Archive for August 2008

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Climatologist Dr. Jason E. Box, Byrd Polar Research Center, to give talk on Greenland ice sheet melt

Greenland: Climate Change’s Hot Topic
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Climatologist Jason Box Presents Lecture Sept. 4

TELLURIDE – Greenland is melting much faster than anyone predicted. This Arctic country, a Climate Change Indicator, is a vital player not just in our understanding and monitoring of climate change. It has a direct influence in how such changes will manifest across the globe.

For those of us in Colorado, what does this rapid, accelerated decrease in the Greenland Continental Icecap mean?

Climatologist Jason E. Box, Ph.D., with the Byrd Polar Research Center, has spent the last 14 years monitoring Greenland’s massive ablation.

Box will be coming to Telluride to present his research, and answer questions, on Sept. 4, at 7 p.m. at the Sheridan Opera House. The event is sponsored by the Telluride Institute, and is free and open to the public.

After 17 expeditions in Greenland, Box has documented some of the most startling ablation events, including the largest iceberg calving ever filmed: Eight square kilometers of ice, a half-mile thick, disintegrating in 90 minutes. Picture a city of skyscraper-sized ice vanishing in an hour-and-a-half.

“Estimates of sea level rise are now known to be significantly underestimated,” said Box. “The IPCC [Intergovernmental Panel on Climate Change] projected sea level rise of around one-and-a-half feet. But this did not take into account the profound ice sheet sensitivity now documented [in Greenland]. Sea level rise could be double, or more [than these predictions]. My best guess is a sea level rise of between three and six feet by the end of this century.”

This will have implications for global populations during our lifetimes. Coastal populations will have to move from low-lying areas, creating sociopolitical turmoil in countries like Bangladesh – one of the most populous, poorest and low-lying countries in the world. Parts of Florida could disappear.

Box sees a vast expenditure on a global scale to “hold back the sea.”

“We will end up spending a lot of money building a lot of flood breakers and sea walls,” he said in a telephone interview Wednesday. “I’m concerned the cost that the U.S. and the world will spend on mitigating sea level rise will slow down global economies. Technology exists to hold back the sea, but it’s very expensive. We need to act now to prevent sea level rise.”

In 2002, monitoring of the Greenland Icecap showed annual losses of 100 cubic kilometers of ice, alarming the scientific community, a bigger and faster loss than had been predicted.

In 2007, however, an even larger ice loss – of more than 300 cubic kilometers (300 gigatons) – was documented.

This is hugely significant for the world at large. No one really knows what will happen as a result – from fresh water plumes altering the Atlantic Ocean’s great gyres (which keep Europe temperate), to dramatic sea level rise. Last year the Intergovernmental Panel on Climate Change predicted an expected sea level rise of two feet over the course of this century. That’s significant enough to inundate areas like Washington, D.C., much of North Carolina, parts of the Gulf Coast, and Florida. It will alter global coastlines like never before. But this may be a low estimate: Even the IPCC noted in its important study last year that, “Larger values [in sea-level rise] cannot be excluded.”

Although Colorado doesn’t have to worry about the direct effects of rising sea levels, the economic ramifications will surely affect us all. Moreover, the warming inherent in climate change, while increasing precipitation events, will only shorten the ski season. Some estimates have quoted a reduction in the ski season by as much as one-third or more. In a state whose majority of revenues come from winter sports, that’s a lot of lost revenue – potentially one third of the winter take, or more than one-sixth of statewide annual revenue.

A further problem may result in the release of CO2 and methane from thawing permafrost regions, creating what is known as runaway climate heating, a positive-feedback loop that spirals climate crisis out of control.

“Melt down in the Artic will likely release a lot of carbon in permafrost in northern Eurasia and Canada and carbon in methane hydrates,” Box said. “This could contribute to runaway climate heating. We could double atmospheric CO2 in one- or two-hundred years. Then, it’s too late. This is the doomsday scenario, but we’re right on course for that. We have to change course now.”

Box noted that a panoply of strategies must be enacted to be effective to preempt runaway climate heating. Conservation, he said, is not enough. A systems approach that involves renewable energy, reforestation, geo-engineering, as well as conservation is needed.

“Conservation is not going to come close to the type of action we need to avert disaster. Conservation at best buys us some time. We need a proactive, portfolio response,” he said, including wind, solar and geothermal energy systems acting together to augment mitigation.

“Science has been looking for a silver bullet to address the climate crisis. But what we need is silver buckshot.”

His presentation Sept. 4 at the Opera House will be full of satellite images, time-lapse photography and graphic products. This is a world first: much of this imagery has yet to be published or released to the public.

Box has been featured in the New York Times, on CBS News, NBC’s Today Show, and the Discovery Channel, among others. This February 60 Minutes will be flying to Greenland with Box to film a special on climate change.

He will show footage of his research, outline repercussions across the world, answer questions, and offer some potential solutions to deal with an accelerating problem, now more evident than ever.

Link to article: http://www.telluridewatch.com/pages/full_story?article-Greenland-Climate-Change-s-Hot-Topic

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Bering Glacier Melting Faster Than Scientists Thought

18.08.2008

A new technology for measuring glacial water melt reveals that the Bering Glacier is melting at twice the rate that scientists believed.

A new system of measuring water melt shows that the Bering Glacier--the largest glacier in North America--is melting at double the rate that scientists thought.

The glacier is releasing approximately 30 cubic kilometers of water a year, more than twice the amount of water in the entire Colorado River, said Robert Shuchman, co-director of the Michigan Tech Research Institute (MTRI).

"This could potentially change the circulation of coastal currents in the Gulf of Alaska," Shuchman said. Those currents are key factors in tempering climate, redistributing nutrients in the water and providing adequate food for the salmon and marine animals, he explained.

As glaciers melt, sea levels rise, and "sea level rise affects everyone," Shuchman added. "If it continues to rise at this rate, parts of the state of Florida could be under water at the turn of the next century."

The MTRI team, working with U.S. Geological Survey (USGS) and U.S. Bureau of Land Management (BLM) scientists, designed the sensor that enabled BLM to accurately measure and analyze the melting of this Alaskan glacier. Shuchman and his team, along with BLM and USGS, have been studying the glacier for the past decade with an interdisciplinary team of geologists, oceanographers, botanists, and marine mammal, bird and fish experts.

"Our glacier observations are 10 times better and 10 times less costly than data collected the old way," Shuchman said. Before MTRI developed its autonomous sensor to collect data as it occurs, scientists had to make dangerous and difficult treks to remote regions to measure glacial melting.

Jennifer Donovan | Source: Newswise Science News
Further information: www.mtu.edu

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Frozen Arctic floor has started to thaw and release long-stored methane gas

Frozen Arctic floor has started to thaw and release long-stored methane gas

By Volker Mrasek, Spiegel, 17 avril 2008

Researchers have found alarming evidence that the frozen Arctic floor has started to thaw and release long-stored methane gas. The results could be a catastrophic warming of the earth, since methane is a far more potent greenhouse gas than carbon dioxide. But can the methane also be used as fuel ?

It’s always been a disturbing what-if scenario for climate researchers : Gas hydrates stored in the Arctic ocean floor — hard clumps of ice and methane, conserved by freezing temperatures and high pressure — could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic ; scientists had warned that such a thing could happen. Now it seems more likely that it will.

Russian polar scientists have strong evidence that the first stages of melting are underway. They’ve studied largest shelf sea in the world, off the coast of Siberia, where the Asian continental shelf stretches across an underwater area six times the size of Germany, before falling off gently into the Arctic Ocean. The scientists are presenting their data from this remote, thinly-investigated region at the annual conference of the European Geosciences Union this week in Vienna.

