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World Meteorological Organization now says: No link yet between climate change & hurricane activity
No link can yet be made between human-caused climate change, and the intensity or frequency of tropical cyclones, the World Meteorological Organization (WMO) stated on 4 December 2006. The WMO is affiliated with the United Nations in Geneva. This was reported as a consensus of 125 researchers and forecasters in the science of tropical cyclones (the generic term that includes hurricanes, typhoons, cyclones and tropical storms of any strength).
The experts said the main cause of the greater impacts of hurricanes on society is a growing concentration of people and buildings along the coasts. There is evidence both for and against a human influence on the climatology of tropical cyclones, so “no firm conclusion can be made on this point,” they conclude. They add that it is difficult to determine any trend in the activity of tropical cyclones for at least two reasons. First, a multi-decade cycle is observed in some oceans, which masks a long-term trend. Whether the cycle is completely natural, or may be linked to humans, is debated among these scientists. Secondly, methods of monitoring hurricane wind speeds have changed drastically, a fact which also makes it hard to monitor trends (see lead article on home page). Though the United States targets instrumented aircraft into the centers of hurricanes in the Atlantic and eastern Pacific Oceans, most regions of the worked do not have such aircraft observations, so the global trends are not really known for sure.
But the WMO scientists add that “it is likely that an increase in tropical cyclone peak wind-speed and rainfall will occur if the climate continues to warm.” And coastal communities would become vulnerable to storm surges from tropical storms if the anticipated rise in sea level occurs due to global warming.
The full report as well as a summary may be seen at the WMO site: http://www.wmo.ch/web/arep/press_releases/ 2006/iwtc_summary.pdf |