Blog Archive

Tuesday, September 30, 2008

Carbon Dioxide Captured Directly From Air: David Keith, University of Calgary

Global Warming Fix? Carbon Dioxide Captured Directly From Air

ScienceDaily (Sep. 30, 2008) — University of Calgary climate change scientist David Keith and his team are working to efficiently capture the greenhouse gas carbon dioxide directly from the air, using near-commercial technology.

In research conducted at the U of C, Keith and a team of researchers showed it is possible to reduce carbon dioxide (CO2) – the main greenhouse gas that contributes to global warming – using a relatively simple machine that can capture the trace amount of CO2 present in the air at any place on the planet.

"At first thought, capturing CO2 from the air where it's at a concentration of 0.04 per cent seems absurd, when we are just starting to do cost-effective capture at power plants where CO2 produced is at a concentration of more than 10 per cent," says Keith, Canada Research Chair in Energy and Environment.

"But the thermodynamics suggests that air capture might only be a bit harder than capturing CO2 from power plants. We are trying to turn that theory into engineering reality."

The research is significant because air capture technology is the only way to capture CO2 emissions from transportation sources such as vehicles and airplanes. These so-called diffuse sources represent more than half of the greenhouse gases emitted on Earth.

"The climate problem is too big to solve easily with the tools we have," notes Keith, director of the Institute for Sustainable Energy, Environment and Economy's (ISEEE) Energy and Environmental Systems Group and a professor of chemical and petroleum engineering.

"While it's important to get started doing things we know how to do, like wind power nuclear power and 'regular' carbon capture and storage, it's also vital to start thinking about radical new ideas and approaches to solving this problem."

Energy-efficient and cost-effective air capture could play a valuable role in complementing other approaches for reducing emissions from the transportation sector, such as biofuels or electric vehicles, says David Layzell, ISEEE's Executive Director.

"David Keith and his team have developed a number of innovative ways to achieve the efficient capture of atmospheric carbon. That is a major step in advancing air capture as a solution to a very pressing problem," Layzell says.

"David Keith's vision and originality are key factors in our ranking this year as the top engineering school in Canada for sustainability initiatives, both in terms of research and curriculum," says Elizabeth Cannon, Dean of the Schulich School of Engineering. "Leaders like this are not commonplace, and we are proud to get behind this kind of leadership at the Schulich School."

Air capture is different than the carbon capture and storage (CCS) technology which is a key part of the Alberta and federal governments' strategies to reduce greenhouse gas emissions. CCS involves installing equipment at, for example, a coal-fired power plant to capture carbon dioxide produced during burning of the coal, and then pipelining this CO2 for permanent storage underground in a geological reservoir.

Air capture, on the other hand, uses technology that can capture – no matter where the capture system is located – the CO2 that is present in ambient air everywhere.

"A company could, in principle, contract with an oilsands plant near Fort McMurray to remove CO2 from the air and could build its air capture plant wherever it's cheapest – China, for example – and the same amount of CO2 would be removed," Keith says.


"This means that if you used electricity from a coal-fired power plant, for every unit of electricity you used to operate the capture machine, you'd be capturing 10 times as much CO2 as the power plant emitted making that much electricity," Keith says.


The technology is still in its early stage, Keith stresses. "It now looks like we could capture CO2 from the air with an energy demand comparable to that needed for CO2 capture from conventional power plants, although costs will certainly be higher and there are many pitfalls along the path to commercialization."

Nevertheless, the relatively simple, reliable and scalable technology that Keith and his team developed opens the door to building a commercial-scale plant.

Richard Branson, head of Virgin Group, has offered a $25-million prize for anyone who can devise a system to remove the equivalent of one billion tonnes of carbon dioxide or more every year from the atmosphere for at least a decade.

Technical details of the air capture technology are available at:

Link to article:

New GRACE measurements of Greenland ice loss, 2002-2008

An Accurate Picture Of Ice Loss In Greenland


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



Sea level rise





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
Adapted from materials provided by Delft University of Technology.
Delft University of Technology (2008, September 30). An Accurate Picture Of Ice Loss In Greenland. ScienceDaily. Retrieved September 30, 2008, from­/releases/2008/09/080930081355.htm

Sunday, September 28, 2008

"Climate-proof" crop hunt begins

'Climate-proof' crop hunt begins

by Mark Kinver, Science and environment reporter, BBC News, September 23, 2008

Farmer handling maize (Image: GCDT)
Future climatic conditions could be too variable for many current crops





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.

