This is an excerpt from EERE Network News, a weekly electronic newsletter.

December 02, 2009

New Reports Catalogue the Worsening Impacts of Climate Change

Two recent compendiums of climate change science compiled by leading climate scientists show that the impacts of climate change are happening sooner and at a greater magnitude than previously thought. The two reports are the latest attempts to update the climate science since the last report of the Intergovernmental Panel on Climate Change (IPCC), the Fourth Assessment Report, which was released in 2007. The first new report, released in late September by the United Nations Environment Programme (UNEP), is titled "Climate Change Science Compendium 2009," while the second, released in late November by 26 climate researchers, is called "The Copenhagen Diagnosis, 2009: Updating the World on the Latest Climate Science." Both are based on published, peer-reviewed climate science.

Both reports reach the same conclusions, namely, that Greenland and Antarctic ice sheets are losing mass and contributing to sea level rise at an increasing rate; that Arctic sea ice has melted far beyond the expectations of climate models; and that global sea-level rise may well exceed 1 meter by 2100, with an upper limit of 2 meters now considered to be the upper range for sea-level rise by 2100. Both reports also note that carbon dioxide emissions from fossil fuels were 40% higher in 2008 than they were in 1990. The increasing emissions are causing the window in which to reduce emissions to narrow. According to the reports, if emissions are maintained at today's levels for the next 20 years, the possibility of limiting global warming to less than 2°C will disappear. Climate scientists generally concur that a global temperature rise of 2°C or more will lead to disastrous consequences. The comprehensive UNEP report also warns of ocean acidification, melting mountain glaciers, and the possibility that "tipping points" in the climate could soon be reached. See the Copenhagen Diagnosis press release, which links to the full report, the UNEP press release, and the UNEP report, which was updated in late October.

Meanwhile, the World Meteorological Organization (WMO) has found that atmospheric concentrations of greenhouse gases are continuing to increase. The WMO's "Greenhouse Gas Bulletin 2008," released in late November, finds that the "radiative forcing," or greenhouse effect, caused by all long-lived greenhouse gases increased by 1.3% from 2007 to 2008, and has increased by 26% since 1990. The globally averaged concentration of carbon dioxide in 2008 was 385.2 parts per million (ppm), an increase of 2 ppm from 2007, while methane increased to 1,797 parts per billion (ppb), an increase of 7 ppb above 2007 levels. After staying stable from 1999 to 2006, methane concentrations showed significant increases in both 2007 and 2008. Nitrous oxide and refrigerants are also on the rise. The report is troubling in light of the "Carbon Budget 2008," a report released in mid-November by the Global Carbon Project, which found that carbon emissions are now overwhelming the natural "sinks" that absorb carbon, such as the ocean. See the WMO press release and report and the Carbon Budget 2008.

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