Tag: ice

2010 Greenland ice sheet melt sets new record, 2011 starts warm

The 2010 ice melt season on the Greenland ice sheet (see video) set new records, according to Marco Tedesco, director of the Cryospheric Processes Laboratory at the City University of New York. The melt season was “exceptional”, Tedesco said. Melting in some areas lasted as much as 50 days longer than average, starting very early at the end of April and ending later than usual in mid-September. During the summer, temperatures over large parts of Greenland were as much as 3ºC above average, snowfall was below average, and the capital, Nuuk, had its warmest spring and summer since records began in 1873.

 

Tedesco is lead author of a paper published today, The role of albedo and accumulation in the 2010 melting record in Greenland(*), which integrates weather, satellite and ground data with modelling to build a detailed picture of the melt season. Here’s the abstract:

Analyses of remote sensing data, surface observations and output from a regional atmosphere model point to new records in 2010 for surface melt and albedo, runoff, the number of days when bare ice is exposed and surface mass balance of the Greenland ice sheet, especially over its west and southwest regions. Early melt onset in spring, triggered by above-normal near-surface air temperatures, contributed to accelerate snowpack metamorphism and premature bare ice exposure, rapidly reducing the surface albedo. Warm conditions persisted through summer, with the positive albedo feedback mechanism being a major contributor to large negative surface mass balance anomalies. Summer snowfall was below average. This helped to maintain low albedo through the 2010 melting season, which also lasted longer than usual.

Jason Box will be posting more on the extraordinary warmth of last summer in Greenland at his meltfactor.org blog soon.

Meanwhile, the summer warmth seems to be persisting through the depths of winter — even become more extreme — as this temperature anomaly map for the last month from an excellent article by Bob Henson of UCAR discusses. Those positive anomalies (in red) are as much as 21ºC above average for the time of year:

Here’s Henson:

[…]Let’s take a look at Coral Harbour, located at the northwest corner of Hudson Bay in the province of Nunavut. On a typical mid-January day, the town drops to a low of –34°C (–29.2°F) and reaches a high of just -26°C (–14.8°F). Compare that to what Coral Harbour actually experienced in the first twelve days of January 2011, as reported by Environment Canada […].

After New Year’s Day, the town went 11 days without getting down to its average daily high.
On the 6th of the month, the low temperature was –3.7°C (25.3°F). That’s a remarkable 30°C (54°F) above average.
On both the 5th and 6th, Coral Harbor inched above the freezing mark. Before this year, temperatures above 0°C (32°F) had never been recorded in the entire three months of January, February, and March.

The unseasonal warmth is associated with what Henson describes as ” a vast bubble of high pressure” which formed near Greenland in mid-December. The high was associated with record-breaking 500mb heights, a measure of the “thickness” of the atmosphere and associated with warmth below. This high helped to direct the atmospheric flows that brought Europe’s December cold spell.

With the delayed freeze-up in Hudson Bay and a warm winter on the fringes of the Greenland ice sheet, it may that 2010′s record for ice melt will not last long. And that’s not good news.

(*)Marco Tedesco, X Fettweis, MR van den Broeke, RSW van de Wal, CJPP Smeets, WJ van de Berg, MC Serreze, and Jason Box, The role of albedo and accumulation in the 2010 melting record in Greenland, Environmental Research Letters DOI: 10.1088/1748-9326/6/1/014005. My thanks to Jason Box for the details.

 

Clear and present danger: Lonnie Thompson on the message in the ice

Paleoclimatologist Lonnie Thompson, distinguished university professor in the School of Earth Sciences at The Ohio State University, is well known and widely respected for his decades of work on ice caps and glaciers, especially in tropical and sub-tropical regions. In the past Thompson has let his research data and conclusions speak for him but he has this week caused something of a stir by voicing in a journal for social scientists and behaviour experts his concern at the grave risks we run in ignoring the evidence of climate change. Climate Change: The Evidence and Our Options is the title of his paper (available here) and it’s published in a special climate-change edition of The Behavior Analyst.

One hopes the paper has many readers. Its eighteen pages, a model of clarity, are highly accessible for the lay person.

Thompson opens by acknowledging that climatologists, like other scientists, tend to be a stolid group.

“We are not given to theatrical rantings about falling skies. Most of us are far more comfortable in our laboratories or gathering data in the field than we are giving interviews to journalists or speaking before Congressional committees.”

Why then, he asks, are climatologists speaking out about the dangers of global warming? Because virtually all of them are now convinced that global warming poses a clear and present danger to civilisation.

“There’s a clear pattern in the scientific evidence documenting that the earth is warming, that warming is due largely to human activity, that warming is causing important changes in climate, and that rapid and potentially catastrophic changes in the near future are very possible. This pattern emerges not, as is so often suggested, simply from computer simulations, but from the weight and balance of the empirical evidence as well.”

