http://news.yahoo.com/s/ap/20060623/ap_on_sc/global_warming

Earth hottest it's been in 2,000 years

By JOHN HEILPRIN, Associated Press Writer
2 hours, 14 minutes ago

WASHINGTON - The Earth is running a slight fever from greenhouse gases, after enjoying relatively stable temperatures for 2,000 years. The National Academy of Sciences, after reconstructing global average surface temperatures for the past two millennia, said Thursday the data are "additional supporting evidence ... that human activities are responsible for much of the recent warming."

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Other new research showed that global warming produced about half of the extra hurricane-fueled warmth in the North Atlantic in 2005, and natural cycles were a minor factor, according to Kevin Trenberth and Dennis Shea of the National Center for Atmospheric Research, a research lab sponsored by the National Science Foundation and universities.

The academy had been asked to report to Congress on how researchers drew conclusions about the Earth's climate going back thousands of years, before data was available from modern scientific instruments. The academy convened a panel of 12 climate experts, chaired by Gerald North, a geosciences professor at Texas A&M University, to look at the "proxy" evidence before then, such as tree rings, corals, marine and lake sediments, ice cores, boreholes and glaciers.

Combining that information gave the panel "a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years," the panel wrote. It said the "recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia," though it was relatively warm around the year 1000 followed by a "Little Ice Age" from about 1500 to 1850.

Their conclusions were meant to address, and they lent credibility to, a well-known graphic among climate researchers — a "hockey-stick" chart that climate scientists Michael Mann, Raymond Bradley and Malcolm Hughes created in the late 1990s to show the Northern Hemisphere was the warmest it has been in 2,000 years.

It had compared the sharp curve of the hockey blade to the recent uptick in temperatures — a 1 degree rise in global average surface temperatures in the Northern Hemisphere during the 20th century — and the stick's long shaft to centuries of previous climate stability.

That research is "likely" true and is supported by more recent data, said John "Mike" Wallace, an atmospheric sciences professor at the University of Washington and a panel member.

Rep. Sherwood Boehlert (news, bio, voting record), R-N.Y., chairman of the House Science Committee, had asked the academy for the report last year after the House Energy and Commerce Committee chairman, Rep. Joe Barton (news, bio, voting record), R-Texas, launched an investigation of the three climate scientists.

The Bush administration has maintained that the threat from global warming is not severe enough to warrant new pollution controls that the White House says would have cost 5 million Americans their jobs.

"This report shows the value of Congress handling scientific disputes by asking scientists to give us guidance," Boehlert said Thursday. "There is nothing in this report that should raise any doubts about the broad scientific consensus on global climate change."

The academy panel said it had less confidence in the evidence of temperatures before 1600.

But it considered the evidence reliable enough to conclude there were sharp spikes in carbon dioxide and methane, the two major "greenhouse" gases blamed for trapping heat in the atmosphere, beginning in the 20th century, after remaining fairly level for 12,000 years.

Between 1 A.D. and 1850, volcanic eruptions and solar fluctuations had the biggest effects on climate. But those temperature changes "were much less pronounced than the warming due to greenhouse gas" levels by pollution since the mid-19th century, the panel said.

The National Academy of Sciences is a private organization chartered by Congress to advise the government of scientific matters.

The ironic thing fellowdem is

If this global warming thing is indeed happening and true, and if you believe that, like I believe that

It really should be the only issue whatsoever to concern the world, because think about it

Any war or terror event will kill a few thousand or so, or even say
100,000 like the # of Iraqi's dead

However, if the ability to kill off the entire planet is coming that is billions and billions, that is everyone black white rich poor north south
them us whatever

So why sweat the small stuff when the temperature is going to make us all sweat the big stuff?

You do make a valid point, g4a. Gore realizes it and this is probably why he's dedicating his life to it right now more than he ever has in prior years.

Gore's plan: Lets try and combat it now and save the planet Earth.

