9 December 2014

Beware the Juice of Freshly Picked California Cherries

Posted by Dan Satterfield

Screen Shot 2014-12-08 at 11.06.34 PMThere has been some talk about a report on the California drought that was released this week, and it’s worth talking about the reaction to it. One thing that seems to have gotten particular attention is the following statement: “The current drought is not part of a long-term change in California precipitation, which exhibits no appreciable trend since 1895. Key oceanic features that caused precipitation inhibiting atmospheric ridging off the West Coast during 2011-14 were symptomatic of natural internal atmosphere-ocean variability.”

As Dr. Kevin Trenberth at NCAR has put so well– “All weather events are connected to climate change these days”. This is because the planet and it’s oceans are warmer, and there is more water vapor in the air etc. That said, it seems that this report is saying that the drought in California, would probably have happened even if the oceans and the planet were not warmer. The long-term proxy records show that California periodically has some amazing dry spells, so this isn’t really much of surprise to anyone familiar with the science.

The takeaway here, is to be very aware of statements that are dripping with the juice of freshly picked cherries, especially when seeing something on the web or social media about climate change. If it is not posted by someone with a background in atmospheric science (or a governmental science body), you should take it with a BIG dose of salt to modify that sweet cherry taste in your mouth!

 Dr. Marshall Shepherd, past President of the American Meteorological Society, posted these wise thoughts on his Facebook page this evening:

“Some broader perspective on this recent NOAA report out this week.. What I see happening is opposing sides of the climate issue are cherry picking perspective from the report. My perspective. I think the study captures aspects of natural variability that would contribute to the West’s drought (La Nina, ocean/SSTs, precipitation, etc.). However, I think it significantly downplays some other aspects . Key points being overlooked: The authors acknowledge climate change and its anticipated effects on drought. They conclude it is not main driver of the current West drought but never conclude human-caused climate change is not happening. They note that this report is not settled. They really didn’t consider the Arctic Amplification hypothesis. Let’s not make too much of this report, but let’s not discount key pieces either. Scientists actually know how to consume a report like this, but there are so many non-experts in the discussion that are not trained as scientists that they take these reports like court reports or a business decision. Science doesn’t work on the premise of reasonable doubt….And, we must end the era of “1-study/1-report” hysteria…”

He is absolutely right. Science moves forward by a preponderance of the published work, not he said/she said, and especially not when they have a political axe to grind.