New study of Greenland under “more realistic forcings” concludes “collapse of the ice-sheet was found to occur between 400 and 560 ppm” of CO2

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"New study of Greenland under “more realistic forcings” concludes “collapse of the ice-sheet was found to occur between 400 and 560 ppm” of CO2"

A new study has lowered the carbon pollution threshold or “tipping point” for collapse of the Greenland ice sheet to 400 to 560 ppm.  We’re currently at about 390 parts per million atmospheric concentrations of CO2, rising about 2 ppm a year (and yes, total collapse would take a while).

Another new study documents the unexpectedly fast spread of ice loss into northwest Greenland (animation below).  And the Director of the International Polar Year [IPY] Program Office, Dr. David Carlson, told the Senate last year:

“A clear consensus has emerged during IPY that the Greenland Ice sheet will disappear as a consequence of this current global warming.”  Carlson added that a “very plausible outcome” was “a meter or more of sea level rise in this century from Greenland alone.”

So, as part of the Climate Science Project, I’ll review what scientists have learned recently about the accelerating mass loss of an ice sheet that by itself could raise sea levels over 20 feet.

A 2009 study by Velicogna of JPL using the GRACE (Gravity Recovery and Climate Experiment) satellite to “determine the ice mass-loss for the Greenland and Antarctic Ice Sheets during the period between April 2002 and February 2009″ concluded:

We find that during this time period the mass loss of the ice sheets is not a constant, but accelerating with time, i.e., that the GRACE observations are better represented by a quadratic trend than by a linear one, implying that the ice sheets contribution to sea level becomes larger with time. In Greenland, the mass loss increased from 137 Gt/yr in 2002-2003 to 286 Gt/yr in 2007-2009, i.e., an acceleration of ˆ’30 ± 11 Gt/yr2 in 2002-2009.

The figure above is from the study via Skeptical Science with the caption, “Ice mass changes for the Greenland ice sheet estimated from GRACE satellite measurements. Unfiltered data are blue crosses. Data filtered for the seasonal dependence are shown as red crosses. The best-fitting quadratic trend is shown as a green line.”

Also in 2009, the University of Alaska reported on a study in the journal Hydrological Processes (subs. req’d) that found “The Greenland ice sheet is melting faster” — and contributing to sea level rise more — than expected.

This research is consistent with data presented at the annual meeting of the American Geophysical Union in December 2008 (see “Two trillion tons of land ice lost since 2003, rate of Greenland summer ice loss triples 2007 record“).  This staggering ice loss is all the more worrisome because it was not predicted by the IPCC’s climate models. As Penn State climatologist Richard Alley said in March 2006, the ice sheets appear to be shrinking “100 years ahead of schedule.” In 2001, the IPCC thought that neither Greenland nor Antarctica would lose significant mass by 2100. They both already are.

And Nick Sundt just blogged on yet another new GRL study, “Spread of ice mass loss into northwest Greenland observed by GRACE and GPS” (subs. req’d).  The AGU press release reports :

“When we look at the monthly values from GRACE, the ice mass loss has been very dramatic along the northwest coast of Greenland,” says CU-Boulder physics professor and study co-author John Wahr….

“This is a phenomenon that was undocumented before this study,” Wahr says. “Our speculation is that some of the big glaciers in this region are sliding downhill faster and dumping more ice in the ocean.”

Above: The animation shows the spread of ice loss into northwest Greenland observed by NASA’s Gravity and Recovery Climate Experiment (GRACE) satellite system from 2003 through 2009. The shift in the color spectrum beginning with turquoise and ending in black over the seven-year time span shows the decreasing mass of ice relative to 2003. Courtesy John Wahr, University of Colorado.

Especially worrisome for North America is that a 2009 study in Geophysical Research Letters (subs. req’d, UCAR summary here) finds that sustained high rates of Greenland ice loss could lead to staggering increases in coastal sea level rise.  As reported:

If Greenland’s ice melts at moderate to high rates, ocean circulation by 2100 may shift and cause sea levels off the northeast coast of North America to rise by about 12 to 20 inches (about 30 to 50 centimeters) more than in other coastal areas. The research builds on recent reports that have found that sea level rise associated with global warming could adversely affect North America, and its findings suggest that the situation is more threatening than previously believed.

“If the Greenland melt continues to accelerate, we could see significant impacts this century on the northeast U.S. coast from the resulting sea level rise,” says NCAR scientist Aixue Hu, the lead author. “Major northeastern cities are directly in the path of the greatest rise.”

All that is needed for the 20 inches of extra sea level rise is if Greenland’s melt rate continues at its current rate through 2050.  And that is on top of new, much high projections for overall SLR (see “Sea levels may rise 3 times faster than IPCC estimated, could hit 6 feet by 2100“)

Another 2009 study in Nature using “high-resolution ICESat (Ice, Cloud and land Elevation Satellite) laser altimetry” found “Dynamic thinning of Greenland and Antarctic ice-sheet ocean margins is more sensitive, pervasive, enduring and important than previously realized.” The study noted that dynamic thinning is “ice loss as a result of accelerated flow,” which is something the IPCC basically ignored in its 2007 sea level rise projections (see here).