Seed collection (Image: Cary Fowler/GCDT)
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:

Saturday, September 27, 2008

An explanation for noctilucent clouds

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


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



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."

California Institute of Technology (2008, September 26). Puzzling Property Of Night-shining Clouds At Edge Of Space Explained. ScienceDaily. Retrieved September 27, 2008, from­ /releases/2008/09/080925144806.htm

Friday, September 26, 2008

Greenhouse gas emissions shock scientists

Carbon dioxide output is rising rather than falling, despite efforts to curb it. 'It's scary,' one researcher says.
From Times Wire Services, September 26, 2008





The U.N.'s Intergovernmental Panel on Climate Change has warned that an increase of between 3.2 and 9.7 degrees Fahrenheit could trigger massive environmental changes, including melting of the Greenland ice sheet, the Himalayan-Tibetan glaciers and summer sea ice in the Arctic.

Corinne Le Quere, professor of environmental sciences at the University of East Anglia and the British Antarctic Survey, said the prediction that current emissions put the planet on track for a temperature rise of more than 11 degrees 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 showed that "we're already locked into more warming than we thought."

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

The new data also shows 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 released since 2000, a drop of 3 percentage points compared with the period between 1959 and 2000.

The pollution leader was China, followed by the United States, which past data show is the leader in emissions per person in carbon dioxide output. And although several developed countries slightly reduced output in 2007, the U.S. churned out more.

Still, it was large increases from China, India and other developing countries that spurred the growth of carbon dioxide pollution to a record high of 9.34 billion tons of carbon. Figures released by science agencies in the U.S., Great Britain and Australia show that China's added emissions accounted for more than half of the worldwide increase. China passed the U.S. as the No. 1 carbon dioxide polluter in 2006.

Emissions in the U.S. rose nearly 2% in 2007, after declining the previous year. The U.S. produced 1.75 billion tons of carbon.

"Things are happening very, very fast," Le Quere told the Associated Press. "It's scary."

Gregg Marland, a senior staff scientist at the U.S. Department of Energy's Oak Ridge National Laboratory in Tennessee, said he was surprised at the results because he thought world emissions would drop because of the economic downturn. That didn't happen.

"If we're going to do something [about reducing emissions], it's got to be different than what we're doing," he said.

The emissions are based on data from oil giant BP PLC, which show that China has become the major driver of world trends. China emitted 2 billion tons of carbon last year, up 7.5% from the previous year.




Denmark's emissions dropped 8%. The United Kingdom and Germany reduced carbon dioxide pollution by 3%, while France and Australia cut it by 2%.

But it remains 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 U.S. fossil fuel consumption will increase. 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 the globe is already destined for a greater worldwide temperature rise than predicted. Last month, two scientists from the Scripps Institution of Oceanography and UC 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 Academies of Science, 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.

What is "kind of scary" is that the worldwide emissions growth is beyond the highest growth in fossil fuel predicted just two years ago by the Intergovernmental Panel on Climate Change, said Benjamin Santer, an atmospheric scientist at the Lawrence Livermore National Laboratory.

Under the panel's scenario then, temperatures would increase by somewhere between 4 and 11 degrees Fahrenheit by 2100.

If this trend continues for the century, we would be exceedingly lucky "for it just to be bad, as opposed to catastrophic," said Stanford University climate scientist Stephen H. Schneider.

Link to article:,0,5554637.story

Carbon Is Building Up in Atmosphere Faster Than Predicted

by Juliet Eilperin, Washington Post Staff Writer, September 26, 2008




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."


Thursday, September 25, 2008

Dr. James Hansen: NASA climate expert warns Kansans of dire consequences of global warming at the Kansas Wind and Renewable Energy Conference

NASA climate expert warns Kansans of dire consequences of global warming

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.


