In overwhelming proportions, this evidence has been in the direction of showing faster change, more danger and greater confidence about the dominant role of fossil fuel burning and tropical deforestation in causing the changes that are being observed.February 2, 2007 (two articles)
NYT -Panel Sees Centuries of Warming Due to Humans
By ELISABETH ROSENTHAL and ANDREW C. REVKIN
NYT -Panel Sees Centuries of Warming Due to Humans
By ELISABETH ROSENTHAL and ANDREW C. REVKINFebruary 2, 2007
Panel Says Humans ‘Very Likely’ Cause of Global Warming
By THE ASSOCIATED PRESS Filed at 6:34 a.m. ET
Panel Says Humans ‘Very Likely’ Cause of Global Warming
By THE ASSOCIATED PRESS Filed at 6:34 a.m. ETFebruary 2, 2007
NYT - Panel Sees Centuries of Warming Due to Humans
By ELISABETH ROSENTHAL and ANDREW C. REVKIN PARIS, Feb. 2 – The world is already committed to centuries of warming, shifting weather patterns and rising seas from the atmospheric buildup of smokestack and tailpipe gases that trap heat, but warming can be substantially blunted with prompt action, an international network of climate experts said today.
In a report released here today, the group, the Intergovernmental Panel on Climate Change of the United Nations, in its fourth assessment since 1990 of the causes and consequences of climate change, for the first time expressed with near certainty – more than 90 percent confidence – that carbon dioxide and other heat-trapping greenhouse gases were the main drivers of warming since 1950.
In its last report, in 2001, the panel, consisting of hundreds of scientists and reviewers, put the confidence level at between 66 and 90 percent. Both reports are online at http://www.nytimes.com/2007/02/02/science/earth/www.ipcc.ch.
Should the concentration of carbon dioxide reach twice the pre-industrial average of 280 parts per million, the report said, the climate will likely warm some 3.5 to 8 degrees Fahrenheit, and there would be more than a one in 10 chance of much greater warming – a situation many earth scientists say poses an unacceptable risk.
Many energy and environment experts see such a doubling as a foregone conclusion sometime after midcentury without a prompt and sustained shift away from the 20th-century pattern of unfettered burning of coal and oil, the main sources of carbon dioxide, and an aggressive quest for expanded and improved nonpolluting energy options.
Even the midrange projection for warming, according to many climate experts and biologists, is likely to powerfully stress ecosystems and disrupt longstanding climate patterns that shape water supplies and agricultural production.
“The new report powerfully underscores the need for a massive effort to slow the pace of global climatic disruption before intolerable consequences become inevitable,” said John P. Holdren, the president of the American Association for the Advancement of Science and an energy and climate expert at Harvard University. “Since 2001 there has been a torrent of new scientific evidence on the magnitude, human origins and growing impacts of the climatic changes that are underway. In overwhelming proportions, this evidence has been in the direction of showing faster change, more danger and greater confidence about the dominant role of fossil fuel burning and tropical deforestation in causing the changes that are being observed.”
The conclusions came after a three-year review of hundreds of studies of clues illuminating past climate shifts, observations of retreating ice, warming and rising seas, and other shifts around the planet, and a greatly expanded suite of supercomputer simulations used to test how earth will respond to a building blanket of gases that hold heat in the atmosphere.
Big questions remain about the speed and extent of some impending changes, both because of uncertainty about future population and pollution trends and the complex interrelationships of the greenhouse emissions, clouds, dusty kinds of pollution, the oceans and earth’s veneer of life, which both emits and soaks up carbon dioxide and other such gases.
But a broad array of scientists, including authors of the report and independent experts, said the latest analysis was the most sobering view yet of a century in which – after thousands of years of relatively stable climate conditions – the new normal is likely to be continual change.
Should greenhouse gases continue to build in the atmosphere at even a moderate pace, temperatures by the end of the century could match those last seen 125,000 years ago, in the previous warm spell between ice ages, the report said.
At that time, the panel said, sea levels were 12 to 20 feet higher than they are now due to the melting of great amounts of ice now stored – but eroding – on Greenland and in parts of Antarctica.
The panel said there was no solid scientific understanding of how rapidly the vast stores of ice in polar regions will begin to erode, so their estimates for how seas will rise by 2100 – probably between 7 and 23 inches – were based mainly on how much the warmed oceans will expand, and not on contributions from melting of ice on land.
Other scientists have recently reported evidence that the glaciers and ice sheets in the Arctic and Antarctic could flow seaward far more quickly than estimated in the past and have proposed risks to coasts could be much more imminent. But the I.P.C.C. is proscribed by its charter from entering into speculation and so could not include such possible instabilities in its assessment.
