An Accurate Picture Of Ice Loss In Greenland

ScienceDaily (Sep. 30, 2008) — Researchers from TU Delft joined forces with the Center for Space Research (CSR) in Austin, Texas, USA, to develop a method for creating an accurate picture of Greenland’s shrinking ice cap. On the strength of this method, it is now estimated that Greenland is accountable for a half millimetre-rise in the global sea level per year.

Greenland (Credit: Image courtesy of Delft University of Technology)

The research was based on data from the German-American GRACE (Gravity Recovery and Climate Experiment) satellites, two satellites that have been orbiting the earth behind each other since mid-2002. Deviations in the earth’s gravitational field cause fluctuations in the distance between the satellites, which is measured to a precision of a millionth of a metre. As gravity is directly related to mass, these data can be used to plot changes in the earth’s water balance, such as the disappearance of the ice caps.

Satellite data of this kind are ideal for measuring areas such as Greenland, where the extreme conditions make local measurements very difficult. With this in mind, researchers from TU Delft and the CSR devised a method that would create a more accurate picture of the changes taking place in Greenland than had previously been possible.

Sea level rise

Greenland lost an average of 195 cubic kilometres of ice per year between 2003 and 2008, which is enough to cause an annual increase in the global sea level of half a millimetre, or 5 cm over the course of the next century. A report recently published by the Dutch Delta commission estimated that the melting ice cap in Greenland would cause the sea level to rise by 13-22 cm by 2100. But these two figures do not necessarily contradict each other: whereas the first two years of the study showed a loss of 131 cubic kilometres of ice per year, during the last two years this figure had risen to 222 cubic kilometres per year, an increase of 70 percent.

This sharp increase was mainly caused by the extremely warm summer of 2007, when more than 350 cubic metres of ice melted in just two months. However, it is not yet clear whether the ice will continue to melt at this rate during the next few years, as ice loss varies greatly from summer to summer. Long-term observations are needed to compile a reliable estimate of Greenland’s contribution to the rising sea level during the next century.

Patterns

The method used also enables scientists to plot the loss of mass per region, thereby providing new insight into the patterns of ice loss. For example, for the first time since measurements were started, the extremely warm summer of 2007 saw a decrease in the ice mass at high altitudes (above 2,000 metres). It also became clear that the ice loss is advancing towards the North of Greenland, particularly on the west coast. The areas around Greenland, particularly Iceland, Spitsbergen and the northern islands of Canada, seem to be particularly affected. A follow-up study will focus on the influence of these smaller glaciers on the sea level.

Journal reference:

1. Wouters, B., D. Chambers, and E. J. O. Schrama. GRACE observes small-scale mass loss in Greenland. Geophys. Res. Lett., October 2008 DOI: 10.1029/2008GL034816

Future climatic conditions could be too variable for many current crops

A global search has begun for food crops with traits that are able to withstand changes to the climate.

The project, co-ordinated by the Global Crop Diversity Trust, is searching national seed banks for "climate proof" varieties, including maize and rice.

The team will screen seeds for natural resistance to extreme events, such as floods, droughts or temperature swings.

They hope the strains will help protect food production from the impacts of climate change.

The trust says a lack of readily available and accurate material severely hinders plant breeders' efforts to identify material that can be used to develop crop varieties that will cope with future conditions.

"Our crops must produce more food, on the same amount of land, with less water, and more expensive energy," explained the trust's executive director, Cary Fowler.

"There is no possible scenario in which we can continue to grow food we require without crop diversity."

The $1.5m (£750,000) scheme will provide grants for projects that will screen developing nations' seed collections.

Open access

The gene hunt is the latest stage in the organisation's ongoing process of conserving the diversity of the world's food crops.

The team will screen developing nations' collections of major food crops

Over the past few years, it has convened a series of meetings that brought together leading experts for each of the main food crops, such as wheat, rice, lentils and maize.

Each meeting was set the task of identifying the best conservation strategy for each of the crops.

"The experts have, among other things, helped us identify which are the most important seed collections in terms of genetic diversity," Mr Fowler told BBC News.

"This has provided us with the scientific foundation for almost everything else we do."

The information has helped the trust, which is also responsible for the "Doomsday seed vault" in the Arctic, pinpoint the exact characteristics needed to ensure that crops have the best chance of thriving in the future.

Mr Fowler said one example was whether a plant displayed a good degree of heat resistance during its flowering period.

This was a time when a plant would be experiencing increased stress, he said, yet very little data had been gathered on this part of the organisms' lifecycles.

Over the next 12-24 months, the project's researchers hope to build up a comprehensive profile of the various "climate-proof" traits and in which crops they are found.

"Then it is a matter of getting these varieties containing those valuable traits into breeding programmes," Mr Fowler explained.

He added that all the data would be made available to everyone -- both public and private organisations -- in an online database.

"Plant breeders will be able to go online and type their search criteria, then up pops the details of the samples that match the breeders' requirements, such as drought tolerance or heat resistance."

Developing crops that will be able to produce higher yields and cope with climate change is one avenue that is also being explored by the biotechnology sector.