NASA climate expert warns of dire results of global warming

by Scott Rothschild, Lawrence Journal-World, September 23, 2008

Experts in green energy hit the state capitol on Tuesday. The keynote speaker was a climate expert from NASA.

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 costal areas around the world, warns James Hansen, of NASA’s Goddard Institute for Space Studies.

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.

— 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:

Steve Connor: The ultimate gas leak that scientists dreaded -- methane

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:

Steve Connor: The Methane Time Bomb

Exclusive: The methane time bomb












"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.



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.


Link to article:

V. Ramanathan and Y. Feng: On avoiding dangerous anthropogenic interference with the climate system -- Formidable challenges ahead


The observed increase in the concentration of greenhouse gases (GHGs) since the preindustrial era has most likely committed the world to a warming of 2.4°C (1.4°C to 4.3°C) above the preindustrial surface temperatures. The committed warming is inferred from the most recent Intergovernmental Panel on Climate Change (IPCC) estimates of the greenhouse forcing and climate sensitivity. The estimated warming of 2.4°C is the equilibrium warming above preindustrial temperatures that the world will observe even if GHG concentrations are held fixed at their 2005 concentration levels but without any other anthropogenic forcing such as the cooling effect of aerosols. The range of 1.4°C to 4.3°C in the committed warming overlaps and surpasses the currently perceived threshold range of 1°C to 3°C for dangerous anthropogenic interference with many of the climate-tipping elements such as the summer arctic sea ice, Himalayan–Tibetan glaciers, and the Greenland Ice Sheet. IPCC models suggest that ≈25% (0.6°C) of the committed warming has been realized as of now. About 90% or more of the rest of the committed warming of 1.6°C will unfold during the 21st century, determined by the rate of the unmasking of the aerosol cooling effect by air pollution abatement laws and by the rate of release of the GHGs-forcing stored in the oceans. The accompanying sea-level rise can continue for more than several centuries. Lastly, even the most aggressive CO2 mitigation steps as envisioned now can only limit further additions to the committed warming, but not reduce the already committed GHGs warming of 2.4°C.

Link to abstract:

Link to full text of the article in the Proceedings of the National Academy of Sciences (free):

Ramanathan & Feng: Warming world is in range of dangerous consequences

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.



"This paper demonstrates the major challenges society will have to face in dealing with a problem that now seems unavoidable," said the paper's lead author, Scripps Atmospheric and Climate Sciences Prof. V. Ramanathan. "We hope that governments will not be forced to consider trade-offs between air pollution abatement and mitigation of greenhouse gas emissions."




Ramanathan and Feng estimated that the increase in greenhouse gases from pre-industrial era levels has already committed Earth to a warming range of 1.4° C to 4.3° C (2.5° F to 7.7° F). About 90 per cent of that warming will most likely be experienced in the 21st Century. In 2007, the Intergovernmental Panel on Climate Change identified a temperature increase range between 1° C and 3°C (1.8° F and 5.4° F) as the threshold at which society commits the planet to biodiversity loss and deglaciation in areas such as Greenland and the Himalayas.



Source: scripps


Michael Mann heckled in Providence, RI: local meteorologist claims no relationship between CO2 and temperature

by Tyler Will, The Good 5-cent Cigar, September 24, 2008

At the Fall 2008 Honors Colloquium last night, some of the audience members criticized joint Nobel Prize winner and Pennsylvania State University professor Michael Mann. One told him to leave the university during his speech.

Herb Stevens, a meteorologist who formerly worked in Providence, said there is no connection between carbon dioxide and temperature, and told Mann to leave the university. After his remarks to Mann, he called global warming a hoax.

"You don't have to have a doctorate to understand the hoax," he said. "It's a hoax. The correlation between CO2 and temperature does not exist. We're on the verge of spending trillions of dollars on a hoax."

Almost 1,000 people heard the speech in Edwards Auditorium, which had five objectives: projections, impacts, vulnerabilities and adaptations and solutions. Mann, who was a joint-winner of the Nobel Prize in 2007 with Al Gore for research on climate change, began his speech with a daunting prediction.

"It turns out, and many people aren't aware of this, if we were to put on the brakes [of greenhouse gasses] ... we would see about half a degree Centigrade of warming over the next century," Mann said. "So we are committed to some change."

