Tag: Antarctica

Warming at the walls of the “citadel of ice”

Australian-born writer Meredith  Hooper was looking for “a route into the complex business of the Earth’s changing climate” when she spent January to March 2002 at Palmer Station on the west coast of the Antarctic Peninsula. She watched and chronicled the work of scientist Bill Fraser and his team who for years have studied the Adélie penguins breeding on nearby islands over the summer months.

I read the account of her time there in her book The Ferocious Summer. It was the summer when the Larsen B ice shelf on the eastern side of the Peninsula spectacularly disintegrated. Her often poignant story tells of diminished numbers of penguins arriving for breeding, weather conditions inappropriate for their nesting, poor nutrition levels and low fledgling survival rates.

The book was also an illuminating account of the working and thinking of the scientists as they gradually amass and interpret the years of data needed for a proper understanding of what is happening to wildlife populations under the inexorable processes of climate change.

Hooper wrote for any who want to understand what global warming might mean for specific places and the life which has developed in close relationship with them. She observes that “climate change isn’t a blanket thrown evenly over the surface of the Earth”. Its impacts are variable and often need to be understood locally.

In the vulnerability of the Adélie penguins she saw a small example of a potentially vast reality ahead. “In one sense, they had become surrogate humans.” Her book was yet another solemn warning from the world of science.

Now another book has appeared by a writer who also spent several months with Bill Fraser’s team. Fraser’s Penguins is written by Fen Montaigne, senior editor of the online Yale 360. I hope to be reading and reviewing it in the near future. But in the meantime I wanted to draw attention to a report he has just written for Yale 360, The Warming of Antarctica: A Citadel of Ice Begins to Melt. Its focus is much wider than the Adélie penguins, though they figure in it: amongst other things he notes that their population has declined from 30,000 breeding pairs in 1975 to 5,600 pairs today.

On the broader Antarctic picture Montaigne explains helpfully for the general reader the developing scientific understanding of the effects of warming on the ice. He begins with a prescient quote from a geologist, John H. Mercer, writing in Nature in 1978.

“If present trends in fossil fuel consumption continue, a critical level of warmth will have been passed in high southern latitudes 50 years from now, and deglaciation of West Antarctica will be imminent or in progress… One of the warning signs that a dangerous warming trend is under way in Antarctica will be the breakup of ice shelves on both coasts of the Antarctic Peninsula, starting with the northernmost and extending gradually southward.”

Montaigne observes that Mercer’s prediction has come true, a couple of decades earlier than he anticipated. Since Mercer wrote those words eight ice shelves have fully or partially collapsed along the Antarctic Peninsula, and the northwestern Antarctic Peninsula has warmed faster than virtually any place on Earth.

Montaigne continues:

“The question now, as humanity pours greenhouse gases into the atmosphere at an accelerating rate, is not whether Antarctica will begin to warm in earnest, but how rapidly. The melting of Antarctica’s northernmost region – the Antarctic Peninsula – is already well underway, representing the first breach in an enormous citadel of cold that holds 90 percent of the world’s ice.

He acknowledges the vastness and coldness of the Antarctic ice dome, the heart of which is not likely to begin to melt any time soon.  But the periphery is another matter, and on that periphery the Antarctic peninsula has warmed faster than any other place. A 60-year temperature record at a research base on the northwest shows winter temperatures 11 degrees F higher and annual average temperatures 5 degrees F higher.

Ninety percent of 244 glaciers along the western Antarctic Peninsula have retreated since 1940. Sea ice covers the Southern Ocean off the western Antarctic Peninsula three fewer months a year than in 1979, according to satellite data. In addition, ice shelves have been disintegrating up and down the peninsula.

He quotes Ted Scambos, the lead scientist at the National Snow and Ice Data Center in Boulder, Colorado.

“We are already at the point where the changes we’re seeing in this part of Antarctica are unprecedented throughout the entire period of human civilization.”

Turning to the Pine Island and Thwaites glaciers further south, Montaigne discusses the effect of warming water. Changing atmospheric and oceanic circulation patterns have caused the water of the deep Antarctic Circumpolar Current to be funnelled up onto the continental shelf in western Antarctica. At 37 degrees F in winter, it is warmer than the surface water and much warmer than air temperatures. It’s a huge volume and is having an enormous impact. In relative terms it is described as “blisteringly hot” by Douglas Martinson, an oceanographer and Antarctic specialist at Columbia University’s Lamont-Doherty Earth Observatory.

The thinking of Robert Bindschadler, a senior fellow at the Goddard Space Flight Center and an expert on Antarctic ice, is that the warmer waters are melting the submerged undersides of the ice shelves attached to the Pine Island and Thwaites glaciers, causing them to grow thinner. The melting is effectively loosening the grip of the Pine Island Glacier on the sea floor, causing the vast river of ice behind it to accelerate into the sea. It is now moving at a rate of about two miles a year.

