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Wednesday, July 29, 2015

The Climate Question That Should Be Asked in the Upcoming Presidential Debates

by Peter H. Gleick, Huffington Post, July 28, 2015

HURRICANE SPACE
Getty Images


Given the seriousness of the global climate change threat, the tremendously strong scientific consensus about it, and the critical role that the United States must play in any international agreements about national and global responses, it is vital to know how the next President would address this issue.









As a result, it is important to understand the position on climate change held by all presidential candidates. Accordingly, here are some variants on questions they should be asked -- and they should answer -- at public debates, including the upcoming Republican debate. First is the preferred question, followed by a few weasel-word alternatives.
Preferred climate question
Accepting as a given the overwhelming scientific agreement that humans are changing the climate of the planet, what policies or strategies, if any, would you support to address this issue?
Weasel-word climate question #1
Do you understand that there is overwhelming scientific agreement that humans are changing the climate? If not, why not? It's not as though every national academy of sciences on the planet, every professional geophysical scientific society, and more than 97 percent of the world's climate scientists haven't been saying this over and over and over for decades.
Weasel-word climate question #2
If you insist on answering "I am not a scientist," do you know how to find a real one to talk to? Because we have lists.
Weasel-word climate question #3
Please spell "climate change."
Weasel-word climate question #4
Batman or Superman? Kirk or Picard?
(Dr. Peter Gleick is a member of the US National Academy of Sciences, which has issued report after report on climate science; belongs to several scientific societies, all of which have formal statements endorsing the science of climate change; and is part of the 97%+ consensus of climate scientists.)

