evidence that imply the 39 inches of sea level rise predicted by IPCC this Century may be quite conservative, even under the better case emissions scenarios.


Surging Seas

Sea Level Could Rise at Least 6 Meters



Antarctica and Greenland’s Simultaneous Destabilization

Concern Over Catastrophic Methane Release

A Faustian Bargain on the Short Road to Hell

The Keeling Curve

Leave a comment


  1. climatehawk1

     /  July 14, 2015

    Tweet scheduled.

  2. wili

     /  July 14, 2015

    jma just announced the warmest June on record.

  3. james cole

     /  July 14, 2015

    Impressive! The Navy has been building up old piers and building new ones in the race against the sea in Norfolk Naval Base. This is sort of a ground zero for visible sea level rise. High tides have been inundating the place, each year growing worse. This news makes it all a vain, or short term effect.
    Reading about the conservative politicians along the Southern Eastern Seaboard, and their futile efforts to keep global warming and sea level rise out of official documents and official planning documents. That effort is truly a level of close minded stupidity. Hundreds of billions of dollars of coastal real estate is at risk from storm surges now, and sea level rise later. Yet they attempt an official black out of that fact. Still luring long term coastal investment dollars right up to the lip of the sea.

  4. Syd Bridges

     /  July 14, 2015

    Thank you, Robert. Reading this reminds me of John Wyndham’s novel, “The Kraken Awakes.” In that story, the alien “Bathies” who have colonised the Ocean Deeps, build huge machines to jet warmer sea water at the Polar ice sheets, causing massive sea level rise. Wyndham was wrong: we did not need aliens to accomplish this; our own greed has sufficed.

    • John Wyndam was a wonderful fantasist. The Crysalids remains one of my favorites.

      • Syd Bridges

         /  July 14, 2015

        I think “The Chrysalids” was his greatest novel. I first came across it as a BBC Radio Play. I just had to buy the book. There are far too many Joseph Strorms around today. We need more Uncle Axels and a Petra to save the day.

    • Mblanc

       /  July 15, 2015

      Wyndham was my favourite author when I was a nipper (a fair while ago!). I read some utter trash when I was young, but also some stuff that I count myself as lucky to have read so early.

      The Midwich Cuckoos deserves a mention too. It’s not often that I can remember the beginning, middle and end, of books that I read over 30 years ago.

  5. Andy in San Diego

     /  July 14, 2015

    Russia has a good load of fires too, we’re just not hearing it on our side of the globe. Take note of how the fires are deflecting the cloud cover. That is what I keep calling “big fires make their own weather”.

    • Working on this, Andy. This year, the big burn has come from the PNW. But sections of Asia have also been burning since April.

  6. wili

     /  July 14, 2015

    “a 150 million person mass migration away from the world’s coasts”

    I know that it’s important not to come off as unreasonably alarmist, but that figure strikes me as an unreasonably low–like by an order of magnitude or so–for a six meter slr.

    Consider just the largest city in the world (~35 million in the metro area), Shanghai, “On the Sea,” which, as it’s name implies, is just above sea level (average elevation: 4 meters).

    Take just the one province of Jiangsu just to the north of Shanghai. Much of it is only a meter or two above sea level, and about 80 million people live there.

    So just looking at one city and one province in one country you get within spitting distance (ok, for a _really_ good spitter ‘-)) from your 150 m number. Maybe that figure if for a _one_ meter rise??

  7. Reblogged this on The Secular Jurist and commented:
    “There are some recent modeling efforts that now show you could get a section of the Antarctic ice sheet, several meters worth of sea level rise, to go in a decade. We used to think it was centuries.” — Andrea Dutton Geochemist at the University of Florida.

  8. wili

     /  July 14, 2015

    The thermosphere collapsed in ’08-09, and then rebounded.

    ” “This is the biggest contraction of the thermosphere in at least 43 years,” says John Emmert of the Naval Research Lab, lead author of a paper announcing the finding in the June 19th issue of the Geophysical Research Letters (GRL).

    “It’s a Space Age record.”

    The collapse happened during the deep solar minimum of 2008-2009—a fact which comes as little surprise to researchers. The thermosphere always cools and contracts when solar activity is low.

    >> In this case, however, the magnitude of the collapse was two to three times greater than low solar activity could explain.

