Scientists Report Further Shrinking of Arctic Ice

Area Is Close To All-Time Low

http://www.washingtonpost.com/wp-dyn/content/article/2008/08/26/AR2008082603014.html?hpid=topnews

A polar bear swims recently in open water off the coast of Alaska. The shrinking sea ice increases the pressure on polar bears, who usually hunt on the ice. (By Geoff York -- World Wildlife Fund)

By Juliet Eilperin

Washington Post Staff Writer
Wednesday, August 27, 2008; Page A03

Arctic sea ice has shrunk to the second-lowest level since record-keeping began three decades ago, a group of international researchers determined yesterday, a revelation underscoring how rapidly climate change is transforming ecosystems in northern latitudes.

The extent of Arctic sea ice is now 2 million square miles below the long-term average for Aug. 26, according to the International Arctic Research Center and the Japanese Aerospace Exploration Agency, a figure that is within 400,000 square miles of the all-time record low set in September 2007. This figure is already below the long-term average for September ice cover and because the ice traditionally reaches its minimum level in mid-September, researchers warned that a new low might be recorded within weeks.

The National Snow and Ice Data Center (NSIDC), which independently analyzes Arctic ice cover, will announce today that it has reached the same conclusion, based on a five-day mean of satellite measurements.

"If we continue to lose ice at this rate, we will best" the 2007 record, said Julienne Stroeve, an research scientist. "We're going to lose that ice, so we've got to understand what this means for the rest of us."

According to the data center's recent reports, the ice over the Chukchi Sea is "already showing patches of open water within the ice. Much of the Beaufort Sea north of Alaska is open and the Laptev Sea and East Siberian Sea have opened extensively in the past 13 days."

Margaret Williams, who directs the World Wildlife Fund's Alaska office and traveled to Barrow, Alaska, last week to assess how sea ice decline is affecting polar bears, said that while these animals have swum in open ocean in the past, they are now traveling much longer distances.

"It is very unusual to see so many bears in the open water at one time during a short flight period," Williams said, noting that government scientists spotted the bears over a six-hour period. "It's very worrisome. It's what we had anticipated, but it's happening right before our eyes."

By comparison, federal scientists spotted a total of 12 polar bears swimming in the open ocean between 1987 and 2003. The federal government conducts the aerial surveys not to assess the status of polar bears in the region, but to determine whether bowhead whales in the Arctic will be affected by offshore oil development there.

Even if researchers spot polar bears swimming in distress, they cannot rescue them, as attempts to tranquilize the bears would cause them to drown. In May, Interior Secretary Dirk Kempthorne listed polar bears as threatened under the Endangered Species Act, saying diminishing sea ice jeopardized their ability to survive in the foreseeable future, but he argued such a listing should not prompt the government to regulate greenhouse gases linked to global warming.

"We never get good news about the polar bears," said Melanie Duchin, a global warming campaigner for the advocacy group Greenpeace. "It's just yet another wake-up call in a long line of wake-up calls to politicians in this country that says, 'Hey, get your act together when it comes to global warming.' "

Researchers now estimate that summer sea ice in the Arctic is likely to disappear altogether by 2030, but Stroeve said the new satellite data suggest sea ice could vanish sooner than that.

Two weeks ago, the federal Climate Change Science Program released a "synthesis and assessment" report examining global warming in the Arctic and northern latitudes that suggests the region has already suffered ice loss of an "immense magnitude and unprecedented nature."

The report, which is open for public comment until Sept. 25, adds that the "current sea ice reduction . . . is progressing at a very fast rate that appears to have no analogs in the past" and that "sustained changes in sea-ice coverage may cause perhaps the largest temperature changes observed on the planet."

Stroeve said researchers anticipated this year's ice decline could rival last year's because so much of the Arctic's ice cover is one-year ice, which is thinner than ice that has built up over multiple years. This year, 73 percent of the Arctic Basin is composed of first-year ice, compared with 60 percent last year. In 1985, first-year ice made up 35 percent of the Arctic Basin.

"We knew we were vulnerable starting out, in terms of ice cover," she said.

Nick Sundt, the World Wildlife Fund's communications director for climate change, said the significance of this week's findings is not that a specific record is being set but that Artic sea ice cover is consistently declining.

"It's not what happens in an individual year, but what the trend is," Sundt said.

Exactly 20 years after warning America about global warming, a top NASA scientist says the situation has got so bad that the world's only hope is drastic action.