Monday, July 27, 2015

Joe Romm: James Hansen Spells Out Climate Danger Of The ‘Hyper-Anthropocene’ Age

by Joe Romm, Climate Progress, July 27, 2015
CREDIT: AP/DENNIS COOK
James Hansen and 16 leading climate experts have written a must-read discussion paper on what humanity risks if it can’t keep total global warming below 2 °C (3.6 °F). The greatest risk they identify is “that multi-meter sea level rise would become practically unavoidable.”
This is warning everyone should heed — not just because Hansen’s co-authors include some of the world’s top sea-level rise experts, such as Eric Rignot and Isabella Velicogna, but also given Hansen’s prescience on climate change dating back more than three decades.
In 1981, Hansen led a team of NASA scientists in a seminal article in Science, “Climate Impact of Increasing Atmospheric Carbon Dioxide.”
They warned: “Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.”
Wow. A 35-year-old, peer-reviewed, climate warning that is 100% dead on. Is there anyone else on the planet who can has been right for so long about climate change?
Hansen and co-authors deftly dismiss those ill-informed Pollyannas who use Orwellian terms like “good Anthropocene.” They explain that we are far past “the era in which humans have contributed to global climate change,” which probably began a thousand years ago, and are now in “a fundamentally different phase, a Hyper-Anthropocene … initiated by explosive 20th century growth of fossil fuel use.”
The “Hyper-Anthropocene” is a very good term to describe the unprecedented acceleration in global warming that humanity has set in motion with the explosive growth of fossil fuels and carbon pollution, as the recent science makes clear:
Marcott et al.
Temperature change over past 11,300 years (in blue, via Science, 2013) plus projected warming this century on humanity’s current emissions path (in red, via recent literature).
The fact that warming as high as 2 °C should be avoided at all costs is not news to people who pay attention to climate science, though it may be news to people who only follow the popular media. Indeed, 70 leading climate experts made that point crystal clear in a May report to the world’s leading governments that received embarrassingly little coverage from the mainstream media.
As an important aside, Hansen and his 16 co-authors continue to be criticized for publicizing this paper prior to peer review. While I probably would have framed the paper’s launch somewhat differently — as an expert opinion and discussion piece coming from one or more major scientific institutions — I think this particular criticism is overblown.
The mainstream media has generally failed to explain to the public the dire nature of our climate situation, repeatedly hitting the snooze alarm even as the world’s scientists shout “Wake Up” louder and louder in every peer-reviewed forum you can imagine. Hansen himself has tried every traditional way possible to inform the media and alert the public for 35 years. If this new piece is what it takes to get any non-Trump, non-Kardashian, coverage in our current media environment, I’m not certain how much criticism scientists deserve for playing by a set of rules they did not make, rules made by the very people nit-picking at them.
The fact that 2 °C total warming locks us in to sea level rise of 10 feet or more has been obvious for a while now. Heck, the National Science Foundation (NSF) issued a news release back in March 2012 on paleoclimate research with the large-type headline, “Global Sea Level Likely to Rise as Much as 70 Feet in Future Generations.” The lead author of that study explained, “The natural state of the Earth with present carbon dioxide levels is one with sea levels about 70 feet higher than now.”
And a 2009 paper in Science showed that the last time CO2 levels were this high, it was 5-10 °F warmer and seas were 75-120 feet higher.
What has changed is our understanding of just how fast sea levels could rise. In 2014 and 2015, a number of major studies revealed that large parts of the Antarctic and Greenland ice sheets are unstable and headed toward irreversible collapse — and some parts may have already passed the point of no return. Another 2015 study found that global sea level rise since 1990 has been speeding up even faster than we knew.
The key question is how fast sea levels rise this century and beyond. Coastal planners — and governments — need to know what the plausible worst-case is. The Intergovernmental Panel on Climate Change, in its 2013 Fifth Assessment Report (AR5) reviewing the scientific literature, threw up their hands. They have no idea how quickly the ice sheets can melt and contribute to sea level rise — so they assume it is very little and plead ignorance: “The basis for higher projections of global mean sea level rise in the 21st century has been considered and it has been concluded that there is currently insufficient evidence to evaluate the probability of specific levels above the assessed likely range.”
And so the IPCC’s sea level rise range for 2100 is instantly obsolete and useless for governments and planners. A study that integrated expert opinion from 2013 on ice sheet melt with the IPCC findings concluded, “seas will likely rise around 80 cm” [31 inches] by 2100, and that “the worst case [only a 5% chance] is an increase of 180 cm [6 feet].” Since that expert opinion predated all of the bombshell findings of the last 18 months, the authors of that study noted, “We acknowledge that this may have changed since its publication. For example, it is quite possible that the recent series of studies of the Amundsen Sea Sector and West Antarctic ice sheet collapse will alter expert opinion.” Precisely.
The main contribution Hansen et al. makes is to warn that “sea level rise of several meters in 50, 100 or 200 years,” which means as early as this century but in any case, sooner than expected. They also warn that even with the less than 1 °C of warming we already have, ice sheet melt appears to be putting sea level rise on an exponential growth path that would bring 10 feet of sea level rise sooner, rather than later — even if we stabilize at 2 °C total warming.
Why does this matter? The authors explain, “The economic and social cost of losing functionality of all coastal cities is practically incalculable.” Heck, even the New York Times reported last year on the news of the accelerating collapse of the West Antarctic ice sheet that “The heat-trapping gases could destabilize other parts of Antarctica as well as the Greenland ice sheet, potentially causing enough sea-level rise that many of the world’s coastal cities would eventually have to be abandoned.”
Team Hansen just carries the analysis to its next logical phase and exposes the dangers of the IPCC’s willful underestimation of the problem: “Our analysis paints a different picture than IPCC (2013) for how this Hyper-Anthropocene phase is likely to proceed if GHG emissions grow at a rate that continues to pump energy at a high rate into the ocean. We conclude that multi-meter sea level rise would become practically unavoidable.”
And what happens in the Hyper-Anthropocene?
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.
That is especially true when you throw in the other part of Hansen’s prediction from 1981 that has come true — “the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones.” Indeed, if this comprehensive new paper has one failing, it is in not discussing the myriad studies and evidence that warming-driven Dust-Bowlification threatens one third of the habited and arable landmass of the planet.
I also think Hansen is pushing the speculative possibility of 10 feet of sea level rise this century harder than he needs to. Yes, there are many experts who consider that a real possibility now, so it would be imprudent to ignore the warning. But the fact is, on our current emissions path, we now appear to be headed toward the ballpark of 4-6 feet of sea level rise in 2100 — with seas rising up to one foot per decade after that — which should be more than enough of a “beyond adaptation” catastrophe to warrant strongest of action ASAP.
The world needs to understand the plausible worst-case scenario for climate change this century and beyond — something that the media and the IPCC have utterly failed to deliver. And the world needs to understand the “business as usual” set of multiple catastrophic dangers of 4 °C if we don’t reverse course now. And the world needs to understand the dangers of even 2 °C warming.
Kudos to James Hansen et al. for figuring out a way to draw attention to these crucial issues.