    “Something is going on that we do not understand,” says Emmert. “

    • Solar activity is already declining and yet the human greenhouse gas emission is still warming the Earth. We may be headed toward a grand minimum, but unlike the Little Ice Age, we won’t feel it because the human ghg forcing is about 10 times stronger.

      • wili

         /  July 14, 2015

        Thanks. I just noticed that this came out in 2010. Have you head any more about why this particular contraction was so much more extreme than can be readily explained by solar variance and increased CO2?

    • wili

       /  July 14, 2015

      Further down: “”The density anomalies,” they wrote, “may signify that an as-yet-unidentified climatological tipping point involving energy balance and chemistry feedbacks has been reached.”

      Just what we need–another freakin’ tipping point and climate feedback.

      It just shows how little we really know about this enormously complex and intricate set of interlocking dynamic systems that we are in the process of wantonly smashing to pieces so we can drive our fancy cars, fly in our fancy jets, and eat our tons of dead cow flesh…

      • One possible explanation is carbon dioxide (CO2).
        Thermosphere (cooling, 200px)
        An NCAR video shows how carbon dioxide warms the lower atmosphere, but cools the upper atmosphere. [more]

        When carbon dioxide gets into the thermosphere, it acts as a coolant, shedding heat via infrared radiation. It is widely-known that CO2 levels have been increasing in Earth’s atmosphere. Extra CO2 in the thermosphere could have magnified the cooling action of solar minimum.

        “But the numbers don’t quite add up,” says Emmert. “Even when we take CO2 into account using our best understanding of how it operates as a coolant, we cannot fully explain the thermosphere’s collapse.”

        But CO2 only accounts for 10 percent. Well, something to keep an eye on at least. But a cooler top of the atmosphere…

      • wili

         /  July 14, 2015

        It’s making me wonder, again, whether methane is a bigger actor that they are factoring in, especially if it gets near the top of the atmosphere.


  9. Effect? It seems this model always go wrong to me?

    • The Navy models do tend to hate the ice and predicted a similar massacre last week. We saw about half of it. But the ice pack is very thin in the regions the models show taking the massacre over the next seven days. I still think there’s a possibility that at least a good portion of this could bear out. But keep in mind, the Navy models do tend to really dislike the ice, especially this year.

  10. – Way to go Robert, et al. Sharp minds in busy times. Caring hearts, and all the rest.
    – Thanks.

  11. – ‘Earth’s vegetated surface’

    Nature Communications | Article Open
    Published 14 July 2015

    Climate-induced variations in global wildfire danger from 1979 to 2013

    Climate strongly influences global wildfire activity, and recent wildfire surges may signal fire weather-induced pyrogeographic shifts. Here we use three daily global climate data sets and three fire danger indices to develop a simple annual metric of fire weather season length, and map spatio-temporal trends from 1979 to 2013. We show that fire weather seasons have lengthened across 29.6 million km2 (25.3%) of the Earth’s vegetated surface, resulting in an 18.7% increase in global mean fire weather season length. We also show a doubling (108.1% increase) of global burnable area affected by long fire weather seasons (>1.0 σ above the historical mean) and an increased global frequency of long fire weather seasons across 62.4 million km2 (53.4%) during the second half of the study period. If these fire weather changes are coupled with ignition sources and available fuel, they could markedly impact global ecosystems, societies, economies and climate.

    • Figure 3: Global patterns of fire weather season length changes from 1979 to 2013.

    • – Firestorms of our times.

    • – Pulled text:

      ‘However, we observed an overall lengthening of the number of days each year that wildfires may burn across more than a quarter of the Earth’s vegetated surface and these fire weather changes could manifest themselves as a positive feedback to global atmospheric carbon accumulations if all the requirements for wildfires are present’

  12. bill shockley

     /  July 14, 2015

    I hope Robert doesn’t mind this long transcription from a recent Hansen video

    youtube: James Hansen Talks To MIT Nuclear Engineering Department_james-hansen
    Published on Apr 16, 2015

    Hansen combines ocean/ice dynamics observations with improved gravity satellite data from a recent paper to form an aggressive forecast for sea level rise that is similar to the modeling study presented in Robert’s post.