James Hansen told US Congress today that the world has long passed the "dangerous level" for greenhouse gases in the atmosphere and needs to get back to 1988 levels.

He said Earth's atmosphere can stay this loaded with man-made carbon dioxide only for a couple more decades without changes such as mass extinction, ecosystem collapse and dramatic sea level rises.

"We're toast if we don't get on a very different path," Hansen, director of the Goddard Institute of Space Sciences, who is sometimes called the godfather of global warming science, told The Associated Press. "This is the last chance."

Hansen brought global warming home to the public in June 1988 during a Washington heat wave, saying global warming was already here. To mark the anniversary, he testified before the House Select Committee on Energy Independence and Global Warming, where he was called a prophet, and addressed a luncheon at the National Press Club, where he was called a hero.

To cut emissions, he said coal-fired power plants that do not capture carbon dioxide emissions should not be used in the United States after 2025, and should be eliminated in the rest of the world by 2030. That carbon capture technology is still being developed and not yet cost-efficient for power plants.

Burning fossil fuels such as coal is the chief cause of manmade greenhouse gases. Hansen said the Earth's atmosphere has got to get back to a level of 350 parts of carbon dioxide per million. Last month, it was 10 per cent higher: 386.7 parts per million.

Hansen said he would testify on behalf of British protesters against new coal-fired power plants. Protesters have chained themselves to gates and equipment at sites of several proposed coal plants in England.

"The thing that I think is most important is to block coal-fired power plants," Hansen told the luncheon. "I'm not yet at the point of chaining myself, but we somehow have to draw attention to this."

Frank Maisano, a spokesman for many US utilities, including those trying to build new coal plants, said while Hansen has shown foresight as a scientist, his "stop them all approach is very simplistic" and shows that he is beyond his level of expertise.

The year of Hansen's original testimony was the world's hottest year on record. Since then, 14 years have been hotter, according to the National Oceanic and Atmospheric Administration.

Two decades later, Hansen spent his time on the question of whether it is too late to do anything about it. His answer: "There still is time to stop the worst, but not much time."

He told the AP before the luncheon: "We see a tipping point occurring right before our eyes. The Arctic is the first tipping point, and it's occurring exactly the way we said it would."

Hansen, echoing work by other scientists, said that in five to 10 years, the Arctic would be free of sea ice in the summer.

A long-time global warming sceptic, Republican Senator James Inhofe, citing a recent poll, said in a statement, "Hansen, [former vice-president Al] Gore and the media have been trumpeting manmade climate doom since the 1980s. But Americans are not buying it."

The response of Democrat Ed Markey, the committee chairman: "Dr Hansen was right. Twenty years later, we recognise him as a climate prophet."

Are Big Oil and Big Coal Climate Criminals?

By Andrew C. Revkin

There were no climate-science bombshells from James E. Hansen on Monday on his trip to Capitol Hill at the invitation of some House Democrats, who wanted to commemorate his momentous global warming testimony 20 years earlier. On that front, he said everything he has been saying for years: unabated warming would erode the ice sheets, flood coastal cities and drive many species into extinction.

But there was a much discussed recommendation in both his oral presentation and a written statement he prepared beforehand: that the heads of oil and coal companies who knowingly delayed action on curbing greenhouse gas emissions were committing a crime. “These CEO’s, these captains of industry,” he said in the briefing, “in my opinion, if they don’t change their tactics they’re guilty of crimes against humanity and nature.” He made the point more strongly in a written statement summarizing his talk (posted below).

He has used strong words and imagery before to drive home points, including comparing cordons of coal cars heading to power plants to the death trains of the Holocaust (because of the mass extinctions foreseen by many biologists should warming go unabated).

Dr. Hansen’s allegations of criminality were already reverberating on the Web earlier in the day after Rush Limbaugh and other conservative commentators circulated excerpts from a story in the Guardian newspaper of Britain quoting Dr. Hansen on this point. . . .
CONTINUES AT http://dotearth.blogs.nytimes.com/2008/06/23/are-big-oil-and-big-coal-climate-criminals/

Extreme weather to increase with climate change

http://ap.google.com/article/ALeqM5jXqXnWulOVVpi1gZO44HR_L01uYAD91DALN8H

By RANDOLPH E. SCHMID – 29 minutes ago

WASHINGTON (AP) — Droughts will get dryer, storms will get stormier and floods will get deeper with changing climate, a government research report said Thursday.

Events that have seemed relatively rare will become commonplace, said the latest report from the U.S. Climate Change Science Program, a joint effort of more than a dozen government agencies.

