James Hansen has often been out ahead of his scientific colleagues.
With his 1988 congressional testimony, the then-NASA scientist is credited with putting the global warming issue on the map by saying that a warming trend had already begun. “It is time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here,” Hansen famously testified.
Now Hansen — who retired in 2013 from his NASA post, and is currently an adjunct professor at Columbia University’s Earth Institute — is publishing what he says may be his most important paper. Along with 16 other researchers — including leading experts on the Greenland and Antarctic ice sheets — he has authored a lengthy study outlining an scenario of potentially rapid sea level rise combined with more intense storm systems.
It’s an alarming picture of where the planet could be headed — and hard to ignore, given its author. But it may also meet with considerable skepticism in the broader scientific community, given that its scenarios of sea level rise occur more rapidly than those ratified by the United Nations’ Intergovernmental Panel on Climate Change in its latest assessment of the state of climate science, published in 2013.
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In the new study, Hansen and his colleagues suggest that the “doubling time” for ice loss from West Antarctica — the time period over which the amount of loss could double — could be as short as 10 years. In other words, a non-linear process could be at work, triggering major sea level rise in a time frame of 50 to 200 years. By contrast, Hansen and colleagues note, the IPCC assumed more of a linear process, suggesting only around 1 meter of sea level rise, at most, by 2100.
Here, a clip from our extended interview with Eric Rignot in December of 2014. Rignot is one of the co-authors of the new study.
The study—written by James Hansen, NASA’s former lead climate scientist, and 16 co-authors, many of whom are considered among the top in their fields—concludes that glaciers in Greenland and Antarctica will melt 10 times faster than previous consensus estimates, resulting in sea level rise of at least 10 feet in as little as 50 years. The study, which has not yet been peer reviewed, brings new importance to a feedback loop in the ocean near Antarctica that results in cooler freshwater from melting glaciers forcing warmer, saltier water underneath the ice sheets, speeding up the melting rate. Hansen, who is known for being alarmist and also right, acknowledges that his study implies change far beyond previous consensus estimates. In a conference call with reporters, he said he hoped the new findings would be “substantially more persuasive than anything previously published.” I certainly find them to be.
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We conclude that continued high emissions will make multi-meter sea level rise practically unavoidable and likely to occur this century. Social disruption and economic consequences of such large sea level rise could be devastating. It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilization.
The science of ice melt rates is advancing so fast, scientists have generally been reluctant to put a number to what is essentially an unpredictable, non-linear response of ice sheets to a steadily warming ocean. With Hansen’s new study, that changes in a dramatic way. One of the study’s co-authors is Eric Rignot, whose own study last year found that glacial melt from West Antarctica now appears to be “unstoppable.” Chris Mooney, writing for Mother Jones, called that study a “holy shit” moment for the climate.
New climate science brings good news as well as bad. Humanity can limit temperature rise to 1.5 degrees C if it so chooses, according to a little-noticed study by experts at the Potsdam Institute for Climate Impacts (now perhaps the world’s foremost climate research center) and the International Institute for Applied Systems Analysis published in Nature Climate Change in May.
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“Actions for returning global warming to below 1.5 degrees Celsius by 2100 are in many ways similar to those limiting warming to below 2 degrees Celsius,” said Joeri Rogelj, a lead author of the study. “However … emission reductions need to scale up swiftly in the next decades.” And there’s a significant catch: Even this relatively optimistic study concludes that it’s too late to prevent global temperature rising by 2 degrees C. But this overshoot of the 2 C target can be made temporary, the study argues; the total increase can be brought back down to 1.5 C later in the century.
Besides the faster emissions reductions Rogelj referenced, two additional tools are essential, the study outlines. Energy efficiency—shifting to less wasteful lighting, appliances, vehicles, building materials and the like—is already the cheapest, fastest way to reduce emissions. Improved efficiency has made great progress in recent years but will have to accelerate, especially in emerging economies such as China and India.
Also necessary will be breakthroughs in so-called “carbon negative” technologies. Call it the photosynthesis option: because plants inhale carbon dioxide and store it in their roots, stems, and leaves, one can remove carbon from the atmosphere by growing trees, planting cover crops, burying charred plant materials underground, and other kindred methods. In effect, carbon negative technologies can turn back the clock on global warming, making the aforementioned descent from the 2 C overshoot to the 1.5 C goal later in this century theoretically possible. Carbon-negative technologies thus far remain unproven at the scale needed, however; more research and deployment is required, according to the study.
Even if Hansen is, as you say, Peter, ‘alarmist’ (I disagree) it’s impossible to be both ‘alarmist’ and ‘right’.