Arctic sea ice expert Peter Wadhams complains to UK press watchdog over Times story

Cambridge professor Peter Wadhams says he was misquoted in a story about the deaths of three leading British scientists in 2013

Peter Wadhams, professor of ocean physics at Cambridge University, during an expedition to the North Pole.

Peter Wadhams, professor of ocean physics at Cambridge University, during an expedition to the North Pole.
by The Guardian, July 27, 2015

One of the world’s leading Arctic sea ice experts has responded strongly to a Times newspaper story claiming that he thought assassins may have murdered three leading British scientists in 2013.
Professor Peter Wadhams, Cambridge professor of ocean physics, has complained to the Independent Press Standards Organisation (IPSO) that his scientific reputation had been damaged by Times environment editor Ben Webster and that he had been inaccurately quoted.
The Times said it had a recording of Wadhams’ comments and stood by the story.
The Times report centred on the deaths within a few months in 2013 of three leading sea ice scientists, two of them from University College London, and a narrow escape for Wadhams after a driver of an unmarked lorry reportedly tried to push his car off the M25.
According to Wadmams: “Webster ... asked for further details. I asked that this be completely off the record because of (a) the sensibilities of relatives of the deceased (b) my own scientific reputation (I did not want to be made out to be a crazy person), (c) the fact that these deaths were investigated and were very clearly simply an extraordinary coincidence.
“He [Webster] raised the question of whether they were murdered. I agreed that for a short time I thought that they were, since I had had the experience of being run off the road at the same time by a lorry, but that it was very clear afterwards that the three deaths were individually explainable accidents.”
He further claimed that a promise of confidentiality was breached. “I did not make any of the statements enclosed in quotation marks by the reporter. Webster promised that this was in confidence and that if he wanted to use it he would contact me first.”
A spokesperson for The Times said: “We have a recording of Professor Wadhams making these statements. Another newspaper [the Telegraph] subsequently reported that he had made similar comments to their journalist. We stand by the story.”
Profesor Wadhams, who is head of the Polar ocean physics group in the Department of Applied Mathematics and Theoretical Physics, is a controversial figure in international science, going further than more cautious colleagues in predicting the final collapse of Arctic sea ice in summer months within a few years.
In an email to the Guardian in 2012, Wadhams said: “I have been predicting [the collapse of sea ice in summer months] for many years. The main cause is simply global warming: as the climate has warmed there has been less ice growth during the winter and more ice melt during the summer.
“Climate change is no longer something we can aim to do something about in a few decades’ time, and that we must not only urgently reduce CO2 emissions but must urgently examine other ways of slowing global warming, such as the various geoengineering ideas that have been put forward.”
http://www.theguardian.com/environment/2015/jul/27/arctic-sea-ice-expert-complains-to-press-watchdog-over-times-story

James Hansen: Atlantis awaits: melting ice and rising water for coastal cities

by James Hansen, The Baltimore Sun, July 27, 2015

Our civilization is built on coastlines. Oceans were the first grocery stores, providing easy protein for early humans who learned to fish and gather shellfish and seaweed. Oceans were the first highways, enabling early exploration, commerce and migration. Oceans remain vital sources of food and trade, even as societies have grown and advanced. That's why three-fourths of the world's major cities are located on coasts.

But despite their many blessings, the Earth's oceans are becoming a curse. By burning fossil fuel, we have already begun to unleash the vast quantities of water locked up in glaciers as ice. That melt has already begun raising sea levels, which are, as revealed by our most recent research, preparing for an invasion of our coastal communities the likes of which modern humans have never encountered.

