Decisive action needed as warming predictions worsen, s...( Stanford CA Greenhouse gases in the ...)

Stanford, CA Greenhouse gases in the atmosphere are rising more rapidly than expected, increasing the danger that without aggressive action to reduce emissions the climate system could cross a critical threshold by the end of the century, warns a leading member of the Nobel Prize-winning Intergovernmental Panel on Climate Change. Studies indicate that greenhouse warming could trigger a vicious cycle of feedback, in which carbon dioxide released from thawing tundra and increasingly fire-prone forests drives global temperatures even higher.

Chris Field, director of the Carnegie Institution's Department of Global Ecology and co-chair of the IPCC Working Group 2, will address these issues at a symposium titled "What Is New and Surprising since the IPCC Fourth Assessment?" at the annual meeting of the American Association for the Advancement of Science (AAAS) in Chicago. The IPCC Fourth Assessment, for which Field was a coordinating author, was published in 2007. As co-chair, Field will oversee the Working Group 2 Report on the predicted impacts of climate change for the IPCC Fifth assessment, scheduled to be published in 2014. The Fifth Assessment will incorporate the results of new studies that predict more severe changes than did previous assessments.

"The data now show that greenhouse gas emissions are accelerating much faster than we thought," says Field. "Over the last decade developing countries such as China and India have increased their electric power generation by burning more coal. Economies in the developing world are becoming more, not less carbon-intensive. We are definitely in unexplored terrain with the trajectory of climate change, in the region with forcing, and very likely impacts, much worse than predicted in the fourth assessment."

New studies are also revealing potentially dangerous feedbacks in the climate system that could convert current carbon sinks into carbon sources. Field points to tropical forests as a prime
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