‘Alarmism’ means ‘crying wolf’—shouting a warning about something that is not there, or real (that’s why ‘those in denial’ so favour it as an insulting description). But climate change is there for all who have eyes to see it: so while Hansen might be ‘alarmed’, he has none of the exaggeration or deception an alarmist uses. That’s why he’s right.
I don’t believe I’ve ever called Hansen an alarmist. I think he’s been on the money for quite a while, and deserves to be heard. He’s going to get pushback on this new paper because the message is so shocking – but there’s nothing out there to prove him wrong, and a lot of reason to be concerned he’s right.
It was the article from Slate that used the “alarmist but right…” statement.
I agree that that was inartfully worded. I would have said “Accused of being alarmist, but vindicated often as being right” or something to that effect.
The journal is Atmospheric Physics and Chemistry (APC), where Hansen has published or been a co-author of several previous studies. The article does not seem to be available yet on the APC website or through the bib services I use. As good as Peter’s piece is, I want to read the original. Did I just overlook it? Does anyone know the exact title?
It must be available somewhere since summaries are appearing. For example, Hertsgaard also produced a good summary on the Daily Beast.
I also looked for it. It’ll be released this week.
“Sixteen other scientists from the U.S., France, China and Germany contributed to the 66-page paper, which will appear in the journal Atmospheric Chemistry and Physics sometime this week.”
Given the paper is not yet ready for full viewing. We can hardly say it is alarmist or reasonable. The goal is clearly to attract attention, that does not make the science better than other studies, but can make it more valuable.
This report appears to have courted some criticism and controversy, perhaps because the peer review has not been performed, in the desire to have it published well before the Paris December Climate meeting. NASA have announced another paper to be published in “Geophysical Research Letters”, led by Eric Rignot of the University of California, Irvine (UCI), and NASA’s Jet Propulsion Laboratory, Pasadena, California, which has been peer reviewed, on a similar topic.
“Greenland’s undercut glaciers melting faster than thought”
What comes strongly across is that most experts agree that the IPCC estimates are very conservative.
NASA Link to the “Geophysical Research Letters”, report.
RTCC (Responding to Climate Change) article Jul 20th “Hansen: 2C warming will raise sea level several metres” on the Atmospheric Chemistry and Physics report:
“Asked why the study was not peer reviewed – a process by which scientists evaluate each other’s work – Hansen said that might have delayed publication until after December’s critical climate summit in Paris.”
Subdued report on the James Hansen work in the National Geographic July 21st:
“Prediction of Rapid Sea Level Rise Won’t Change Global Climate Talks”
“A bombshell climate study due out this week warns that sea levels may rise a catastrophic 10 feet (3 meters) by the end of this century, rather than the currently predicted 3 feet (.9 meters). But mainstream climate scientists say the report appears speculative and is not in sync with the leading understanding of melting sea ice.”
Another excellent piece in the AAAS science magazine on this Hansen led report, with interesting responses from Mann, Trenberth and others.
What strikes me is the fact that the paper predicts a lot faster melt, not the more linear mainstream assumption. The fact is whether the melt remains nearly linear or becomes increasingly exponential, the end result will be similar, just a hundred or so years in difference. Why is 2100 so important ?, a hundred years is just over a single generation, is two hundred, three hundred, four hundred years so much more unfathomable, beyond our responsibility and deserving of indifference ?.
Do we really have so much trouble thinking that far into our future (just a couple of generations)?. We have truly been blinded and shackled by the denial campaign created from vested interests. Like our attitude towards tobacco smoking, AGW denial is crumbling away very very fast and it’s time to see reality, without the constraints imposed by think tanks and spin doctors.
“Do we really have so much trouble thinking that far into our future?” – Yes; not scientifically, but politically and culturally. Remember the 20th Century, right up through the 1990s, when any date in the 21st was seen by the press and pop-culture as being in a far-distant sci-fi future? Getting any kind of popular consensus to plan for 2101 now – just ain’t gonna happen.
Reblogged this on gwn1943.
New “carbon negative” technologies? How about putting out coal mine fires first?
https://en.wikipedia.org/wiki/Centralia_mine_fire
Lot more carbon there.
Even if Hansen is, as you say, Peter, ‘alarmist’ (I disagree) it’s impossible to be both ‘alarmist’ and ‘right’.
‘Alarmism’ means ‘crying wolf’—shouting a warning about something that is not there, or real (that’s why ‘those in denial’ so favour it as an insulting description). But climate change is there for all who have eyes to see it: so while Hansen might be ‘alarmed’, he has none of the exaggeration or deception an alarmist uses. That’s why he’s right.
