Gathering Storms

A new study has added to the evidence that global warming is triggering stronger storms. According to an analysis of tide gauge records, storm surges similar to Hurricane Katrina’s have happened twice as often during warm years.

Linking climate change to damaging tropical storms isn’t straightforward. The number of Atlantic hurricanes seems to have risen over the last century, but scientists also have developed better methods of detecting these storms. And while researchers often analyze the total number of hurricanes, the storms that reach land are the most devastating.

The study authors decided to look at storm surges, which are “the most harmful aspect of tropical cyclones in the current climate,” they write. To find surge patterns, the team examined data from tide gauges that monitor sea level in the western Atlantic Ocean.

The analysis showed that large surges have become more frequent since 1923, the team reports in Proceedings of the National Academy of Sciences. The researchers also studied cold and warm years separately and found that events comparable to Hurricane Katrina were about twice as frequent during the warm periods.Roberta Kwok | 16 October 2012

Source: Grinsted, A. et al. 2012. Homogeneous record of Atlantic hurricane surge threat since 1923. Proceedings of the National Academy of Sciences doi: 10.1073/pnas.1209542109.

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