Bush's plan: Lets just say to hell with Earth and move to Mars!

Yup. I agree with this.

I know its naive, but just imagine if the world got together to save everybody in the world

That would be something

Even the people who say America is better than anyone, then use that logic and say, well America, let's build us not only hybrids but brand new cars, and then if everyone is working and everyone is building new cars, wouldn't the auto companies then make millions in new sales?

And you can start a re-training program for Halliburton
Sure they would be one of a few business now that loses money if there is no war, but they can give them new training and maybe the workers of Halliburton and the oil company ceo's can, in 20 to 30 years, make a living too

I can't imagine any other administration past dem or repub that would be so blind as to not see what is going on (but of course Nixon didn't have the ulterior motives Bush has).
Any other president in the past would have thought, WOW! What a challenge, what a legacy I could have if I am the one to save the world.

But Bush once said said something like, History? I'll be dead when that happens.

And now a word of support for global warming:

Glacial cycles tend to take 100,000 years, the first 80,000 of them having the planet covered with ice nearly everywhere except the equator, the last 20,000 of them being the "interglacial warming period."

Well guys - - TIME IS ALMOST UP.

Let's delay the onset of the next one.

Published on Thursday, August 11, 2005 by the Guardian/UK
Warming Hits 'Tipping Point'
Siberia feels the heat: A frozen peat bog the size of France and Germany combined contains billions of tonnes of greenhouse gas, and for the first time since the ice age, it is melting.
By Ian Sample

A vast expanse of western Siberia is undergoing an unprecedented thaw that could dramatically increase the rate of global warming, climate scientists warn today.

(If we don't take action very soon, we could unleash runaway global warming that will be beyond our control and it will lead to social, economic and environmental devastation worldwide.) - Tony Juniper, director of Friends of the Earth

Researchers who have recently returned from the region found that an area of permafrost spanning a million square kilometers - the size of France and Germany combined - has started to melt for the first time since it formed 11,000 years ago at the end of the last ice age.

The area, which covers the entire sub-Arctic region of western Siberia, is the world's largest frozen peat bog and scientists fear that as it thaws, it will release billions of tonnes of methane, a greenhouse gas 20 times more potent than carbon dioxide, into the atmosphere.

It is a scenario climate scientists have feared since first identifying "tipping points" - delicate thresholds where a slight rise in the Earth's temperature can cause a dramatic change in the environment that itself triggers a far greater increase in global temperatures.

The discovery was made by Sergei Kirpotin at Tomsk State University in western Siberia and Judith Marquand at Oxford University and is reported in New Scientist today.

The researchers found that what was until recently a barren expanse of frozen peat is turning into a broken landscape of mud and lakes, some more than a kilometer across.

Dr Kirpotin told the magazine the situation was an "ecological landslide that is probably irreversible and is undoubtedly connected to climatic warming". He added that the thaw had probably begun in the past three or four years.

Climate scientists yesterday reacted with alarm to the finding, and warned that predictions of future global temperatures would have to be revised upwards.

"When you start messing around with these natural systems, you can end up in situations where it's unstoppable. There are no brakes you can apply," said David Viner, a senior scientist at the Climatic Research Unit at the University of East Anglia.

"This is a big deal because you can't put the permafrost back once it's gone. The causal effect is human activity and it will ramp up temperatures even more than our emissions are doing."

In its last major report in 2001, the intergovernmental panel on climate change predicted a rise in global temperatures of 1.4C-5.8C between 1990 and 2100, but the estimate only takes account of global warming driven by known greenhouse gas emissions.

"These positive feedbacks with landmasses weren't known about then. They had no idea how much they would add to global warming," said Dr Viner.

Western Siberia is heating up faster than anywhere else in the world, having experienced a rise of some 3C in the past 40 years. Scientists are particularly concerned about the permafrost, because as it thaws, it reveals bare ground which warms up more quickly than ice and snow, and so accelerates the rate at which the permafrost thaws.