In the permafrost bottom of the 200-meter-deep sea, enormous stores of gas hydrates lie dormant in mighty frozen layers of sediment. The carbon content of the ice-and-methane mixture here is estimated at 540 billion tons. “This submarine hydrate was considered stable until now,” says the Russian biogeochemist Natalia Shakhova, currently a guest scientist at the University of Alaska in Fairbanks who is also a member of the Pacific Institute of Geography at the Russian Academy of Sciences in Vladivostok.

The permafrost has grown porous, says Shakhova, and already the shelf sea has become “a source of methane passing into the atmosphere.” The Russian scientists have estimated what might happen when this Siberian permafrost-seal thaws completely and all the stored gas escapes. They believe the methane content of the planet’s atmosphere would increase twelvefold. “The result would be catastrophic global warming,” say the scientists. The greenhouse-gas potential of methane is 20 times that of carbon dioxide, as measured by the effects of a single molecule.

Shakhova and her colleagues gathered evidence for the loss of rigor in the frozen sea floor in a measuring campaign during the Siberian summer. The seawater proved to be “highly oversaturated with solute methane,” reports Shakhova. In the air over the sea, greenhouse-gas content was measured in some places at five times normal values. “In helicopter flights over the delta of the Lena River, higher methane concentrations have been measured at altitudes as high as 1,800 meters,” she says.

The methane climate bomb is also ticking on land : A few years ago researchers noticed higher concentrations of methane in northern Siberia. The Siberian permafrost is known as one of the tipping points for the earth’s climate, since the potent greenhouse gas develops wherever microorganisms decompose the huge masses of organic material from warmer eras that has been frozen here for thousands of years.

“A Wake-Up Call for Science”

Data from offshore drilling in the region, studied by experts at the Alfred Wegener Institute for Polar and Marine Research (AWI), also suggest that the situation has grown critical. AWI’s results show that permafrost in the flat shelf is perilously close to thawing. Three to 12 kilometers from the coast, the temperature of sea sediment was -1 to -1.5 degrees Celsius, just below freezing. Permafrost on land, though, was as cold as -12.4 degrees Celsius. “That’s a drastic difference and the best proof of a critical thermal status of the submarine permafrost,” said Shakhova.

Paul Overduin, a geophysicist at AWI, agreed. “She’s right,” he said. “Changes are far more likely to occur on the sea shelf than on land.”

Climate change could give an additional push to these trends. “If the Arctic Sea ice continues to recede and the shelf becomes ice-free for extended periods, then the water in these flat areas will get much warmer,” said Overduin. That could lead to a situation in which the temperature of the sea sediment rises above freezing, which would thaw the permafrost.

“We don’t have any data on that — those are just suspicions,” the Canadian scientist said. Natalia Shakhova also passed on the question of whether to expect a gradual gas emission or an abrupt burst of large quantities of methane. “No one can say right now whether that will take years, decades or hundreds of years,” she said. But one cannot rule out sudden methane emissions. They could happen at “any time.”

One thing is clear, though : The thawing of the Arctic sea floor will create “new potential sources for methane … which no one had reckoned with until now,” said Laurence Smith, a professor for geography at the University of California in Los Angeles. Smith is researching North Pole frost zones and expects that a thawing of the permafrost will “supply fuel for methane engines.”

The first methane rocket thruster was tested by the US’s National Aeronautics and Space Administration (NASA) in 2007, and methane from manure has been collected as “biogas” to heat and power homes (more…) in experimental German towns.

In any case, the team taking part in the Siberian study installed a number of probes in the Laptev Sea, a central part of the broad Siberian shelf sea. These probes are measuring the temperature on the upper edge of the submarine permafrost. Overduin wants to pull up the probes in August. Then, for the first time, scientists will have access to a full year’s worth of data on the conditions of the sea floor.

For her part, Shakhova thinks researchers should be doing a lot more. She says too little is known about the fragile shelf sediment and the methane it stores, which could be explosive for the environment. “Actually,” she says, “this is a wake-up call for science.”

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Achim Brauer et al.: An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period

Letter abstract

Nature Geoscience 1, 520-523 (2008)
Published online: 1 August 2008 | doi:10.1038/ngeo263

An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period

Achim Brauer1, Gerald H. Haug2,3, Peter Dulski1, Daniel M. Sigman4 & Jörg F. W. Negendank1

The Younger Dryas cooling 12,700 years ago is one of the most abrupt climate changes observed in Northern Hemisphere palaeoclimate records1, 2, 3, 4. Annually laminated lake sediments are ideally suited to record the dynamics of such abrupt changes, as the seasonal deposition responds immediately to climate, and the varve counts provide an accurate estimate of the timing of the change. Here, we present sub-annual records of varve microfacies and geochemistry from Lake Meerfelder Maar in western Germany, providing one of the best dated records of this climate transition5. Our data indicate an abrupt increase in storminess during the autumn to spring seasons, occurring from one year to the next at 12,679 yr BP, broadly coincident with other changes in this region. We suggest that this shift in wind strength represents an abrupt change in the North Atlantic westerlies towards a stronger and more zonal jet. Changes in meridional overturning circulation alone cannot fully explain the changes in European climate6, 7; we suggest the observed wind shift provides the mechanism for the strong temporal link between North Atlantic Ocean overturning circulation and European climate during deglaciation.

  1. GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473 Potsdam, Germany
  2. Geological Institute, Department of Earth Sciences, ETH Zürich, 8092 Zürich, Switzerland
  3. DFG-Leibniz Center for Surface Process and Climate Studies, Institute for Geosciences, Potsdam University, 14476 Potsdam, Germany
  4. Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA

Correspondence to: Achim Brauer1 e-mail: brau@gfz-potsdam.de

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Chien-Lu Ping et al.: High stocks of soil organic carbon in the North American Arctic region

Nature Geoscience
Published online: 24 August 2008 | doi:10.1038/ngeo284

High stocks of soil organic carbon in the North American Arctic region

Chien-Lu Ping1, Gary J. Michaelson1, Mark T. Jorgenson2, John M. Kimble3, Howard Epstein4, Vladimir E. Romanovsky5 & Donald A. Walker6

The Arctic soil organic-carbon pool is a significant, but poorly constrained, carbon store. The most cited pool size estimates are based on a study that severely undersamples Arctic soils, with only five out of the 48 soils examined actually from the Arctic region. Furthermore, previous measurements have been confined to the top 40 cm of soil. Here, we present 1-m-deep measurements of soil organic carbon obtained at 117 locations in the North American Arctic region. To this dataset we add previously published measurements to generate a total sample size of 139 North American Arctic soils. We show that soil organic-carbon stores are highly dependent on landscape type, being highest in lowland and hilly upland soils, where values average 55.1 and 40.6 kg soil organic carbon m-2 respectively, and lowest in rubbleland and mountain soils, where values average 3.4 and 3.8 kg soil organic carbon m-2, respectively. Extrapolating our measurements using known distributions of landscape types we estimate that the total organic carbon pool in North American Arctic soils, together with the average amount of carbon per unit area, is considerably higher than previously thought. Our estimates of the depth distribution and total amount of organic carbon in North American Arctic soils will form an important basis for studies examining the impact of climate warming on CO2 release in the region.