Michel Jarraud, the secretary general of the United Nations World Meteorological Organization, said the lack of clarity should offer no one comfort. “The speed with which melting ice sheets are raising sea levels is uncertain, but the report makes clear that sea levels will rise inexorably over the coming centuries,” he said. “It is a question of when and how much, and not if,” he said, adding: “While the conclusions are disturbing, decision makers are now armed with the latest facts and will be better able to respond to these realities.”
Achim Steiner, the executive director of the United Nations Environment Program, which oversees the I.P.C.C. along with the meteorological group, said society now had plenty of information on which to act.
“The implications of global warming over the coming decades for our industrial economy, water supplies, agriculture, biological diversity and even geopolitics are massive,” he said. “This new report should spur policymakers to get off the fence and put strong and effective policies in place to tackle greenhouse gas emissions.”
The warming and other climate shifts will be highly variable around the world, with the Arctic particularly seeing much higher temperatures, said Susan Solomon, the co-leader of the section of the I.P.C.C. report on basic science and an atmospheric scientist for the National Oceanic and Atmospheric Administration.
“The kinds of vulnerabilities are very much dependent on where you are,” Dr. Solomon said in a telephone interview. “If you’re living in parts of tropics and they’re getting drier and you’re a farmer there are some very acute issues associated with even small changes in rainfall. Changes we’re already seeing are significant. If you are an Inuit and you’re seeing your sea ice retreating already that’s affecting your lifestyle and culture.”
The 20-page summary is a sketch of the findings that are most germane to the public and world leaders.
The full I.P.C.C. report, thousands of pages of technical background, will be released in four sections through the year – the first on basic science, then sections on impacts and options for limiting emissions and limiting inevitable harms, and finally a synthesis of all of the findings near year’s end.
In a news conference in Paris, Dr. Solomon declined to provide her own views on how society should respond to the momentous changes projected in the study.
“I honestly believe that it would be a much better service for me to keep my personal opinions separate than what I can actually offer the world as a scientist,” she said. “My stepson, who is 29, has an utterly different view of risks than I do. People are going to have to make their own judgments.”
Elisabeth Rosenthal reported from Paris, and Andrew C. Revkin from New York.
February 2, 2007
Panel Says Humans ‘Very Likely’ Cause of Global Warming
By THE ASSOCIATED PRESS
Filed at 6:34 a.m. ET
PARIS (AP) -- International scientists and officials hailed a report Friday saying that global warming is ''very likely'' caused by man, and that hotter temperatures and rises in sea level ''would continue for centuries'' no matter how much humans control their pollution.
The head of the Intergovernmental Panel on Climate Change, Rajendra Pachauri, called it a ''very impressive document that goes several steps beyond previous research.''
A top U.S. government scientist, Susan Solomon, said ''there can be no question that the increase in greenhouse gases are dominated by human activities.''
The 21-page summary of the panel's findings released Friday represents the most authoritative science on global warming. The panel comprises hundreds of scientists and representatives of 113 governments.
The scientists said the changes are ''very likely'' caused by human activity, a phrase that translates to a more than 90 percent certainty that global warming is caused by man's burning of fossil fuels. That was the strongest conclusion to date, making it nearly impossible to say natural forces are to blame.
The report said no matter how much civilization slows or reduces its greenhouse gas emissions, global warming and sea level rise will continue on for centuries.
''This is just not something you can stop. We're just going to have to live with it,'' co-author Kevin Trenberth, director of climate analysis for the National Center for Atmospheric Research in Boulder, Colo., told The Associated Press in an interview. ''We're creating a different planet. If you were to come up back in 100 years time, we'll have a different climate.''
Sharon Hays, associate director of the Office of Science and Technology Policy at the White House, welcomed the strong language of the report.
''It's a significant report. It will be valuable to policy makers,'' she told The Associated Press in an interview in Paris.
Hays stopped short of saying whether or how the report could bring about change in President Bush's policy about greenhouse gas emissions.
The panel predicted temperature rises of 2-11.5 degrees Fahrenheit by the year 2100. That was a wider range than in the 2001 report.
However, the panel also said its best estimate was for temperature rises of 3.2-7.1 degrees Fahrenheit. In 2001, all the panel gave was a range of 2.5-10.4 degrees Fahrenheit.
On sea levels, the report projects rises of 7-23 inches by the end of the century. An additional 3.9-7.8 inches are possible if recent, surprising melting of polar ice sheets continues.
Trenberth said scientists do worry that world leaders will take the message in the wrong way and throw up their hands. Instead, the scientists urged leaders to reduce emissions and also adapt to a warmer world with wilder weather.
''The point here is to highlight what will happen if we don't do something and what will happen if we do something,'' co-author Jonathan Overpeck at the University of Arizona said. ''I can tell if you will decide not to do something the impacts will be much larger than if we do something.''