He explains the evidence from diverse data sources that points to relative stability in temperatures over the past 1000 years until the late twentieth century. Acknowledging that regional, seasonal and altitudinal variability can nevertheless make it difficult to convince the public and even scientists in other fields that global warming is occurring, he adds from his own area of expertise the evidence of melting ice.

The retreat of mountain glaciers is an early warning of climate change. He details the ice fields on the highest crater of Kilimanjaro which have lost 85% of their coverage since 1812. The Quelccaya ice cap in Peru, the largest tropical ice field on Earth, has lost 25% of its cover since 1978. Ice fields in the Himalayas that have long shown traces of the radioactive bomb tests in the 1950s and 1960s have since lost that signal as surface melting has removed the upper layers and thereby reduced the thickness of these glaciers. All of the glaciers in Alaska’s vast Brooks Range are retreating, as are 98 percent of those in southeastern Alaska.  And 99 percent of glaciers in the Alps, 100 percent of those in Peru and 92 percent in the Andes of Chile are likewise retreating. Some telling photographic sequences illustrate the findings. It’s a pattern repeated around the world. To glacier retreat Thompson adds the loss of polar ice and sees global warming as the only plausible explanation.

From there he moves to consideration of the natural forcers of climate change and the consensus among climatologists that the warming trend we have been experiencing for the past 100 years or so cannot be accounted for by any of the known natural forcers.

“The evidence is overwhelming that human activity is responsible for the rise in CO2, methane, and other greenhouse gas levels, and that the increase in these gases is fueling the rise in mean global temperature.”

The effects include sea level rise. He points out that if the Earth were to lose just 8% of its ice, the consequences for some coastal regions would be dramatic. The lower part of the Florida peninsula and much of Louisiana, including New Orleans, would be submerged, and low-lying cities, including London, New York, and Shanghai, would be endangered. Low-lying continental countries such as the Netherlands and Bangladesh are already battling flooding as never before and several small island states are facing imminent destruction. Other effects of warming Thompson touches on include the threats to glacier-fed fresh water sources on which populations in parts of the world depend and the increase in arid regions as the Hadley Cell expands.

Many of the models predicting future rises in temperature assume a linear rise in temperature. But in fact the rate of global temperature rise is accelerating, which is reflected in increases in the rate of ice melt, and in turn an increase in the rate of sea level rise.

“This [acceleration] means that our future may not be a steady, gradual change in the world’s climate, but an abrupt and devastating deterioration from which we cannot recover.”

At this point he discusses positive feedbacks, instancing forest fires, more dark areas opened through ice melt, and the release of CO2 and methane from melting tundra permafrost. He explains the possibility of tipping points as a result, with their ominous implications. But tipping points apart, if, as predicted, global temperature rises by another 3 degrees by the end of the century, the earth will be warmer than it has been in about 3 million years. Oceans were then about 25 metres higher than they are today.

What are our options for dealing with the crisis?  Not prevention, for global warming is already with us. We are left with three: mitigate, adapt, suffer. Mitigation is the best option, but so far the US and other large emitters have done little more than talk about its importance. Many Americans don’t even accept the reality of global warming. Disinformation campaigns have been amazingly successful. Unless appropriate steps are taken we will be left with only adaptation and suffering. And the longer the delay the more unpleasant the adaptation and the greater the suffering will be. Those with the fewest resources for adaptation will suffer most.

It’s a grim picture. The information is not new.  But it gains impetus when a leading scientist steps into the public arena and weaves his specialist contribution into the overall account in a way which leaves the reader with absolutely no doubt that the writer is convinced by the science and deeply alarmed at what it means for humanity. Like John Veron, whom I wrote about earlier this week, Thompson doesn’t allow scientific reticence to mute his message.

“Sooner or later, we will all deal with global warming. The only question is how much we will mitigate, adapt, and suffer.”

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]

Greenland ice melt spreads northwest

This animation shows Greenland’s ice mass loss over 2003 to 2009, estimated by combining data from NASA’s GRACE satellites with high precision GPS measurements of “rebound” in the underlying rock as the weight of ice is removed. The lightest blue shows low levels of mass loss, black the highest. From the University of Colorado press release:

“Our results show that the ice loss, which has been well documented over southern portions of Greenland, is now spreading up along the northwest coast,” said Shfaqat Abbas Khan, lead author on a paper that will appear in Geophysical Research Letters.

Khan goes on to suggest what this might imply for the future:

If this activity in northwest Greenland continues and really accelerates some of the major glaciers in the area — like the Humboldt Glacier and the Peterman Glacier — Greenland’s total ice loss could easily be increased by an additional 50 to 100 cubic kilometers (12 to 24 cubic miles) within a few years.

Another good reason to keep an eye on the Arctic this summer. Climate Progress has a very good overview of recent work on Greenland ice loss and its implications for sea level rise. Well worth a read, if not exactly comforting.