Some of the projections Mann presented strongly suggested that human activity has contributed to a spike in carbon dioxide. Carbon dioxide is measured in parts-per-million, and pre-industrial levels were about 280 ppm, and current levels are about 386 ppm, and rising at about by two ppm a year, Mann said.

"There's been nothing like the spike we've seen in the last 10,000 years," Mann said while pointing to a graph that showed carbon dioxide levels taken from ice cores.

If the Earth warms by two degrees Celsius, Mann said, Arctic ice sheets could melt and the Greenland ice sheet could also melt, raising sea levels up to eight meters. Computer models he showed to the audience presented various scenarios, from what Mann called "burn baby burn," a continued use of fossil fuels, to an adoption of serious measures such as decreased energy use and renewable sources of energy.

In some of the scenarios, Mann explained that sea levels might only rise by two meters by the end of the 21st century, when carbon dioxide levels are expected to be around 630 ppm. At two meters, sea levels would threaten cities like New Orleans, but do fairly insignificant damage around the planet. But at eight meters, a chart Mann showed presented the southern third of Florida underwater, and nearly half of Louisiana. Major cities along the East Coast, including Providence, Mann said, would also be threatened.

Other effects include the extinction of species and the decrease of biodiversity in the ocean, Mann said. Hurricanes could become more violent and heat waves may become more prevalent. Mann pointed to a heatwave in Europe a few years ago that killed almost 30,000 people.

"I could show you 100 other variables, and they would all tell a consistent story," Mann said.

A lot of the change, he said, was not directly related to the effects of the warming itself, but of what he called "feedback" effects, such as clouds, which deflect some radiation and help keep the Earth cool, and the melting Arctic ice, which will raise sea levels and threaten coastal towns and cities.

He also explained the necessity of the greenhouse effect.

"There probably would not be life on this planet as we know it without the greenhouse effect," he said.

The greenhouse effect, Mann said, is caused by the absorption of radiation from the sun, and the Earth naturally emits some of that radiation, and retains the rest. Greenhouse gasses, such as carbon dioxide, methane, and water vapor, also absorb some of the sun's radiation and send some of it back to Earth, and the rest into space.

The amount of carbon dioxide, Mann said, is included in computer models, but the models can only be so accurate. After the speech, Mann said the fact that India and China are exponentially increasing their fossil fuel usage has not been factored into the models, and other natural effects, such as volcanic eruptions and the water warming effect called El Nino, also make models inaccurate.

Volcanic eruptions actually help cool the Earth, Mann said. Sulfur is released into the atmosphere during the eruption, and it blocks radiation from the sun.

The effect of El Nino, he said, could be significant. "If you want to know how the climate is going to change in these regions, you not only have to know how much the globe is going to warm, you have to know how the warming is going to change El Nino," Mann said.

Mann said he would leave solutions largely to future discussions, but presented the audience with a picture of the painting The Four Horsemen of the Apocalypse, a portrait of a prophecy from the Christian Bible about the end of the Earth.

"They will make an appearance if we chose to remain on the course we're on," Mann said, pointing to the painting.

During a question and answer session, Mann explained that two degrees Celsius of warming is considered a danger zone because two degrees Celsius higher than the average temperature of the Earth today is the temperature when Greenland had no ice sheet.

Mann also dodged "ad hominem" attacks from audience members. When someone commented that the melting of the ice on Mount Kilamanjaro has nothing to do with climate change, Mann replied, "the statements you make are simply not correct."

At the conclusion of the speech, Shannon Marks told Mann that students speak for the university, and apologized for remarks made about his research. "Overall, it was very enjoyable," Marks said. "I think it was easy to follow. We're here to hear what [Mann] has to say."

Link to article:

Saturday, September 20, 2008

Andrew Weaver: Keeping Our Cool -- Canada in a Warming World

Scientist delivers political shots with climate change book

by Margaret Munro, Canwest News Service, September 11, 2008

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.

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Friday, September 19, 2008

Abrupt Climate Change Focus Of U.S. National Laboratories; Investigation of the Magnitudes and Probabilities of Abrupt Climate Transitions (IMPACTS)

Abrupt Climate Change Focus Of U.S. National Laboratories


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.