Back in 2004, the Arctic Climate Impact Assessment, warned “Models indicate that warming over Greenland is likely to be of a magnitude that would eventually lead to a virtually complete melting of the Greenland ice sheet, with a resulting sea-level rise of about seven meters (23 feet).”  And that was before we had better modeling of the high emissions path we are now on coupled with carbon-cycle feedbacks.

It is implausible that Greenland could survive sustained exposure to the warming we face if we stay anywhere near our current emissions path “” see “M.I.T. doubles its 2095 warming projection to 10°F “” with 866 ppm and Arctic warming of 20°F.”

Indeed, as John Cook of Skeptical Science notes, the last time global temperatures were just 1 to 2°C higher than today (with polar temps ~3-5 °C warmer) was 125,000 years ago.  A December 2009 Nature study of that time, “Probabilistic assessment of sea level during the last interglacial stage” (subs. req’d), concluded:

We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m….  The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming.

That is, sea levels were probably more than 26 feet (!) higher when it was as warm as most models suggest it will be by mid-century if we stay near our current emissions path.  Greenland and Antarctic ice sheets thus appear to be very sensitive to sustained warming.

Moreover, it seems likely that there is a “point of no return” or threshold beyond which collapse cannot be stopped because of dynamic feedbacks.  As a Geophysical Research Letters paper led by Kaser (subs. req’d) noted, the warming-driven melting is

reinforced by feedbacks among which the most important are probably the balance-altitude feedback (net melting lowers the glacier surface to warmer altitudes, increasing net loss) and the albedo feedback (more darker ice exposed at the surface promotes further melting).

So it is no surprise scientists are trying to figure out what that threshold might be.  The new study that attempts to do so is “The effect of more realistic forcings and boundary conditions on the modelled geometry and sensitivity of the Greenland ice-sheet,” in The Cryosphere, “An Interactive Open Access Journal of the European Geosciences Union” Cook has a nice summary:

This paper uses updated data on bedrock topography and ice thickness to produce more accurate modelling results of Greenland ice sheet behaviour. They model how the Greenland ice sheet will respond to three different scenarios with atmospheric CO2 held at 400 ppm, 560 ppm and 1120 ppm. The simulations are run over a 400 year period.Although not completely collapsed, the 400 ppm ice-sheet loses ice mass in the north of the island, with a total reduction in ice volume ranging between 20 to 41%. Note – due to the large inertia of the Greenland ice sheet, this mass loss doesn’t happen at the moment CO2 levels reach 400 ppm but over a period of centuries. Under a 560 ppm climate, the Greenland ice sheet loses between 52 to 87% of its ice volume. If CO2 reaches 1120 ppm, there is almost complete elimination of the Greenland ice sheet with loss between 85 to 92%. The important result from this paper is that there is a critical threshold where the Greenland ice sheet becomes unstable somewhere between 400 and 560 ppm.

This is a large uncertainty range and one imagines there will be much research in the next few years to reduce the uncertainty. However, the 400 to 560 ppm range is put into perspective when you look at the projected CO2 levels for the various IPCC scenarios. The business as usual scenario has CO2 levels reaching 1000 ppm by 2100. Even the most optimistic scenario tops 500 ppm by 2100.

Projected CO2 levels for various IPCC emission scenarios
Figure 3: Atmospheric CO2 concentrations as observed at Mauna Loa from 1958 to 2008 (black dashed line) and projected under the 6 IPCC emission scenarios (solid coloured lines). (IPCC Data Distribution Centre)

Of course, Figure 3 displays projected scenarios. What has been happening in the real world? Observed CO2 emissions in recent years have actually been tracking close to or above the worst case scenario.


Figure 4: Observed global CO2 emissions from fossil fuel burning and cement production compared with IPCC emissions scenarios. The coloured area covers all scenarios used to project climate change by the IPCC (Copenhagen Diagnosis).

Satellite measurements, paleoclimate data and ice sheet modelling all paint a consistent picture. Global warming is destabilising the Greenland ice sheet which is highly sensitive to sustained warmer temperatures. Our current trajectory with CO2 emissions will likely cause at least several metres sea level rise from the Greenland ice sheet over the next few centuries. Of course, we shouldn’t forget that this estimate doesn’t include Antarctica – the Antarctic ice sheet is also losing ice at an accelerating rate.

The time for action was quite some time ago, but now is still better than later!

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51 Responses to New study of Greenland under “more realistic forcings” concludes “collapse of the ice-sheet was found to occur between 400 and 560 ppm” of CO2

  1. Rahj Majendra says:

    So why didn’t Greenland collapse when CO2 hit 400 in 1942?

  2. Matt says:

    The Greenland ice-sheet certainly represents the “fat-tail” of sea-level rise. I’ve always wondered if there is an effort in the glaciology community to develop dynamic models (as in 4D mass, temperature, etc. like we use in the atmos. biz.) to simulate the behavior of ice sheets or if any newer studies use this. Most of the work I’ve seen (older) used very simple models or statistical inferences.

  3. paulm says:

    Any one want to buy a house near Miami?