The panel, created by the United Nations in 1988, releases its assessments every five or six years -- although scientists have been observing aspects of climate change since as far back as the 1960s. The reports are released in phases -- this is the first of four this year.
The next report is due in April and will discuss the effects of global warming. But that issue was touched upon in the current document.
------
On the Net:
Report: http://www.ipcc.ch/SPM2feb2007.pdf
NYT - Panel Sees Centuries of Warming Due to Humans
By ELISABETH ROSENTHAL and ANDREW C. REVKIN PARIS, Feb. 2 – The world is already committed to centuries of warming, shifting weather patterns and rising seas from the atmospheric buildup of smokestack and tailpipe gases that trap heat, but warming can be substantially blunted with prompt action, an international network of climate experts said today.
In a report released here today, the group, the Intergovernmental Panel on Climate Change of the United Nations, in its fourth assessment since 1990 of the causes and consequences of climate change, for the first time expressed with near certainty – more than 90 percent confidence – that carbon dioxide and other heat-trapping greenhouse gases were the main drivers of warming since 1950.
In its last report, in 2001, the panel, consisting of hundreds of scientists and reviewers, put the confidence level at between 66 and 90 percent. Both reports are online at http://www.nytimes.com/2007/02/02/science/earth/www.ipcc.ch.
Should the concentration of carbon dioxide reach twice the pre-industrial average of 280 parts per million, the report said, the climate will likely warm some 3.5 to 8 degrees Fahrenheit, and there would be more than a one in 10 chance of much greater warming – a situation many earth scientists say poses an unacceptable risk.
Many energy and environment experts see such a doubling as a foregone conclusion sometime after midcentury without a prompt and sustained shift away from the 20th-century pattern of unfettered burning of coal and oil, the main sources of carbon dioxide, and an aggressive quest for expanded and improved nonpolluting energy options.
Even the midrange projection for warming, according to many climate experts and biologists, is likely to powerfully stress ecosystems and disrupt longstanding climate patterns that shape water supplies and agricultural production.
“The new report powerfully underscores the need for a massive effort to slow the pace of global climatic disruption before intolerable consequences become inevitable,” said John P. Holdren, the president of the American Association for the Advancement of Science and an energy and climate expert at Harvard University. “Since 2001 there has been a torrent of new scientific evidence on the magnitude, human origins and growing impacts of the climatic changes that are underway. In overwhelming proportions, this evidence has been in the direction of showing faster change, more danger and greater confidence about the dominant role of fossil fuel burning and tropical deforestation in causing the changes that are being observed.”
The conclusions came after a three-year review of hundreds of studies of clues illuminating past climate shifts, observations of retreating ice, warming and rising seas, and other shifts around the planet, and a greatly expanded suite of supercomputer simulations used to test how earth will respond to a building blanket of gases that hold heat in the atmosphere.
Big questions remain about the speed and extent of some impending changes, both because of uncertainty about future population and pollution trends and the complex interrelationships of the greenhouse emissions, clouds, dusty kinds of pollution, the oceans and earth’s veneer of life, which both emits and soaks up carbon dioxide and other such gases.
But a broad array of scientists, including authors of the report and independent experts, said the latest analysis was the most sobering view yet of a century in which – after thousands of years of relatively stable climate conditions – the new normal is likely to be continual change.
Should greenhouse gases continue to build in the atmosphere at even a moderate pace, temperatures by the end of the century could match those last seen 125,000 years ago, in the previous warm spell between ice ages, the report said.
At that time, the panel said, sea levels were 12 to 20 feet higher than they are now due to the melting of great amounts of ice now stored – but eroding – on Greenland and in parts of Antarctica.
The panel said there was no solid scientific understanding of how rapidly the vast stores of ice in polar regions will begin to erode, so their estimates for how seas will rise by 2100 – probably between 7 and 23 inches – were based mainly on how much the warmed oceans will expand, and not on contributions from melting of ice on land.
Other scientists have recently reported evidence that the glaciers and ice sheets in the Arctic and Antarctic could flow seaward far more quickly than estimated in the past and have proposed risks to coasts could be much more imminent. But the I.P.C.C. is proscribed by its charter from entering into speculation and so could not include such possible instabilities in its assessment.
Michel Jarraud, the secretary general of the United Nations World Meteorological Organization, said the lack of clarity should offer no one comfort. “The speed with which melting ice sheets are raising sea levels is uncertain, but the report makes clear that sea levels will rise inexorably over the coming centuries,” he said. “It is a question of when and how much, and not if,” he said, adding: “While the conclusions are disturbing, decision makers are now armed with the latest facts and will be better able to respond to these realities.”