To say that we're not ready for this oceanic assault would be an understatement. Our international goal for limiting warming won't be enough to hold the waters back. Even if we meet the target goal of limiting global warming to 2 degrees Celsius, we will have already released enough CO2 to drive a dangerous amount of melting. Without concerted efforts to tackle climate change, we are condemning our biggest, most prosperous and populated cities to an underwater existence.

We are, in effect, creating a world where there won't be just one Atlantis, but many. A world where thriving cities are invaded not by barbarians or battalions, but by the same waters that first facilitated their growth.

In the ancient past, long before the rise of humanity, the wobble of Earth's axis changed the amount of sunlight on polar regions, causing dramatic temperature changes over thousands of years. Using those episodes as reference points to how the oceans and ice sheets react to temperature changes, we are able to project what will happen as humanity continues polluting the atmosphere with fossil fuel's carbon dioxide waste.

What lies in store — according to the science — is startling. Sea levels are poised to rise as much as several meters in just 50 to 90 years. This means that billions of people currently living alongside the coast will likely be forced inland to new areas, triggering massive immigration problems (not to mention the infrastructure complications and economic costs of abandoning or adapting our most prosperous cities).

Our study — based on current observations, paleoclimate records and modeling — shows that the current framework of a 2-degree target as a "guardrail" of safety is misguided. We're publishing this study now, for discussion purposes and prior to a complete peer review, because the findings require greater awareness and understanding as the world works toward an international climate agreement in Paris this December.

To protect our coastal communities, we need to protect our climate. Protecting our climate means cutting out fossil fuels and focusing on clean energy. With a revenue-neutral price on carbon we can quickly stimulate exactly the sort of switch that's necessary to slow the ocean's rise, instead of allowing it to take over our coastal cities.

If this threat were from a foreign nation our response would be unequivocal, immediate and forceful. But because the enemy is us, we have dragged our feet for decades and resisted the necessary changes. Paralyzed by fears propagated by industrial interests, we remain unwilling to change the energy infrastructure that's fueling this problem. By putting a price on carbon and returning that revenue to the people, we can begin to turn back the rising tide that threatens to engulf our coastal communities.

Otherwise, Los Angeles, New York, Miami and three-quarters of the biggest cities on the planet should prepare for life underwater. With temperatures rising and ice melting, time is dwindling to save our cities. So let's get started — or else Atlantis awaits.

James Hansen is an adjunct professor at Columbia University Earth Institute and former director of the NASA Goddard Institute for Space Studies.


http://www.baltimoresun.com/news/opinion/oped/bs-ed-climate-scientist-20150727-story.html

Sunday, July 26, 2015

James Hansen on CNN discusses rapid sea level rise

Dr. James Hansen gives his idea to curb climate change on CNN's Fareed Zakaria GPS, July 26, 2015

The following transcript is of an interview by host Fareed Zakaria with former director of the NASA Goddard Institute for Space Studies, Dr. James Hansen. They discussed Hansen’s hypothesis for the Earth’s future climate due to the unstable sea levels, the public’s skepticism, and his idea to curb climate change.

VIDEO HIGHLIGHT
A dire warning on climate change



TEXT HIGHLIGHTS
Hansen’s hypothesis on sea levels rising as much as 10 feet within 50 years:“Not only would it be 10 feet, but it would imply that in the next decades after that it would be even more. Because where this water is coming from is the west Antarctic ice sheet, and then there’s another part of the east Antarctic ice sheet which also has several meters of sea level rise in its ice. So what that would mean is coastal cities would become dysfunctional. Parts of the city would still be above water, but it wouldn’t make sense to try to rebuild them partially because they know the water is going to keep rising. So we can’t let it go unstable. We would lose all the coastal cities in the world, and that’s enormous a cost, which would affect everybody, whether they’re living on the coast or not.”

Hansen on public skepticism: “Oh, sure. That's the nature of science. That's the lifeblood of science. You always are skeptical of any new conclusion. And so that's not surprising at all. But compare it to the 1980s, when I testified to Congress. There was an overwhelming skepticism and criticism, and then, over a few years, the story changed. Here, there were a lot of people becoming very suspicious that the IPCC was underestimating the sea level problem.”