    With regard to ice sheets and sea level… I think that situation is much more serious than IPCC leads you to believe. They’re kind of slowly moving in the direction that I think is the right answer. And I’m working on a paper on that subject, which I don’t want to be too specific about, because last time I talked about a paper before it was submitted for journal, it ended up causing a long delay in its publication. But we do see that the area that has melt-water on Greenland fluctuates from year to year with the weather. But it has been increasing, and this is an old slide that only goes up to 2008. The red area is the area that had melting in the summer… 2012, almost the entire ice sheet had surface melting. And that meltwater will burrow a hole in the ice sheet where it goes all the way to the base of the ice sheet and lubricates the base of the ice sheet and speeds up the discharge of ice to the ocean. These brave fellows standing on the edge of this ice stream… If one those fellows slip in that water, this hole goes down about 2 km, 3 km to the base of the ice sheet. But the professor is standing further behind. But here’s a river of water—those are brave fellows standing on the edge up there. But, these glaciers are now expelling ice to the ocean more rapidly… Greenland is now losing more than 300 cubic kilometers of ice per year, which we can now measure very accuately with the gravity satellite which measures the gravitational field so precisely that you can see changes in the mass of the ice sheet. And both Greenland and Antarctica are now losing mass at increasing rates.

    The rate of sea level rise over the last century has been increasing. It’s now 3.2mm/year, which is 32 cm in a century, which is still not dramatic but… And my argument is that the disintegration of ice sheets
    is very likely non-linear, and can be characterized better by a doubling time than by a linear process.
    But this particular curve for sea level includes all the contributions—not just the ice sheets—the thermal expansion of the ocean and the change of the amount of water locked in continents and aquifers, but the component of that from the ice sheets is the component that I think is highly non-linear. And thats… There’s a paper published a few months ago, by Velicogna … I think it’s in GRL. But the gravity satellite, the analyses of that… it’s not so simple because you have to… it’s not only that the mass of the ice sheet is changing… you still have the isostatic rebound. So you have the fluid in the Earth’s interior is still responding to the absence of an ice sheet on North America. So you have to correct for isostatic adjustment. But they’re getting better and better at doing that and the error bars are getting smaller. And what we find is that, in the case of Greenland, it’s losing mass, especially in the southern part of the continent. And in Antarctica, it is especially West Antarctica. However, also, what’s just been realized in the last few years is that the Aurora Basin and East Antarctica is also fronting. The reason the West Antarctic ice sheet is very important and potentially could yield a large sea level rise rapidly is because the ice is sitting on bedrock several hundred meters below sea level. So the ocean has access to the ice sheet. And it’s this interaction between the ocean water and the ice sheet, which I think makes it a very non-linear problem, where as the ocean warms, it can begin to cause rapid disintegration of the ice sheet.

