Climate change behind rise in weather disasters

http://www.usatoday.com/story/weather/2012/10/10/weather-disasters-climate-change-munich-re-report/1622845/

Doyle S. Rice
October 10. 2012

The number of natural disasters per year has been rising dramatically on all continents since 1980, but the trend is steepest for North America where countries have been battered by hurricanes, tornadoes, floods, searing heat and drought, a new report says.

The study being released today by Munich Re, the world's largest reinsurance firm, sees climate change driving the increase and predicts those influences will continue in years ahead, though a number of experts question that conclusion.

Whatever the causes, the report shows that if you thought the weather has been getting worse, you're right.

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Some of the report's findings:

-- The intensities of certain weather events in North America are among the highest in the world, and the risks associated with them are changing faster than anywhere else.

-- The second costliest year of the study period, 2011, was dominated by strong storms. Insured losses in the U.S. due to thunderstorms alone was the highest on record at an estimated $26 billion, more than double the previous thunderstorm record set in 2010.

-- Insured losses from disasters averaged $9 billion a year in the 1980s. By the 2000s, the average soared to $36 billion per year.

Global warming combined with natural cycles such as the El Niño or La Niña phenomena also intensify the risk of severe weather. "This will result in higher natural peril losses and affect not only the onset of heat waves, droughts and thunderstorms but also, in the long term, the intensity of tropical cyclones," the report finds.

[The occurrence and intensity of El Niños and La Niñas should also be affected by global warming.]

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"We see some trends that are linked with changes in atmospheric conditions, such as more water content in the atmosphere due to global warming," Hoppe says. Additional water vapor in the atmosphere is the fuel for the big storms, he says.

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