Alister Doyle, PlanetArk 25 Nov 09;
OSLO - Global warming is happening faster than expected and at worst could raise sea levels by up to 2 meters (6-1/2 ft) by 2100, a group of scientists said on Tuesday in a warning to next month's U.N. climate summit in Copenhagen.
In what they called a "Copenhagen Diagnosis," updating findings in a broader 2007 U.N. climate report, 26 experts urged action to cap rising world greenhouse gas emissions by 2015 or 2020 to avoid the worst impacts of climate change.
"Climate change is accelerating beyond expectations," a joint statement said, pointing to factors including a retreat of Arctic sea ice in summer and melting of ice sheets on Greenland and Antarctica.
"Accounting for ice-sheets and glaciers, global sea-level rise may exceed 1 meter by 2100, with a rise of up to 2 meters considered an upper limit," it said. Ocean levels would keep on rising after 2100 and "several meters of sea level rise must be expected over the next few centuries."
Many of the authors were on the U.N.'s Intergovernmental Panel on Climate Change, which in 2007 foresaw a sea level rise of 18-59 cms (7-24 inches) by 2100 but did not take account of a possible accelerating melt of Greenland and Antarctica.
Coastal cities from Buenos Aires to New York, island states such as Tuvalu in the Pacific or coasts of Bangladesh or China would be highly vulnerable to rising seas.
"This is a final scientific call for the climate negotiators from 192 countries who must embark on the climate protection train in Copenhagen," Hans Joachim Schellnhuber, Director of the Potsdam Institute for Climate Impact Research, said in a statement.
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Copenhagen will host a December 7-18 meeting meant to come up with a new U.N. plan to succeed the Kyoto Protocol beyond 2012. But a full legal treaty seems out of reach and talks are likely to be extended into 2010.
"Delay in action risks irreversible damage," the researchers wrote in the 64-page report, pointing to a feared runaway thaw of ice sheets or possible abrupt disruptions to the Amazon rainforest or the West African Monsoon.
The researchers said global carbon dioxide emissions from fossil fuels were almost 40 percent higher in 2008 than in 1990.
"Carbon dioxide emissions cannot be allowed to continue to rise if humanity intends to limit the risk of unacceptable climate change," said Richard Somerville of the Scripps Institution of Oceanography at the University of California.
In a respite, the International Energy Agency has said emissions will fall by up to 3 percent in 2009 due to recession.
The report said world temperatures had been rising by an average of 0.19 Celsius a decade over the past 25 years and that the warming trend was intact, even though the hottest year since records began in the mid-19th century was 1998.
"There have been no significant changes in the underlying warming trend," it said. A strong, natural El Nino weather event in the Pacific pushed up temperatures in 1998.
Climate science update: from bad to worse
Marlowe Hood Yahoo News 24 Nov 09;
PARIS (AFP) – The planet could warm by seven degrees Celsius (10.8 degrees Fahrenheit) and sea levels could rise by more than a metre (3.25 feet) by 2100, scenarios that just two years ago were viewed as improbable, scientists said on Tuesday.
In the widest overview on global warming since a landmark report by the UN Intergovernmental Panel on Climate Change (IPCC) report in 2007, the authors said manoeuvering room for tackling the carbon crisis was now almost exhausted.
The 64-page "Copenhagen Diagnosis" aims at the December 7-18 UN conference in Denmark, tasked with forging a planet-wide deal on greenhouse-gas emissions.
"This is a final scientific call for climate negotiators from 192 countries who must embark on the climate protection train in Copenhagen," said Hans Schellnhuber, director of Germany's Potsdam Institute for Climate Impact Research (PIK), which oversaw the paper.
"They need to know the stark truth about global warming and the unprecedented risks involved," he said.
The scientists billed the summary as "an interim scientific evaluation" between the IPCC's Fourth Assessment Report, known as AR4, and its next big handbook, due in 2013. Several authors were part of that Nobel-winning group.
New evidence published in peer-reviewed scientific literature suggests many of the estimates published in 2007 are too low, the "Copenhagen Diagnosis" suggested.
Among the findings:
-- Emissions of heat-trapping carbon dioxide from fossil fuels "are tracking near the highest scenarios considered so far" by the IPCC.
They were nearly 40 percent higher in 2008 than in 1990, the benchmark year for the Kyoto Protocol, whose pledges expire in 2012.
Over the past 25 years temperatures have rise by 0.19 C (0.34 F) per decade, and current emissions place Earth on track for global mean warming as high as 7.0 C (10.8 F).
In 2007, the IPCC predicted warming of between 1.1 C (1.98 F) and 6.4 C (11.52 F) compared to 1980-99 levels, with the likeliest rise being 1.8-4.0 C (3.24-7.2 F). Added to this is warming of around 0.74 (1.33 F) during the 20th century.
-- To limit global warming to 2.0 C (3.6 F) compared to pre-industrial times, emissions must peak before 2020 and reach a "zero"-level "well within this century," the researchers conclude.
"Our available emissions to ensure a reasonably secure climate future are just about used up," said Matthew England, co-director of the Climate Change Research Centre of the University of New South Wales in Australia.
In July, leaders from the world's major developed and developing economies agreed on the need to prevent average global temperatures from climbing more than 2.0 C (3.6 F) over pre-industrial times.
-- Summer-time melting of Arctic sea ice has outstripped IPCC climate models by about 40 percent for the period 2007 to 2009.
A wide array of satellite and ice measurements leave no doubt that both Greenland and West Antarctic icesheets -- with enough frozen water between them to raise sea levels by 12 metres (40 feet) -- are losing mass at an increasing rate.
The IPCC estimated sea levels would rise 18-59 centimetres (7.2-23.2 inches) by 2100, but this was from thermal expansion (water expands when it warms) and did not factor in runoff from melting land ice.