    Well it turns out that the same thing is true in this East Antarctic area fronted by the Toten Glacier, which is part of this Aurora Basin and part of the Wilkes Basin, which has more than 10 meters of potential sea level in it. So, what is found is that in all 3 cases—Greenland, East Antarctica and West Antarctica—the mass loss is accelerating at a rate which would give you a doubling time of the order of 10 years. If it really turns out to be 10 years, that means we get several meters of sea level rise within 50 years. If it’s a 20 year doubling then it means in a hundred years you’re going to get several meters. Which means all coastal cities would be dysfunctional. Entire cities might not be under water, but so much of it would be that the city would no longer be functional. In the case of Greenland it’s shocking that it’s a 10 year doubling time, and I think that may not continue, because it’s been partly a case of the weather there being very unusual—high pressure so there’s been a lot of sunlight there in the summer, so it’s less a matter of the ice shelves—but what is happening is that the ice shelves are melting because of the warming ocean, and that’s why it’s a very non-linear problem. What we find in our modeling is that there are amplifying feedbacks. So… this is a sketch of the ocean circulation in 2 dimensions. Deep water is formed in 2 different places on the planet. In the North Atlantic Ocean in the winter, the salty… the ocean water when it gets very cold, can sink to a depth of a couple km, and that’s driving this circulation—the ocean conveyor, which brings warm water… in the Gulf Stream, and the interior ocean to the high latitudes in the northern hemisphere and keeps Europe much warmer than it would be without that ocean circulation. But, in the southern hemisphere, the Antarctic bottom water forms near the coast of Antarctica—it sinks all the way to the bottom—but—and that process is actually a valve for the ocean to release heat—sometimes you even get open ocean—midwinter convection by this process… You get these so-called polynya in the middle of the sea ice around Antarctica in the winter… you get this open water… because this warm north atlantic deep water coming up melts the sea ice and then in the dead of the Antarctic Winter when it’d normally be 30 degrees below zero… instead it’s making the ocean at the freezing point, so it’s losing a lot of heat… to the atmosphere and to space. Now with the Antarctic beginning to melt, it’s the ice shelves that are melting, especially. It’s making fresh water… it’s making the vertical column stable. So… you’re no longer getting the release of heat to the atmosphere, or it’s reduced as this convection is reduced, and that means that the ocean there is warming, and it melts the ice shelves faster. And as that process continues, you actually get increasing sea ice in the Antarctic Ocean and that causes more of the precipitation to fall on the Southern Ocean rather than on the continent. So the assumption that people were making that on a warming planet, Antarctica will grow faster—more snowfall—is not going to be true, because of this process. So this is an amplifying feedback which is going to increase the rate of melt of the Antarctic Ice Sheet and the rate of sea level rise. And we know from the Earth’s history that the last time the planet was warmer than it is today was during the Eemian, when it was less than one degree warmer than it is now, and sea level was 6 to 8 meters higher. So the notion that we should try to limit global warming to 2 degrees Celsius is actually a disaster scenario, in my opinion. You’re eventually going to get sea level rise of at least several meters. And the timescale for that is still uncertain, but I think it’s a lot shorter—and it’s clearly a lot shorter than CO2’s time-constant. The CO2 we’re putting in the atmosphere by burning fossil fuels will not be taken out of the climate system for millenia. And we know that from cases when there were large emissions of CO2 in the past. So, we’re setting up a situation where we’re guaranteeing that there’s going to be sea level rise of many meters; we lose all the history that went with our coastal cities all around the world… it’s just a question of how fast that will happen… unless we move to… actually, to reduce the amount of CO2 in the atmosphere. And the places—China, for example, has about 350 million people living near sea level. So there’s a big incentive… The country of Bangladesh would be under water, and India would suffer the repercussions. Actually, there’s significant cities in India also. So, there’s a big incentive for figuring this out. And of course there are practical effects of climate change besides these irreversible ones in terms of impacts on climate extremes—I think I will not go into that… but, let me mention that, we now… the fundamental problem is… we’re right now, importing energy into the ocean, and that’s why the ice shelves are under threat, but we have to stop pouring energy into the ocean; we have to rebalance the planet’s energy balance. Right now there’s more energy coming into Earth than there is energy being radiated into space… because we’ve added greenhouse gases and reduced the radiation into space. And we know what that imbalance is quite accurately… You can’t actually measure it accurately from satellites from space, because you’d have to measure the radiation going in every direction. But, where does that energy go? Most of it has to go into the ocean because the atmosphere is very thin, it has a very small heat capacity; and the continents have a low conductivity so only the upper 10s of meters change temperature. So, almost all the energy—about 90%—is going into the ocean.

    And we now have more than 3000 Argo floats distributed around the world’s oceans which dive down to a depth of 2 kilometers and come back to the surface and radio their measurements to a satellite, and actually, new argo floats are being developed that will go all the way down to 4 km and also go under the sea ice. But what the measurements tell us is that the planet is out of balance by about 6 tenths of a watt/m2. Which means,other things being equal, if you want to remove that imbalance—and it’s quite a lot of energy actually—but to remove that imbalance you have to reduce CO2 from 400ppm to 350ppm. And if we don’t do that we’re going to have to figure out some geo-engineering, which is not… there are other reasons like ocean acidification—you really want to limit the amount of CO2 you put in the atmosphere. We pointed out in this paper that to do that, if we make an assumption that if we improve our agricultural and forestry practices enough to restore some of the carbon in the forests and in the soil by as much as a hundred gigatons of carbon—which we thought was an ambitious target—then you would need to reduce CO2 emissions 6% per year if you want to stabilize the planet’s energy balance this century. And that seems a little difficult, practically speaking. But one positive thing is that… the system is taking up approximately half of our CO2 emissions, so we’re burning enough fossil fuels to increase CO2 by about 5ppm—almost 5ppm per year— but it’s only going up 2 point some ppm per year. The other half is going into the ocean and into the soil or biosphere. And, in fact, that number is not understood very well. Because the models had said, 25 years ago, that it was 40 per cent disappearing, and they said, well these sinks are filling up and so it’s acutally going to decrease to 30% or 20%. Well, it hasn’t decreased—instead it’s increased to 50%, even though the emissions have gone up, so the size of the sink has really increased, a lot, for reasons that aren’t fully understood. So I think the potential for getting more stored in the soil and the biosphere is maybe more than a hundred gigatons, so we wouldn’t have to reduce as fast as 6% per year, but we need to understand that better.