Siberia's peat bogs have been producing methane since they formed at the end of the last ice age, but most of the gas had been trapped in the permafrost. According to Larry Smith, a hydrologist at the University of California, Los Angeles, the west Siberian peat bog could hold some 70bn tons of methane, a quarter of all of the methane stored in the ground around the world.

The permafrost is likely to take many decades at least to thaw, so the methane locked within it will not be released into the atmosphere in one burst, said Stephen Sitch, a climate scientist at the Met Office's Hadley Center in Exeter.

But calculations by Dr Sitch and his colleagues show that even if methane seeped from the permafrost over the next 100 years, it would add around 700m tons of carbon into the atmosphere each year, roughly the same amount that is released annually from the world's wetlands and agriculture.

It would effectively double atmospheric levels of the gas, leading to a 10% to 25% increase in global warming, he said.

Tony Juniper, director of Friends of the Earth, said the finding was a stark message to politicians to take concerted action on climate change. "We knew at some point we'd get these feedbacks happening that exacerbate global warming, but this could lead to a massive injection of greenhouse gases.

"If we don't take action very soon, we could unleash runaway global warming that will be beyond our control and it will lead to social, economic and environmental devastation worldwide," he said. "There's still time to take action, but not much.

"The assumption has been that we wouldn't see these kinds of changes until the world is a little warmer, but this suggests we're running out of time."

In May this year, another group of researchers reported signs that global warming was damaging the permafrost. Katey Walter of the University of Alaska, Fairbanks, told a meeting of the Arctic Research Consortium of the US that her team had found methane hotspots in eastern Siberia. At the hotspots, methane was bubbling to the surface of the permafrost so quickly that it was preventing the surface from freezing over.

Last month, some of the world's worst air polluters, including the US and Australia, announced a partnership to cut greenhouse gas emissions through the use of new technologies.

The deal came after Tony Blair struggled at the G8 summit to get the US president, George Bush, to commit to any concerted action on climate change and has been heavily criticized for setting no targets for reductions in greenhouse gas emissions.

http://www.commondreams.org/headlines05/0811-03.htm

Yes, it would be something. Maybe it could happen if they would actually try. We're in desperate need for a new administration.

Sorry, too late... maybe next time... in a few billion years...

I sadly think it is too late. I don't think unity is going to happen, until they start screaming in the streets for us to save them, one day too late to turn it back

Conservationist sounds alarm on global warming

By KATE CHENEY DAVIDSON
Anchorage Daily News
26-JUN-06

ANCHORAGE, Alaska -- For a woman committed to a depressing subject, Deborah Williams is disarmingly optimistic. Like her hero Paul Revere, Williams has crisscrossed the state over the past 10 months spreading the alarm, and the need for hope, about global warming.

A year ago, Williams left her position as executive director of the Alaska Conservation Foundation to spread word of global warming's dangers. Part passionate conservationist, part savvy politician, she calls it the biggest threat to Alaska and the world. On a warm summer day in Anchorage, Williams doesn't so much sit at her desk as scoot between ringing phones, dinging e-mails and frequent trips to answer the door. The looming question is: Can a one-woman show change comfortable habits and spur the audience to action?

Our conversation was edited for space and clarity.

Q. What sparked your interest in global warming?

A. I was first introduced to the issue of global warming as it was impacting Alaska when I was special assistant (to) the secretary of the interior (for) Alaska. Since then, the science has evolved and the clear seriousness of this issue has grown. I realized that if I was going to effectively be a part of protecting Alaska for present and future generations, it was time to focus on the greatest threat to Alaska: global warming.