Hansen’s idea to curb climate change:  “…As long as fossil fuels are the cheapest energy, people are going to keep burning them and going to find them, to dig them up wherever they can find them. …what we need to do is add a gradually rising fee to the fossil fuels, which you would collect from the fossil fuel companies at the source... And that money should be distributed to - all legal residents of the country. That way the person who does better than average in limiting his carbon footprint will make money, and it will be a big incentive for them to pay attention to their carbon footprint. It will be a big incentive for entrepreneurs to develop no carbon and low carbon energy sources and products. And the economic studies that have been done show that this actually stimulates the economy. So it doesn't cost anything.”

FULL INTERVIEW TRANSCRIPT BELOW:
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

POPE FRANCIS (TRANSLATOR): I ask the Lord that he may give us the grace to gain the awareness of this problem of destruction that we ourselves are responsible for.

FAREED ZAKARIA, CNN GPS HOST: That was Pope Francis on Tuesday praying in front of a group of more than 60 mayors from around the world who had come to the Vatican to talk about climate change. Well, his prayers may have been answered.  A controversial paper released this week, claims to bring new understanding to just how much damage we've done and says it may be worse than previously believed, predicting much faster polar melting and thus potentially catastrophic sea level rises - much faster than we ever believed possible, as much as 10 feet within just 50 years.

The paper's lead author is a name you may know. The Washington Post calls him the world's most famous climate scientist. James Hansen is the former director of the NASA Goddard Institute for Space Studies. He is the man who many credit with bringing global warming to the world's attention in the 1980s, through some striking congressional testimony. He's now an adjunct professor at Columbia University's Earth Institute.

You say that there will be a 10-feet rise in 50 years. What does that mean? It feels like a long way off; it’s numbers. What would that mean?

JAMES HANSEN, ADJUNCT PROFESSOR, COLUMBIA UNIVERSITY: Not only would it be 10 feet, but it would imply that in the next decades after that it would be even more. Because where this water is coming from is the west Antarctic ice sheet, and then there’s another part of the east Antarctic ice sheet which also has several meters of sea level rise in its ice. So what that would mean is coastal cities would become dysfunctional. Parts of the city would still be above water, but it wouldn’t make sense to try to rebuild them partially because they know the water is going to keep rising. So we can’t let it go unstable. We would lose all the coastal cities in the world, and that’s enormous a cost, which would affect everybody, whether they’re living on the coast or not.

ZAKARIA: And most of the world lives around coastlines.

HANSEN: That’s right.

ZAKARIA: But your hypothesis, you look back - you know, you look at a period that's really 120,000 years ago. And some of your critics are saying, well, who knows if that's applicable now? Why did you choose that point?

HANSEN: Well, we did several things. That was one of the things we did, is to look at the last time it was warmer than today. And it was less than one degree Celsius warmer than today and sea level reached heights of six to eight meters higher than today. So if we allow the temperature to go two degrees higher, we're guaranteeing that that sea level rise will occur; we just aren't sure how fast it will occur. And what our study shows, it's a lot faster than the glaciologists had imagined.

ZAKARIA: You saw The Washington Post asked some other scientists - there have been people on Twitter, like Ruth Mottram, who have responded. And some of them are skeptical. Do you - do you understand the skepticism?

HANSEN: Oh, sure. That's the nature of science. That's the lifeblood of science. You always are skeptical of any new conclusion. And so that's not surprising at all. But compare it to the 1980s, when I testified to Congress. There was an overwhelming skepticism and criticism, and then, over a few years, the story changed. Here, there were a lot of people becoming very suspicious that the IPCC was underestimating the sea level problem.

ZAKARIA: So here's the million dollar question, trillion dollar question. What do we do about it?

HANSEN: What the science is telling us is that we have an emergency. If we want our children and grandchildren to inherit a planet which is not running out of their control, we're going to have to reduce emissions as fast as practical. As long as fossil fuels are the cheapest energy, people are going to keep burning them and going to find them, to dig them up wherever they can find them. But we have to make them pay their cost to society. So what we need to do is add a gradually rising fee to the fossil fuels, which you would collect from the fossil fuel companies at the source - the domestic mine or the port of entry.