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.”

Adapted from materials provided by DOE/Lawrence Berkeley National Laboratory.

DOE/Lawrence Berkeley National Laboratory (2008, September 18). Abrupt Climate Change Focus Of U.S. National Laboratories. ScienceDaily. Retrieved September 19, 2008, from­ /releases/2008/09/080918192943.htm

Thursday, September 18, 2008

Catherine Brahic: America's oldest ice discovered... then it melts

by Catherine Brahic, New Scientist, September 18, 2008

Seen emerging from a mud cliff, the smooth, near-black surfaces look like a long-lost objects from some high-tech civilisation. In fact, they are huge chunks of ice – the oldest ice ever found in North America.

More than 750,000 years old, the wedges have survived through times when the planet was even warmer than it is today. Duane Froese of the University of Alberta in Canada and colleagues say their discovery could us predict the fate of the deep Arctic permafrost and its frozen methane stores.

Ice wedges form when spring melt-water runs into fissures and freezes. Thermal expansion widens the cracks and allows the wedge to grow, up to around 3 metres wide and 6 metres deep.

The team discovered the ancient ice several years ago at Dominion Creek – a site in the Canadian Yukon, just east of the Alaskan border. It had been exposed by mining activities in the area. They were able to date it thanks to a layer of ancient volcanic ash that had been deposited a few dozen centimetres above its top margin. The ash was about 740,000 years old, making the ice the oldest known in North America.

"Much of the relic ice in the region dates to the last 100,000 years and most to the last 25,000 years," says Froese.

Carbon store

Remarkably, this means the Dominion Creek ice wedges must have survived two interglacial ages: 120,000 and 400,000 years ago. Computer models estimate that temperatures at the time rose to between 2 °C and 3 °C higher than the average today, which to Froese "illustrates how stubborn permafrost can be in the face of climate warming."

Permafrost is ground that remains frozen all year round. This arrests the decay of vegetation, preventing the carbon which it contains from being released into the atmosphere as greenhouse gases.

But Froese's findings do not mean that the Arctic permafrost, including the huge stores that cover much of Siberia, will survive the few degrees of warming predicted for the end of this century.

For starters, Andrew Slater of the University of Colorado points out that although they are surrounded by permafrost, the ice wedges themselves are very different. "A block of solid ice like this wedge takes considerably more energy to thaw than a mixture of soil, ice and organic matter," he says.

Melted away

Moreover, the top of the ice wedges are several metres beneath the soil surface and reach down a further 6 metres.

"The near-term worries about northern hemisphere permafrost concern the shallow layer. There is abundant evidence that this permafrost is warming," and is releasing carbon dioxide and methane, says Froese. How fast the upper few metres will degrade remains uncertain.

Even less certain is how long the deeper permafrost will hold out. "The survival of this ice for the last 750,000 years or so indicates that it is quite resilient to climate change," says Froese. Slater agrees that it may survive for hundreds, thousands or nearly a million years.

For the ancient ice wedges at Dominion Creek, however, the game is up. Since their discovery they have melted away entirely. Others, though, may remained buried just a few metres beneath the nearby forest floor.

Journal reference: Science (DOI: 10.1126/science.1157525)

Link to article:

Duane G. Froese et al., Ancient permafrost and a future, warmer Arctic, Science, Vol. 321, No. 5896

Science, 19 September 2008, Vol. 321, No. 5896, p. 1648; DOI: 10.1126/science.1157525

Ancient Permafrost and a Future, Warmer Arctic

Duane G. Froese,1* John A. Westgate,2 Alberto V. Reyes,1 Randolph J. Enkin,3 Shari J. Preece2

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.

* To whom correspondence should be addressed. E-mail:

Permafrost May Not Thaw Even During Global Warming

Permafrost May Not Thaw Even During Global Warming

by Henry Fountain, New York Times, September 18, 2008

One of the potential consequences of a warmer world, according to scientists who study such things, is the deep thawing of the permafrost. Thawing could release huge quantities of carbon into the atmosphere, as vegetation, bones and other organic material, long locked up in the deep freezer that is the permafrost, decompose.