  1. Agriculture and Forestry Experiment Station, University of Alaska Fairbanks, 533 E. Fireweed, Palmer, Alaska 99645, USA
  2. Alaska Biological Research, Box 80410, Fairbanks, Alaska 99708, USA
  3. Professional Soil Scientist, 151 East Hill Church Road, Addison, New York 14801, USA
  4. Department of Environmental Sciences, University of Virginia, PO Box 400123, Charlottesville, Virginia 22904, USA
  5. Geophysical Institute, University of Alaska Fairbanks, PO Box 755780, Fairbanks, Alaska 99775, USA
  6. Institute of Arctic Biology, University of Alaska Fairbanks, PO Box 757000, Fairbanks, Alaska 99775, USA

Correspondence to: Chien-Lu Ping1 e-mail: ffcp@uaf.edu

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Walter, Chanton, Chapin III, Schuur, Zimov: Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways, ages

Journal of Geophysical Research, Vol. 113, 2008, G00A08; doi:10.1029/2007JG000569

Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways and ages

K. M. Walter (Institute of Northern Engineering and International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, U.S.A.)

J. P. Chanton (Department of Oceanography, Florida State University, Tallahassee, Florida, USA)

F. S. Chapin III (Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA)

E. A. G. Schuur (Department of Botany, University of Florida, Gainesville, Florida, USA)

S. A. Zimov (Northeast Science Station, Cherskii, Republic of Sakha, Russia)

Abstract

This study reports an atmospheric methane (CH4) source term previously uncharacterized regarding strength and isotopic composition. Methane emissions from 14 Siberian lakes and 9 Alaskan lakes were characterized using stable isotopes (13C and D) and radiocarbon (14C) analyses. We classified ebullition (bubbling) into three categories (background, point sources, and hot spots) on the basis of fluxes, major gas concentrations, and isotopic composition. Point sources and hot spots had a strong association with thermokarst (thaw) erosion because permafrost degradation along lake margins releases ancient organic matter into anaerobic lake bottoms, fueling methanogenesis. With increasing ebullition rate, we observed increasing CH4 concentration of greater radiocarbon age, depletion of 13CCH4, and decreasing bubble N2 content. Microbial oxidation of methane was observed in bubbles that became trapped below and later within winter lake ice; however, oxidation appeared insignificant in bubbles sampled immediately after release from sediments. Methanogenic pathways differed among the bubble sources: CO2 reduction supported point source and hot spot ebullition to a large degree, while acetate fermentation appeared to contribute to background bubbling. To provide annual whole-lake and regional CH4 isofluxes for the Siberian lakes, we combined maps of bubble source distributions with long-term, continuous flux measurements and isotopic composition. In contrast to typical values used in inverse models of atmospheric CH4 for northern wetland sources (δ 13CCH4 = −58‰, 14C age modern), which have not included northern lake ebullition as a source, we show that this large, new source of high-latitude CH4 from lakes is isotopically distinct (δ 13CCH4 = −70‰, 14C age 16,500 years, for North Siberian lakes).

(Received 9 August 2007; accepted 11 April 2008; published 2 August 2008.)

Key words: arctic lakes, methane, ebullition, isotopes, thermokarst

Index Terms: 0490 Biogeosciences: Trace gases; 0454 Biogeosciences: Isotopic composition and chemistry (1041, 4870); 0428 Biogeosciences: Carbon cycling (4806); 0458 Biogeosciences: Limnology (1845, 4239, 4942); 0708 Cryosphere: Thermokarst.

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Citation: Walter, K. M., J. P. Chanton, F. S. Chapin III, E. A. G. Schuur, and S. A. Zimov (2008), Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways and ages, J. Geophys. Res., 113, G00A08, doi:10.1029/2007JG000569.

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2008 Arctic Sea ice loss as point of no return

by the Associated Press, August 27, 2008

WASHINGTON (AP) — The National Snow and Ice Data Center has reported that sea ice in the Arctic now covers about 2.03 million square miles. The lowest point since satellite measurements began in 1979 was 1.65 million square miles, last September.

With about three weeks left in the Arctic summer, this year could wind up breaking that record, scientists said.

Arctic ice always melts in summer and refreezes in winter. But over the years, more of the ice is lost to the sea with less of it recovered in winter. While ice reflects the sun’s heat, the open ocean absorbs more heat, and the melting accelerates warming in other parts of the world.

Sea ice also serves as primary habitat for threatened polar bears.

“We could very well be in that quick slide downward in terms of passing a tipping point,” said Mark Serreze, a senior scientist at the data center, in Boulder, Colo. “It’s tipping now. We’re seeing it happen now.”

Five climate scientists, four of them specialists on the Arctic, told The Associated Press that it was fair to call what was happening in the Arctic a “tipping point.”

Last year was an unusual year when wind currents and other weather conditions coincided with global warming to worsen sea ice melt, Dr. Serreze said. Scientists wondered if last year was an unusual event or the start of a new and disturbing trend.

This year’s results suggest the latter because the ice had recovered a bit more than usual thanks to a somewhat cooler winter, Dr. Serreze said. Then this month, when the melting rate usually slows, it sped up instead, he said.

The most recent ice retreat primarily reflects melt in the Chukchi Sea, off Alaska’s northwest coast, and the East Siberian Sea, off the coast of eastern Russia, according to the center.

The Chukchi Sea is home to one of two populations of Alaska polar bears.

Federal observers flying for a whale survey on Aug. 16 spotted nine polar bears swimming in open ocean in the Chukchi. The bears were 15 to 65 miles off the Alaska shore. Some were swimming north, apparently trying to reach the polar ice edge, which on that day was 400 miles away.

Polar bears are powerful swimmers and have been recorded on swims of 100 miles, but the ordeal can leave them exhausted and susceptible to drowning.

And the melt in sea ice has kicked in another effect, long predicted, called “Arctic amplification,” Dr. Serreze said.

That is when the warming up north is increased in a feedback mechanism and the effects spill southward starting in autumn, Dr. Serreze said. Over the last few years, the bigger melt has meant more warm water that releases more heat into the air during fall cooling, making the atmosphere warmer than normal.

On top of that, researchers are investigating “alarming” reports in the last few days of the release of methane from long-frozen Arctic waters, possibly from the warming of the sea, said Bill Hare, a Greenpeace climate scientist, who was attending a climate conference in Ghana. Giant burps of methane, which is a potent greenhouse gas, is a long-feared effect of warming in the Arctic that would accelerate warming even more, according to scientists.

Over all, the picture of what is happening in the Arctic is getting worse, said Bob Corell, who headed a multinational scientific assessment of Arctic conditions a few years ago. “We’re moving,” he said, “beyond a point of no return.”