    Regional acceleration in ice mass loss from Greenland and Antarctica using GRACE time-variable gravity data
    I. Velicogna,
    T. C. Sutterley,
    M. R. van?den Broeke
    25 November 2014

    • I think Hansen’s work has led the pack when it comes to pertinent warnings regarding potential melt scenarios. Unfortunately, we are further out on that limb now.

      • bill shockley

         /  July 15, 2015

        He doesn’t seem to miss much. I really love how you champion him.

        It occurs to me that Hansen is relying on mere data and “extrapolating without physics” in the same way Wadhams does with Arctic sea ice.

        Here’s Gavin Schmidt toeing the IPCC line:

        youtube: “VICE on HBO Season 2: Greenland Is Melting & Bonded Labor” (12:20)

        I think you nailed it a while ago when you characterized Schmidt as not seeming to care much for new science. I could phrase it more crudely…

        Hansen in 2010 with Clayton Thomas-Muller and Naomi Klein. Hansen just seems to care.

        There’s also a great new articleprofiling Jason Box in Esquire that puts a lot of things in perspective, notably the difference in climate politics between the US and Europe. Note also the eloquent Schmidt cameo.

        • The physics, sadly, has giant gaps you could plow a 6 meter SLR through. We can fill some of those gaps, but physical modeling also ends in extrapolation at the limits of your foresight, accuracy, and the resolution of your computing power. The problem, for Hansen, Wadhams, Archer, Schmidt and us all is that the ice sheets are not giant slabs that simply melt at the surface contact points. There’s a dynamic energy exchange that implies a number of feedbacks and tipping points. Until we know it all, forecasting the end result involves a degree of extrapolation.

          Wadhams may have been wrong regarding the extremity of the NH sea ice melt problem, possibly due to the fact that he also didn’t take the negative feedback impact of Greenland melt, AMO and AMOC into account. But Wadhams was right in that the broader community was too conservative on the issue of sea ice melt overall. That our picture of this neat, slow decline was not realistic, regardless of our current understanding of the physics. We have a similar issue with glacial ice and with carbon store stability. Basically, we’re at the mercy of ultimately flawed physical tools and imperfect human beings. We’ve gotten the story right overall, but the niddling details regarding timing, impacts and unforeseen or previously discredited outcomes are the devils which are likely to come back to haunt us.

      • bill shockley

         /  July 15, 2015

        Amen. But I think Hansen is more confident with Antarctic ice where he doesn’t see any potential countervailing forces. Schmidt, OTOH, will take the IPCC view in either case–it’s his job.

      • bill shockley

         /  July 15, 2015

        Speaking of David Archer.

        I came across a recent presentation of his

        Youtube: David Archer – Subsea Permafrost and the Methane Cycle on the Siberian Continental Shelf

        There’s a slide at 27:44

        citing the Arctic Ocean as contributing a minuscule 0.3 MtC (vs Shakhova’s 17MtC!) of methane to the global methane budget. He is directly dismissive of the methane controversy throughout the presentation. One must wonder what assumptions he feeds his model to come up with such numbers.

  13. Daniel Ferra

     /  July 14, 2015

    In Dec. World Leaders are to meet in Paris to discuss Global Warming, at issue is the amount of greenhouse gases we our emitting, and their plan of action.

    “A greenhouse gas is any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere. By increasing the heat in the atmosphere, greenhouse gases are responsible for the greenhouse effect, which ultimately leads to global warming.” Live Science

    Globally we our emitting 40 – 50 Billion Toxic Tons a Year.