Q. What would you say is the biggest adverse impact on Alaska as a result of global warming?

A. Actually, I think there are four.

Melting ice: Since 1979, the summer extent of the Arctic ice cap has shrunk significantly; the equivalent of two Texases' worth of ice has disappeared. Now we are beginning to see the biological impact of that melting ice on the species that depend on it for habitat. Probably the most recent, and the most dramatic, is polar bear cannibalism. Prior to 2004, there was no reported evidence of polar bear cannibalism for food (as opposed to territory) in Alaska or Canada. Over the course of 2 1/2 months in 2004, a period of extreme ice retreat, there were three separate instances of polar bear cannibalism for food in Alaska and Canada. Probably the most shocking of these was a male polar bear that attacked a den containing a mother and two cubs. The cubs were smothered, and the female was dragged from the cave and eaten. This is the brutal evidence of global warming. It is shocking, but it's not surprising.

Drying forests: Trees like white spruce, black spruce and birch, are experiencing reduced growth with warmer temperatures. They are also being adversely affected by a whole range of diseases that weren't problems before, such as spruce bud worm, various leaf miners and much more intense instances of spruce bark beetle. Combined with that, you have melting permafrost, which causes big areas of collapse and tree death, and increased fire. Scientists like Dr. Glenn Juday at the University of Alaska Fairbanks are predicting that we will no longer have boreal trees in Interior Alaska by the end of the century if we continue emitting carbon dioxide at rates similar to today.

Diseased salmon: This represents a threat that is really underappreciated by Alaskans. Increased water temperatures are impacting both salmon eggs and allowing diseases to proliferate in adults. Siltation from melting glaciers is also disrupting the salmon's food chain. The Alaska Department of Fish and Game says that salmon eggs should not be exposed to water temperatures above 55 degrees Fahrenheit, but we are seeing these temperatures in salmon streams throughout the state. In the Yukon, a disease called ichthyophonus is infecting our salmon. Ichthyophonus is a dreadful protozoan parasite that attacks salmon muscle, spoils the meat and kills them.

Coastal communities and inundation: The communities on the Bering Sea and the Arctic Ocean are losing their land at unprecedented rates due to sea level rise and stronger storm cycles. I believe we have an obligation to move these communities intact to suitable land. Shishmaref, for example, has been an intact tribe for at least 4,000 years in that area, and to expect these peoples, who do not contribute much carbon dioxide, to dissipate and lose their tribal ties is reminiscent of the extermination of tribal activities in the 19th century. And it's not going to get better. Scientists now believe that if we triple the level of carbon dioxide in our atmosphere, we are at risk of raising sea levels by up to 20 feet. When you map out what Alaska looks like under 13 to 20 feet of water (rise), it's a devastating portrayal. Take the Bethel region, for example. Under 13 feet of water, almost every community in that area will be inundated, and all the critical goose habitat in the Yukon Delta Wildlife Refuge will be underwater. This should be unacceptable to the American public.

Q. You've called Alaska the Paul Revere of global warming. What do you mean by that?

A. Alaska is indeed the Paul Revere of global warming. Alaska has warmed 4 degrees Fahrenheit on average over the last 50 years _ that's four times the average global warming. We see the threat more acutely than anyone else, and we must spread the word.

Q. So you do you see global warming as a moral issue?

A. I feel strongly that we have a moral responsibility to reduce human-caused emissions. We have a moral responsibility to protect, not diminish, biodiversity and the richness of species. There are predictions that if we continue on our reckless emission curve that we will reduce both plant and animal species by 25 percent by midcentury. We are stealing from future generations if we do not act responsibly on global warming. For those people who may not feel the moral imperative to reduce carbon dioxide and methane emissions, I think there are compelling reasons to do it for economic purposes.

Q. What are some realistic adaptations and/or solutions to global warming?

A. To address global warming, we need to take steps at the individual, local, state, federal and international levels.

As individuals, we can do several things. First, look at your patterns of activity and consumption and ask if there are areas in which you can conserve. Second, use the most energy-efficient appliances, light bulbs and vehicles that you can. This will save money in the mid- and long term, and it will reduce emissions significantly. Lastly, express your concerns about global warming, and demand action on local, state, federal and utility levels.