Link to article: http://www.nytimes.com/2008/08/28/science/earth/28seaice.html

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Geert Lenderink & Erik van Meijgaard: Increase in hourly precipitation extremes beyond expectations from temperature changes

Letter abstract

Nature Geoscience 1, 511–514 (2008)
Published online: 20 July 2008 | doi:10.1038/ngeo262

Subject Categories: Atmospheric science | Climate science | Hydrology, hydrogeology and limnology

Increase in hourly precipitation extremes beyond expectations from temperature changes

Geert Lenderink & Erik van Meijgaard

Changes in precipitation extremes under greenhouse warming are commonly assumed to be constrained by changes in the amounts of precipitable water in the atmosphere1, 2, 3, 4. Global climate models generally predict only marginal changes in relative humidity5, implying that the actual amount of atmospheric precipitable water scales with the water vapour content of saturation, which is governed by the Clausius–Clapeyron relation. Indeed, changes in daily precipitation extremes in global climate models seem to be consistent with the 7% increase per degree of warming given by the Clausius–Clapeyron relation3, 4, but it is uncertain how general this scaling behaviour is across timescales. Here, we analyse a 99-year record of hourly precipitation observations from De Bilt, the Netherlands, and find that one-hour precipitation extremes increase twice as fast with rising temperatures as expected from the Clausius–Clapeyron relation when daily mean temperatures exceed 12 °C. In addition, simulations with a high-resolution regional climate model show that one-hour precipitation extremes increase at a rate close to 14% per degree of warming in large parts of Europe. Our results demonstrate that changes in short-duration precipitation extremes may well exceed expectations from the Clausius–Clapeyron relation. These short-duration extreme events can have significant impacts, such as local flooding, erosion and water damage.
  1. Royal Netherlands Meteorological Institute (KNMI), 3730 AE De Bilt, The Netherlands

Correspondence: Geert Lenderink e-mail: lenderin@knmi.nl

Link to abstract: http://www.nature.com/ngeo/journal/v1/n8/abs/ngeo262.html

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NSIDC: Arctic sea ice now second-lowest on record

From the National Snow and Ice Data Center, August 26, 2008

Sea ice extent has fallen below the 2005 minimum, previously the second-lowest extent recorded since the dawn of the satellite era. Will 2008 also break the standing record low, set in 2007? We will know in the next several weeks, when the melt season comes to a close. The bottom line, however, is that the strong negative trend in summertime ice extent characterizing the past decade continues.

Note: The NSIDC will issue an an update with finalized numbers tomorrow morning.

Map of sea ice from space, showing sea ice, continents, ocean
Figure 1. Daily Arctic sea ice extent for August 25, 2008, fell below the 2005 minimum, which was 5.32 million square kilometers (2.05 million square miles). The orange line shows the 1979 to 2000 average extent for that day. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data. —Credit: National Snow and Ice Data Center.

Overview of conditions

With several weeks left in the melt season, sea ice extent dipped below the 2005 minimum to stand as the second-lowest in the satellite record. The 2005 minimum, at 5.32 million square kilometers (2.05 million square miles), held the record-low minimum until last year.

Recent ice retreat primarily reflects melt in the Chukchi Sea off the Alaskan coast and the East Siberian Seas off the coast of eastern Russia.

Note: The NSIDC will issue an update with finalized numbers tomorrow morning.

Graph with months on x axis and extent on y axisFigure 2. The graph above shows daily sea ice extent.The dashed blue line indicates 2008; the dark blue dotted line indicates 2005; the dotted green line shows extent for 2007; the gray line indicates average extent from 1979 to 2000. Sea Ice Index data. —Credit: National Snow and Ice Data Center.

High-resolution image

Conditions in context

Through the beginning of the melt season in May until early August, daily ice extent for 2008 closely tracked the values for 2005.

In early August of 2005, the decline began to slow; in August of 2008, the decline has remained steadily downward at a brisk pace. The 2005 minimum of 5.32 million square kilometers (2.05 million square miles) occurred on September 21.

Link: http://nsidc.org/arcticseaicenews/

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Arctic Tundra Holds Global Warming Time Bomb

by Michael Reilly, Discovery News, August 25, 2008

Aug. 25, 2008 -- Locked away in the frozen soils of the Arctic tundra, there lies a ticking time bomb.

Nothing more than accumulated leaves, roots and other plant matter, the unassuming detritus is rich in carbon, giving it the power to dramatically enhance the effects of global warming should it ever get into the atmosphere. But for now it mostly lies dormant, in cold storage in the permafrosts of Siberia, Alaska, and Canada.

That's starting to change, according to some scientists. The planet has already begun to warm as a result of humans pumping billions of tons of carbon into the atmosphere each year. The permafrost is starting to melt, and that pent-up carbon is already leaking into the air in the form of carbon dioxide and methane, powerful greenhouse gases.

Even worse, there may be more of the stuff than anyone ever thought.

Chien-Liu Ping and a team of researchers at the University of Alaska, Fairbanks spent the last 13 years meticulously sampling tundra soils across North America. In a study published this week in the journal Nature Geoscience, they estimate there may be almost 100 billion tons of carbon in the first meter of soil alone.

That's equivalent to about a quarter of the amount currently in Earth's atmosphere, or 10 years' worth of global emissions from human activity.

It also nearly doubles previous estimates of carbon content in Arctic soil. Despite decades of work, such approximations are rough at best, because land in the far North is vast, remote, and inhospitably cold. Even in the height of summer, soil scientists can rarely dig deeper than 50 centimeters before they hit rock-solid permafrost.

But worst-case scenario climate projections from the Intergovernmental Panel on Climate Change (IPCC) suggest Arctic temperatures could climb as much as 6 degrees centigrade by the end of the century.

If that happens, the Arctic region, which has already shown signs of thawing, will change dramatically. Already scientists have begun seeing areas where permafrost tundra has melted into muddy bogs called 'thermokarsts.' In other places, steep hillsides, no longer supported by rigid ice crystals, are giving way in landslides.

As the land melts bacteria intrude, decomposing the plant matter that has built up over thousands of years. They release methane and carbon dioxide into the air as byproducts, gases that warm the planet by trapping heat energy from the sun.

"Permafrost temperatures in Alaska have gone up about 1 degree Centigrade over the last 50 years," Ping said, pushing soils to within a fraction of a degree of freezing temperature. "In Russia, they've been monitoring permafrost for over a century. It has warmed 2 degrees Centigrade, so almost 5 degrees Fahrenheit."

It's not all bad news though. The warmer temperatures should allow plants to grow vigorously, and they can suck up huge amounts of carbon out from the atmosphere through photosynthesis -- perhaps even enough to cancel out greenhouse gas emissions from the soil.

In fact, many scientists say the jury is still out on whether or not the thawing Arctic could quicken the pace of global warming.

"The carbon losses you have to have from soil to affect climate need to be fast and big," David McGuire of the University of Alaska, Fairbanks said. "There are two ways do that: mass erosion from slumping or along the coasts and rivers, and through fires."

Last year, McGuire, who was not involved with Ping's research, ran computer simulations of what would happen if catastrophe struck vast swaths of Arctic tundra in the form of wildfires and massive erosion.

"The most carbon we could get into the atmosphere was about 50 billion tons," he said, or about half of what Ping's team thinks is stored in the soil.

That's not enough to make much difference by the year 2100, but Ted Schuur of the University of Florida thinks we need to look further into the future.

In a paper to be published in the September issue of the journal Bioscience, he estimates that 1,672 billion tons of carbon are locked in Arctic permafrosts, much of it in Siberia. The carbon leak is slow -- he estimates it could only be as high as 1 billion tons each year worldwide, or about 10 percent of what is emitted today through human activity emissions. But over the next four centuries it could end up in the atmosphere, drastically altering Earth's climate.

"The Ping paper is great so far as it goes, but it's only dealing with this one zone: North America," Schuur said. "That's like describing what an elephant looks like by talking all about its foot. We're trying to describe the whole elephant."

If Schuur's estimate is right, Arctic soils harbor two to three times more carbon than is currently aloft in Earth's atmosphere. If it were to be released as greenhouse gases over the course of the next few centuries, the effect on the climate might not be noticeable by the year 2100. But by the year 2400 or 2500 it would be tremendous.

"Right now there's about 780 billion tons of carbon in the atmosphere. And now you say you're going to take and slowly put much of 1,600 billion tons from the soil up there. That's going to have a huge effect on the heat-trapping capacity of the Earth," Schuur said.

"Say you look at Earth in 500 years," he said. "It's probably going to be a very different place."