Campaigners in favour of genetically modified organisms (GMOs) hope that developments in this area will lessen public opposition to GM food.

When asked whether he was concerned that the information gathered by the trust could be used to produce commercial GM crops, Mr Fowler said: "We don't have a horse in that race.

"Agriculture is facing a lot of challenges, and diversity holds a lot of the keys to meeting those challenges.

"I wish I had a crystal ball good enough to see what agriculture is going to need 100 years or 500 years from now, but I don't.

"All I would say is that the people involved in fighting the pro-GMO or anti-GMO battle don't have that crystal ball either -- the best we can do is conserve all the options."

Link to article: http://news.bbc.co.uk/2/hi/science/nature/7622920.stm

Puzzling Property Of Night-shining Clouds At Edge Of Space Explained

ScienceDaily (Sep. 26, 2008) — An explanation for a strange property of noctilucent clouds--thin, wispy clouds hovering at the edge of space at 85 km altitude--has been proposed by an experimental plasma physicist at the California Institute of Technology (Caltech), possibly laying to rest a decades-long mystery.

Noctilucent clouds, also known as night-shining clouds, were first described in 1885, two years after the massive eruption of Krakatoa, a volcanic island in Indonesia, sent up a plume of ash and debris up to 80 km into Earth's atmosphere. The eruption affected global climate and weather for years and may have produced the first noctilucent clouds.

The effects of Krakatoa eventually faded, but the unusual electric blue clouds remain, nestled into a thin layer of Earth's mesosphere, the upper atmosphere region where pressure is 10,000 times less than at sea level. The clouds, which are visible during the deep twilight, are most often observed during the summer months at latitudes from 50 to 70 degrees north and south--although in recent years they have been seen as far south as Utah and Colorado. Noctilucent clouds are a summertime phenomenon because, curiously, the atmosphere at 85 km altitude is coldest in summer, promoting the formation of the ice grains that make up the clouds.

"The incidence of noctilucent clouds seems to be increasing, perhaps because of global warming," says Paul M. Bellan, a professor of applied physics at Caltech.

Twenty-five years ago, researchers at Poker Flat, Alaska, discovered that the clouds were highly reflective to radar. This unusual property has long puzzled scientists. Bellan, reporting in the August issue of the Journal of Geophysical Research-Atmospheres, now has an explanation: the ice grains in noctilucent clouds are coated with a thin film of metal, made of sodium and iron. The metal film causes radar waves to reflect off ripples in the cloud in a manner analogous to how X-rays reflect from a crystal lattice.

Sodium and iron atoms collect in the upper atmosphere after being blasted off incoming micrometeors. These metal atoms settle into a thin layer of vapor that sits just above the altitude at which noctilucent clouds occur. Astronomers recently have been using the sodium layer to create laser-illuminated artificial guide stars for adaptive optics telescopes that remove the distorting affects of atmospheric turbulence to produce clearer celestial images.

Measurements of the density of sodium and iron atomic vapor layers show that the metal vapor is depleted by over 80 percent when noctilucent clouds are present. "Noctilucent clouds have been shown to act very much like a flycatcher for sodium and iron atoms," Bellan says. Indeed, in laboratory experiments, other researchers have found that at the frigid temperatures (-123 degrees Celsius) within noctilucent clouds, atoms in sodium vapor quickly become deposited on the surface of ice to form a metallic film.

"If you have metal-coated ice grains in noctilucent clouds, the radar reflectivity can become enormous" he says. "This reflectivity is not the sum of reflections from individual ice grains, which would not produce a very large reflection. Instead, what happens is that ripples in the cloud of metal-coated ice grains reflect in unison and reinforce each other, somewhat like an army marching in step across a bridge causes the bridge to vibrate."

The rise in global carbon dioxide emissions last year outpaced international researchers' most dire projections, according to figures being released today, as human-generated greenhouse gases continued to build up in the atmosphere despite international agreements and national policies aimed at curbing climate change.

In 2007, carbon released from burning fossil fuels and producing cement increased 2.9% over that released in 2006, to a total of 8.47 gigatons, or billions of metric tons, according to the Australia-based Global Carbon Project, an international consortium of scientists that tracks emissions. This output is at the very high end of scenarios outlined by the Intergovernmental Panel on Climate Change (IPCC) and could translate into a global temperature rise of more than 11 degrees Fahrenheit by the end of the century, according to the panel's estimates.

"In a sense, it's a reality check," said Corinne Le Quéré, a professor at the School of Environmental Sciences at the University of East Anglia and a researcher with the British Antarctic Survey. "This is an extremely large number. The emissions are increasing at a rate that's faster than what the IPCC has used."

The new statistics also underscore the growing contribution to the world's "carbon budget" from rapidly industrializing countries such as China, India and Brazil. Developing nations have roughly doubled their carbon output in less than two decades and now account for slightly more than half of total emissions, according to the new figures, up from about a third in 1990. By contrast, total carbon emissions from industrialized nations are only slightly higher than in 1990.