But a study published in Science suggests that the impact of warming on the permafrost may not be as bad as forecast. The evidence comes in the form of a wedge of ancient ice found at an old mining site in the Yukon in Canada.

Ice wedges form in permafrost when the ground cracks because of cold, and spring meltwater seeps in and freezes. Over hundreds of years, the wedge builds up, like an in-ground icicle.

Duane G. Froese of the University of Alberta, the lead author of the study, said ice wedges could provide clues to the long-term stability of the permafrost. The problem is figuring out how old they are.

In this case, the top of the wedge was a couple of yards deep in the permafrost, and the researchers found volcanic ash on its top surface. By dating the ash (which presumably came from eruptions in what is now southeastern Alaska), Dr. Froese and his colleagues were able to say how long the ice has been there: about 740,000 years. Because the ash had to have been deposited after the wedge formed, that’s “very clear proof,” Dr. Froese said, that the ice is at least that old.

That means the ice survived through several warming periods, including the last major one, 120,000 years ago. “The general view is that everything would have melted out back then,” Dr. Froese said. The new finding suggests that wasn’t the case, and that models of future melting need to be rethought.

“But I don’t want people to think we don’t have to worry about global climate change,” Dr. Froese said. The top couple of yards of permafrost are still likely to melt as temperatures warm, and there’s plenty of carbon stored in them. “But the deeper part of the permafrost is probably relatively stable,” he said.

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Wednesday, September 17, 2008

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

Environmental Research Letters, September 17, 2008


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.

A new study shows that the dozens of much smaller outflow glaciers dotting Greenland’s coast together account for three times more loss from the island’s ice sheet than the amount coming from their huge relatives.

In a study just published in the journal Geophysical Research Letters, scientists at Ohio State University reported that nearly 75 percent of the loss of Greenland ice can be traced back to small coastal glaciers.

Ian Howat, an assistant professor of earth sciences and researcher with Ohio State’s Byrd Polar Research Center, said their discovery came through combining the best from two remote sensing techniques. It provides perhaps the best estimate so far of the loss to Greenland’s ice cap, he says.

Aside from Antarctica, Greenland has more ice than anywhere else on earth. The ice cap covers four-fifths of the island’s surface, is 1,491 miles (2,400 kilometers) long and 683 miles (1,100 kilometers) wide, and can reach 1.8 miles (3 kilometers) deep at its thickest point.

As global temperatures rise, coastal glaciers flow more quickly to the sea, with massive chunks breaking off at the margins and forming icebergs. And while some of the largest Greenland glaciers, such as the Jakobshavn and Petermann glaciers on the northern coast, are being closely monitored, most others are not.

Howat and his colleagues concentrated on the southeastern region of Greenland, an area covering about one-fifth of the island’s 656,373 square miles (1.7 million square kilometers). They found that while two of the largest glaciers in that area, Kangerdlugssuaq and Helheim, contribute more to the total ice loss than any other single glaciers, the 30 or so smaller glaciers there contributed 72 percent of the total ice lost.


"We’re talking about the region that is within 62 miles (100 kilometers) from the ice edge. That whole area is thinning rapidly," he said.


To reach their conclusions, the researchers turned to two ground-observing satellites. One of them, ICESAT (Ice, Cloud, and land Elevation Satellite), does a good job of gauging the ice over vast expanses which were mostly flat.

On the other hand, ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) does a better job at seeing changes at the steeper, less-flat margins of the ice sheet, Howat said.

"We simply merged those data sets to give us for the first time a picture of ice elevation change, the rate at which the ice is either going up or down, at a very high (656-foot or 200-meter) resolution.

"They are a perfect match for each other," Howat said.

"What we found is the entire strip of ice over the southeast margin, all of these glaciers, accelerated and they are just pulling the entire ice sheet with it," he said.

Howat said that their results show that such new findings don’t necessarily require new types of satellites. "These aren’t very advanced techniques or satellites. Our work shows that by combining satellite data in the right way, we can get a much better picture of what’s going on," Howat said.

Along with Howat, B.E. Smith and I Joughin, both of the University of Washington, and T.A. Scambos from the National Snow and Ice Data Center at the University of Colorado worked on the project.

The research was funded in part by the National Aeronautics and Space Administration.

Source: edu

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