Link to article: http://dsc.discovery.com/news/2008/08/25/warming-arctic-tundra.html

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Heavy Rain Triggers Destructive Tornadoes

by Michael Reilly, Discovery News, August 22, 2008

When the spring skies blacken over the Midwestern United States and the clouds begin to rotate ominously, residents know a tornado could be on its way.

But just how the deadly twisters form is a mystery that has puzzled scientists for decades. They know a range of atmospheric conditions must be in place, including strong, closely paired up- and downdrafts, windshear at high altitudes, and usually a foreboding supercell thunderstorm, spinning slowly in the sky.

Amid this stormy cocktail, new research suggests that the heavy rains that often accompany supercells may be key in triggering tornadoes to form. According to Robert Davies-Jones of the National Severe Storms Laboratory in Oklahoma, rain falling in heavy sheets from a supercell storm cloud provides a strong push to updrafting air, causing it to spin up into a fully fledged twister.

"You can have a rotating storm but until you have rain you don't get a tornado," Robert Davies-Jones of the National Severe Storm Laboratory said.

Scientists have known this simple fact since 1953, when radar first allowed meteorologists to peer into supercells. In tornadic storms, they noticed the rain swirled into a hook shape. The feature, called a 'hook echo' quickly became known as a tell-tale radar marker for a tornado.

But the swirling rain was regarded as a by-product of a tornado, merely the effect of its powerful corkscrewing winds. Davies-Jones believes the opposite may be true.

"The hook echo is usually thought to be a passive feature of tornadoes," he said. "I'm saying it's not passive, it's an active mechanism for tornado formation."

His work is published in the August issue of Journal of the Atmospheric Sciences.

Davies-Jones ran computer simulations of supercell storms to see if falling rain could provide the needed kick that turned diffuse updrafts rising off the warm plains into tight-spinning, lethal tornadoes. As the rain falls out of a rotating supercell cloud it is also twisting, and as it falls he found it transfers the rotational energy into the updrafting air adjacent to it.

The rain also acts as a sort of wall, confining the swirling, rising air. As it continues to head skyward the air inside the rain curtain stretches out like a figure skater raising her arms. The spinning speeds up, and a tornado is born.

"The mechanism is a good one," David Lewellen of the University of West Virginia said. "But until these things are seen more conclusively out in the field, it's not at all clear whether rain is involved in the formation of most tornadoes, a few, or none at all."

Lewellen points out that rain is only one of myriad weather conditions that have to be just right for a tornado to form. A massive field campaign of experiments is scheduled for the spring season in 2009 and 2010 that he hopes will determine if the implications in the models are correct.

Link to article: http://dsc.discovery.com/news/2008/08/22/tornado-rain.html


NOAA 2008 Monthly Tornado Statistics

Number of Tornadoes Number of Tornado Deaths Killer Tornadoes

20082007200620053 Year Avg.20082007200620053 Year Avg.20082007200620053 Year Avg.

PrelimActualPrelimActualFinalFinal
PrelimFinalFinalFinal
PrelimFinalFinalFinal
JAN 136 84 29 21 47 33 34 7 2 1 4 2 4 1 1 2 1
FEB 230 148 87 52 12 10 25 59 22 0 0 7 12 3 0 0 1
MAR 150 126 214 171 150 62 128 4 27 11 1 13 3 10 7 1 6
APR 189 189 187 165 245 132 181 0 9 38 0 16 0 3 9 0 4
MAY 597 460 282 250 139 123 171 43 14 3 0 6 10 4 1 0 2
JUN 394 ? 152 128 120 316 188 7 0 0 0 0 4 0 0 0 0
JUL 120 ? 55 69 71 138 93 1 0 0 0 0 1 0 0 0 0
AUG 59 ? 87 73 80 123 92 ? 1 1 4 2 ? 1 1 3 2
SEP ? ? 63 51 84 133 89 ? 0 1 1 1 ? 0 1 1 1
OCT ? ? 115 87 76 18 60 ? 5 0 0 2 ? 3 0 1 1
NOV ? ? 7 7 42 150 66 ? 0 10 28 13 ? 0 3 5 3
DEC ? ? 22 19 40 26 33 ? 1 2 0 1 ? 1 2 0 1
Total 1875 1007 1300 1093 1106 1264 1159 121 81 67 38 62 34 26 25 13 21

Note:? means final number not yet available.
Important! Prelim. numbers represent tornado reports. Columns marked Final represent total tornadoes.
2008 numbers updated through May.

Click to see the larger Daily Tornado Trend Image

Link: http://www.spc.noaa.gov/climo/torn/monthlytornstats.html

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Air Circulates Above The Earth In Four Distinct Cells

Air Circulates Above The Earth In Four Distinct Cells

From Live Science, submitted by News Staff on 21 August 2008 - 11:00am. Atmospheric

Air circulates above the Earth in four distinct cells, with two either side of the equator, says new research out today in Science.

The new observational study describes how air rises and falls in the atmosphere above the Earth’s surface, creating the world’s weather. This process of atmospheric circulation creates weather patterns and influences the climate of the planet. It is important to understand these processes in order to predict weather events, and to improve and test climate models.

Previous theories have claimed that there are just two large circular systems of air in the atmosphere, one either side of the equator. These theories suggested that air rises at the equator and then travels towards either the north or south polar regions, where it falls.

The new research suggests instead that there are two cells in both the northern and southern hemispheres. In the first cell, air rises at the equator and then falls in the subtropics. In the second cell, air rises in the mid-latitudes - approximately 30 to 60 degrees north and south of the equator – and then falls in the polar regions.

The researchers say that this second cell of rising air is a mechanism responsible for setting the distribution of temperature and winds in the mid-latitudes which has not been fully appreciated before. The mid-latitudes include the UK, Europe and most of the United States.

Dr Arnaud Czaja from Imperial College London’s Department of Physics and the Grantham Institute for Climate Change, one of the authors of the new research, explains: “Our model suggests that there is a second cell of air in each hemisphere which is characterised by air rising, clouds forming, storms developing and other processes associated with moisture in the air occurring in the mid-latitudes.”

Current theories to describe weather patterns in the mid-latitudes do not take these moisture-based processes into consideration. Dr Czaja argues that these theories are therefore incomplete, and that water vapour plays as much of an important role in the weather systems of the mid-latitudes as it does in the tropics, where it is a well-documented driver of weather events.

The research team carried out their study by conducting new analyses of extensive meteorological data. Dr Czaja says that he hopes the research will lead to a more detailed understanding of how air circulation in our atmosphere works, and how it affects the weather:

“With more attention than ever before being focused on understanding our planet’s climate, weather systems and atmosphere, it’s important that scientists challenge their own assumptions and current theories of how these complex processes work. I think our study sheds new light on the driving forces behind the weather in the mid-latitudes,” Dr Czaja added.

1. “The Global Atmospheric Circulation on Moist Isentropes”, Science, 21 August 2008.

Olivier Pauluis (1), Arnaud Czaja (2), Robert Korty (3)

(1) Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012, USA.

(2) Space and Atmospheric Physics Group, Department of Physics, Imperial College, Huxley Building, Room 726, London SW7 2AZ, UK.

(3) Department of Atmospheric Sciences, Texas A&M University, 3150 TAMU, College Station, TX 77843–3150, USA.