"By 2100, global sea-level is likely to rise at least twice as much as projected (in) AR4; for unmitigated emissions it may well exceed one metre (3.25 feet)," said the new report.
-- Major ecosystems are nearing individual "tipping points," the threshold beyond which they may spiral into irretrievable decline and will no longer mitigate global warming but, instead, amplify it.
Some of these ecosystems -- the Amazon forest, the West African monsoon, coral reefs -- directly support populations in the hundreds of millions, and could create huge numbers of migrants were they to collapse.
Meanwhile, a study published by the World Wildlife Fund (WWF) and the German insurer Allianz calculated the risk to port cities from a global sea level rise of 50 cms (20 inches) by 2050.
Worldwide, property worth up to 28.21 trillion dollars in 136 coastal megacities would be exposed.
On the US Eastern Seaboard alone, a 50cm (20-inch) rise, when coupled with a local storm surge of 15 cms (six inches), would imperil assets potentially worth 7.4 trillion dollars.
CO2 curve ticks upward as key climate talks loom
John Heilprin, Associated Press Yahoo News 24 Nov 09;
MAUNA LOA OBSERVATORY, Hawaii – The readings at this 2-mile-high station show a troubling upward curve as the world counts down to crucial climate talks: Global warming gases are building in the atmosphere at record levels from emissions that match scientists' worst-case scenarios.
Carbon dioxide concentrations this fall are hovering at around 385 parts per million, on their way to a near-certain record high above 390 in the first half of next year, at the annual peak.
"For the past million years we've never seen 390. You have to wonder what that's going to do," said physicist John Barnes, the observatory director.
One leading atmospheric scientist, Stephen Schneider, sees "coin-flip odds for serious outcomes for our planet."
Far from this mid-Pacific government observatory, negotiators from 192 nations gather in wintry Copenhagen, Denmark, next month to try to agree on steps to head off the worst of the climate disruptions researchers say will result if concentrations hit around 450 parts per million — in 30 years at the current rate. Some say the world has already passed a danger point, at 350 ppm, and must roll back.
Today's emissions curve is tracking the worst case among seven emissions scenarios set out in 2001 by the U.N.'s Intergovernmental Panel on Climate Change (IPCC), British climatologists reported in September.
The U.N. expert group projects that such a path would raise global temperatures between 2.4 and 6.4 degrees Celsius (4.3 and 11.5 degrees F) by century's end. That would come on top of a global temperature increase of about 0.6 degrees Celsius (1 degree Fahrenheit) in the past century, a warming trend the authoritative IPCC says is mainly due to the buildup of carbon dioxide and other greenhouse gases.
Such warming will shift climate patterns, cause more extreme weather events, spread drought and floods to new areas, kill off plant and animal species, and cause seas to rise from heat expansion and the melting of land ice, the IPCC says.
"Changing several degrees may not seem like much, but we're just changing things too fast," Barnes said. "So the consequences could well be drastic."
The IPCC has urged industrialized countries to reduce global emissions by 25 to 40 percent below 1990 levels by 2020. As of 2007, they stood only 4 percent below 1990 levels, and the rest of the world continued pouring out more and more heat-trapping gases, chiefly from the burning of coal, gasoline and other fossil fuels.
Through this decade global emissions have grown by 23 percent. In 2008, almost three-quarters of the increase came from China, researchers reported last week. Other big contributors among developing countries were India, Saudi Arabia, Brazil, South Africa, South Korea, Indonesia, Iran and Mexico.
Experts see no sign of a slowdown.
It would "probably be at 390 (ppm) next year at Mauna Loa," said Fred T. Mackenzie, a professor emeritus of oceanography at the University of Hawaii at Manoa. That would represent almost a 40-percent increase in carbon-dioxide density in the atmosphere since before the industrial age and extensive use of fossil fuels.
Schneider, a Stanford University climatologist, said the world faces a huge risk.
"I think meters of sea-level rise are virtually inevitable, unless we can stop this. But I'm not such an optimist," he told journalists on a fellowship program with the Honolulu-based East-West Center. "The main message is we're in risk management. We do not know the science well enough to know exactly what the temperature is at when a tipping point will occur."
This U.S. government observatory, 11,141 feet up Mauna Loa's northern flank, also measures methane and other significant greenhouse gases. It was here on Hawaii's Big Island that climatologist Charles David Keeling pioneered the measurement of carbon dioxide in the atmosphere, installing his experimental manometer on the gently sloping volcano in 1958.
He chose the site, already a U.S. Weather Service station, because the trade winds blowing over it had some of the cleanest air on the planet. Barnes said the CO2 measurements here, thousands of miles from major industry, were the first to show that manmade carbon dioxide emissions were accumulating throughout the global atmosphere.
The upward trend, averaging 1.9 parts per million per year in the past decade, undergoes seasonal fluctuations. In summer, during the growing season, plants absorb carbon dioxide from the atmosphere. But in winter, the concentration of C02 rises as vegetation and other biomass decompose.
The observatory is part of the National Oceanic and Atmospheric Administration's worldwide network for measuring greenhouse gases. It coordinates measurements with other U.S.-run research stations in Alaska, California, American Samoa and the South Pole. Japan and Australia also run such networks.
The Mauna Loa researchers extend their measurements through their "flask network" — containers sent to dozens of places around the world each week or carried on commercial ships so people can fill them with air and send them back to be measured for C02 and other gases.
Barnes, watching the carbon dioxide "ppm" curve track ever upward on Mauna Loa, while some other greenhouse gases decline, noted that long-lived CO2 is "more and more the bigger player."
"It is going into the ocean, and there's some plant uptake, but a whole lot of it just goes into the air and it's going to stay there for thousands of years," he said.
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