"UN Update: Climate Change Hitting Sooner and Stronger"

"With a handful of weeks remaining before the climate convention meeting in Copenhagen, the UN Environment Programme (UNEP) has released an updated summary of the findings of the Intergovernmental Panel on Climate Change (IPCC). The report, "Climate Change Science Compendium 2009," warns that many predictions that were at the upper ranges of 2007 IPCC forecasts are increasingly likely, and some events that were seen previously as probable over the long term are on the verge of occurring or are occurring already. 'The pace and the scale of climate change is accelerating, along with the confidence among researchers in their forecasts,' UNEP Director Achim Steiner states in the document.

The analysis incorporates results from more than 400 major studies published since 2007 and addresses impacts on Earth systems, glaciers and ice sheets, oceans, and ecosystems. Increasingly, scientists are framing some of these transformations as 'commitments' -- inevitabilities that will play out even after the climate stabilizes. Fundamentally, the centuries-long buildup in atmospheric concentrations of greenhouse gases 'has most likely committed the world to a warming of 1.4-4.3 °C [by 2100], above pre-industrial surface temperatures,' the report says. The study points to the 21st-century expansion of the global economy and continued reliance on high-carbon-intensity fuels as obvious factors that contribute to warming."

Noreen Parks reports for Environmental Science & Technology October 14, 2009.