Warmer Oceans, Stronger Hurricanes

TOMADO DE: Scientific American, http://www.scientificamerican.com/article.cfm?id=warmer-oceans-stronger-hurricanes

Evidence is mounting that global warming enhances a cyclone's damaging winds and flooding rains

The summer of 2004 seemed like a major wake-up call: an unprecedented four hurricaneshit Florida, and 10 typhoons made landfall in Japan—four more than the previous record in that region. Daunted, scientists offered conflicting explanations for the increase in these tropical cyclones and were especially divided about the role of global warming in the upsurge. Then Mother Nature unleashed a record-breaking 2005 season in the North Atlantic, capped by the devastating hurricanes Katrina and Rita. But in 2006, as insurance rates in the southeastern U.S. soared, the number of North Atlantic storms dropped well below predictions. If global warming was playing a role, why was the season so quiet?Careful analyses of weather patterns are yielding a consensus explanation for both the dramatic rises in 2004 and 2005, as well as the strangely tame 2006 season. Unfortunately, that explanation forebodes meteorological trouble over the long term.

Lightning-Fast Warnings
Storms could become more intense as the world warms. Researchers studying 58 hurricanes found that an increase in lightning tended to precede the strongest winds by a day. For instance, monitors tracking Hurricane Dennis in 2005 recorded a surge in lightning flashes—from 600 a day to 1,500—nearly 24 hours before wind speeds doubled and peaked at 150 miles per hour. The correlation, reported online April 6 in Nature Geoscience, needs more data before lightning can be considered a definitive predictor of storm intensity.