Kevin Trenberth was on NPR's
Talk of the Nation today, talking about relationships between global warming and tornadoes (and a few other things). He didn't say anything too surprising. When asked he said he thinks the best way to keep a tab on global warming is by watching sea level, since it incorporates both ocean heat changes and the melting of land ice, and is less subject to short term variations. You can listen to him
here (though it hasn't been posted yet as I write this).
Fortunately, he didn't say much about tornadoes and climate change, since there's no consensus that there will be an increase in number or intensity as the planet warms.
ReplyDeleteUnfortunately, he implied that tornado season has moved earlier in the year. There's zero evidence if you take anything reasonable as a marker for defining the beginning of the season. If, say, you look at the date on which the 50th F1 or stronger tornado (roughly 10% of an average year)occurs, the trend is zero. There's a hint of increased variability in the last decade, but that's such a small sample that you can't say anything with confidence. The season certainly hasn't gotten earlier. 2011, for instance, got off to a late start and 2003 had the longest period at the beginning of the year without any tornadoes.