I believe every municipality or local government has the responsibility to be leaders on carbon dioxide and methane emission reductions for their community. Fortunately, there are organizations that can help municipalities first assess the amount of carbon dioxide and methane emissions they are responsible for and come up with a very practical, cost-effective way to reduce emissions. The primary organization that is doing this work is called ICLEI (the International Council for Local Environmental Initiatives).

On the state level, we should have a leadership role not only in determining the cost of global warming and ways to reduce its impacts but also in setting standards. Many states throughout the nation have set standards of how much renewable energy should be part of a utility's energy base _ these are called renewable portfolio standards. They set standards, and then the utility companies respond appropriately.

On a national level, there are two major categories of laws that need to be passed. One is embodied by the McCain-Lieberman legislation, which essentially caps the amount of emissions and then allows companies to trade their emission reductions. The other thing that Congress must do is increase the required fuel efficiency of vehicles.

http://www.shns.com/shns/g_index2.cfm?acti...ARMING-06-26-06

Sierra Club leader: Global warming debate at 'tipping point'
By Terence Chea
ASSOCIATED PRESS WRITER

SAN FRANCISCO - The debate over global warming has reached a "tipping point" in the U.S. as more citizens, politicians and companies see climate change as a serious threat, the leader of the country's most influential environmental organization said.

In an interview with The Associated Press, Sierra Club Executive Director Carl Pope said Tuesday that over the past year the debate has shifted from whether global warming was a real problem to what must be done to lessen its potentially devastating impacts.

"I think we're at a tipping point," said Pope, who has headed the nation's oldest and largest environmental group since 1992. He said Hurricane Katrina, rising energy prices and other meteorological events have "set the stage for a big change in public opinion."

Nearly all scientists agree that global warming -- the rise in temperatures caused by emissions of carbon dioxide and other heat-trapping gases from cars, factories and power plants -- is taking place and its effects are being felt worldwide. For years, experts have predicted that climate change would lead to rising sea levels, higher temperatures, more severe droughts and increasingly violent storms.

For many Americans, the devastation of New Orleans and parts of the Gulf Coast from Hurricane Katrina was the clearest sign that global warming was real, he said. Many scientists believe that climate change is raising ocean temperatures, and warmer waters are increasing the intensity of hurricanes.

"Katrina showed that when the climate changes, it's catastrophic," Pope said. "It's not just about it getting warmer. It's about climate becoming chaotic, weather becoming extreme."

Al Gore's new documentary, "An Inconvenient Truth" -- along with a slew of news stories about melting glaciers, raging wildfires and record temperatures -- has also provoked public discussion of global warming, he said.

While the federal government has been slow to address climate change, many cities, states and corporations are moving forward with plans to lower greenhouse gas emissions and develop cleaner energy sources, Pope said.

More than 240 U.S. cities have agreed to voluntarily reduce carbon emissions to meet standards set by the Kyoto Protocol, the international climate treaty that was ratified by 141 countries but not the United States. By 2012, the treaty seeks to reduce greenhouse gases below 1990 levels in 35 industrialized countries.

Last week, the Western Governors' Association, a coalition of governors from 18 states and three U.S.-flag Pacific islands, adopted a resolution calling for action to reduce greenhouse gas emissions and develop alternative fuels such as ethanol and biodiesel.

"You're seeing more and more politicians embracing the idea that we have to act on global warming," said Pope, who criticized the White House for having its "head in the sand."

The Bush administration's climate change plan relies on voluntary cutbacks by industry and on government investment in clean-energy technologies to reduce emissions. Kyoto-style mandates would hurt the U.S. economy and send energy-intensive industries and jobs overseas, said Jim Connaughton, chairman of the White House Council on Environmental Quality

"The president treats the issue of global warming very seriously," Connaughton said. "The president has focused his energy on a strong emphasis on technology as the solution and thriving economies as the way to pay for those solutions."