Achim Steiner, the executive director of the United Nations Environment Program, which oversees the I.P.C.C. along with the meteorological group, said society now had plenty of information on which to act.
“The implications of global warming over the coming decades for our industrial economy, water supplies, agriculture, biological diversity and even geopolitics are massive,” he said. “This new report should spur policymakers to get off the fence and put strong and effective policies in place to tackle greenhouse gas emissions.”
The warming and other climate shifts will be highly variable around the world, with the Arctic particularly seeing much higher temperatures, said Susan Solomon, the co-leader of the section of the I.P.C.C. report on basic science and an atmospheric scientist for the National Oceanic and Atmospheric Administration.
“The kinds of vulnerabilities are very much dependent on where you are,” Dr. Solomon said in a telephone interview. “If you’re living in parts of tropics and they’re getting drier and you’re a farmer there are some very acute issues associated with even small changes in rainfall. Changes we’re already seeing are significant. If you are an Inuit and you’re seeing your sea ice retreating already that’s affecting your lifestyle and culture.”
The 20-page summary is a sketch of the findings that are most germane to the public and world leaders.
The full I.P.C.C. report, thousands of pages of technical background, will be released in four sections through the year – the first on basic science, then sections on impacts and options for limiting emissions and limiting inevitable harms, and finally a synthesis of all of the findings near year’s end.
In a news conference in Paris, Dr. Solomon declined to provide her own views on how society should respond to the momentous changes projected in the study.
“I honestly believe that it would be a much better service for me to keep my personal opinions separate than what I can actually offer the world as a scientist,” she said. “My stepson, who is 29, has an utterly different view of risks than I do. People are going to have to make their own judgments.”
Elisabeth Rosenthal reported from Paris, and Andrew C. Revkin from New York.
February 2, 2007
Panel Says Humans ‘Very Likely’ Cause of Global Warming
By THE ASSOCIATED PRESS
Filed at 6:34 a.m. ET
PARIS (AP) -- International scientists and officials hailed a report Friday saying that global warming is ''very likely'' caused by man, and that hotter temperatures and rises in sea level ''would continue for centuries'' no matter how much humans control their pollution.
The head of the Intergovernmental Panel on Climate Change, Rajendra Pachauri, called it a ''very impressive document that goes several steps beyond previous research.''
A top U.S. government scientist, Susan Solomon, said ''there can be no question that the increase in greenhouse gases are dominated by human activities.''
The 21-page summary of the panel's findings released Friday represents the most authoritative science on global warming. The panel comprises hundreds of scientists and representatives of 113 governments.
The scientists said the changes are ''very likely'' caused by human activity, a phrase that translates to a more than 90 percent certainty that global warming is caused by man's burning of fossil fuels. That was the strongest conclusion to date, making it nearly impossible to say natural forces are to blame.
The report said no matter how much civilization slows or reduces its greenhouse gas emissions, global warming and sea level rise will continue on for centuries.
''This is just not something you can stop. We're just going to have to live with it,'' co-author Kevin Trenberth, director of climate analysis for the National Center for Atmospheric Research in Boulder, Colo., told The Associated Press in an interview. ''We're creating a different planet. If you were to come up back in 100 years time, we'll have a different climate.''
Sharon Hays, associate director of the Office of Science and Technology Policy at the White House, welcomed the strong language of the report.
''It's a significant report. It will be valuable to policy makers,'' she told The Associated Press in an interview in Paris.
Hays stopped short of saying whether or how the report could bring about change in President Bush's policy about greenhouse gas emissions.
The panel predicted temperature rises of 2-11.5 degrees Fahrenheit by the year 2100. That was a wider range than in the 2001 report.
However, the panel also said its best estimate was for temperature rises of 3.2-7.1 degrees Fahrenheit. In 2001, all the panel gave was a range of 2.5-10.4 degrees Fahrenheit.
On sea levels, the report projects rises of 7-23 inches by the end of the century. An additional 3.9-7.8 inches are possible if recent, surprising melting of polar ice sheets continues.
Trenberth said scientists do worry that world leaders will take the message in the wrong way and throw up their hands. Instead, the scientists urged leaders to reduce emissions and also adapt to a warmer world with wilder weather.
''The point here is to highlight what will happen if we don't do something and what will happen if we do something,'' co-author Jonathan Overpeck at the University of Arizona said. ''I can tell if you will decide not to do something the impacts will be much larger than if we do something.''
The panel, created by the United Nations in 1988, releases its assessments every five or six years -- although scientists have been observing aspects of climate change since as far back as the 1960s. The reports are released in phases -- this is the first of four this year.
The next report is due in April and will discuss the effects of global warming. But that issue was touched upon in the current document.
------
On the Net:
Report: http://www.ipcc.ch/SPM2feb2007.pdf
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