Link to article: http://www.scientificblogging.com/news_releases/air_circulates_above_the_earth_in_four_distinct_cells

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NOAA: Fifth Warmest July on Record for Globe

NOAA: Fifth Warmest July on Record for Globe

August 15, 2008

The combined average global land and ocean surface temperature for July 2008 tied with 2001 and 2003 as the fifth warmest July since worldwide records began in 1880, according to an analysis by NOAA’s National Climatic Data Center in Asheville, N.C.

Also, the 7 months from January to July 2008 ranked as the 9th warmest 7-month period for combined average global land and ocean surface temperature.

Global Temperatures

* The July 2008 combined global land and ocean surface temperature was 0.88 F (0.49 C) above the 20th century mean of 60.4 F (15.8 C). For the January–July period, the combined global land and ocean surface temperature was 0.81 F (0.45 C) above the 20th century mean of 56.9 F (13.8 C).

* Separately, the global land surface temperature for July was 1.22 F (0.68 C) above the 20th century mean of 57.8 F (14.3 C). For January–July, the global land surface temperature was 1.35 F (0.75 C) above the 20th century mean of 46.8 F (8.3 C).

* The July global ocean surface temperature was 0.76 F (0.42 C) above the 20th century mean of 61.5 F (16.4 C). The January–July global ocean surface temperature was 0.61 F (0.34 C) above the 20th century mean of 61.0 F (16.1 C).

* El Niño-Southern Oscillation conditions continued neutral through July in the tropical Pacific Ocean, ending the La Niña event that began in mid-2007.

* Northern Hemisphere sea ice extent ranked 4th lowest on record for July. Since 1979, Northern Hemisphere sea ice extent in July has decreased by 6.1% per decade. In contrast, the Southern Hemisphere sea ice extent was slightly above the 1979-2000 average and ranked 10th largest for July out of the last 30 years.

Link to article: http://www.noaanews.noaa.gov/stories2008/20080815_ncdc.html

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Fewer April Showers for U.S. Southwest as Climate Changes

Things could get uglier for desert flowers looking to bloom in May--and for the region's water supply, year-round

by David Biell, Scientific American, August 20, 2008



STORM TRACKER: The jet stream that carries moisture from Pacific storms over the U.S. has shifted north in recent decades, making the arid Southwest even drier. COURTESY OF STEPHANIE MCAFEE/UNIVERSITY OF ARIZONA/2008
The already parched U.S. Southwest is drying up even more, at least in early spring, because of climate change. A new study in Geophysical Research Letters shows that since 1978, the jet stream that brings rainstorms from the Pacific over the western U.S. has been shifting northward—and so has the rain and snow.

"That northward shift in the storm track is tied to reduced early spring precipitation, especially over the southwest U.S.," says atmospheric scientist Stephanie McAfee of the University of Arizona (U.A.) in Tucson, who led the research identifying the loss of a few storms per season. "It looks like the northern Great Plains seem to get a little bit more rain."

The total amount is only a fraction of an inch, McAfee notes, drawing on precipitation and storm data from the U.S. National Oceanic and Atmospheric Adminstration. But this is lengthening "the dry season in parts of the country that are already quite arid," she says.

Greenhouse gases emitted by burning fossil fuels are piling up in the atmosphere, warming its lowest layer. At the same time, human-produced chemicals have eaten holes in the ozone layer over the poles, ultimately cooling the uppermost part of the atmosphere. This temperature differential creates pressure differences that have been shifting the powerful high-altitude winds known as jet streams in both the Northern and Southern hemispheres closer to the poles since the 1980s. "It's man-made either way you look at it," says U.A. biogeochemist Joellen Russell, senior author of the study.

Climate change has arrived in the Southwest in the form of an earlier seasonal shift to summerlike weather, bringing an end to April showers in the lowlands and spring snowfalls in the mountains. "The change so far in total precipitation is pretty small," Russell notes. But "we expect that this may continue or even get worse."

The Southwest is already suffering through an extended drought that has lowered water levels in Lake Mead and threatens agriculture. McAfee says the climatic shift may also decrease the mountain snowpack that provides water for cities as well as dry out soils, thereby starting fire season earlier in the year, although she has no data on those phenomena yet. "People are going to need to change a little bit in their expectations of what a season is going to be like," adds McAfee, who is now looking at how this is impacting area vegetation. "If we keep doing this, the climate response becomes more extreme."

Link to article: http://www.sciam.com/article.cfm?id=fewer-april-showers-for-southwest

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U.S. Court of Appeals rejects E.P.A. limits on emissions rules

by Felicity Barringer, New York Times, August 19, 2008

A federal appeals court on Tuesday threw out an Environmental Protection Agency rule limiting the ability of states to require monitoring of industrial emissions.

The 2-to-1 ruling by the United States Court of Appeals for the District of Columbia Circuit is the most recent in a series of judicial setbacks to the Bush administration’s efforts to reshape federal policies under the Clean Air Act.

Under 1990 amendments to the original Clean Air Act, states were allowed to issue permits limiting pollution emissions from industrial facilities, like refineries or utilities. To ensure compliance, Congress required states to set more stringent monitoring requirements if they deemed federal requirements inadequate.

The E.P.A. gave states this leeway until 2006, when it reversed course and prohibited the states from requiring new monitoring. Environmental groups challenged the agency, saying that the new rule kept public agencies from gathering and making available the best data about industrial contributions to air pollution.

“E.P.A.’s about-face means that some permit programs do not comply” with federal law, Judge Thomas B. Griffith wrote in the majority opinion. He added that thousands of permits allowing the operation of industrial facilities might not comply with the law “because their monitoring requirements are invalid.”

Judge David B. Sentelle joined Judge Griffith’s opinion.

The ruling by the court, which has jurisdiction over most federal agency rules, was another judicial rebuke to the E.P.A.’s recent policies, leaving few of its major initiatives on air pollution intact.

The suit, brought by the Sierra Club, was opposed by the environmental agency and several industry groups, including the Alliance of Automobile Manufacturers and the American Petroleum Institute.

“I think it is fair to say that the D.C. Circuit has repudiated the vast bulk of the Bush administration’s clean-air regulatory reforms, which were the administration’s most notable and significant (if not always wise) environmental policy initiatives,” Jonathan Adler, a law professor at Case Western Reserve University, commented on the case on a legal affairs blog, The Volokh Conspiracy. In an interview, Professor Adler said the agency “was giving business a bit of a break; was saying to states: You can’t do more.”

But he added, “One of the ways states experiment is not only being more protective but being more protective more cheaply. They win if they figure out a way to make environmental controls less costly.”

Keri N. Powell, a lawyer with Earthjustice who argued the case for the environmental groups, said the 1990 law was designed to give states power to fill any gaps left by the federal government and provide the public with data about industrial emissions.

“The idea was to make this information accessible to public and to state governments,” Ms. Powell said. “States are the front lines. They issue the permits.”

She added that, with the 2006 rule, “what they did was ban monitoring.”

“They did it,” she said, “even though the E.P.A. admitted that existing monitoring wasn’t good enough.”

Ms. Powell concluded, “That was just outrageous and defied the plain language” of the law.

Representatives of the Alliance of Automobile Manufacturers and the American Petroleum Institute did not immediately return calls seeking comment.

In his dissent, Judge Brett A. Kavanagh, like his colleagues, made reference to a famous dictum from Justice Felix Frankfurter. “I strongly align myself with the majority’s quotation from Justice Frankfurter about the best tool of statutory interpretation: 1) Read the statute. 2) Read the statute. 3) Read the statute!” Judge Kavanagh wrote.

And, he added, the relevant parts of the Clean Air Act support the E.P.A.