California has taken a leadership role in confronting global warming, Pope said. The state has raised fuel economy standards for cars and trucks, boosted energy efficiency and created incentives for renewable energy such as wind and solar.

Pope said he expected global warming and energy to be major issues in state elections in November, and expects them to play a big role in the 2008 presidential election.

"The price of failing to get this right is very, very high," Pope said. "The benefits of getting this right is incalculable. It's one of those times that civilization faces two utterly different roads."

------
Sierra Club: http://www.sierraclub.org

http://www.contracostatimes.com/mld/cctimes/14871178.htm

Surface Temperature Reconstructions for the Last 2,000 Years
June 22, 2006

Running Time: 01:09:12
Format: RealAudio (Requires free RealPlayer)

There is sufficient evidence from tree rings, retreating glaciers, and other "proxies" to say with confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years, according to a new National Research Council report. There is less confidence in reconstructions of surface temperatures from 1600 back to A.D. 900, and very little confidence in findings on average temperatures before then.

audio file - 63.4 MB
http://www.nationalacademies.org/podcast/20060622.mp3

webpage -
http://www.nap.edu/webcast/webcast_detail.php?webcast_id=327

Dead on Arrival

Did you ever see that old Edmund O'Brien movie DEAD ON ARRIVAL? It opens with a scene of O'Brien walking into the police station to report a murder—his own.

It seems that someone slipped a slow-acting poison into his drink. By the time that he discovered the poison, it was too late for an antidote. Now he's a walking corpse, all he can do is try to catch the guy that killed him.

Same thing with us and global warming. By the time we even heard about it, the corporations had already murdered us.

More -
http://dieoff.org/page124.htm

When Oceans burp or Plates shatter...

http://en.wikipedia.org/wiki/Paleocene-Eoc...Thermal_Maximum

May 12, 2003

Seafloor sediments hold clues to runaway global warming

By Kasey White

Scientists from UCSC and other institutions around the world arrived in Rio de Janeiro last week after spending two months at sea on the research ship JOIDES Resolution near an ancient submarine mountain chain off Africa, known as the Walvis Ridge.

There they studied evidence of a massive release of methane that caused extreme global warming 55 million years ago.

This extraordinary episode of global warming, often referred to as the Paleocene-Eocene Thermal Maximum, is unique in Earth's history in terms of magnitude and rate of warming, as well as in the manner in which it began.

Scientists think that roughly 2,000 gigatons (2 trillion tons) of methane, a potent greenhouse gas, was released to the ocean and atmosphere 55 million years ago, triggering a runaway process of global warming.

The scientists on Ocean Drilling Program (ODP) Leg 208 set out to test this hypothesis about the origin of the Paleocene-Eocene Thermal Maximum.

Geochemists speculate that methane escaped from submarine clathrates, ice crystals that trap methane and are distributed in sediments on the outer edges of continental margins worldwide. For reasons that remain unknown, the clathrates suddenly began to decompose on a massive scale, increasing the amount of methane in the atmosphere and ocean. This decomposition process appears to have lasted for a period of 40,000 years, ultimately warming the planet by more than 5 degrees Celsius.

Sediments far below the seafloor hold evidence of the methane release and its consequences.

"The rapid release of methane 55 million years ago should have left a distinct signature in the form of calcite-poor or clay-rich layers, the distribution and thickness of which would be controlled by the total mass of methane released," said James Zachos, cochief scientist of ODP Leg 208 and professor of Earth sciences at UCSC.

This is because the rapid release of such a large mass of methane and its subsequent oxidation to carbon dioxide would have significantly altered ocean chemistry. The added carbon dioxide would have increased the overall acidity or corrosiveness of seawater. This, in turn, would increase the dissolution of calcite shells of microplankton, which are the dominant component of seafloor sediments, leaving behind only nonsoluble clays. The dissolution of calcite would initiate in the deepest parts of the ocean and rapidly spread upwards as additional carbon dioxide entered the ocean. The overall extent and duration of dissolution would ultimately be controlled by the total mass of methane released.