"What's happening is the major developed countries' plans are converging for emissions growth that will stop and be able to come down significantly," said James L. Connaughton, who chairs the White House Council on Environmental Quality. "But that's being completely overtaken now by the increasing greenhouse gas emissions in developing counties. It underscores the need for a broader and more aggressive effort by the major economies to come together."

It is unclear how much industrialized countries will be able to reduce their carbon output in the years to come, regardless of whether developing nations seek to restrain their greenhouse gas emissions. The federal government predicts that U.S. fossil fuel consumption will increase, not decrease. Japan, Canada and several other countries that committed to reducing their carbon emissions under the 1997 Kyoto Protocol have fallen far behind in meeting their targets.

Moreover, new scientific research suggests Earth is already destined for a greater worldwide temperature rise than previously predicted. Last month, two scientists from the Scripps Institution of Oceanography and the University of California at San Diego published research showing that even if humans stopped generating greenhouse gases immediately, the world's average temperature would "most likely" increase by 4.3 degrees Fahrenheit by the end of this century. Writing in the journal Proceedings of the National Academy of Sciences, they based their calculations on the fact that new air-quality measures worldwide are reducing the amount of fine particles, or aerosols, in the atmosphere and diminishing their cooling effect.

The IPCC has warned that an increase of between 3.2 and 9.7 degrees Fahrenheit could trigger massive environmental changes, including major melting of the Greenland ice sheet, the Himalayan-Tibetan glaciers and summer sea ice in the Arctic. The prediction that current emissions put the planet on track for a temperature rise of more than 11 degrees Fahrenheit, Le Quéré said, means the world could face a dangerous rise in sea level as well as other drastic changes.

Richard Moss, vice president and managing director for climate change at the World Wildlife Fund, said the new carbon figures and research show that "we're already locked into more warming than we thought."

"We should be worried, really worried," Moss said. "This is happening in the context of trying to reduce emissions."

The new data also show that forests and oceans, which naturally take up much of the carbon dioxide humans emit, are having less impact. These "natural sinks" have absorbed 54% of carbon dioxide emissions since 2000, a drop of 3% compared with the period between 1959 and 2000.

Connaughton argued that the Bush administration's "major economies" meetings, a series of talks among both developed and rapidly industrializing nations, have moved the world closer toward achieving significant cuts in greenhouse gases because the group is developing a common measurement system for emissions and is exploring how different industrial sectors can commit to worldwide reductions.

"We are unquestionably moving toward each other," he said of the industrialized and developing countries, "but there's a ways to go."

But Moss, who characterized the latest round of negotiations as "a lot of talk but not much action," said the administration cannot expect emerging economies to constrain their carbon emissions when the United States has yet to adopt binding targets for cutting its greenhouse gases. He noted that since 1990, the United States has released about 30 gigatons of carbon into the atmosphere, compared with China's seven gigatons and India's one.

"We really do have to start showing some leadership and start doing some changes ourselves," he said. "If we did that, China and India, which are developing rapidly, would be willing to come along."

Link: http://www.washingtonpost.com/wp-dyn/content/article/2008/09/25/AR2008092503989.html

NASA climate expert warns Kansans of dire consequences of global warming

Photo by Thad Allender. James Hansen answers questions from the public about global warming on Tuesday at the Kansas Wind and Renewable Energy Conference in Topeka. A capacity crowd filled the Ramada Inn to hear Hansen, one of the nation’s foremost climate experts, explain climate change and the factors that raise temperatures on Earth. In the foreground is Kansas Lt. Gov. Mark Parkinson.

Courtesy of Cornelis J. van der Veen/Center for Remote Sensing of Ice Sheets

As sea level rises because of melting ice sheets like this one in Greenland, so do the risks to the more than 1 billion people living in coastal areas around the world, warns James Hansen, of NASA’s Goddard Institute for Space Studies.

TOPEKA — One day after a scientist told Kansas leaders not to worry about global warming, one of the leading experts on climate change stated Tuesday that if carbon dioxide emissions continue to increase it will eventually mean the end of life.

“If we don’t get this thing under control we are going to destroy the creation,” said James Hansen, who heads the NASA Goddard Institute for Space Studies and was one of the first scientists to raise the alarm about global warming in the 1980s.

Speaking to more than 500 people at the Kansas Wind and Renewable Energy Conference, Hansen called for policymakers to phase out coal-burning power plants by 2030. This will reduce carbon dioxide emissions that he said have already caused serious and possibly irreversible damage to Earth.

“We do have a planetary emergency,” Hansen said.

Hansen said some scientists claim global warming is part of a natural climate cycle by pointing to past eras of higher temperatures.

But Hansen said the CO2 increases over the past few decades have been caused by humans burning fossil fuels, such as coal, oil and natural gas. Along with the increase in CO2 have come dramatic temperature shifts and environmental distress signals, such as the melting of glaciers, rising sea levels and expansion of deserts, he said.

“Humans are now controlling the mechanisms for climate change,” he said.

