The hurricane season that begins Saturday is likely to be more active than average. But it's not because of climate change — or at least, not in any way that's easy to detect.
"Here's the bottom line," said Paul Huttner, MPR News' chief meteorologist. "Climate change does not seem to have a link to producing more hurricanes. The numbers just don't show that."
Speaking with host Tom Weber on The Daily Circuit, Huttner added that climate change may be a factor in the severity of the hurricanes, if not the number. "There's some evidence that these warmer oceans are producing more intense storms, more major hurricanes," he said. "In fact, since 1970 the number of Category 3 storms has doubled."
"All I know is that as we look at climate change and hurricanes, the only real link we're seeing is stronger storms. We're also extending the season ... Sandy's a great example, in that it happened very late in the season. Unusual to get a hurricane that far north, that late in the season. That was clearly a result of warmer-than-average ocean temperatures for that time of the year."
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Asked for a clear example of an effect of climate change, Huttner pointed to "the amount of water vapor in the atmosphere," which he said had increased by 4 percent.
"That's believed to be a result of more evaporation, because the planet is getting warmer," he said. "So you get a warmer planet, you have more moisture. What we're seeing is a documentable increase in these extreme rainfall events, the flash flooding. When it rains, it rains harder. ... In the last 30 years for example in Minnesota, we've had a doubling of these extreme 3-inch-plus rainfall events. We're seeing that as a trend. Droughts are becoming more severe.
"The extremes are becoming more extreme."
Huttner said long-range hurricane predictions are of little use, and suggested that forecasters should focus more of their attention and resources on short-range predictions.
"Last fall, with Sandy, was an excellent example," he said. "The NOAA computer models, the National Weather Service, they missed it a few days out. They had Sandy curving out into the open Atlantic, harmlessly passing the United States. The European model, which... has a higher resolution, more computing power, that nailed Sandy's track a good five, six, seven days in advance. And that was really the model that tipped off NOAA that hey, we may have a major problem here for the East Coast."