  4. Democracy Center says:

    Here at the Democracy Center we are working hard to draw attention to the impact of climate change already happening in some of the most vulnerable parts of the world. We’ve recently produced:

    A a video on Bolivia’s melting glaciers (http://democracyctr.org/blog/2009/12/visit-to-cemetery-of-glaciers.html)

    A new article in Yes! Magazine (http://www.yesmagazine.org/planet/as-glaciers-melt-bolivia-fights-for-the-good-life).

    We are also getting ready to report on the upcoming World People’s Conference on Climate Change and the Rights of Mother Earth (http://democracyctr.org/blog/2010/03/global-climate-change-conference-coming.html), an alternative response to failures of Copenhagen.

    Keep your eyes out for our coverage!
    (www.democracyctr.org)

  5. Chris Dudley says:

    Seems to me that a sigmoid of the form 1-1/(1+e^-t) or 1-erf(t) would be more realistic curves to fit since presumably there was no recent buildup of ice in the past to justify the implied rising part of the quadratic.

  6. caerbannog says:


    So why didn’t Greenland collapse when CO2 hit 400 in 1942?

    CO2 levels were nowhere near 400 ppm in 1942.

    To melt/collapse a significant portion of the Greenland ice-sheet, CO2 levels will have to go over 400 ppm *and stay at that level or higher* for a few centuries, which is exactly on track to happen.

  7. Joe says:

    The interesting question is how fast could it melt if we go to the 866 ppm and 20F Arctic warming?

  8. Leif says:

    A point about sea level rise not appreciated by most is that low pressure systems lift water as well, (soda straw effect). We are all aware of the storm serge of a hurricane but that tends to come and go quite fast. Traumatic in its own right, but think about this for a moment. The “Frankenstorm” that we had parked off the West Coast last January with record low pressure and expanse raised the water level ~2 feet above predicted for almost two days. Fortunately it was a 1/4 Lunar cycle and maximum high water did not exceed normal full/new moon tides. If these “mega” systems become more prolific, and my reading is that they will, the odds of an extra two feet of water at a big Lunar cycle are greatly enhanced. This system raised the water level for the most of the west coast buy the buy. Need I do the math for you. Two feet is now four feet, 4 feet is now 6 feet. Even a week later on the January “Frankinstorm” the 12 feet normal high tide for this area, water which is already lapping at the steps of many, is now 14 feet. Clearly a problem.

  9. Leif says:

    Rahj Majendra, #1: A quick GOOGLE search produced this tidbit. FYI you can do this too.
    “The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland,” said the paper’s lead author, Aradhna Tripati, a UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences.

    The earth is responding as fast as it can.

    I hope that you are learning as fast as you can.

  10. paulw says:

    Most CO2 estimates in the paleoclimate show there has been little change for the past 23 million years (280 ppm – 185 ppm at the height of the ice ages).

    Greenland didn’t start glaciating over until about 8 million years and it wasn’t more than 50% glaciated until about 2.5 million years ago.

    In the last Eemian interglacial, 125,000 years ago, temperatures around Greenland were probably about 4C to 5C higher than today and the southern third of Greenland’s glaciers melted. CO2 levels – 285 ppm.

    Greenland’s glaciation history does not indicate a particular CO2 level will lead to glacial melt.

  11. Lewis Cleverdon says:

    The persistence of a rather comforting delusion observable in many scenario studies, including one of the above, is rather puzzling.
    It is the idea that, rather than CO2 ppmv peaking at some value and then being reduced, it could somehow be ‘stabilized’ at some level higher than the present ~390. (Viz. : 400, 560, or 1,100 ppm for 400 years . . .).

    Given that the study itself concerns the exponential growth of one of a diverse range of feedbacks, various of which are accelerating significantly at just 390 ppm, the idea that a higher concencentration would could allow a stable plateau at a higher level is at best misleading.

    It is perhaps worth noting that the peat-decay CO2 feedback, that is driven by elevated CO2 affecting peat’s microbial ecology, would yield an output equal to the entire 2003 anthro-CO2 output by around 2064 under a moderate BAU scenario. (See Dr Foreman’s report in Nature, (subs.req’d) or google New Scientist peat bog).

    This convenient notion of ‘stabilizing’ GHGs at some level is patently unhelpful – it does not reflect reality – both for politicians’ mindsets and for science itself. For example, the same research of long-term change in Greenland’s Ice could be far more informative if it modelled scenarios assuming CO2 peaks & steady declines at, say, 420 x 2025, 450 x 2040, and 500 x 2080.

    Given that it is implausible that scientists are blithely assuming that some notional high precision geo-engineering would provide that stabilization, can anyone say why the patent nonsense of ‘stabilizing airborne CO2′ has persisted so long ?

    Regards,

    Lewis

  12. mike roddy says:

    Lewis, #11:

    You raised an important point. Human emissions have destabilized our climate, just as biological sinks (especially on land) are becoming more degraded. The paradigm of stopping the annual 2 ppm march upward and then holding steady for a while does not correspond with our knowledge of geochemistry, where disequilibriums create new dynamics.

    As you know, it’s not just peat, it’s methane, too. Hansen and McKibben’s goal of getting back to 350 may sound like a dream, but it corresponds with the task that we actually have to accomplish.

  13. Ivy Bear says:

    So now what will Andy Revkin come up with to explain this? More high winds?