    The United States emitted 6.8 Billion Toxic Tons in 2014

    In the 1850s – 1870s parts per million of Carbon in our atmosphere was between 260 – 280.

    In the 1980s, there was 350 ppm of Carbon.

    2015 – 404 ppm in Our Atmosphere.

    The Pacific Ocean is 3 – 6 degrees warmer than Normal.

    The Jet Stream is acting like a balloon that is loosing air.

    The Arctic Ice and Snow may be gone at the end of this Summer. A Huge Natural Cooler for the Northern Hemisphere.

    The meeting in Paris, should be about Closing the Fossil Fuel Faucet.

    “Professor Chris Field is bullshitting the planet. On whether 1.5C is still feasible” Kevin Hester

    “The message is already clear, that if the world does want to strive to limit warming to 1.5C or less, we don’t have very much of the carbon budget left.” Professeor Chris Field

    “There is no carbon budget any more and 5C is baked in according to both Shell petroleum and the International Energy Authority. ” Kevin Hester

    “Chris Field is the founding director of the Carnegie Institution’s department of global ecology and professor for interdisciplinary environmental studies at Stanford University. He is the co-chair of the Intergovernmental Panel on Climate Change’s (IPCC) working group two (WGII) and US nominee for the chair of the IPCC.”
    With people like this driving the IPCC you can see why we are all done for.” Kevin Hester.

    There is No Carbon Budget

    What will the Temp. be at 415 ppm ?

    “Ice sheets contain enormous quantities of frozen water. If the Greenland Ice Sheet melted, scientists estimate that sea level would rise about 6 meters (20 feet). If the Antarctic Ice Sheet melted, sea level would rise by about 60 meters (200 feet).” National Snow and Ice Data Center.

    When will Sea Level Rise to 220 – 300 Feet ? 2020 ? 2025 ? ?

    What will the ppm of Carbon be, when this happens ?

    As of Now, they are talking about capping GHGs at 450 ppm.

    What will the Temp. be at 450 ppm ?

    We must transition to 100% Renewable Energy

    Implement a California Residential and Commercial Feed in Tariff.

    California Residential Feed in Tariff would allow homeowners to sell their Renewable Energy to the utility, protecting our communities from, Global Warming, Poison Water, Grid Failures, Natural Disasters, Toxic Natural Gas and Oil Fracking.

    A California Commercial FiT in Los Angeles, Palo Alto, an Sacramento Ca. are operating NOW, paying the Business Person 17 cents cents per kilowatt hour.

    Sign and Share this petition for a California Residential Feed in Tariff.

    • Shell has a part in this discussion? How about they stop investing in carbon based resources first. Otherwise anything they say carries the big red tag — moral hazard.

    • danabanana

       /  July 15, 2015

      Talking of Greenland melt…. this is the first year I have seen melt lakes all around the edge of the ice sheet. Some also on the back of glaciers, one of which (glacier) calved big time 2 days ago. Located at the north near Peterman’s.

      • We’ve seen this melt signature before. This year’s is a bit stronger, but not in the range of 2012. The melting up north is tending to increase. You also may want to take a look at the strong SSTAs in Baffin Bay. These back right up to the NW coast of Greenland.

  14. Re wild fires and climate: please note the current special series on this topic on Radio Ecoshock. Last week’s show (available for download at soundcloud/radioecoshock) is:

    “Three experts from American Academy for the Advancement of Science meeting February 19th, 2012. Michael Flannigan, U of Alberta on fire and climate. From UBC medical unit, Dr. Michael Brauer on health impacts and personal protection during smoke events. Tasmania’s Fay Johnston’ estimation of global annual deaths from landscape fire smoke. Best of Radio Ecoshock replay from 120418. Radio Ecoshock 150708 in CD Quality (56 MB)”

    This week I’ll have my three best interviews with experts on wildfires, especially looking at the Canadian north. Posted Wednesday at

  15. Hi Robert, One thing that’s been bugging me with rising sea levels even at just one metre many coal fired and nuclear power stations would be not to be able to function and closed down, that would mean for the coal fired stations that there will be no particulate emissions and of course that’s going to have an effect on global dimming. Has anyone done any calculations on that effect on our warming world

  16. jimmy

     /  July 15, 2015

    I’m very interested to understand how this will effect future food production. Flooding the coastal cities is one thing but flooding the coastal deltas of SE Asia will drastically impact rice production. I’ve heard it said that much of Vietnams rice growing is done within a meter of sea level. It is home to millions of people and grows rice for 100’s of millions of people. Long before the coastal cities become an issue I suspect we’ll see coastal rice production cease.