He said many energy companies try to confuse the issue in the public’s mind and are successful because some of the environmental changes take decades to detect. He accused those fossil fuel companies of being guilty of “crimes against humanity and nature.”

Hansen said the increase of CO2 must and can be reversed. In addition to removing coal-burning electric plants, he called on increased use of renewable energy and nuclear energy.

On Monday, research scientist Roy Spencer, who wrote “Climate Confusion,” said at a Kansas Chamber of Commerce event that burning fossil fuels wasn’t the cause of climate change, and that even if it was, the environment would be able to absorb the changes.

But Lt. Gov. Mark Parkinson, who introduced Hansen at the renewable energy conference, said, “The overwhelming amount of scientific evidence is that climate change is real and we have reached a point that if we don’t do something about it, future generations will be adversely affected.”

Parkinson said businesses that deal with climate change will be the ones that thrive.

“Companies that will survive the next 10, 20, 30, 50 years are companies that recognize these changes are taking place and will take advantage of them,” he said.

Hansen called on the United States to take the lead in reducing CO2 emissions, noting that it has produced the most. He said at some point humans will have to do without fossil fuels because there is a finite supply.

“Why not do it a little sooner and save the planet in the meantime?” he said.

Hansen also praised Kansas politicians who earlier this year blocked the construction of two coal-fired power plants in western Kansas.

“At least you have leaders who are trying to do the right thing,” he said.

Link to article: http://www2.ljworld.com/news/2008/sep/23/nasa_climate_expert_warns_dire_consequences_global/

by Steve Connor, Science Editor, The Independent, September 23, 2008

There are two significant facts about methane in terms of global warming. It is about 20 times more potent as a greenhouse gas than carbon dioxide, and there are massive stores of it locked away under the permafrost of the northern hemisphere.

Methane is produced naturally by the decay of water-logged vegetation. Over thousands of years it has accumulated under the ground at northern latitudes and has effectively been taken out of circulation by the permafrost acting as an impermeable lid.

What makes methane so potentially dangerous is that its release from under the now-leaking permafrost could accelerate global warming, which in turn would speed the melting of the permafrost and release even more methane. Scientists believe this has happened in the geological past with devastating consequences for the global climate and life.

Like carbon dioxide, average methane concentrations in the atmosphere have risen significantly since the Industrial Revolution, increasing from about 700 parts per billion (ppb) in 1800 to about 1,790ppb today. Much of this increase is down to human activities, notably oil and gas exploration, and agriculture.

For the past 10 years, average global methane concentrations have levelled out, probably because of improvements in Russian gas exploration. However, for the first time in more than a decade, scientists recorded an increase in global methane in 2007 and are set to measure a further increase this year.

Scientists at the US National Oceanic and Atmospheric Administration (NOAA) have identified the Arctic as a potentially important new source of methane as temperatures in the region increase; it is one of the most rapidly warming places on Earth. "We're on the look-out for the first sign of a methane release from thawing Arctic permafrost. It's too soon to tell whether last year's spike in emissions includes the start of such a trend," said NOAA's methane expert Ed Dlugokencky last April.

The good news about methane is that it is quickly degraded in the environment, with an average lifetime of about 12 years, compared to the 100 years of carbon dioxide. The bad news is that we do not understand how the methane stores in the north will behave as the region experiences more extensive thaws. The fear is that the amounts released will make global warming far worse than expected.

Link to article: http://www.independent.co.uk/opinion/commentators/steve-connor-the-ultimate-gas-leak-that-scientists-dreaded-938935.html

Exclusive: The methane time bomb

by Steve Connor, Science Editor, The Independent, September 23, 2008

Arctic scientists discover new global warming threat as melting permafrost releases millions of tons of a gas 20 times more damaging than carbon dioxide.

Preliminary findings suggest that massive deposits of subsea methane are bubbling to the surface as the Arctic region becomes warmer and its ice retreats

The first evidence that millions of tons of a greenhouse gas 20 times more potent than carbon dioxide is being released into the atmosphere from beneath the Arctic seabed has been discovered by scientists.

The Independent has been passed details of preliminary findings suggesting that massive deposits of sub-sea methane are bubbling to the surface as the Arctic region becomes warmer and its ice retreats.

Underground stores of methane are important because scientists believe their sudden release has in the past been responsible for rapid increases in global temperatures, dramatic changes to the climate, and even the mass extinction of species. Scientists aboard a research ship that has sailed the entire length of Russia's northern coast have discovered intense concentrations of methane – sometimes at up to 100 times background levels – over several areas covering thousands of square miles of the Siberian continental shelf.

In the past few days, the researchers have seen areas of sea foaming with gas bubbling up through "methane chimneys" rising from the sea floor. They believe that the sub-sea layer of permafrost, which has acted like a "lid" to prevent the gas from escaping, has melted away to allow methane to rise from underground deposits formed before the last ice age.

They have warned that this is likely to be linked with the rapid warming that the region has experienced in recent years.

Methane is about 20 times more powerful as a greenhouse gas than carbon dioxide and many scientists fear that its release could accelerate global warming in a giant positive feedback where more atmospheric methane causes higher temperatures, leading to further permafrost melting and the release of yet more methane.

