Figure 7: Projected Frequency of Intense Hurricanes. Via a high-resolution version of the GFDL hurricane prediction system, the model-projected increase in frequency of intense hurricanes can be seen by comparing the "control" simulation of a climate model run with present-day levels of greenhouse gases (yellow circles) to a simulation corresponding approximately to the year 2080 in which carbon dioxide levels were increased by 1% per year (brown circles). Category 4 hurricane wind speeds range from 131 to 155 mph and Category 5 wind speeds exceed 155 mph. Credit: T. Knutson, NOAA/ Geophysical Fluid Dynamics Laboratory.

US Climate Change Science Program / US Global Change Research Program, Suite 250, 1717 Pennsylvania Ave, NW, Washington, DC 20006. Tel: +1 202 223 6262. Fax: +1 202 223 3065. Email: information@usgcrp.gov. Web: www.usgcrp.gov. Webmaster: WebMaster@usgcrp.gov