    • The flooding of wetlands/deltas combined with the drying of land interiors and the severe loss in ocean life support are a triple whammy to food production.

  17. James

     /  July 15, 2015

    Hi, my first time to post but I have been reading for a while. This is the best climate change site on the web in my opinion.
    For sea level rise, if you haven’t seen it, this is an interesting interactive map,63.1497&zoom=2

    • Thanks for the fantastic resource James. Welcome!

    • Steven Blaisdell

       /  July 15, 2015

      “…best climate change site on the web…”
      Yep. Keep hanging out here, James; Robert, et. al, are documenting and predicting, in irrefutable detail, the ongoing destruction of the planet as amenable to civilization as we know it. I personally think this blog needs to be on the front page of the NYT, above the fold.

      Off topic, but I’m wondering if it’s going to take the rest of the industrialized world uniting against US (right wing, corporatist/imperialist) intransigence and forcing (‘nudging’?) domestic change. So many variables, though, and a lot of them not good. We are the stupid, nearsighted bull raging through the china shop, oblivious to anything but puerile impulse gratification, seduced by our empire engendered collective narcissism, immune to adult reflection and restraint, saturated with the oxygen of gluttonous consumerism and grade school mythos of “exceptionalism” and moral purity. We are the morbidly obese, insatiable, ruinous child, gorged on our own ‘success,’ lost to the same inexorable fate that engulfs all unchecked life or society, in whatever form. We are, ultimately, as a culture very uncivilized primates, with the misfortune of relative isolation and essentially unfettered expansion. The only thing standing in our way is the Earth itself; she is and will continue to kick back, but it looks as though we might salt the planet in the process.

      • Kudos. To me you just channeled Ginsberg and Eliot forward to the modern day.

      • Greg

         /  July 15, 2015

        In an interview about his new climate change book about water scarcity in the Western U.S., called Water Knife, Bacigalupi said “I feel really bad that almost everything I do somehow screws up the environment and probably makes the future worse for my children, yet I keep doing those thing because they are so pleasurable.” Not Ginsberg or Eliot but about sums it up.

  18. Reblogged this on jpratt27.

  19. bill shockley

     /  July 15, 2015

    Bernie Sanders Could Be the Next FDR

    I would like to see Ventura/Stern with direct phone lines to Hansen/Chomsky but Bernie would be my second choice.

  20. Sea level rise will cause so much loss of infrastructure that it will bankrupt the economy. This is New Zealand.

    • We really need to get off fossil fuels yesterday if we want to have much hope of mitigating this. The continued burning locks in more harm, more sea level rise each year. So the question for me is, when do we decide to stop inflicting this pain? Even when just looking at the impact of sea level rise, and not the myriad other crises related to climate change, there is no proposition where continued burning of oil, gas, and coal comes anywhere close to producing an equivalent value to what we are certain to lose. That’s the madness here. The continued belief by many that economies rely on this junk. It’s economic, atmospheric, oceanic, and geological poison. And that’s what so many have put the highest value, the highest priority for investment on. Madness. Just plain unadulterated madness. Dr Strangelove of goop.

  21. Franklin & Marshall College
    Common Hour
    Jeremy Jackson: Ocean Apocalypse Now
    @27:10 in the video:
    “When the West Antartic Ice Sheet breaks, sea levels will rise by four metres in a couple of years”.

    • Mblanc

       /  July 16, 2015

      Interesting lecture, I like how he apologises repeatedly for being ‘depressing’. You can really see the scars of the climate wars on some of these scientists.

      I think it must be really hard to tell people in the US, that there are some things that only the Govt is equipped to do, given the history, and the prevailing power structures of the country.

      If the most powerful nation in the world has an intellectual aversion to recognising this ‘market failure’, then it’s maybe not surprising, that we are where we are.

      My sympathies to all those fighting for change in the US. I may be wrong, but I think it is the key battleground.

