August 13 Issue of Science Paper on Occurrence of Extreme Heat Wave Events Under Greenhouse Gas Forcing Climate Change Scenario

Summary

Results under a “business-as-usual” scenario using a global coupled climate model indicate that there is a distinct geographic pattern to future changes in heat waves. Model results for areas of Europe and North America, associated with the severe heat waves in Chicago in 1995 and Paris in 2003, show that future heat waves in these areas will become more intense, more frequent, and longer lasting in the second half of the 21st century. Observations and the model show that present-day heat waves over Europe and North America coincide with a specific atmospheric circulation pattern that is intensified by ongoing increases in greenhouse gases, indicating that it will produce more severe heat waves in those regions in the future. This research was sponsored by the Office of Biological and Environmental Research, Climate Change Prediction Program and Weather and Climate Impact Assessment Initiative at the National Center for Atmospheric Research. The same issue of Science, Richard Kerr’s News Focus entitled “Three Degrees of Consensus” discusses climate sensitivities evidenced in the latest generation of climate models enabled by both more powerful computers and a better understanding of climate processes. The range in climate sensitivity from eight high-end coupled climate models is 2.6°- 4°C. Kerr cites research work by several scientists sponsored by the Biological and Environmental Research/Climate Change Research Division.

References

Gerald A Meehl and Claudia Tebaldi: “More Intense, More Frequent, and Longer Lasting Heat Waves in the 21st Century,” Science, 304, 994-997 (2004).

Richard A Kerr: “Three Degrees of Consensus,” Science, 304, 932-934 (2004).