Climate Change Impacts on Tropical Cyclones

The World Meteorological Organization’s (WMO) Expert Team on Climate Change Impacts on Tropical Cyclones (i.e. hurricanes, typhoons) concluded that, if twenty-first century warming occurs as projected, there will likely be an increase, on average worldwide, in the maximum wind speed of tropical cyclones of +2 to +11 % and in rainfall rates of approximately 20% within 100 km of the storm centre. The experts concluded that the total number of tropical cyclones worldwide will likely either decrease or remain unchanged. However, a likely increase in tropical cyclone intensity means that the frequency of the strongest tropical cyclones will more likely than not increase under the projected warming scenarios.

Substantial scientific progress has led the Expert Team to raise their confidence levels on several aspects of how tropical cyclone activity may change under projected climate scenarios. An update of possible consequences of climate change on tropical cyclones has been completed and published in the March 2010 issue of the peer-reviewed journal Nature Geoscience by the WMO Expert Team on Climate Change Impacts on Tropical Cyclones. The Expert Team is composed of leading international researchers, from five WMO Member countries, in the field of tropical cyclones.

Significant uncertainty still exists in the projected changes in tropical cyclone characteristics for any single ocean basin. Therefore, given the societal and economic impacts of tropical cyclones, additional research and observations is strongly recommended to further reduce the uncertainties in detection of changes and projections of tropical cyclone characteristics in relation to climate change.  The Expert Team concluded that it remains uncertain whether any past changes in tropical cyclone characteristics exceed the natural variability.

For more information:

The Expert Team is a component of the World Weather Research Programmes’ Working Group on Tropical Meteorology Research and was established in 2006. This Expert Team was formed to advise WMO Members of the state of knowledge regarding tropical cyclones and climate change. The team is co-chaired by  Thomas R. Knutson of the National Oceanic and Atmospheric Administration in the United States and by Dr John McBride of the Bureau of Meteorology Australia. The Nature Geoscience article is an update of their 2006 assessment. The past statement is available at  http://www.wmo.int/wwrp/2006Stmt

The web site for Nature Geoscience is http://www.nature.com/ngeo/index.html and reprints of this article will soon be available online at:
http://www.wmo.int/wwrp/ClimImpact

Fact sheet on Tropical Cyclones: http://www.wmo.int/pages/mediacentre/factsheet/tropicalcyclones.html