And that money should be distributed to the public - all legal residents of the country. That way the person who does better than average in limiting his carbon footprint will make money, and it will be a big incentive for them to pay attention to their carbon footprint. It will be a big incentive for entrepreneurs to develop no carbon and low carbon energy sources and products. And the economic studies that have been done show that this actually stimulates the economy. So it doesn't cost anything. It's - and it's just common sense that in order to move to a future with clean energies, we have to make the fossil fuels pay their cost to society, but do it in a way which is not a tax. You know, the conservatives will never accept it if it's a tax in which the government takes the money and then uses it to make the government bigger. We've got to make it revenue neutral. And the best way to do that is to give the money back to the public.

ZAKARIA: James Hansen, pleasure to have you on.

HANSEN: Thank you.

Wednesday, July 22, 2015

"Linking interannual variability in extreme Greenland blocking episodes to the recent increase in summer melting across the Greenland ice sheet," by J. T. McLeod & T. L. Mote, International Journal of Climatology, 19 July 2015: doi: 10.1002/joc.4440

International Journal of Climatology, 19 July 2015; doi: 10.1002/joc.4440

Linking interannual variability in extreme Greenland blocking episodes to the recent increase in summer melting across the Greenland ice sheet

Jordan T. McLeod and Thomas L. Mote

Abstract


Atmospheric blocking commonly occurs over the high latitudes of the Northern Hemisphere, resulting from the development of persistent areas of high pressure that lead to warmer-than-average surface temperatures west of the high centre. While the variability and trends in anticyclonic circulation patterns (including blocking) over Greenland have been previously documented, an analysis of the most extreme blocking events within the observational record is lacking. In this study, a historical climatology of extreme Greenland blocking episodes (GBEs) from 1958 to 2013 is examined within the context of anomalous anticyclonic circulation patterns over the North Atlantic region during recent years. Based on a combination of the ERA-40 (1958–1978) and ERA-Interim (1979–2013) reanalysis data sets, the Greenland Blocking Index (GBI) is used to quantify 500-hPa geopotential-height anomalies for the identification of extreme GBEs. The annual rate of extreme blocking days has doubled since 1958, reaching an average of approximately 20 days per year by 2013. The frequency and, to some extent, duration of extreme GBEs were unprecedentedly high from 2007 to 2013 compared to the 56-year period of record, with a majority of the increase occurring during the spring (MAM) and summer (JJA). A multiple linear regression analysis reveals that interannual variability in extreme blocking and the Atlantic Multidecadal Oscillation (AMO) are the two predominant drivers of surface meltwater production across the entire Greenland ice sheet (GrIS), but Arctic sea ice extent and North Atlantic cyclone activity can also influence the extent of summer melting over portions of the GrIS. Thus, in addition to the larger-scale atmospheric and oceanic variability, smaller-scale features such as extratropical cyclones can play a significant role in modulating GrIS surface melting each summer.

Key words: atmospheric blocking, Greenland ice sheet, extratropical cyclones, North Atlantic, Arctic amplification, cryosphere, Arctic sea ice, climate change

http://onlinelibrary.wiley.com/doi/10.1002/joc.4440/abstract

James Hansen: ‘Emergency Cooperation Among Nations’ Is Needed to Prevent Catastrophic Sea Level Rise

"Roughly 10 feet of sea level rise—well beyond previous estimates—would render coastal cities such as New York, London, and Shanghai uninhabitable." Photo credit: Woodbine
“Roughly 10 feet of sea level rise—well beyond previous estimates—would render coastal cities such as New York, London, and Shanghai uninhabitable.” Photo credit: Woodbine