The amount of methane stored beneath the Arctic is calculated to be greater than the total amount of carbon locked up in global coal reserves so there is intense interest in the stability of these deposits as the region warms at a faster rate than other places on earth.

Orjan Gustafsson of Stockholm University in Sweden, one of the leaders of the expedition, described the scale of the methane emissions in an email exchange sent from the Russian research ship Jacob Smirnitskyi.

"We had a hectic finishing of the sampling programme yesterday and this past night," said Dr Gustafsson. "An extensive area of intense methane release was found. At earlier sites we had found elevated levels of dissolved methane. Yesterday, for the first time, we documented a field where the release was so intense that the methane did not have time to dissolve into the seawater but was rising as methane bubbles to the sea surface. These 'methane chimneys' were documented on echo sounder and with seismic [instruments]."

At some locations, methane concentrations reached 100 times background levels. These anomalies have been seen in the East Siberian Sea and the Laptev Sea, covering several tens of thousands of square kilometres, amounting to millions of tons of methane, said Dr Gustafsson. "This may be of the same magnitude as presently estimated from the global ocean," he said. "Nobody knows how many more such areas exist on the extensive East Siberian continental shelves.

"The conventional thought has been that the permafrost 'lid' on the sub-sea sediments on the Siberian shelf should cap and hold the massive reservoirs of shallow methane deposits in place. The growing evidence for release of methane in this inaccessible region may suggest that the permafrost lid is starting to get perforated and thus leak methane... The permafrost now has small holes. We have found elevated levels of methane above the water surface and even more in the water just below. It is obvious that the source is the seabed."

The preliminary findings of the International Siberian Shelf Study 2008, being prepared for publication by the American Geophysical Union, are being overseen by Igor Semiletov of the Far-Eastern branch of the Russian Academy of Sciences. Since 1994, he has led about 10 expeditions in the Laptev Sea but during the 1990s he did not detect any elevated levels of methane. However, since 2003 he reported a rising number of methane "hotspots", which have now been confirmed using more sensitive instruments on board the Jacob Smirnitskyi.

Dr Semiletov has suggested several reasons why methane is now being released from the Arctic, including the rising volume of relatively warmer water being discharged from Siberia's rivers due to the melting of the permafrost on the land.

The Arctic region as a whole has seen a 4C rise in average temperatures over recent decades and a dramatic decline in the area of the Arctic Ocean covered by summer sea ice. Many scientists fear that the loss of sea ice could accelerate the warming trend because open ocean soaks up more heat from the sun than the reflective surface of an ice-covered sea.

Link to article: http://www.independent.co.uk/environment/climate-change/exclusive-the-methane-time-bomb-938932.html

Environmental Research Web, September 22, 2008

Even if greenhouse gas emissions are fixed at 2005 levels, new analysis shows that irreversible warming will lead to biodiversity loss and substantial glacial melt.

When Environment Canada scientists were ordered to refer all media calls to Ottawa earlier this year, climatologist Andrew Weaver denounced the Harper government for "muzzling" federal researchers.

After the Conservatives announced "aspirational" targets for reducing Canada's greenhouse gas emissions, the University of Victoria researcher said he could see no scientific rationale for the numbers. "Maybe they have a Ouija board or something," he suggested.

Now the colourful and outspoken academic has a new book, Keeping Our Cool, Canada in a Warming World, coincidentally published by Viking Canada the same week Prime Minister Stephen Harper called the election.

Prof. Andrew Weaver's latest book is getting high praise in some quarters, but is not likely to win him many friends on the Conservative campaign plane.

Ray Smith/ Victoria Times Colonist

It is getting high praise in some quarters, but it is not likely to win Weaver many friends on the Conservative campaign plane.

The book gives a sobering account of climate change and includes colourful commentary on the increasingly wacky weather -- Weaver was visiting family in Greece during last summer's wild fires. There is also an insider's perspective on the United Nation's Intergovernmental Panel on Climate Change (IPCC), which was co-winner of the last's year Nobel Peace Prize. Weaver was one of the lead authors.

Weaver's overriding message is that the planet is fast approaching the threshold of "acceptable" global warming and society must slash greenhouse gasses by weaning itself off fossils fuels, one of the largest sources of carbon dioxide.

But he notes how Alberta, by far Canada's largest greenhouse gas emitter, plans to reduce emissions by 14% by 2050, far less than is required. If Alberta is to only cut emissions by 14%, the rest of Canada would have to cut emissions by 81% to meet Harper's "aspirational" target of 60% reduction by 2050, he says, calling attention to the "staggering" disconnect between the national and provincial targets.

Environmentalist David Suzuki says the book "should be the final alarm."

Thomas Homer-Dixon, who specializes in environmental security at the Balsillie School of International Affairs, has also endorsed the book saying: "For Canadians, this is the best single book on our climate crisis and what we should do about it."