  14. Wit's End says:

    I am not a scientist but still it is obvious to me that we are careening towards runaway heating. We aren’t slowing down the release of greenhouse gases, oh no, they are ever increasing. The amplifying feedbacks have already begun – dying forests that release rather than absorb CO2 – melting ice and the albedo effect – methane, etc…

    Maybe, just maybe, if humankind turned all our efforts towards conservation, mitigation, and adaptation, we could avoid turning into a dead planet (Venus). Even that might not work but certainly – COME ON! – if we don’t go all out, we as a species are doomed.

    I think there is no other option than to try, as someone said, morally and ethically, but…why the pretense about where we are headed?

  15. Lou Grinzo says:

    mike(12):

    350 sounds more like utopia than a dream right now, I’d say.

    I’ve been saying for a long time that the steady drumbeat of “worse than we thought” news indicated not just that there was a persistent gap between what climate experts knew and what was really happening, but that we couldn’t be sure it wasn’t getting larger, i.e. that reality was accelerating quicker than our knowledge. We still don’t know, but this news from Greenland sure isn’t comforting.

    I think we need to see a conference called between government leaders and scientists, and let the latter tell the former what they need in terms of resources–satellites, boots on the ground, remote sensors, whatever–to close that knowledge gap ASAP. And then the leaders need to pony up whatever it will cost to do it.

  16. Fredo says:

    I used to spend lots of time every day reading this blog and these comments. Not so much anymore. For the last week I set my homepage to a search results page for “global warming.”

    Now, when I want to procrastinate, instead of reading every word of this blog while biting my nails, I just click on whatever inane, badly-reported, denier-fueled news story tops the search results… and add a comment at the bottom.

    I’m even starting to compile a list of such comments for future cut-and-paste use.

    See me in action on this new US News feature putting Romm head-to-head with Inhofe.

    We need to get out there, people. We need to stop talking to each other and start taking to all the confused people out there who know so much less about this than all of us do already.

    Romm himself has blogged (repeatedly) that repetition is the key to messaging. Right now, we are not repeating ourselves nearly enough… which is why the deniers are beating the pants off us.

    This issue is an existential threat to big polluters, and they are responding with an all-out assault on the epistemological foundations of our society… from the traditional media to the Internet to our children’s textbooks.

    But what most readers here know is that this is also an existential threat to HUMANITY. When you have two existential threats head-to-head what you get is all-out war, and it is a war we cannot afford to lose. We cannot afford to be passive readers, or isolated researchers and technocrats any longer. We must all dedicate a little time EVERY DAY to being WARRIORS for the generations to come. Get out there and spread the TRUTH!

  17. Jim Eager says:

    Re Rahj Majendra @1: “when CO2 hit 400 in 1942″

    Repeating Herr Instructor Beck’s nonsense will not win you much respect here.

  18. Ivy Bear says:

    Lou:
    I don’t think we need any more information to act. So while I certainly support more scientific research, the facts are clear – act now, act fast, and act like your life depends on it – which it does! The long lead times to change infrastructure, build the alternative energy systems, stop deforestation, and enact energy efficiency measures across a global economy demand that we start acting now if we want to have any hope of staying below 4 degrees C. We are already committed to 2.4 degrees C, which is well into the area of dangerous anthropogenic climate disruption. Seems to me the only thing we can try to prevent now is catastrophic anthropogenic interference with the climate system.

  19. paulm says:

    That should have been a negative carbon economy.

  20. From Peru says:

    Greenland is ALREADY suffering accellerated melting.

    The terrifying graph and animated map above doesn’t show that the collapse is already happening, so that the “critical CO2 concentration” was passed rougly a decade ago?

  21. European says:

    Yes! More global warming! Unfortunately we people can’t do anything else but watch. We don’t have the means to increase it.

    Oh, was the warming a problem? I don’t think so. I really don’t want a kilometer thick glacier here where I live. And africans wouldn’t like the increased droughts, either. Simple arithmetic: More water locked in larger glaciers means less water everywhere else.

  22. Laffer says:

    European #20 – LOL – hope you live on high ground

  23. Wonhyo says:

    JR: I like your new tagline: “The time for action was quite some time ago, but now is still better than later!”. I suggest a slight change: “The time for action started quite some time ago…”. They say the first stage of recovery from emotional trauma is acknowledgement. I think it is healthy to acknowledge that even if we do everything possible (which we are not likely to do), we will probably not prevent catastrophic, long-term (1000 years long-term) climate change. However, it is still worthwhile to do everything we can, as soon as we can, to minimize the rate and severity of the change. The slower the change comes, the more time we will have to adapt to it, so now is certainly better than later!

    Democracy Center (#4): Too many people, even among those who understand climate change, continue talking as if it hasn’t already started. It’s great that your org is highlighting what is already happening. Acknowledging what’s already happening is an important step toward an effective response.

    Lewis Cleverdon (#11): I agree that there is currently no scientific justification for the assumption that we can hold the CO2 concentration steady at some value above 300 ppm (the 800,000 year pre-industrial upper limit). However, we haven’t proven it to be impossible, either. If we can restore natural carbon sinks fast enough, perhaps we can counterbalance the feedback cycles of CO2 (and methane) emissions with newly-restored carbon sinks through activities such as reforestation. I’m interested in how much CO2 sink potential there is in reforestation, how quickly we can do it, and how effective it might be at “stabilizing” the CO2 concentration. Simply reducing emissions will not be enough to stabilize CO2. We have to aim for net negative emissions to counter positive feedbacks.