There has been an increase in the frequency of heavy downpours, especially over northern states, and these are likely to continue in the future, Thomas R. Karl, director of the National Climatic Data Center, said in a briefing.

For example, Karl said, by the end of this century rainfall amounts expected to occur every 20 years could be taking place every five years.

Such an increase "can lead to the type of events that we are seeing in the Midwest," said Karl, though he did not directly link the current inundations to climate change.

But the report cautioned that preparing for weather than has been relatively common can leave people vulnerable as extreme events occur more and more.

"Moderate flood control measures on a river can stimulate development in a now 'safe' floodplain, only to see those new structures damaged when a very large flood occurs," the report said.

At the same time heavy rains increase, there'll be more droughts, especially in the Southwest, Karl said.

"When it rains, it rains harder and when it's not raining, it's warmer — there is more evaporation, and droughts can last longer," he explained.

The Southwestern drought that began in 1999 is beginning to rival some of the greatest droughts on record including those of the 1930s and 1950s, he added.

Gerald A. Meehl, a senior scientist at the National Center for Atmospheric Research, said there has been a trend toward increasing power in hurricanes since the 1970s in the Atlantic and western Pacific, a change that can be linked to rising sea surface temperatures.

There is a statistical connection between rising sea surface temperatures and hurricane activity, Meehl said, but linking changes in hurricanes to human actions will require more study.

More easily attributed to human impact, through release of greenhouse gases, is an overall increase in temperatures, he said.

It's not getting as cold at night as it did in earlier decades and there are fewer nights with frosts, a trend expected to continue into the future, Meehl said.

"A day so hot that it is experienced only once every 20 years would occur every three years by the middle of the century," under the mid-range projections of climate models, the report said.

Researchers can use computer models of climate to separate out cause and effect of this warming, he explained — looking at the effect of things like changes in solar radiation or volcanic eruptions — and the result is to attribute climate warming to the burning of fossil fuels.

Participating in the Climate Change Science Program are the Agency for International Development, Department of Agriculture, National Oceanic and Atmospheric Administration, National Institute of Standards and Technology, Department of Defense, Department of Energy, National Institutes of Health, Department of State, Department of Transportation, U.S. Geological Survey, Environmental Protection Agency, National Aeronautics and Space Administration, National Science Foundation and the Smithsonian Institution.

• http://www.usgcrp.gov/usgcrp/default.php

McCain Global Warming Plan: Laudable Goal but Fails to Reach It

Statement of Sierra Club Executive Director, Carl Pope

http://www.washingtonpost.com/wp-dyn/content/article/2008/03/13/AR2008031304175.html

By Juliet Eilperin
Washington Post Staff Writer
Friday, March 14, 2008; A01

The Environmental Protection Agency weakened one part of its new limits on smog-forming ozone after an unusual last-minute intervention by President Bush, according to documents released by the EPA.

EPA officials initially tried to set a lower seasonal limit on ozone to protect wildlife, parks and farmland, as required under the law. While their proposal was less restrictive than what the EPA's scientific advisers had proposed, Bush overruled EPA officials and on Tuesday ordered the agency to increase the limit, according to the documents.

"It is unprecedented and an unlawful act of political interference for the president personally to override a decision that the Clean Air Act leaves exclusively to EPA's expert scientific judgment," said John Walke, clean-air director for the Natural Resources Defense Council.

The president's order prompted a scramble by administration officials to rewrite the regulations to avoid a conflict with past EPA statements on the harm caused by ozone.

Solicitor General Paul D. Clement warned administration officials late Tuesday night that the rules contradicted the EPA's past submissions to the Supreme Court, according to sources familiar with the conversation. As a consequence, administration lawyers hustled to craft new legal justifications for the weakened standard.

The dispute involved one of two distinct parts of the EPA's ozone restrictions: the "public welfare" standard, which is designed to protect against long-term harm from high ozone levels. The other part is known as the "public health" standard, which sets a legal limit on how high ozone levels can be at any one time. The two standards were set at the same level Wednesday, but until Bush asked for a change, the EPA had planned to set the "public welfare" standard at a lower level.

The documents, which were released by the EPA late Wednesday night, provided insight into how White House officials helped shape the new air-quality rules that, by law, are supposed to be decided by the EPA administrator.

The White House Office of Management and Budget (OMB) questioned in a March 6 memo to the EPA why the second standard was needed. EPA officials answered in a letter that high ozone concentrations can cause "adverse effects on agricultural crops, trees in managed and unmanaged forests, and vegetation species growing in natural settings."