The book is also laced with harsh criticism of the Harper government's handling of the climate file. He writes that the Conservatives have in the last two years dismantled and cut funding to important federal climate programs and research initiatives, rebuffed calls for action and requests for meetings by leading climate scientists, and "played a major role in obstructing international efforts to reduce greenhouse gas emissions."

The Conservatives' media office declined to respond to the criticisms raised in the book.

Link to article: http://www.canada.com/vancouversun/news/story.html?id=8259fbc8-7760-436a-b001-e5d56be8e659

Abrupt Climate Change Focus Of U.S. National Laboratories

ScienceDaily (Sep. 18, 2008) — Abrupt climate change is a potential menace that hasn’t received much attention. That’s about to change. Through its Climate Change Prediction Program, the U.S. Department of Energy’s Office of Biological and Environmental Research (OBER) recently launched IMPACTS – Investigation of the Magnitudes and Probabilities of Abrupt Climate Transitions – a program led by William Collins of Berkeley Lab’s Earth Sciences Division (ESD) that brings together six national laboratories to attack the problem of abrupt climate change, or ACC.

Sparked by the 2007 Nobel Peace Prize that was shared by Al Gore and the Intergovernmental Panel on Climate Change (IPCC), the reality of global warming finally got through to the majority of the world’s population. Most people think of climate change as something that occurs only gradually, however, with average temperature changing two or three degrees Celsius over a century or more; this is the rate at which ‘forcing’ mechanisms operate, such as the accumulation of carbon dioxide in the atmosphere due to the burning of fossil fuels or widespread changes in land use.

But climate change has occurred with frightening rapidity in the past and will almost certainly do so again. Perhaps the most famous example is the reverse hiccup in a warming trend that began 15,000 years ago and eventually ended the last ice age. Roughly 2,000 years after it started, the warming trend suddenly reversed, and temperatures fell back to near-glacial conditions; Earth stayed cold for over a thousand years, a period called the Younger Dryas (named for an alpine wildflower). Then warming resumed so abruptly that global temperatures shot up 10 °C in just 10 years.

Because civilizations hadn’t yet emerged, complex human societies escaped this particular roller-coaster ride. Nevertheless, some form of abrupt climate change is highly likely in the future, with wide-ranging economic and social effects.

Collins, who heads the Climate Science Department in ESD, is the principal investigator for IMPACTS, which will bring together the work of experts in physical, chemical, and biogeochemical climate processes and in computer simulations of the whole Earth system. Argonne, Los Alamos, Lawrence Berkeley, Lawrence Livermore, Oak Ridge, and Pacific Northwest are the participating national laboratories.

“IMPACTS is one part of a two-pronged approach to studying abrupt climate change, one based in the universities and the other in the national labs,” says Collins. “Both elements will share a central web-based portal, with all the participants meeting annually.” The goal is to understand possible mechanisms of abrupt climate change well enough to build comprehensive computer models, Collins says, and to make accurate predictions before abrupt climate change strikes again.

Collins coordinated the development of the most recent version of the Community Climate System Model (CCSM), one of the leading models underpinning the physical science basis of the IPCC’s 2007 climate change assessment; the IMPACTS program will be based on CCSM and will add new capabilities and new diagnostics for processes that could initiate abrupt climate change. CCSM, called by Science magazine “the nation’s foremost academic global climate model,” has long been supported by both DOE and the National Science Foundation.

“There are lots of names for abrupt climate change: nasty surprises, the jokers in the deck, the tipping point,” Collins says. “When the national lab participants first met to decide on the most significant potential sources of abrupt climate change in future, the first thing we had to do was define what we meant: a large-scale change that happens more quickly than that brought on by forcing mechanisms – on a scale of years to decades, not centuries – and that persists for a very long time.”

The IMPACTS team will initially focus on four types of ACC:

1. instability among marine ice sheets, particularly the West Antarctic ice sheet;
2. positive feedback mechanisms in subarctic forests and arctic ecosystems, leading to rapid methane release or large-scale changes in the surface energy balance;
3. destabilization of methane hydrates (vast deposits of methane gas caged in water ice), particularly in the Arctic Ocean; and
4. feedback between biosphere and atmosphere that could lead to megadroughts in North America.

Only half joking, Collins refers to these as “the Four Horsemen of the Apocalypse.”

The Four Horsemen of the Apocalypse

Marine ice sheet instability: marine ice sheets flow from the land into the sea and are partly grounded below sea level, extending across the ocean surface as floating ice shelves. Greenland and the West Antarctic ice sheets are already losing mass at an accelerating rate, with the primary cause apparently the warming of the oceans, not the air, through melting of ice buttresses below the water’s surface. Topographical and other features make the West Antarctic ice sheet particularly vulnerable.

For 40 years earth scientists have worried about what would happen if global warming eventually caused the West Antarctic ice sheet, some 3.8 million cubic kilometers of ice, to break up and slide into the ocean. Sea level would rise four to six meters – 13 to 20 feet. Port facilities worldwide would be submerged; atolls and island chains would vanish; parts of Bangladesh, Brazil, Burma, America’s Gulf States, and other low-lying areas would flood; Venice, New Orleans, and many other cities would sink. It’s now apparent that these events may not be “eventual” – abrupt climate change could cause rapid melting and the subsequent rise of sea level not by centimeters but by meters per century.

