Reuters, Nov. 24, 2009
OSLO (Reuters) - 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.
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.
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Discovery.com, Nov. 24, 2009
By just about any measure, global warming is matching or exceeding experts' worst projections, and could bring drastic change to our planet, including a 19-foot sea level rise and the extinction of many species, according to a new report released today.
The study was published by 26 climate scientists, the majority of whom were authors of the Intergovernmental Panel on Climate Change report in 2007.
The researchers point to a gloomy slate of evidence: Carbon dioxide emissions are 40 percent higher than in 1990. Greenland and Antarctic ice sheets are melting at an accelerated pace. Sea level crept 80 percent higher over the last 15 years than projected in 2001. It is on track to rise twice as much by 2100 as the IPCC projected in 2007.
Arctic sea ice melted 40 percent more than the average prediction in the IPCC report.
"This stunned the scientific community because it was far greater than any projection," said climate scientist and study co-author Andrew Weaver of the University of Victoria in Canada's British Columbia.
"Things are happening faster and with greater magnitude than when the IPCC was published in 2007," Weaver said.
"We are in the lead-up to an historic climate summit -- the Copenhagen climate summit -- and it is absolutely essential that any policy making regarding climate change be based on the best and most up-to-date science," said co-author Michael Mann of Pennsylvania State University in State College.
Scientists have learned a lot since summer 2006 -- the cutoff for publication of research considered in the 2007 IPCC report. "What this report is an attempt to do is to provide an update of the current scientific understanding," Mann said.
"We are all concerned that we are basically on target for changes that are in general larger than what was projected from the IPCC report," he continued. "The observations are telling us that changes in many respects are happening faster than models projected."
Researchers have identified a global average temperature increase of about 3.6 degrees Fahrenheit as a threshold past which serious negative consequences are very likely. This amount of warming is close to the threshold for complete melting of Greenland and a resulting six-meter sea level increase, Weaver said.
"Something like 15 to 37 percent of all species become committed to extinction around (3.6 degrees Fahrenheit)," he added.
"In my opinion the single most important observation is that we are now able to quantify the amount of emissions we as humans can put in the air and stay below various temperature thresholds. What we can say now is climate cares about cumulative emissions and not emissions from any given year."
To avoid a 3.6 degree increase, immediate action is needed, the researchers said. Global emissions must peak within the coming decade and they most drop off rapidly after that.
"Among the things we've learned that we were not so sure of three years ago is that there is an urgency to this problem that isn't a political issue," said report author Richard Somerville of Scripps Institution of Oceanography at the University of California, San Diego. "It's Mother Nature herself."