by Jon Queally, Common Dreams, July 21, 2015
If a new scientific paper is proven accurate, the international target of limiting global temperatures to a 2 °C rise this century will not be nearly enough to prevent catastrophic melting of ice sheets that would raise sea levels much higher and much faster than previously thought possible.
According to the new study—which has not yet been peer-reviewed, but was written by former NASA scientist James Hansen and 16 other prominent climate researchers—current predictions about the catastrophic impacts of global warming, the melting of vast ice sheets and sea level rise do not take into account the feedback loop implications of what will occur if large sections of Greenland and the Antarctic are consumed by the world’s oceans.
A summarized draft of the full report was released to journalists on Monday, with the shocking warning that such glacial melting will “likely” occur this century and could cause as much as a 10 foot sea-level rise in as little as 50 years. Such a prediction is much more severe than current estimates contained in reports issued by the Intergovernmental Panel on Climate Change (IPCC) — the UN-sponsored body that represents the official global consensus of the scientific community.
“If the ocean continues to accumulate heat and increase melting of marine-terminating ice shelves of Antarctica and Greenland, a point will be reached at which it is impossible to avoid large scale ice sheet disintegration with sea level rise of at least several meters,” the paper states.
Separately, the researchers 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 Daily Beast‘s Mark Hertsgaard, who attended a press call with Dr. Hansen on Monday, reports that the work presented by the researchers is
"...warning that humanity could confront “sea level rise of several meters” before the end of the century unless greenhouse gas emissions are slashed much faster than currently contemplated.
This roughly 10 feet of sea level rise—well beyond previous estimates—would render coastal cities such as New York, London, and Shanghai uninhabitable. “Parts of [our coastal cities] would still be sticking above the water,” Hansen said, “but you couldn’t live there.”
This apocalyptic scenario illustrates why the goal of limiting temperature rise to 2 degrees Celsius is not the safe “guardrail” most politicians and media coverage imply it is, argue Hansen and 16 colleagues in a blockbuster study they are publishing this week in the peer-reviewed journal Atmospheric Physics and Chemistry. On the contrary, a 2C future would be “highly dangerous.”
If Hansen is right—and he has been right, sooner, about the big issues in climate science longer than anyone—the implications are vast and profound.
In the call with reporters, Hansen explained that time is of the essence, given the upcoming climate talks in Paris this year and the grave consequences the world faces if bold, collective action is not taken immediately. “We have a global crisis that calls for international cooperation to reduce emissions as rapidly as practical,” the paper states.
Hansen said he has long believed that many of the existing models were under-estimating the potential impacts of ice sheet melting, and told the Daily Beast: “Now we have evidence to make that statement based on much more than suspicion.”
Though he acknowledged the publication of the paper was unorthodox, Hansen told reporters that the research itself is “substantially more persuasive than anything previously published.”
For his part, Eric Holthaus, a meteorologist who writes about weather and climate for Slate, said the “bombshell” findings are both credible and terrifying. Holthaus writes:
To come to their findings, the authors used a mixture of paleoclimate records, computer models, and observations of current rates of sea level rise, but “the real world is moving somewhat faster than the model,” Hansen says.
[…] The implications are mindboggling: In the study’s likely scenario, New York City—and every other coastal city on the planet—may only have a few more decades of habitability left. That dire prediction, in Hansen’s view, requires “emergency cooperation among nations.”
In response to the paper, climate scientist Michael Oppenheimer of Princeton University affirmed: “If we cook the planet long enough at about two degrees warming, there is likely to be a staggering amount of sea level rise. Key questions are when would greenhouse-gas emissions lock in this sea level rise and how fast would it happen? The latter point is critical to understanding whether and how we would be able to deal with such a threat.”
The new research, Oppenheimer added, “takes a stab at answering the ‘how soon?’ question but we remain largely in the dark. Giving the state of uncertainty and the high risk, humanity better get its collective foot off the accelerator.”
And as the Daily Beast‘s Hertsgaard notes, Hansen’s track record on making climate predictions should command respect from people around the world. The larger question, however, is whether humanity has the capacity to act.
“The climate challenge has long amounted to a race between the imperatives of science and the contingencies of politics,” Hertsgaard concludes. “With Hansen’s paper, the science has gotten harsher, even as the Nature Climate Change study affirms that humanity can still choose life, if it will. The question now is how the politics will respond—now, at Paris in December, and beyond.”
http://ecowatch.com/2015/07/21/james-hansen-climate-report/