Bob CollinsIt is climate change. It isn’t climate change.
Welcome to another day of science trying to explain March and the recently expired winter.
“Clearly, this is outstanding and well outside any expectation under an unchanging climate. The magnitude and duration of the events in March certainly indicate that some unusual factors are afoot,” Kevin Trenberth, a senior scientist at the independent National Center for Atmospheric Research (NCAR) in Boulder, Colo., tells LiveScience today about a March that broke heat records in 7,755 locations in the U.S.
Is that a lot? There are 175,000 observing stations in the country. Still, the webiste says only one other March — 2007 — broke more than 7,000 records.
Certain extremes related to heating are becoming more evident, according to Trenberth.
So it’s climate change, then?
“Climate change was certainly a factor, but it was certainly a minor factor,” National Oceanic and Atmospheric Administration meteorologist Martin Hoerling says.
His analysis of March says a persistent warm wind sent warm air north from the Gulf of Mexico. It’s freaky wind and little more, he suggests.
“”Why wouldn’t we embrace it as a darn good outcome,” Hoerling tells the Associated Press. “This was not the wicked wind of the east. This was the good wind of the south.”
In his analysis — available here — Mr. Hoerling observes that if the March heat wave were pinned primarily to climate change, meteorologists would’ve predicted it:
In sum, the initialized forecasts possess many of the essential attributes of what crime scene investigators would look for in pinning a crime (the heatwave, in this case) to an individual (a physical cause, in this case). The forecast models give probable cause, namely that a particular atmospheric initial condition – emergent sometime in early February – led to a high probability outcome in the form of a large magnitude March heatwave. The sequence of forecasts allows one to largely reject other probable and immeditate causes for such a large magnitude event. For example, the GHG conditions that were known to be operative in prior months, had failed to predict or project an outcome of the magnitiude that was eventually observed. The forecasts further identify this particular culprit because those evolving internal atmospheric initial conditions yielded the precise location of the heatwave, at precisely the particular time of its occurrence, and with a high confidence of exceeding prior record heatwave magnitudes.
He also says the fact it was so warm in March, doesn’t mean we’ll bake in July. That’s something comforting to think about while you mow your lawn in Minnesota in the first week of April.