Link to article: http://www.nytimes.com/2008/08/20/washington/20air.html

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9 Polar Bears Spotted on Risky Open Ocean Swims

Thursday, August 21, 2008

ANCHORAGE, Alaska (AP) — Nine polar bears were observed in one day swimming in open ocean off Alaska's northwest coast, an increase from previous surveys that may indicate warming conditions are forcing bears to make riskier, long-distance swims to stable sea ice or land.

The bears were spotted in the Chukchi Sea on a flight by a federal marine contractor, Science Applications International Corp.

It was hired for the Minerals Management Service in advance of future offshore oil development. The MMS in February leased 2.76 million acres within an offshore area slightly smaller than Pennsylvania.

Observers Saturday were looking for whales but also recorded walrus and polar bears, said project director Janet Clark. Many were swimming north and ranged from 15 to 65 miles off shore, she said.

Department of Interior Secretary Dirk Kempthorne in May declared polar bears a threatened species because of an alarming loss of summer sea ice and forecasts the trend will continue.

Polar bears spend most of their lives on sea ice, which they use as a platform to hunt their primary prey, ringed seals. Shallow water over the continental shelf is the most biologically productive for seals, but pack ice in recent years has receded far beyond the shelf.

Conservation groups fear that one consequence of less ice will be more energy-sapping, long-distance swims by polar bears trying to reach feeding, mating or denning areas.

Steven Amstrup, senior polar bear scientist for the U.S. Geological Survey in Anchorage, said the bears could have been on a patch of ice that broke up northwest of Alaska's coast.

"The bears that had been on that last bit of ice that remained over shallow shelf waters, are now swimming either toward land or toward the rest of the sea ice, which is a considerable distance north," he said in an e-mail response to questions.

It probably is not a big deal for a polar bear in good condition to swim 10 or 15 miles, Amstrup said, but swims of 50-100 miles could be exhausting.

"We have some observations of bears swimming into shore when the sea ice was not visible on the horizon," he said. "In some of these cases, the bears arrive so spent energetically, that they literally don't move for a couple days after hitting shore."

Only further research can tell the effect of greater swimming distances on polar bear populations, he said.

"Polar bears can swim quite well, but they are not aquatic animals," he said. "Their home is on the surface of the ice."

Satellite data Saturday showed the main body of pack ice about 400 miles offshore with one ribbon about 100 miles off Alaska's coast, said Mark Serreze of the National Snow and Ice Data Center.

Clark said the animals' origin and destination could not be known without radio collar monitoring.

"To go out there and say they were going from this point to this point would be complete speculation," Clark said.

Observers have no indication of the fate of the nine polar bears observed Saturday.

Link to article: http://www.foxnews.com/story/0,2933,408502,00.html

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Expansion of oxygen-minimum zones in the oceans

header image
Oxygen Depletion: A New Form of Ocean Habitat Loss

Scientists confirm computer model predictions that oxygen-depleted zones in tropical oceans are expanding, possibly because of climate change

Scripps Institution of Oceanography, UC San Diego, Calif., U.S.A., May 1, 2008

An international team of physical oceanographers including a researcher from Scripps Institution of Oceanography at UC San Diego has discovered that oxygen-poor regions of tropical oceans are expanding as the oceans warm, limiting the areas in which predatory fishes and other marine organisms can live or enter in search of food.

Half of the science party aboard R/V Roger Revelle during an April cruise was female, a marker of progress from the days when some oceanographic institutions did not allow women to take part in research cruises.

Janet Sprintall (standing, fourth from left) aboard an April 2007 CLIVAR cruise aboard R/V Roger Revelle. Sprintall contributed data from the cruise to a new study describing declining oxygen levels in tropical oceans.

The new study is led by Lothar Stramma from the Leibniz Institute of Marine Sciences (IFM-GEOMAR) in Kiel, Germany, and is co-authored by Janet Sprintall, a physical oceanographer at Scripps Oceanography and others. The researchers found through analysis of a database of ocean oxygen measurements that levels in tropical oceans at a depth of 300-700 m (985-2,300 ft.) have declined during the past 50 years. The ecological impacts of this increase could have substantial biological and economical consequences.

"We found the largest reduction in a depth of 300-700 m (985-2,300 ft.) in the tropical northeast Atlantic, whereas the changes in the eastern Indian Ocean were much less pronounced," said Stramma. "Whether or not these observed changes in oxygen can be attributed to global warming alone is still unresolved. The reduction in oxygen may also be caused by natural processes on shorter time scales."

Sprintall said the oxygen-poor areas have the potential to move into coastal areas via currents that flow from the mid-depth tropical oceans, where the oxygen changes were observed, and along the west coast of continents.

Mean dissolved oxygen concentrations in the world's oceans at a depth of 400 meters (1,312 feet) with blue contours representing the lowest concentrations. Boxed areas represent ocean regions analyzed in the study. Image courtesy of AAAS/Science

Mean dissolved oxygen concentrations in the world's oceans at a depth of 400 m (1,312 ft.) with blue contours representing the lowest concentrations. Boxed areas represent ocean regions analyzed in the study. Image courtesy of AAAS/Science.

"The width of the low-oxygen zone is expanding deeper but also shoaling toward the ocean surface," said Sprintall, a specialist in observing changes of fluxes in ocean properties such as heat distribution.

Sprintall contributed data to the study gathered during recent cruises undertaken as part of the Climate Variability and Predictability (CLIVAR) program, a long-running study operated by the World Climate Research Programme that seeks to understand climate through ocean-atmosphere interactions.

The study, "Expanding Oxygen-Minimum Zones in the Tropical Oceans," appears in the May 2 edition of the journal Science. The research team includes Stramma, Sprintall, NOAA scientist Gregory Johnson, and Volker Mohrholz from the Institute for Baltic Sea Research in Warnemünde, Germany.

The team selected ocean regions for which they could obtain the greatest amount of data to document the decline in oxygen. Some of the more recent data came from oxygen sensors which have been added to about 150 of the profiling floats used in Argo, a worldwide network of sensors that track basic ocean conditions such as temperature and salinity. There are more than 3,000 Argo floats operating in the world's oceans, and Sprintall said the quality of the data gathered by the Argo floats suggests that more units in the network should be outfitted with oxygen sensors.

Lisa Levin, a biological oceanographer at Scripps Oceanography who studies oxygen-minimum zones that intercept the seafloor, said an expansion of oxygen-minimum zones in the oceans could lead to diminished biodiversity and to the expanded distributions of organisms that have adapted to live in hypoxic, or oxygen-poor waters.

During an April 2007 CLIVAR cruise, researchers collected water samples from the Indian Ocean to measure their oxygen content. An international team incorporated the results into an analysis of global oxygen-minimum zone expansion.

During an April 2007 CLIVAR cruise, researchers collected water samples from the Indian Ocean to measure their oxygen content. An international team incorporated the results into an analysis of global oxygen-minimum zone expansion.

"I think it's uncharted territory," said Levin, who was not affiliated with the study. "Thicker oxygen minimum zones could affect nutrient cycling, predator-prey relationships and plankton migrations. Where the expanding oxygen-minimum zones impinge on continental margins, we could see huge ecosystem changes."

The results of the study are an important milestone for the ongoing work of the new Collaborative Research Centre (SFB 754) "Climate: Biogeochemistry Interactions in the Tropical Ocean" funded by the German Research Foundation, which started its first phase in January 2008 in close cooperation with the University of Kiel. The SFB aims to better define the interactions between climate and biogeochemistry on a quantitative basis.