Montaigne reports Bindschadler as saying that if all the ice from the ice streams feeding the Pine Island and Thwaites glaciers were to flow into the Southern Ocean, global sea levels could increase by five feet, inundating low-lying coastal areas from Florida to Bangladesh. “Such an event, said Bindschadler, “could happen in the next half-century.”

The warming of the Antarctic is already bad news for ice-dependent penguin species.  It will also be bad news for humanity if we mindlessly continue our assault on the citadel of ice.

World leaders pretend

Apparently the American Geophysical Union’s readiness to speak out on climate change which I reported in a recent post was not as the LA Times portrayed it.  Joseph Romm has written of his disappointment that the AGU is constrained by a determination to veer away from anything that could be construed as advocacy. They state that the email exchange forum they have set up for journalists is designed to answer questions about the current state of scientific knowledge, with a special emphasis on the physical sciences that relate to climate change. Non-science questions such as those relating to policy, ethics, or economics will be returned to sender for refinement.

One example they provide is the question, “Is current U.S. infrastructure adequate for sea level rise?”  Such a question will be returned to sender on the grounds that judgments of adequacy involve tradeoffs in risk and in policy. The scientists will only answer the question if it is changed to “What amount of sea level rise might occur this century?”

It’s a stark contrast with climatologist  James Hansen, who recently delivered an open lecture in Japan on the occasion of his being awarded the prestigious Blue Planet Prize. The text and powerpoint charts can be accessed on his website. He doesn’t hold back. Here are the opening words:

 

“Human-made climate change is a moral issue. It pits the rich and the powerful against the young and the unborn, against the defenseless and against nature.

“Climate change is a political issue. But politics fails when there is a revolving door between government and the fossil fuel-industrial complex.

“Climate change is a legal issue. The judiciary provides the possibility of holding our governments accountable for their duty to protect the public interest.”

The accompanying slide has a footnote that statements relating to policy are personal opinion.

Of course Hansen then proceeds with the science of climate change, explaining the current position with his usual clarity.

“It is difficult for the public to recognize that we have a crisis, because human-made global warming, so far, is small compared to day-to-day weather fluctuations. Yet the fact is: we have an emergency. Because of the great inertia of the ocean, which is four kilometers deep, and the ice sheets, which are two to three kilometers thick, the climate system responds slowly to climate forcings such as increasing greenhouse gases. But this inertia is not our friend, because it increases the danger that we may pass tipping points, beyond which the dynamics of the climate system takes over and rapid changes occur out of humanity’s control.”

He offers three examples of tipping points. The ice sheets of Greenland and Antarctica, especially the West Antarctic ice sheet, are one. If an ice sheet is weakened to the point that it begins to collapse then the dynamics of the process take over. Another non-linear problem is the extermination of species which can accelerate because of the interdependencies among species. A third is methane hydrates, essentially frozen methane. If they begin to disintegrate the process could become self-sustaining. He notes these tipping points have all occurred during Earth’s history in conjunction with warming climates.

At this point in his lecture he again crosses into the kind of territory that the AGU eschews for its scientists.

“Climate inertia and tipping points give rise to potential intergenerational injustice. Today’s adults enjoy the benefits of fossil fuel use, but the impacts will be borne by young people and future generations. Our parents did not know that their actions would affect future generations. We do not have that excuse. We can only feign ignorance. It is called denial.”

There was a lengthy period following Hansen’s testifying to Congress in the 1980s during which he decided to concentrate on research and leave public communication to others. He tells how  it was the arrival of his grandchildren combined with the growing gap between what was understood of the science and what was known by the public that brought him back to public communication. In 2004 he gave a carefully prepared public talk titled “Dangerous anthropogenic interference: a discussion of humanity’s Faustian climate bargain and the payments coming due”.

His public lecture in Japan is the latest example of his readiness to couple the communication of the science with clear assessment of the risk and with concrete recommendations as to how that risk may yet be avoided.  As his lecture proceeds he explains the basis of our current scientific understanding. It depends most of all on Earth’s paleoclimate history, then on ongoing global observations showing how climate is responding to rapid changes of atmospheric composition, and finally on climate models and theory which are helpful in interpreting what is happening and needed to predict future changes. There’s a pile of interesting material which follows which I won’t try to summarise here, save to say that he points out that the human-caused rise in atmospheric carbon dioxide is occurring at a rate 10,000 times faster than the natural geologic change of the Cenozoic era of the past 65 million years. He also explains his assessment that a level of no more than 350ppm of atmospheric carbon dioxide is required if we wish to preserve the planet on which civilisation developed.