Under the direction of Bill Lipscomb of Los Alamos National Laboratory, IMPACTS researchers including Rob Jacob from Argonne National Laboratory will undertake the difficult task of realistically modeling the processes of ice-shelf melting, the retreat of a shelf’s underwater grounding line, and the calving of icebergs. Concentrating on the West Antarctica ice sheet, they will use the Hybrid Parallel Ocean Program (HYPOP) developed at Los Alamos and other programs to simulate ocean currents beneath ice shelves up to hundreds of meters thick and hundreds of kilometers in extent; to model the exchange of heat between ocean and ice; to model the shifting grounding lines of the ice shelves; and to model the changing shore lines of the world’s oceans as the ice shelves evolve. The goal is to assess the likelihood of abrupt ice-sheet retreat under different conditions and to incorporate the regional ice-sheet model into the fully coupled CCSM global model.

Positive feedbacks in boreal and Arctic ecosystems: more than a third of Earth’s terrestrial organic carbon is concentrated in the ecosystems north of the 45th parallel, much of it in soil, peatland basins, and permafrost. Positive feedback within ecosystems and among terrestrial ecosystems, climate, and ocean currents could rapidly release much of this stored carbon into the atmosphere.

Higher air temperatures and increased precipitation have already reduced snow cover and increased runoff from melting permafrost; vegetation types have started to shift, affecting, for example, how much sunlight reaches the soil or is intercepted by forest canopies. Less snow cover means less reflectivity (albedo); dark soil and trees absorb more heat from the sun. The kind of permafrost called yedoma is particularly rich in carbon, an important substrate for methane formation. Methane, a greenhouse gas 26 times more powerful than carbon dioxide in the short term, is released when the permafrost melts. Even ordinary soil will exchange more carbon with the atmosphere as it warms and wets.

In addition, as more fresh water flows into the Arctic, changes in salinity could alter the exchange of water with the North Atlantic and shut off ocean currents that keep Europe warm in winter. Northern Europe may grow colder even as the oceans’ ability to absorb carbon dioxide decreases and the planet as a whole grows warmer, faster.

Positive feedback involving ice-melt has already accelerated the pace of global warming in the far north. It now seems likely that changes in terrestrial ecosystems, which could occur over only 20-30 years, may amplify currently predicted global warming by two or three times, in the Arctic and possibly globally.

Led by Collins, IMPACTS researchers including ESD’s William Riley and Margaret Torn, plus Mac Post from Oak Ridge National Lab and Qianlai Zhuang from Purdue University, will add significant new capabilities to the Community Land Model (CLM) component of CCSM. Their goal is to produce dramatically improved predictions of abrupt climate change resulting from positive feedbacks between the climate and ecosystems of the boreal and Arctic region.

Methane hydrate destabilization: a vast quantity of carbon – possibly more than all the recoverable fossil fuels on Earth – is trapped in frozen methane hydrates under the oceans. Methane gas molecules are locked inside cages of water ice in a form so concentrated that when the ice melts the gas expands to 164 times its frozen volume.

Over time this methane, if released into the atmosphere, would be up to 72 times more potent than carbon dioxide as a greenhouse gas. During a thermal maximum 55 million years ago, which marked the boundary between the Paleocene and Eocene epochs, the planet warmed rapidly by five to eight °C; the pattern of deep-sea extinctions and spikes in methane concentrations in the fossil record during this 20,000-year period point to methane release as a possible cause.

High pressure and low temperature insure that most deep-water methane hydrate deposits would be stable even with considerable warming of the atmosphere. But in the Arctic, methane hydrate deposits exist near the edge of the safe temperature-pressure zone; in these locales, methane release could be abrupt. The resultant rapid warming would trigger yet more releases of methane: permafrost would melt, the deep sea would become a dead zone, the hole in the Arctic ozone would grow bigger and occur more frequently.

IMPACTS researchers, led by Philip Cameron-Smith of Lawrence Livermore National Laboratory and including ESD’s Matthew Reagan and Scott Elliot and Mathew Maltrud of Los Alamos, will study a range of rapid-change scenarios by coupling a number of proven models: Berkeley Lab’s TOUGH+HYDRATE code has been successfully used by oil companies and geologists to model subsurface hydrate dissociation and gas production, and Los Alamos’s Parallel Ocean Program (POP) and Lawrence Livermore’s Community Atmosphere Model (CAM) are already components of CCSM. By accommodating improved methane dynamics in climate and ocean models and studying coupled methane-hydrate dissociation and transport at the seafloor, the researchers hope to make accurate assessments of methane releases and the consequences for oceanic and atmospheric chemistry.

Megadroughts in North America: “ordinary” greenhouse warming as forecast by the IPCC will result in warmer and dryer conditions in the subtropics, including Mexico and the southwestern U.S. More than warming of the air and sea surface are involved. Storm tracks are likely to shift north, and the jet stream will probably stabilize in a new configuration. Dried-out soil and hot, dry atmosphere could interact to start abrupt climate change.