    Fredo (#16): You’re right. The problem is, progressives (including those who support climate action) are generally wimps compared to the Ridiculous Right. Progressives need to promote their (just) causes as aggressively as the Ridiculous Right promotes their (destructive) ones. What I’m seeing is that a small minority in the Ridiculous Right is being very vocal and getting a majority of the attention, while progressives are being mice. We should aggressively educate those in the middle who are not beholden to the Ridiculous Right, but have not woken up to reality.

  24. European says:

    Seriously this time. Why worry about global warming? We live now in the middle of an Ice Age, near the cold end of the world’s temperature scale. It would be only natural for the climate to get a bit warmer than today. It has been much warmer, and the nature flourished.

    I ask you again: Why would it be so bad? 10 meter rise of the sea level? Well, I maybe need to move a few kilometers inland, maybe I just get a seaside view. So?

    What I read in [Stephen Oppenheimer: Out of Eden], Sahara desert has been at its largest DURING the coldest glaciation periods, absent during warm periods. Once again, why would losing deserts be so bad? Do you guys really want glaciers and deserts everywhere?

  25. shpilk says:

    Not accounted for in the total GHG budget is methane.

    Methane is normally a bit GHG player, but methane will become an increasing influence as more is released and the upper atmosphere saturates. The process methane’s breakdown in the upper atmosphere is fixed, it cannot be increased as solar radiation itself is part of the process. This effective lengthening in the ‘half’life’ of methane as a GHG, as well as increase the GHG effect by higher concentration of it are going to jack up the total GHG load even higher than just CO2 projections show.

    Large amounts of methane generation is potentially present in the land exposed as glaciers melt and bacteria become active, it’s present even in the glacial ice and methanogenic bacteria become activated as glaciers melt, and of course in huge deposits as clathrates on the ocean floor.

    Tipping point?

    We’re already way past it. There’s no stopping this process now; all we can hope to do is mitigate the worst effects, maybe slow it down.

  26. jyyh says:

    “The requirement of some people to have the 95% certainty of the AGW has forced scientists to use linear equations on quadratic, exponential and logarithmic natural phenomena as the certainty in statistical treatment of complex natural systems is best achieved this way. Though the relative CO2-effect on radiative equilibrium diminishes with increasing consentrations, this addition may start the positive feedback events, whatever they were, that produced the PETM, with all it’s consequences like completely de-iced planet with ocean levels at +70-85m of current levels and 50% (citation needed) loss of ocean and terrestrial life.”

    I’ll try to go back to history issues on my blog, this is almost too depressing.

  27. substanti8 says:

    Fredo, that’s one of the best comments that I’ve ever read about this quandary.  I strongly agree with your conclusion that this is a war.  I think it will unfortunately turn violent before it’s over.  (I won’t go into detail because it might give ideas to the unimaginative and unstable.)

    Denial of science is the inevitable result of the ideology of modern industrialism – with its central tenet that the mind of man can always overcome nature.  In other words, there are NO LIMITS.

    Now comes a scientific theory with a robust conclusion that humanity must change its behavior to conform to limits.  This is heresy to capitalism, and its proponents will fight this like a holy war.

  28. European says:

    Fredo, You’re not warriors, you’re all fools. Fighting windmills.

    The climate is too big a foe to you.

    And, moreover, why the hell would you want the glaciers covering europe and canada and half of the US again?

  29. substanti8 says:

    In response to the European troll and his wishful thinking, I would only note that Jiminy Cricket is the patron saint of endless growth and climate denial.

  30. Steve Bloom says:

    European, there’s nothing intrinisically better or worse about a warmer or colder planet. The problem is the transition.

    You mention that the Sahara will likely get wetter, but the problem is that as it does so the Mediterranean region will get drier; both are a consequence of the poleward shift of the subtropics driven by the expansion of the tropics (already underway globally, and note that more water vapor does *not* equal fewer deserts). Losing the coastlines will not only have obvious bad implications for much of our existing infrastructure, but if it happens quickly enough will wipe out estuary productivity for probably centuries. And let’s not forget ocean acidification. I’ll stop there, but I could list dozens of other examples.

    If we like our current climate, all we need to do is keep CO2 in the 280-300 ppm range (the interglacial average). Doing so is entirely within our ability.

  31. Heraclitus says:

    Fredo – spot on. We need to be pushing these conversations, not just on blogs, where we have so little control over the course of the debate and frustration is almost unberable (but I’m going to keep doing it anyway), but in everyday lives with people we meet and pass day in day out. We all avoid those difficult discussions, because it’s easier not to rock the boat. We need to stop avoiding them. We need to force this issue because it’s too late for nicities.

  32. PSU Grad says:

    While I agree with the need to have these conversations, everyone seems to be missing something. The views of the “Ridiculous Right” are put forward through CORPORATE interests. Do you really think those racist, gay baiting (see this weekend’s videos) “Tea Party” protesters just sort of got together on their own? No, they were gathered together by Freedom Works, led by the cowardly Dick Armey. Freedom Works is awash in corporate money.