The preamble to the new regulations alluded to this tug of war, stating there was a "robust discussion within the Administration of these same strengths and weaknesses" in setting the secondary standard. The preamble went on to say that the decision to make the two ozone limits identical "reflects the view of the Administration as to the most appropriate secondary standard."

The effort to rewrite the language -- on the day the agency faced a statutory deadline -- forced EPA Administrator Stephen L. Johnson to postpone at the last moment a scheduled news conference to announce the new rules. It finally took place at 6 p.m., five hours later than planned.

Under the Clean Air Act, the federal government must reexamine every five years whether its ozone standards are adequate, and the rules that the EPA issued Wednesday will help determine the nation's air quality for at least a decade.

Ozone, which is formed when pollutants such as nitrogen oxides and other chemical compounds released by industry and motor vehicles are exposed to sunlight, is linked to an array of heart and respiratory illnesses.

The EPA set the allowable amount of ozone in the air at 75 parts per billion, a level stricter than the current limit but higher than what the scientific advisers had recommended.

Carol M. Browner, who served as EPA administrator under President Bill Clinton, also encountered objections from the OMB when she established new ozone standards in 1997. In that instance, the president backed the EPA over White House budget officials.

"We did not allow OMB to push us into a decision we were quite certain was outside the boundaries of the law," Browner said in an interview. The Clean Air Act, she added, creates "a moral and ethical commitment that we're going to let the science tell us what to do."

Asked for a comment yesterday, EPA spokesman Timothy Lyons said the agency had complied with the Clean Air Act. "The secondary standard we set is fully supported by both the law and the record, and it is the most protective eight-hour standard ever for ozone."

When asked about Clement's role, White House spokesman Tony Fratto said: "The White House sought legal advice from the Justice Department and made its decision based on that advice."

The EPA's documents suggest that senior officials and scientific advisers resisted the White House's position. Last year, the agency's Clean Air Scientific Advisory Committee wrote -- using italics for emphasis -- that it unanimously supported the EPA staff's conclusion that "protection of managed agricultural crops and natural terrestrial ecosystems requires a secondary [ozone standard] that is substantially different from the primary ozone standard. . . ."

When the OMB's Susan E. Dudley urged the EPA to consider the effects of cutting ozone further on "economic values and on personal comfort and well-being," the EPA's Marcus Peacock responded in a March 7 memo: "EPA is not aware of any information that ozone has beneficial effects on economic values or on personal comfort and well being."

Lisa Heinzerling, a Georgetown University law professor who specializes in the Clean Air Act, said Dudley's letter to the EPA represents "a misunderstanding of the statute, a misunderstanding of Supreme Court precedent and a misunderstanding of the science as the expert agency understands it."

The western part of Antarctica is shedding ice much faster today than it was just ten years ago, according to new satellite measurements.

The measurements, which surveyed the coasts of nearly the entire continent, suggest that climate models underestimate how quickly Antarctica responds to ongoing global warming, said study co-author Jonathan Bamber of the University of Bristol in England.

Many past studies have tried to estimate how much ice Antarctica is losing.

But the new study is the first to show that this loss is accelerating, at least in western Antarctica and the Antarctic Peninsula, the researchers say.

As to whether Antarctica will lose or gain ice as global warming proceeds, the measurements disagree with existing climate models that suggest "[the ice sheet] is going to get bigger because of increased snowfall with warming temperatures," Bamber said.

"We don't see that. We see the ice sheet losing mass," he said. "So there's a bit of a paradigm shift in what the ice sheet has done recently and what it could do in the future."

Scientists are concerned the melting ice will contribute to a dangerous sea level rise.

See the whole story at http://news.nationalgeographic.com/news/2008/01/080114-antarctica-melting_2.html

 _________________________________________________________________________________________________________________________________________

Issue #241
January 25, 2008
Lying, Just by Another Name
Josh Dorner
Truthiness appeared to be the watchword of the day on Capitol Hill yesterday, as a parade of officials appeared at Congressional hearings to defend the Bush administration’s failed global warming policies. 

EPA Administrator Stephen Johnson was summoned to appear before the Senate Environment and Public Works Committee to explain exactly why -- for the record and while under oath no less -- he chose to overrule the unanimous opinion of EPA's professional staff in denying that waiver California and some 17 states need to move forward with their landmark global warming emissions standards for cars.