  22. Greg

     /  July 15, 2015

    2015 hurricane season off to a records setting start as of July 13th:

  23. Jeremy Jackson is not the most pessimistic of the speed of WAIS collapse.

    • bill shockley

       /  July 16, 2015

      Wow, 2008! The history of the science is fascinating. From 1968:

      “As far back as 1968, John Mercer had predicted that the collapse of ice shelves along the Antarctic Peninsula could herald the loss of the ice sheet in West Antarctica, and 10 years later contended that: “a major disaster — a rapid deglaciation of West Antarctica — may be in progress … within about 50 years.”

      People get ready!

    • Interesting 2008 study. Some evidence that we may be following along on that path.

      • bill shockley

         /  July 16, 2015

        Hansen was saying the same thing back then. But the data weren’t solid enough, statistically. They needed more years. Sadly…

        Did you see the thing in the Spratt article about the “Mercer Effect”?

        “(James Hansen says it was not clear at the time whether Mercer or his many critics were correct, but those who labelled Mercer an alarmist were considered more authoritative and better able to get funding. Hansen believes funding constraints can inhibit scientific criticisms of the status quo. As he wrote in New Scientist on 28 July 2007: ‘I believe there is pressure on scientists to be conservative.’ Hansen is responsible for coining the term ‘The John Mercer Effect’, meaning to play down your findings for fear of losing access to funding or of being considered alarmist.)”

        I wonder if we do the right thing whether we can actually slow down the collapse. My guess is not. If we get to 350ppm, that is only energy balance, and the heat will remain in the ocean and the doubling time will remain the same. Hansen doesn’t acknowledge this. I wonder sometimes if he is a bit of a denier?

  24. Aaron Lewis

     /  July 22, 2015

    As we look back on past sea level rises, we see temperature after all carbon feedback.
    Our modeled future temperatures from IPCC models do not include carbon feedback,
    Unless we can plug all the methane leaks in the sea floor, and put out all the wild fires in the Arctic, our future temperatures will be warmer than those modeled, and hence our sea level rise will be larger than expected.

    And, the IPCC calculates methane at a CO2 equivalent of 20 over a 100 year period. However, if we are looking at feedback on a year by year basis (as it occurs and affects us), then CH4 has a CO2 equivalent in the range of 80 to 100.

    Thus, a plume of CH4 drifting across the Arctic at a concentration of 4 ppm has the warming effect of 400 pm of CO2. Since 400 ppm of CO2 is already there, and the spectra do not fully overlap, the total warming is ~700 ppm CO2 equivalent. That is enough to help warm the surface of ice and allow some surface melt and reduce the albedo of the ice and get some water vapor in the air to jump start some real warming.

    Now, what is the concentration of CH4 in plumes rising out of the Arctic ? 40%?? That is 400,000 ppm. So, current CH4 plumes can be diluted 100,000 : 1, and sill push the local current CO2 equivalent concentration to 700 ppm (over small areas).

    As long as I am writing an alarmist tract, I would remind you that sun warmed melt water from Siberia, Alaska, and Canada flows down to float on the Arctic Ocean. As the ice melts and runs off, the tundra is more subject to wild fire removing the insulation that protects permafrost. And thus, sun warmed breezes from Siberia, Alaska, and Canada, now kiss Greenland.

    • If we stop human carbon emissions now, we are stuck with an Earth Systems feedback by 2100 equal to about 10 percent of that emission. Without significant land use changes and other methods that help to draw down more carbon, that feedback alone means we are probably already locked into changes that put us in the range of the Pliocene 2-3 million years ago.

      Getting to 450 ppm CO2 and 550 ppm CO2e over the next few decades makes this picture look rather worse. I’d prefer we don’t get there.

    • To this point, stopping human fossil fuel emissions soon brings us to 1.5 to 3 C warming this Century and 3-5 C warming long term. We can hit the lower range of this estimate if we move very fast.

      Failing to stop human fossil fuel emissions locks in 4-9 C warming this century and 8-18 C warming long term. There’s a drastic difference between these two futures that should be clear to anyone who’s been paying attention. One future is possibly survivable. The other is a completely unmanageable climate disaster worse than the Permian extinction due to its velocity alone. The choice, at this time, should be a no-brainer.


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