I don’t believe I’ve ever called Hansen an alarmist. I think he’s been on the money for quite a while, and deserves to be heard. He’s going to get pushback on this new paper because the message is so shocking – but there’s nothing out there to prove him wrong, and a lot of reason to be concerned he’s right.
It was the article from Slate that used the “alarmist but right…” statement.
I agree that that was inartfully worded. I would have said “Accused of being alarmist, but vindicated often as being right” or something to that effect.
Yes it was ‘Slate’, sorry Peter. So many indents I lost my place…
The journal is Atmospheric Physics and Chemistry (APC), where Hansen has published or been a co-author of several previous studies. The article does not seem to be available yet on the APC website or through the bib services I use. As good as Peter’s piece is, I want to read the original. Did I just overlook it? Does anyone know the exact title?
It must be available somewhere since summaries are appearing. For example, Hertsgaard also produced a good summary on the Daily Beast.
I also looked for it. It’ll be released this week.
“Sixteen other scientists from the U.S., France, China and Germany contributed to the 66-page paper, which will appear in the journal Atmospheric Chemistry and Physics sometime this week.”
http://insideclimatenews.org/news/21072015/new-study-says-even-2-degrees-warming-highly-dangerous
Hertsgaard’s summary is worth reading in full.
Given the paper is not yet ready for full viewing. We can hardly say it is alarmist or reasonable. The goal is clearly to attract attention, that does not make the science better than other studies, but can make it more valuable.
This report appears to have courted some criticism and controversy, perhaps because the peer review has not been performed, in the desire to have it published well before the Paris December Climate meeting. NASA have announced another paper to be published in “Geophysical Research Letters”, led by Eric Rignot of the University of California, Irvine (UCI), and NASA’s Jet Propulsion Laboratory, Pasadena, California, which has been peer reviewed, on a similar topic.
“Greenland’s undercut glaciers melting faster than thought”
What comes strongly across is that most experts agree that the IPCC estimates are very conservative.
NASA Link to the “Geophysical Research Letters”, report.
http://climate.nasa.gov/news/2312/
RTCC (Responding to Climate Change) article Jul 20th “Hansen: 2C warming will raise sea level several metres” on the Atmospheric Chemistry and Physics report:
“Asked why the study was not peer reviewed – a process by which scientists evaluate each other’s work – Hansen said that might have delayed publication until after December’s critical climate summit in Paris.”
http://www.rtcc.org/2015/07/20/hansen-2c-warming-will-raise-sea-level-several-metres/
Subdued report on the James Hansen work in the National Geographic July 21st:
“Prediction of Rapid Sea Level Rise Won’t Change Global Climate Talks”
“A bombshell climate study due out this week warns that sea levels may rise a catastrophic 10 feet (3 meters) by the end of this century, rather than the currently predicted 3 feet (.9 meters). But mainstream climate scientists say the report appears speculative and is not in sync with the leading understanding of melting sea ice.”
http://news.nationalgeographic.com/2015/07/150721-james-hansen-sea-level-rise-climate-change-global-warming-science/
When a few years ago, Dr Hansen went out on a limb and predicted five meters of SLR by 2100, he was out on that limb alone.
Seems he now has some prestigious company out there.
Another excellent piece in the AAAS science magazine on this Hansen led report, with interesting responses from Mann, Trenberth and others.
What strikes me is the fact that the paper predicts a lot faster melt, not the more linear mainstream assumption. The fact is whether the melt remains nearly linear or becomes increasingly exponential, the end result will be similar, just a hundred or so years in difference. Why is 2100 so important ?, a hundred years is just over a single generation, is two hundred, three hundred, four hundred years so much more unfathomable, beyond our responsibility and deserving of indifference ?.
Do we really have so much trouble thinking that far into our future (just a couple of generations)?. We have truly been blinded and shackled by the denial campaign created from vested interests. Like our attitude towards tobacco smoking, AGW denial is crumbling away very very fast and it’s time to see reality, without the constraints imposed by think tanks and spin doctors.
http://news.sciencemag.org/climate/2015/07/climate-researcher-blasts-global-warming-target-highly-dangerous
“Do we really have so much trouble thinking that far into our future?” – Yes; not scientifically, but politically and culturally. Remember the 20th Century, right up through the 1990s, when any date in the 21st was seen by the press and pop-culture as being in a far-distant sci-fi future? Getting any kind of popular consensus to plan for 2101 now – just ain’t gonna happen.