Johnson of course had refused to attend an earlier hearing in California and last Friday EPA exerted bizarre claims of executive privilege in refusing to turn over documents the Senate. It seems someone at EPA failed Symbolism 101 at Hacks State U, as they justified their refusal to turn over the documents by citing a case about the most notorious cover-up of all time (pdf): United States v. Nixon. Apparently EPA believes that the public shouldn’t be able to see "pre-decisional documents" arguing for approval of the waiver because then they might be confused about why it was later denied. Gee, do you think so Captain Obvious!? Oh, and apparently EPA is also holding back because it's worried losing the lawsuit brought by the states and enviros if they get hold of the documents (i.e. the truth). And, yes, that is in fact the very same lawsuit the agency's own lawyers warned Johnson would be "almost certain" and that EPA would "likely lose" if it denied the waiver.

Boxer started the hearing with a bit of theatrics, showing the pile of white redacting tape her committee staff had had to remove from the documents EPA supplied -- documents they were only allowed to hand copy while EPA staffers literally stood over their shoulders. Johnson put on a good show of his own. Despite being reminded repeatedly by several senators that he was under oath, he stood by his claim that even though he cited the energy bill as the reason for denying the waiver in the press teleconference announcing the waiver decision, that the timing was somehow really just one big coincidence. The questioning got so heated I'm pretty sure Johnson was sorry that he hadn't taken advantage of Hillary Clinton's absence from the hearing to borrow her famed asbestos pantsuit. 

Not be outdone, James Connaughton, the administration's top environmental official (and, faithful to the Bush administration's high standards of integrity, a former top lobbyist for polluters), appeared before the Senate Foreign Relations Committee and claimed that the Energy Policy Act of 2005 -- called "the most anti-environmental piece of legislation signed into law in recent memory" by the League of Conservation Voters -- was really a "climate bill," but just by another name. Funny that, we call it a piece of crap, but by another name.

This follows on several other pieces of anti-environmental mutton dressed up as lamb by the Bush administration. That hit parade includes the Healthy Forests Initiative -- a logging bill by a different name -- and the Clear Skies Initiative -- a gutting of the Clean Air Act by another name.

George W. Bush: greenest president ever!*

*just by another name

Sierra Club | 85 Second St., San Francisco, CA 94105 | sierraclub.org | w.watch@sierraclub.org

Watch poles, U.N. climate chief warns-Previous reports didn't factor in 'frightening' possibility of significant melt

OSLO, Norway - The next report by the Intergovernmental Panel on Climate Change should deal with the "frightening" possibility that both Antarctic and Greenland ice sheets start melting at the same time, the chief U.N. climate scientist said Tuesday.

The panel, which shared the 2007 Nobel Peace Prize with U.S. activist and politician Al Gore, has released four climate assessment reports already, including summaries for policy makers that are approved by government representatives.

Though there are no firm plans for a fifth report, the panel is still inviting scientists to submit material on glaciers in both the far north and south, IPCC chairman Rajendra Pachauri said.

"My hope is in the next report, if there is one, will be able to provide much better information on the possibility of these two large bodies of ice possibly melting, in what seems what seems like a frightening situation," Pachauri said during a visit to Oslo.

Pachauri is set to visit Antarctica next week with a Norwegian delegation, after being invited during his December visit to Norway to accept the Nobel prize with Gore.

He said evidence of climate change was most apparent at the world's poles, especially in the Arctic, where the climate panel says the melting of the vast glaciers of Greenland could cause a 13-foot rise in sea levels in coming centuries.

Less is known, he said, about the impact of global warming at the Earth's opposite pole — on the vast West Antarctic Ice Sheet, a wasteland of ice and snow roughly the size of Texas.

"Unless you go to these places, you just don't get a feeling for the reality," Pachauri said. "You can read as much as you want on these subjects but it doesn't really enter your system, you don't really appreciate the enormity of what you have."

If ice sheets at both poles begin melting simultaneously, the results could be extreme, he said.

"Both Greenland and the West Antarctic Ice Sheet are huge bodies of ice and snow which are sitting on land. If through a process of melting they collapse and are submerged in the sea then we really are talking about sea level rises of several meters (yards)," he said.

Pachauri and Norwegian Prime Minister Jens Stoltenberg's delegation planned to visit Norway's Troll research base in Antarctica, and return on Jan. 21.