    Similarly, some of the local “Tea Party” gatherings have been sponsored by far right wing radio stations, often owned by Clear Channel Communications. These are NOT spontaneous “grass roots” gatherings, and don’t let anyone tell you otherwise. It just ain’t so.

    How hard is getting the message out? I recently sat at a red light and carefully looked at the vehicles moving on the cross street. About half were large SUVs. Some of the drivers were on cellphones. Do you think, for one minute, these people will respond to a message on climate change by giving any of that up? Really? The answer is no. Not until they see something that affects THEM. If it doesn’t affect THEM, it’s someone else’s problem.

    I don’t think that’s being defeatist, I think it’s being real. However, there are some things we can do. When a far right wing think tank says that a snowstorm or one week of cold weather “disproves” global warming, perhaps a call to a local newspaper editor is in order asking why nobody has interviewed anyone from this same think tank about the much longer streak of very mild weather we’ve just had (virtually every day in March has had above average temperatures in our area).

    I’m sorry, it’s going to take a slow, long slog through the muck. Ultimately, however, people will have to see an impact on their lives. Until that happens, it’s easy to dismiss it as someone else’s problem.

  33. Heraclitus says:

    PSU Grad, I agree with what you say but I think there is a large proportion of the population (perhaps more here in the UK than the US) who basically accept the science and are concerned but not enough to actually make difficult changes in their lives. It’s just too easy at the moment to keep on living life and we need to start chipping away at those who are amenable to the message, making it less easy for them to keep ignoring it. As these come on board then the momentum will build and those further down the line will start having pressure put on them. I’m not convinced that it is as concerted by corporate interests as some think, I’d say it is more to do with inertia.

    At the moment the debate is being swamped by denialism and this makes it too easy for the average person to disengage. We do need to improve the balance particularly on ‘neutral’ sites like the newspapers’. I think that means being more supportive of others who are already posting – it’s a sordid and draining business.

  34. Brooks Bridges says:

    Heraclitus(33): I agree.

    Along with letters to the editor and other mass approaches I think we should each be trying to motivate people close to us. So, walking my talk I brought up my AGW concerns with two very liberal/progressive friends. I found it difficult to do this – my nature.

    They said basically “Oh yeah. We understand it’s very serious. But you’re not going to get people to freeze in the dark and give up their cars to prevent it so we’re screwed.” They haven’t brought up the subject since. Note how the Right has gotten their message across to two supposedly liberal progressives.

    This caused me to rethink my approach for similar attempts for one on one situations(will be an ongoing process):

    1) Using Stephen Covey’s 3’rd (?) habit: First try to understand, then to be understood. By first genuinely listening to them and asking question you defuse defenses. Then they’re more likely to listen to your responses (hopefully correcting their ignorance of crucial facts, e.g., we don’t HAVE to freeze in the dark to make major improvements.

    2) If they agree it’s a problem but lack motivation then at some point asking them: In 10 or 15 years, imagine one of your children/grandchildren asking you what you did to prevent the catastrophes they see all around them, what will you be able to say? (What did you do in the war daddy?)

    3) Have some concrete actions they can take and get them to agree to let you keep giving them things to do.

  35. Heraclitus says:

    I like your three steps there Brooks. Quite a few of the conversations I’ve had have gone a similar way – amazing how many people seem already to have accepted that humanity’s doomed, and have believed this for most of their lives. Even more amazing how many of these same people worry about their pensions, the state of society and the suffering of people in distant countries, yet can be blase’ about the consequences of climate change. On the otherhand I’ve also had conversation where people have admitted that they’d never really thought about it or were grateful to have been reminded of the urgency.

    I’m setting myself a goal of five conversations a week that I wouldn’t have otherwise.

  36. Leif says:

    European, #28: “The climate is too big a foe to you.”

    In my view the “climate” is NOT the foe, the climate is a manifestation of the ignorance of the incomplete world view of capitalism and corporate philosophy. Trying to mitigate climate change without addressing the fact that there is NO mandate for capitalism and corporations to endorse the long term survivability of humanity in capitalist/corporate decisions is hopeless. Convince, or mandate C/C to work in common with humanities long term survivability… I believe we might surprise ourselves.

  37. sasparilla says:

    Just to respond to #1 regarding the CO2 level in 1942 nonsense.

    Ice Cores taken from Antartica indicate CO2 levels around 310 ppm during the first half of the 1940’s with little variation. That was ~ 80ppm ago since we’re around 389ppm today.

  38. Leif says:

    Like wise, the fight against global climatic disruption is not a all out war with capitalism and corporate business. On the contrary, both could prosper beyond their wildest expectations in a WW III approach to humanities long term survivability. (i.e. WW II) Humanity needs, nay requires, the success of both to have a chance in hell of success. However, C/C must acknowledge humanities rights to long term survivability. Humanity cannot survive without C/C but C/C cannot survive without HUMANITY.
    Define the problem, solutions follow…

  39. umop episdn says:

    PSU Grad has it exactly right. Huge amounts of money are being made doing things the way they have always been done, so very large amounts of money will be spent to keep doing these things. On one side, you have all this money, which never sleeps and cannot be reasoned with. Don’t wear yourselves out trying. People who are paid to troll websites like this will continue to do so, for as long as the money comes in.

