02 March 2009
Latest Climate Change Science Indicates Worsening Effects Ahead
New findings show rising CO2, melting Arctic ice, a warming Antarctic
Cliffs and rocky shoreline along southern part of Baffin Island on the Hudson Strait in Canadian Arctic.
Washington ― In 2007, the governments and scientists who contributed to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) agreed that global warming was unequivocal, already happening and almost surely due to human activity.
Since then, a range of scientific studies have updated some of the IPCC findings, showing that the pace of climate change, at least in terms of increasing carbon dioxide emissions, melting Arctic ice and warming in Antarctica, might be faster than the scientists initially estimated.
“If you look at new observations,” Christopher Field, director of the Carnegie Institution for Science's Department of Global Ecology at Stanford University in California, told the Senate Environment and Public Works Committee February 25, “it’s clear that things have continued to change and they’ve changed very rapidly, mostly in ways that were discussed by the IPCC but hadn’t been confirmed because the evidence wasn’t yet strong enough.”
Field was co-chairman of Working Group II (climate change impacts, adaptation and vulnerability) of the IPCC for the fourth assessment report. (See “High Stakes Accompany Global Climate Change.”)
Earlier that week, during a trip to China on February 21, Secretary of State Hillary Rodham Clinton discussed climate change in remarks at the Taiyang Gong Power Plant in Beijing.
“When 30 years ago this year the United States and China established diplomatic relations, we weren’t thinking at that time about climate change,” Clinton said. “But today we know that climate change and clean energy are two of the biggest challenges our countries and the world face.”
“Climate change is an epic challenge,” U.S. Special Envoy for Climate Change Todd Stern said during the same visit. “Scientists have been warning us about this threat for many years. And mounting evidence suggests that, if anything, scientists have underestimated the seriousness of the threat, not the other way around.”
GLOBAL CONCERNS
A recent study, published in Proceedings of the National Academy of Sciences on February 23 by an international group of scientists, updates findings in the IPCC third assessment report, published in 2001, about five areas of global concern.
Secretary of State Hillary Rodham Clinton chats with Wang Yongliang, manager of Taiyang Gong Power Plant in China, on February 21.
Secretary of State Hillary Rodham Clinton chats with Wang Yongliang, manager of Taiyang Gong Power Plant in China, on February 21.
In the latest report, the authors say there is new and stronger evidence since 2001 of observed impacts of climate change on unique and vulnerable systems ― coral reefs, tropical glaciers, endangered species, unique ecosystems and more ― with adverse effects increasing as temperatures rise further.
They find new and stronger evidence of the likelihood and likely impacts of extreme weather events with consequences for societies and natural systems. They also find increased evidence that low-latitude and less-developed areas generally face greater risk than higher-latitude and more-developed countries.
The authors say it is likely there will be more severe damages than previously thought due to increases in average global temperature, and climate change over the next century is likely to adversely affect hundreds of millions of people.
The risk of additional contributions to sea-level rise from melting of the Greenland and Antarctic ice sheets, the authors say, might be larger than projected by ice sheet models assessed in the fourth assessment report, and several additional meters of sea level rise could occur on century time scales.
“The more we learn about the problem, the more severe the risk becomes and the nearer it looms,” co-author Michael Oppenheimer, a professor of geosciences and international affairs at Princeton University, said in a February 23 statement from Stanford. “Cutting emissions of the greenhouse gases promptly is the surest way to reduce the risk, and that's how governments should be responding.”
INSPIRED MITIGATION
The global record of greenhouse gas mitigation “has not been inspiring,” IPCC Chairman Rajendra Pachauri told the Senate committee, yet it would cost less to reduce greenhouse gas emissions than it would to do nothing as emission concentrations rise.
“This is not going to be an expensive proposition,” he said in testimony. “The IPCC has assessed, for instance, that if temperature increase has to be limited to 2.0 to 2.4 degrees Celsius, then carbon dioxide emissions must peak by 2015 and decline thereafter.”
The cost of this stringent path of mitigation, Pachauri said, would not exceed 3 percent of the global gross domestic product in 2030.
The IPCC is starting to outline its fifth assessment report, which will be made final in 2014. Its outline will be developed through a process that involves climate change experts from relevant disciplines and representatives from governments.
Governments and organizations involved in the fourth assessment report were asked to submit comments in writing for the fifth report and those submissions are being analyzed. More input is expected at the 30th session of the IPCC April 21-23 in Antalya, Turkey.
More information about the IPCC is available at the organization’s Web site.
Science Writer
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