Conditions as severe as the Dust Bowl of the 1930s will return and could persist for decades: a megadrought. Until seven or eight hundred years ago, Central North America seems to have been characterized by much longer and more severe droughts than at present. The Dust Bowl of the thirties turned many once productive fields and rangelands into shifting sand dunes; the past was even worse, with vast sheets of sand on the move all across the High Plains.

IMPACTS researchers, led by Ruby Leung of Pacific Northwest National Laboratory and including Celine Bonfils and Thomas Phillips of Lawrence Livermore, will test two hypotheses. The first is that plants modulate soil hydration in the early stages of a drought by redistributing deep ground water through their roots and leaves. But when the water table drops too low, plants accelerate the desiccation of the soil surface by their one-way transpiration of moisture into the atmosphere.

The second hypothesis is that dust storms will alter the North American monsoon, which brings water from the Gulf of Mexico and the Gulf of California during the summer months to contribute one-half to two-thirds of the annual precipitation in the Southwest. Complex interactions of surface conditions, atmospheric stability, dust-particle aerosols, and other factors could profoundly alter monsoon circulation in unpredictable ways.

To predict now unpredictable megadroughts, researchers will improve global and regional climate models, including the Weather Research and Forecasting (WRF) model developed at the National Center for Atmospheric Research and other agencies, coupled with the Variable Infiltration Capacity (VIC) model of water-energy exchange developed at the University of Washington, as well as land surface and plant models.

What to Do Next

“IMPACTS starts by using primary scientific research to build detailed models of processes that have been included only roughly, if at all, in climate models – the effects of methane on sunlight, for example, which has never before been incorporated, or the role of vegetation in moisture exchange between soil and atmosphere,” Collins says. “We will use our improved models to help build an even more powerful CCSM, one we hope will be able to make very robust predictions.”

And when they succeed?

“Suppose we see something,” says Collins. “Suppose, for example, our models predict the abrupt onset of a megadrought in the Southwest.” The first step will be to assess the prediction by measuring it against the past. “We go back in time. If the conditions we think will lead to abrupt climate change would not have produced this result in the past, we still have work to do. On the other hand, if our models can use data from past conditions to recover what actually did happen, it’s an excellent test.”

A believable ACC prediction would mean “we are facing the largest imaginable negative impacts on human civilization, conditions that will take society outside all normal modes of adaptation very quickly,” says Collins. “The consequences will be especially dire for resource-limited populations. This is a huge threat to the security and stability of our nation and the world, which is one reason DOE has made a major investment in CCSM.”

Collins says that the 30-year quest to make climate models truly comprehensive has only recently met with success. “We used to build in the carbon cycle by telling the model how it would work – but we’ve learned that we can’t assume that; the carbon cycle is extremely sensitive to even relatively small changes in temperature and rainfall. We’ve only recently been able to simulate vegetation; we used to model forests by just placing them into the model arbitrarily – now we allow them to grow themselves. Much of this is possible because of DOE’s huge contribution to climate modeling through supercomputers. That’s why Berkeley Lab’s NERSC” – the National Energy Research Scientific Computing Center – “is such an important part of our IMPACTS partnership.”

One of the great benefits of IMPACTS, in Collins’s view, will be to bring together parts of the climate community whose communication has traditionally been poor. For scientists concerned with the effects of climate change and those concerned with modeling it, “the working relationship hasn’t been there,” says Collins. “For example, of the major threats to human health from global warming, the worst is malnutrition – but the second worst is extreme weather!”

Collins says that modelers now have the ability to take lessons from likely impacts back into their basic research. “Modeling a specific region with a specific set of circumstances in high resolution and making a solid prediction of what’s going to happen in the next few decades is much tougher than modeling what’s going to happen to the whole globe a century from now,” he says. “Those concerned with the effects of climate change on humans have never asked modelers to do this before. We hope that IMPACTS will demonstrate that it can be done.”

Ancient Permafrost and a Future, Warmer Arctic

Climate models predict extensive and severe degradation of permafrost in response to global warming, with a potential for release of large volumes of stored carbon. However, the accuracy of these models is difficult to evaluate because little is known of the history of permafrost and its response to past warm intervals of climate. We report the presence of relict ground ice in subarctic Canada that is greater than 700,000 years old, with the implication that ground ice in this area has survived past interglaciations that were warmer and of longer duration than the present interglaciation.

¹ Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T5M 0M3, Canada.
² Department of Geology, University of Toronto, Toronto, ON M5S 3B1, Canada.
³ Geological Survey of Canada–Pacific, Sidney, BC V8L 4B2, Canada.

Environmental Research Letters, September 17, 2008

Small glaciers, not large, account for most of Greeenland's recent loss of ice, study shows

COLUMBUS, Ohio: The recent dramatic melting and breakup of a few huge Greenland glaciers have fueled public concerns over the impact of global climate change, but that isn’t the island’s biggest problem.