    What can you do? Convince people you know that things are serious, and that Business As Usual will likely increase human suffering. Make the trolls look ridiculous whenever possible-that’s a pretty effective way of ‘neutering’ them. But most of all, *do not* support BAU. Spend as little of your money and time as you can get away with. Money is the most effective way to vote in this crazy consumer culture, so don’t vote for things you fear and hate. Try to have fun living a low-impact lifestyle. Perhaps others will follow your good example.

  40. Jim Eager says:

    Re European @28: “why the hell would you want the glaciers covering europe and canada and half of the US again?”

    Argue by straw man often do you?

    (That is, to set up a nonsense argument to knock down.)

    The Milankovitch orbital insolation forcing is well known and has been calculated: the next chance for the formation of a glacial stade won’t come round for as much as 40,000 years. Next?

    European: “It has been much warmer, and the nature flourished.”

    But humans haven’t, nor have any of the plants that they have domesticated for agriculture.

    Atmospheric CO2 levels are presently higher than at any time in at least the last 3 million years, perhaps the last 15-20 million years. That is not only before Earth’s climate cooled enough for the current glacial-interglacial cycle to begin, it’s before the species Homo sapiens, Homo erectus and Homo habilis evolved. Humans have never experienced the climate that we are creating.

    European: “Why would it be so bad? 10 meter rise of the sea level? Well, I maybe need to move a few kilometers inland, maybe I just get a seaside view. So?”

    In other words, I’ll be alright, Jack.

    How nice for you. Too bad for the citizens of Bangladesh, Burma, Vietnam, Cambodia, etc who will have to move hundreds of kilometers with a 10 meter sea level rise. The question is to where? India? Remember how well that partition went?

    Never mind resettling several million refugees, how do you propose to replace the rice currently grown in the Brahmaputra, Irrawaddy, and Mekong deltas?

    And as Steve Bloom pointed out, the Sahara won’t actually get wetter, it will just move northward to encompass the north shore of the Mediterranean and southern Europe proper.

    Your ignorance and cavalier lack of concern for your fellow human beings is so touching.

    You are intellectually and morally bankrupt.

  41. john atcheson says:

    Well, if we do the math – at 2ppm per year — we reach the point of irrevocability in 5 years.

    This central fact must animate all discussions about energy and climate policy and the Senate bill.

    We are well past the time when phrases like “don’t let the perfect be the enemy of the good,” or “politics is the art of the possible” have any place in rational discourse.

    The only rational response to where we are is to demand the perfect and work toward the seemingly impossible.

    Unrealistic? Probably. The only thing more unrealistic would be settling for a “start” that dooms us to a world in which Katrina is the baseline condition for virtually all coastal cities, and annihilation is inevitable fate for most islands and low-lying coastal regions.

  42. James Newberry says:

    The concept that Earth is responding to 390 ppm is fraud. The earth is responding to total radiative forcing, which is represented by the Equivalent PPM figure of approximately 440 and rising. That is why we are on the edge of the greatest disaster in recorded history. (Approx. eight million cubic miles of present land-ice is equivalent to some 250 feet of sea level rise.)

  43. Aaron Lewis says:

    Nothing in the post, and only one comment address ice dynamics. Big ice tends to melt slowly, even when floating in sea water. However, it can move down hill in a hurry. That is ice dynamics.

    I do not worry much about ice melt. That would be a bother, but we could deal with it by abandoning some infrastructure, such as our major cities, over the course of a few hundred years.

    We now have moist air flowing over Greenland, and that suggests large amounts of melt water available to flush significant amounts of ice into the sea in Lake Missoula like events. This mechanical erosion of ice by water would be much faster than any kind of in-situ melting as assumed by references cited in the post. As for calculations of limited ice flows resulting from channel size limitations, the Lake Missoula outflows formed 100 meter deep “pot holes” in basalt in a matter of hours. Thus, it is likely that similar erosion processes could remodel the outflow channels on Greenland to meet the flow’s needs.

    Ice dynamics in the context of warmer oceans adjacent to ice sheets http://www.osdpd.noaa.gov/data/sst/anomaly/2010/anomnight.3.22.2010.gif , suggests scenarios where it would be very difficult to replace abandoned infrastructure as fast as the sea level could rise. It is time to honestly consider ice dynamics.

  44. another alum says:

    why would we want to stabilize CO2 at any 420 ppm or some such level? There is a significant cost to going from current emissions path to carbon neutrality given current technologies and current demands for GDP growth in the LDC’s. But the additional costs to go from carbon neutral, to slightly carbon negative, should not be nearly as large. Esp with additional techs and lower implementation costs in 2050, and with higher GDP per capita globally meaning less pressure for growth, it should be possible to go more carbon neg more rapidly, I would think.

  45. Leif says:

    I want to see the cost of sustainable energy pegged to the cost of all social services, from schools to defense and health care. But only after humanity has “point of use” production, which should be humanities goal anyway. At that point produce more energy than you use and you have a cash cow in your yard. There would be no more taxes or health insurance or water and sewer bills. The “rat race” would be cut in half or more. No more unemployment. Use more energy than you produce and you are a benefit to humanity, not a carbon stomper leaving a legacy of toxic waste for the taxpayer to mitigate.