URL: http://www.msnbc.msn.com/id/22560311/

China reels from worst drought in a decade

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BEIJING (Reuters) - China is suffering its worst drought in a decade, which has left millions of people short of drinking water and has shrunk reservoirs and rivers, state media said on Friday.

Hardest hit are large swathes of the usually humid south, where water levels on several major rivers have plunged to historic lows in recent months.

"The drought is the most serious of the decade and is affecting almost the whole country," the China Daily quoted Zhang Jiatuan, an official from the State Flood Control and Drought Relief Headquarters, as saying.

The surface area of the country's largest fresh water lake, Poyang, in the southern province of Jiangxi, had fallen to a record 50 sq km (19 sq miles) from several thousand sq km at its peak, the newspaper said.

More than 760,000 residents faced drinking water shortages in the rice-growing province.

A Jiangxi official news portal showed pictures of children playing on bare beds of the Gan river, Poyang's main tributary hit by serious boat traffic jams due to the shallow water.

Similar congestion has also occurred on the Xiang river in neighboring Hunan province and authorities have had to release water from behind the massive Three Gorges Dam to ease cargo ship stranding downstream on the Yangtze River, China's longest.

The southwestern region of Guangxi has been hit by its worst drought since 1951, with over a million people suffering from drinking water shortages.

About 400,000 hectares (1,545 sq miles) of crops have been damaged by drought this year, leading to total grain losses of 37.4 million metric tonnes, the China Daily said, adding the consecutive droughts over past years had compounded the situation.

Drought and floods are perennial problems in China, whose meteorologists have complained about the increased extreme weather and partly blamed it on global climate change.

About 30 million Chinese in the countryside and more than 20 million in urban areas face drinking water shortages every year despite huge government investment to address the problem, the China Daily said.

(Reporting by Guo Shipeng; Editing by Nick Macfie)

Global warming causing China's glaciers to melt quickly: survey

A survey of nearly 20,000 square kilometres (8,000 square miles) of China's glaciers showed they were on average 7.4 percent smaller than five years ago, Caijing magazine said, citing a government-funded survey.

A glacier along the upper reaches of the Brahmaputra River on the Tibetan plateau had shrunk by more than 18 percent, the survey found.

Two other glacial areas in China's far northwest Xinjiang region had also melted by more than 18 percent.

"Global warming is causing grave loss to glaciers and it has become a burning need to monitor changes of glacial reserves," the researchers from the China Academy of Sciences said as they released their findings.

The survey, covering roughly one third of China's glaciers, was conducted to trace the impacts of global warming.

China's glaciers, in the west of the country, feed many of Asia's greatest rivers, including the Yangtze, Mekong, Yellow and Ganges, as well as the Brahmaputra.

In the past four decades, China's glaciers shrank by 3,248 square kilometres, or 5.5 percent since the 1960s, according to previous studies published in the state-run press.

One of China's top glaciologists, Yao Tangdong, warned last year of an "ecological catastrophe" in Tibet because of global warming.

He said most glaciers in the region could melt away by 2100.

America will keep on wrecking climate talks as long as those with vested interests in oil and gas fund its political system

WASHINGTON (Reuters) - The world's sea levels could rise twice as high this century as U.N. climate scientists have predicted, according to researchers who looked at what happened more than 100,000 years ago, the last time Earth got this hot.

Experts working on the U.N.'s Intergovernmental Panel on Climate Change have suggested a maximum 21st century sea level rise -- a key effect of global climate change -- of about 32 inches.

But researchers said in a study appearing on Sunday in the journal Nature Geoscience that the maximum could be twice that, or 64 inches.

They made the estimate by looking at the so-called interglacial period, some 124,000 to 119,000 years ago, when Earth's climate was warmer than it is now due to a different configuration of the planet's orbit around the sun.

That was the last time sea levels reached up to 20 feet (6 meters) above where they are now, fueled by the melting of the ice sheets that cover Greenland and Antarctica.

The researchers say their study is the first robust documentation of how quickly sea levels rose to that level.

"Until now, there have been no data that sufficiently constrain the full rate of past sea level rises above the present level," lead author Eelco Rohling of Britain's National Oceanography Centre said in a statement.

Rohling and his colleagues found an average sea level rise of 64 inches each century during the interglacial period.

Back then, Greenland was 5.4 to 9 degrees Fahrenheit warmer than now -- which is similar to the warming period expected in the next 50 to 100 years, Rohling said.

Current models of ice sheet activity do not predict rates of change this large, but they do not include many of the dynamic processes already being observed by glaciologists, the statement said.