04/20/2009

Reducing Current Carbon Emissions Has Big Benefits for Climate

Summary

In a paper being published this week in Geophysical Research Letters, Dr. Warren Washington and colleagues at the National Center for Atmospheric Research (NCAR) report that current patterns of global warming can still be greatly diminished if nations cut emissions of heat-trapping greenhouse gases by 70% this century. Their analysis is based on assumptions about carbon emissions from the U.S. Climate Change Science Program Synthesis and Assessment Report #2.1. This report cites 450 ppm carbon dioxide as an attainable target if the world quickly adapts conservation practices and new green technologies to cut emissions dramatically. Left unchecked, emissions are currently on track to reach about 750 ppm by 2100. The team’s results showed that if atmospheric CO₂ were held to 450 ppm, global temperatures would only increase by 0.6^oC by the end of the century. In contrast, the study showed that temperatures would rise by almost four times that amount, or 2.2^oC, if emissions are allowed to continue on their present course. The more modest increase would partially avoid some of the most dangerous impacts of climate change, massive losses of Arctic sea ice and permafrost and significant sea level rise, in addition to lesser impacts on Arctic fisheries and mammals, and less global and regional changes of surface temperature and precipitation. Such reductions in emissions would stabilize atmospheric CO₂ (and the climate system) by 2100 whereas the non-mitigation scenario would not result in stabilization in the present century.

References

Washington, W. M., R. Knutti, G. A. Meehl, H. Teng, C. Tebaldi, D. Lawrence, L. Buja, and W. G. Strand. 2009. “How Much Climate Change Can Be Avoided by Mitigation?” Geophysical Research Letters 36, L08703. DOI: 10.1029/2008GL037074.