"By establishing the vertical extent of carbonate dissolution, as well as the duration of dissolution, it should be possible to determine the total amount of carbon dioxide that was added to the ocean during the event," Zachos said.

Retrieving the sediments proved to be a formidable challenge. To accurately reconstruct past climate, technicians needed to retrieve the sediments without deformation of layers and other structures.

"Imagine the difficulties of retrieving a layer of sediment about 1 meter thick with the consistency of mud from 200 to 300 meters below the seafloor at a water depth of 4,800 meters, without disturbing the centimeter-scale layering," said Dick Kroon, cochief scientist from Vrije Universiteit Amsterdam.

Technicians used a device known as the Advanced Piston Corer (APC) to obtain the cores. The extreme stress placed on the system, however, quickly began to take its toll on the APC. In the very first hole, the steel core barrel literally snapped in half from the enormous stresses applied while attempting to extract it from the sediment. The lower half of the barrel could not be retrieved, and the hole had to be abandoned. On several other occasions, the steel rods that secure the core barrels came back to the surface twisted or bent.

"At this point, we were a little concerned about whether we could achieve our objectives," Zachos said.

Determined, the drilling crew made the necessary repairs, adjusted their drilling strategy, and pushed on. Their efforts ultimately paid off; the thin boundary layer was recovered at five sites in water depths between 2,500 and 4,800 meters. Remarkably, at each site the layer was fully intact and in perfect condition.

Initial examination of the sediments provided immediate insight into the scale of calcite dissolution during this event. Micah Nicolo, a graduate student at Rice University, remarked, "When the cores were opened in the ship's lab, we were stunned by the change in colors of the sediment, from bright white carbonate to deep red clays."

Each core, regardless of depth, yielded a sequence of carbonate-rich sediment dissected by a distinct, dark clay layer, varying in thickness from 100 to 50 centimeters. The base of each clay layer, regardless of depth, contained essentially no calcite--indicating dissolution of calcite sediment throughout the ocean.

Ellen Thomas of Wesleyan University studied additional impacts of the methane release.

"The extent of dissolution may explain why so many bottom-dwelling organisms that precipitate calcite shells became extinct at that time," she said.

The scale of carbonate dissolution recorded in these cores is significant. It is suggestive of a much larger flux of methane, possibly double original estimates. It may also point toward an additional source of greenhouse gas.

"It far exceeds what has been estimated by models assuming a release of 2,000 gigatons of methane," Kroon said.

The initial results also suggest that the deposition of carbonate shells on the deeper reaches of the seafloor did not resume for at least 50,000 years, and that the total recovery time to a "normal state" took as long as 100,000 years. This result suggests that full recovery from these extreme events takes considerable time.

The cores recovered on this leg may also provide insight into the ultimate cause of the thermal maximum. Toward the end of the Paleocene epoch, the planet was slowly warming due to rising levels of carbon dioxide emitted from volcanoes.

"Several of us suspect that the melting of clathrates and rapid release of methane was initiated by gradual warming that pushed the climate system across a physical threshold," Zachos said.

Once started, the release of methane and resultant warming fueled the release of more methane, a positive feedback effect. This phenomenon is a concern for future global warming, Zachos said.

Studies of the sediment cores from Walvis Ridge and others recently recovered in the Atlantic and Pacific Oceans will allow scientists to test these and other ideas about the origin of the Paleocene-Eocene Thermal Maximum.

ODP is an international partnership of scientists and research institutions organized to study the evolution and structure of the Earth. It is funded principally by the U.S. National Science Foundation, with substantial contributions from its international partners. The Joint Oceanographic Institutions (JOI) manages the program. Texas A&M University is responsible for science operations, and Lamont-Doherty Earth Observatory of Columbia University is responsible for logging services.

http://www.ucsc.edu/currents/02-03/05-12/warming.html