He’s not backward in spelling out policy implications. We must halt all coal emissions in 20 years, not develop tar sands, oil shale or methane hydrates, and not pursue the last drops of oil in polar regions, deep sea drilling or pristine land. “In other words, we must move on to the clean energy future now, rather than using all the remaining fossil fuels.”

There’s as yet no sign of our doing so:

“But what is really happening? The United States has signed an agreement with Canada for a pipeline to carry tar sands oil to Texas. New coal plants are being built all around the world, some being financed by the World Bank. Environmentally destructive mountaintop removal continues. Oil is pursued in pristine places. The environmentally destructive practice of shale fracturing is being developed and implemented to find the last bits of gas.

“There is a huge gap between government rhetoric and policy reality. Leaders say that we have a ‘planet in peril’, yet their proposed policies barely differ from business-as-usual. Greenwash is plentiful, but the leaders follow a path of appeasement of fossil fuel special interests. There is no Winston Churchill willing to stand up and tell the truth about what is needed.”

Hansen then moves to his policy prescriptions which include a rising price on carbon, government regulation, and technology development driven by the certainty of the carbon price. He is not diffident in offering them, but his audience would have no difficulty recognising when he has moved from presentation of the science to advocacy of a particular response.

The notion that a scientist’s responsibility ends where a politician’s begins is simplistic. Politicians often enough show little sign of fully appreciating the reality of the science, and even if they do they appear to have an endless capacity to shy away from appropriate action. Are scientists like Hansen supposed to stay in their sanctums and be satisfied with issuing bulletins on the state of the science? And when they see the mayhem created by industry denial and media confusion and political timidity are they supposed to just shrug their shoulders and get on with their research? Even though they know what that research indicates for the human future if we carry on as usual?

Hansen’s record makes it quite clear that advocacy doesn’t mean compromising research. His scientific work continues and wins respect in its own right. Joe Romm has  reason to be disappointed that the AGU has put such stringent limits on its scientists’ communication with journalists.

[REM]

House by the sea (not a good idea)

The Royal Society of New Zealand has just published an interesting paper on sea level rise [pdf], the latest in a series on “emerging issues” of public concern. It’s a very good overview of the current state of our understanding of the risk of future sea level rises, reviewing the evidence that’s accumulated since the IPCC’s Fourth Report (AR4), and puts that information into the NZ context.

The paper suggests that as we’re learning more about the behaviour of the great ice sheets of Greenland and West Antarctica it’s becoming clear that there’s a risk of sea level rise this century much greater than the upper limits given in AR4 (which ignored increasing ice sheet melt). On the other hand, the extreme rates of sea level rise seen during the last deglaciation (4-5 metres per century at times) look less likely, with data from the last interglacial (LIG, aka the Eemian) suggesting 1.5 metres/century is more plausible.

The RS paper also includes a useful summary of various SLR planning guidelines issued around the world. New Zealand’s guidelines (Bryan’s take here), based on AR4, look to be on the low side, but speaking at the press conference to launch the paper, Prof Martin Manning, director of Climate Change Research Institute at Victoria University , suggested that in his recent experience Environment Court judges were taking care to stay abreast of current scientific knowledge. That’s important, because as NIWA’s Doug Ramsay pointed out at the conference, 12 of the 15 largest towns and cities in NZ are on low-lying coastal and estuarine margins, there’s been enormous pressure to develop on prime beachfront locations and large chunks of our road and rail infrastructure are within 5 metres of current sea level.

[Iron & Wine]

Down to the sea

An interview with climatologist Ellen Mosley-Thompson published yesterday in Yale Environment 360is a reminder that for those working with ice there’s not much doubt about where we’re heading. She spent six weeks of the summer on her ninth visit to Antarctica drilling ice cores on the Antarctic Peninsula, one of the fastest-warming places on earth. Its winter temperatures have increased by 6 degrees over the past 60 years and year-round temperatures by 2.8 degrees. As a result, sea ice now covers the western Antarctic Peninsula three months less a year than three decades ago, 90 percent of glaciers along the western Antarctic Peninsula are in retreat, and large floating ice shelves are crumbling.

 

Mosley-Thompson headed a team of six for the drilling, and they were part of a larger group attempting to understand the warming behind the break-up of the Larsen B ice shelf in 2002. Ecologists were looking at an ecosystem on the ocean bottom that until eight or nine years ago had been covered by ice for thousands of years and considering how it is adjusting to the new normal. Glaciologists were looking at how much more rapidly the glaciers are discharging into the ocean with the disappearance of the buttressing ice shelf. A marine group was looking at changes in marine geo-chemistry, collecting new cores in the area that was covered by ice to compare with the cores previously drilled in the ocean bottom along the outer margins of Larsen B when it was in place.

It’s an impressive range of investigation she describes. The ice drilling on the Bruce Plateau was able to get right down to bedrock at 455 metres, and the cores will be closely analyzed back in Ohio for the information they contain about past climate, perhaps to the last glacial period and beyond.