  46. From Peru says:

    Given current acceleration of Greenland meltdown, it seems that COLLAPSE OF GREENLAND ICE SHEET HAS ALREADY BEGUN

  47. Peer G. Dudda says:

    @Peru in 46: Considering that southern Greenland was near or above freezing for most of January, the ice cover there has continued retreating right through this past winter. How’s that for a scary thought?

  48. This central fact must animate all discussions about energy and climate policy and the Senate bill.

    We are well past the time when phrases like “don’t let the perfect be the enemy of the good,” or “politics is the art of the possible” have any place in rational discourse.

  49. Lewis Cleverdon says:

    Wonhyo – with regard to your response –
    Quote :
    “If we can restore natural carbon sinks fast enough, perhaps we can counterbalance the feedback cycles of CO2 (and methane) emissions with newly-restored carbon sinks through activities such as reforestation. I’m interested in how much CO2 sink potential there is in reforestation, how quickly we can do it, and how effective it might be at “stabilizing” the CO2 concentration. Simply reducing emissions will not be enough to stabilize CO2. We have to aim for net negative emissions to counter positive feedbacks.”

    We could do better than to restore forest carbon sinks, if the proposals to irrigate and reforest desserts were to be enacted. But the sheer scale of the task even without them implies probably two decades for planting, with a further decade or two of growth for substantial annual carbon recovery to be achieved.
    As to the overall potential for GTC/yr sequestered, the eminent soil scientist Dr Lehmann was speaking of 5 to 9 GTC/yr from forestry & farm wastes via biochar, while the deserts scenario proposes a further 8 to 13 GCT/yr. (I know nothing about the integrity of the latter).

    To put this in perspective, we add about 4 to 6 GTC/yr to the atmosphere, while the sinks remove a further 2 to 3 GTC/yr of our output. (Very rough numbers reflect large inter-annual variations).
    Given a very rapid end to anthro-carbon outputs, and given Lehmann’s upper out-take figure via biochar, and given the continuation of say 3GTC/yr going to natural sinks, a total of 12 GTC/yr could be cut from the atmosphere, implying a cut of around 4 ppmv/yr of CO2 – Then, given sufficient Albido Enhancement capacity to halt further warming-driven feedbacks’ CO2 outputs in the interim, and given the gigahectare of new forest-biochar sinks becoming effective by, say, by 2040 at the earliest, this best case scenario might restore 280 ppmv around 30 years after that, which implies a feasible date of 2070.

    None of the various listed benign factors needed for this would be easily provided; all would reflect a new confidence in international co-operation reflecting prior diplomatic success in negotiating a global climate treaty, under which all nations’ GHG output-rights will converge to per capita parity by an agreed date. (The seminal test of nations’ acknowledgement of equity in rights of resource usage).

    Nor would the time lags between planting and sequestration allow any prospect of steering the latter to provide stabilization of CO2 at a significantly elevated level. In this context it is worth noting that the Peat-Decay feedback was first observed in peat-sourced watercourses worldwide in the early ’60s, with CO2 at around a mere 315 ppmv. (Note ‘first observed,’ not ‘first initiated’).

    Given that we’ve not so much a mountain to climb as a whole mountain range to get to know intimately, I’d say we’d be doing pretty well to get back to 280 ppmv in this century. Definitely better later than never !

    Regards,

    Lewis

  50. John McCormick says:

    James Newberry thanks for reminding us again this is not only about CO2 emissions and accumulation.

    We have wasted four decades focusing, talking, making policy decisions on CO2 emissions while ignoring the other climate forcing gases. You are on point. WE have perpetuated the fraud you mention.

    When are we going to wake up and realize a 400 ppm tipping point has come and the 450 ppm fatal blow will soon be upon us. When will AGW believers start factoring in the CO2 equivalents into our view of the real climate world?

    Joe, you are aware of CO2 eqs but you don’t make it clear that we all must be.

    AS you said James:

    “The concept that Earth is responding to 390 ppm is fraud. The earth is responding to total radiative forcing, which is represented by the Equivalent PPM figure of approximately 440 and rising.”

    Say it again and often. Maybe we will stop referring to the 390 ppm of CO2 concentration as if that was our safe spot and not 400 ppm … our danger zone.

    We can fool ourselves but the earth’s climate knows better.

    John McCormick

    [JR: I take the same basic convention as Hansen in focusing on CO2. Yes, one needs aggressive policies for methane and black carbon and other forcings, but they are all really a piece of cake compared to CO2.]

  51. PatrickW says:

    Coal seems intransigent but big oil was heavily invested in future renewable technologies like wind, solar etc. but when givernments reniged on placing a fee or tax on carbon big oil reduced their commitments. The obvious solution is we must be prepared to accept at leasg $50 a ton on GHGs. As soon as investors can make more money on renewables than fossil fuels the low carbon economy will grow exponentially. That will leave the problem of removing existing GHGs. One study suggests that it takes at least 100 years for todays CO2 to make its way to outer space. This earth was very favourable to present life forms at around 300ppm. Let’s at least aim to get it back under 400ppm. It’s going to cost us more than $50 per ton if we don’t do it!