Link to article: http://scrippsnews.ucsd.edu/Releases/?releaseID=905

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Jeremy B. C. Jackson: Ecological extinction and evolution in the brave new ocean (Proc. Natl. Acad. Sci.)

Ecological extinction and evolution in the brave new ocean
  1. Jeremy B. C. Jackson*
  1. Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0244; and Smithsonian Tropical Research Institute, Box 2072 Balboa, Republic of Panama

Abstract

The great mass extinctions of the fossil record were a major creative force that provided entirely new kinds of opportunities for the subsequent explosive evolution and diversification of surviving clades. Today, the synergistic effects of human impacts are laying the groundwork for a comparably great Anthropocene mass extinction in the oceans with unknown ecological and evolutionary consequences. Synergistic effects of habitat destruction, overfishing, introduced species, warming, acidification, toxins, and massive runoff of nutrients are transforming once complex ecosystems like coral reefs and kelp forests into monotonous level bottoms, transforming clear and productive coastal seas into anoxic dead zones, and transforming complex food webs topped by big animals into simplified, microbially dominated ecosystems with boom and bust cycles of toxic dinoflagellate blooms, jellyfish, and disease. Rates of change are increasingly fast and nonlinear with sudden phase shifts to novel alternative community states. We can only guess at the kinds of organisms that will benefit from this mayhem that is radically altering the selective seascape far beyond the consequences of fishing or warming alone. The prospects are especially bleak for animals and plants compared with metabolically flexible microbes and algae. Halting and ultimately reversing these trends will require rapid and fundamental changes in fisheries, agricultural practice, and the emissions of greenhouse gases on a global scale.

Footnotes

  • *E-mail: jbjackson@ucsd.edu

  • Author contributions: J.B.C.J. designed research, performed research, analyzed data, and wrote the paper.

  • The author declares no conflict of interest.

Link to abstract: http://www.pnas.org/content/early/2008/08/08/0802812105.abstract

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Scripps scientist Jeremy Jackson warns of mass extinctions and "Rise of Slime"

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Oceans on the Precipice: Scripps Scientist Warns of Mass Extinctions and 'Rise of Slime'

Threats to marine ecosystems from overfishing, pollution and climate change must be addressed to halt downward trends

Scripps Institution of Oceanography, UC San Diego, Calif., U.S.A., August 13, 2008

Human activities are cumulatively driving the health of the world's oceans down a rapid spiral, and only prompt and wholesale changes will slow or perhaps ultimately reverse the catastrophic problems they are facing.

Such is the prognosis of Jeremy Jackson, a professor of oceanography at Scripps Institution of Oceanography at UC San Diego, in a bold new assessment of the oceans and their ecological health. Publishing his study in the online early edition of the Proceedings of the National Academy of Sciences (PNAS), Jackson believes that human impacts are laying the groundwork for mass extinctions in the oceans on par with vast ecological upheavals of the past.

Jeremy Jackson, Scripps Professor of Oceanography

Jeremy Jackson, Scripps Professor of Oceanography

BLOGGER'S NOTE: go to the link at the bottom of this post to get to the web page with the video cast of the interview of Prof. Jackson.

He cites the synergistic effects of habitat destruction, overfishing, ocean warming, increased acidification and massive nutrient runoff as culprits in a grand transformation of once complex ocean ecosystems. Areas that had featured intricate marine food webs with large animals are being converted into simplistic ecosystems dominated by microbes, toxic algal blooms, jellyfish and disease.

Jackson, director of the Scripps Center for Marine Biodiversity and Conservation, has tagged the ongoing transformation as "the rise of slime." The new paper, "Ecological extinction and evolution in the brave new ocean," is a result of Jackson's presentation last December at a biodiversity and extinction colloquium convened by the National Academy of Sciences.

"The purpose of the talk and the paper is to make clear just how dire the situation is and how rapidly things are getting worse," said Jackson. "It's a lot like the issue of climate change that we had ignored for so long. If anything, the situation in the oceans could be worse because we are so close to the precipice in many ways."

In the assessment, Jackson reviews and synthesizes a range of research studies on marine ecosystem health, and in particular key studies conducted since a seminal 2001 study he led analyzing the impacts of historical overfishing. The new study includes overfishing, but expands to include threats from areas such as nutrient runoff that lead to so-called "dead zones" of low oxygen. He also incorporates increases in ocean warming and acidification resulting from greenhouse gas emissions.

Jackson describes the potently destructive effects when forces combine to degrade ocean health. For example, climate change can exacerbate stresses on the marine environment already brought by overfishing and pollution.

"All of the different kinds of data and methods of analysis point in the same direction of drastic and increasingly rapid degradation of marine ecosystems," Jackson writes in the paper.

During a recent research expedition to Kiritimati, or Christmas Island, Jeremy Jackson and other researchers documented a coral reef overtaken by algae, featuring murky waters and few fish. The researchers say pollution, overfishing, warming waters or some combination of the three are to blame. Photo credit: Jennifer E. Smith

During a recent research expedition to Kiritimati, or Christmas Island, Jeremy Jackson and other researchers documented a coral reef overtaken by algae, featuring murky waters and few fish. The researchers say pollution, overfishing, warming waters or some combination of the three are to blame. Photo credit: Jennifer E. Smith.

Jackson furthers his analysis by constructing a chart of marine ecosystems and their "endangered" status. Coral reefs, Jackson's primary area of research, are "critically endangered" and among the most threatened ecosystems; also critically endangered are estuaries and coastal seas, threatened by overfishing and runoff; continental shelves are "endangered" due to, among other things, losses of fishes and sharks; and the open ocean ecosystem is listed as "threatened" mainly through losses at the hands of overfishing.

"Just as we say that leatherback turtles are critically endangered, I looked at entire ecosystems as if they were a species," said Jackson. "The reality is that if we want to have coral reefs in the future, we're going to have to behave that way and recognize the magnitude of the response that's necessary to achieve it."

To stop the degradation of the oceans, Jackson identifies overexploitation, pollution and climate change as the three main "drivers" that must be addressed.

"The challenges of bringing these threats under control are enormously complex and will require fundamental changes in fisheries, agricultural practices and the ways we obtain energy for everything we do," he writes.

"So it's not a happy picture and the only way to deal with it is in segments; the only way to keep one's sanity and try to achieve real success is to carve out sectors of the problem that can be addressed in effective terms and get on it as quickly as possible."

The research described in the paper was supported by the William E. and Mary B. Ritter Chair of Scripps Institution of Oceanography.

Link to article: http://scrippsnews.ucsd.edu/Releases/?releaseID=920



WASHINGTON, Aug. 14 (UPI) -- A U.S. scientist predicts continued overfishing will lead to the extinction of the Earth's edible species of fish and affect other levels of the food chain.

But Jeremy Jackson, a senior scientist at the Smithsonian Tropical Research Institute and the Scripps Institution of Oceanography, says just the enforcement of fishery regulations would help prevent such extinctions.

Jackson says certain steps, if taken immediately, might reverse the demise of the Earth's ocean species. Those measures include establishing marine reserves, eliminating subsidies for fertilizer use and limiting fossil fuel consumption.

In addition to the extinction of edible fish species, he said without the immediate implementation of ocean-protection measures, larger dead zones and toxic algal blooms may form along the coastal zones of all of the world's continents, increasing disease outbreaks and inhibiting vertical mixing of ocean waters.

"Some may say that it is irresponsible to make such predictions pending further detailed study to be sure of every point," said Jackson. "However, we will never be certain about every detail, and it would be irresponsible to remain silent in the face of what we already know."

The study appears in the early online edition of the Proceedings of the National Academy of Sciences.