Mosley-Thompson is married to Lonnie Thompson, the highly respected glaciologist. While his wife has been working mostly in Greenland and Antarctica he has done more ice corings of low-latitude glaciers –- in the Andes, Africa, and the Himalayas –- than any other person alive. Yale Environment comments that their work, taken together, paints a sobering portrait of the rapid retreat of most of the world’s glaciers and ice caps in the face of the buildup of planet-warming greenhouse gases.

Here are some of the things Mosley-Thompson has to say in the interview about the overall global picture. In response to the interviewer’s observation that the deep Antarctic ice cores taken at Dome C years show that we have got more CO2 in our atmosphere than at any time in 800,000 years:

“Very clearly. If you look back over the eight glacial/interglacial cycles, you essentially see that CO2 never rises above 300 parts per million and we’re at about 389 now. Methane never rises above about 800 parts per billion, and I think we’re at about 1,700 parts per billion. So we’re clearly outside the range of natural variability. I personally think that graph simply showing the natural fluctuations in those two important greenhouse gases, over almost a million years of Earth history — and then you see the two dots [today] that are so much higher than anything that we see in that near-million history — tells us very clearly that we have a serious problem.”

What does the cumulative ice coring  work show about what we’re experiencing in the last century or so in terms of the warming of the planet?

“ Well, from the tropical work, the cores in the Andes and the Himalaya, the oxygen isotopic ratio in those cores, when you stack those cores together, show very clearly that the last 50 or 60 years have been the warmest in the last 2,000 years.”

The ice cores from the Andes do show a Medieval Warm Period signature and a very distinct Little Ice Age cool signature.  Not surprising, she says, because both those periods are expressed most strongly around the Atlantic Basin and the moisture that builds the glaciers in the Andes of Peru actually comes from the Atlantic.  But the cores from the Tibetan Himalaya show virtually no signature of these periods.

“so when we put these records together, the medieval warming is very modest and the Little Ice Age signature is strongly muted as well. And what really stands out when you put these all together and into the composite, is the last 60 years. The oxygen isotopic enrichment in the tops of the cores [indicating warming] is very striking.”

She notes that particularly in the case of the tropical ice fields the glaciers are retreating very rapidly:

“And, in fact, several of the ice fields, particularly one that we recently published the results [for] in the southwestern Himalaya, it has not gained mass or has no ice that was deposited after 1950. It’s like these glaciers are just literally being decapitated. And it’s very frightening.”

And what about the IPCC error on Himalayan melting?

“…when you look at the breadth of the Intergovernmental Panel on Climate Change reports, and how much information is in there, the fact that this must be the most egregious error, otherwise they would be making more of something else –  I think it’s astounding that the IPCC got as much right as they did because there was just tremendous potential for error.”

And if we don’t begin to rein in CO2 emissions, where is the cryosphere, the Earth’s ice zone, heading?

“To the oceans. Ultimately that’s where all water goes, to the lowest level.”

Tipping and other points

During the Copenhagen kerfuffle a lot of interesting stuff hit the web: here’s something that deserves a bit more air – a Proceedings of the National Academy of Science (PNAS) special issue on tipping elements in the earth system, edited by John Schellnhuber, the director of the Potsdam Institute for Climate Impact Research in Germany.

Tipping elements (or points, as Malcolm Gladwell would have them) are changes that once started take on a life of their own, and can’t easily be returned to their original state. In the climate system that might be the rapid loss of an ice sheet in a few decades or hundreds of years, while regrowing it might take many thousands. The PNAS special issue deals with nine: dust production in the Bodélé Depression in Chad, ENSO, Arctic sea ice and ice sheets, the Atlantic Meridional Overturning Circulation, deep ocean hydrates (not shallow sea bed, Siberian methane) — David Archer dubs them a “slow tipping point”, the Amazon rainforest (no “Amazongate” here, just a confirmation that concern is justified), monsoons, oceans, and policy responses to the climate challenge. And the best thing is that all the articles are available online, free (click on the link above). Schellnhuber contributes an introduction, and the Potsdam press release also provides a good overview. For some introductory thoughts, check out Tim Lenton’s discussion here.

Another recent example of a real tipping point is the Pine Island Glacier in West Antarctica. Recent modelling suggests that the glacier’s grounding line retreated beyond a ridge in 1996, and is now free to retreat by several hundred kilometres inland. This could happen in a hundred years and result in the loss of half of the ice in the glacier — enough to raise sea level by 24cm. New Scientist reports:

Observations already show that the model severely underestimates the rate at which PIG’s grounding line is retreating, says Katz. “Ours is a simple model of an ice sheet that neglects some important physics,” says Katz. “The take-home message is that we should be concerned about tipping points in West Antarctica and we should do a lot more work to investigate,” he says.

Amen to that.