Thursday, April 26, 2012

Cliff Mass on Extreme Weather Events

Dr. Cliff Mass of the University of Washington is a friend of mine and an excellent meteorologist.

Cliff believes, more than I do, that global warming due to CO2 and other greenhouse emissions is a problem. The thing I so much respect about Cliff is that he demands scientific evidence before coming to a conclusion.

So, with the Great Plains currently experiencing much above normal temperatures, I want post a few items from Cliff's blog on the non-correlation between recent extreme weather events and CO2 concentrations/global warming before someone (inevitably) blames the heat on global warming. I urge you to click here to read his entire post.


Extreme Silliness

It is happening frequently lately.  A major weather event occurs---perhaps a hurricane, heat wave, tornado outbreak, drought or snowstorm-- and a chorus of activist groups or media folks either imply or explicitly suggest that the event is the result of human-caused (anthropogenic) global warming.  Perhaps the worst offender is the organization www.350.org and their spokesman Bill McKibben...

But what is so disturbing about all this is that there is very little evidence that these claims are true....that the extreme events of late are the result of greenhouse gas increases caused by humans.

Take the recent amazing heat wave in the eastern and central U.S.:  canary in the coal mine for global warming?   No evidence of this.  In fact, an in-depth analysis by Dr. Martin Hoerling of  NOAA Earth Systems Research Lab (ESRL), found here, suggest that the heat wave was the result of natural variability and an unusual, but not unprecedented, change in the upper level flow pattern that pushed tropical air northward over the eastern U.S..  A recent discussion of the March warming by UW Professor Michael Wallace, one of the nation's leading climate scientists and a member of the U.S. National Academy of Sciences, found here, reaches a similar conclusion.

Well, what about the extensive tornado outbreaks of 2011 over the southeast U.S. and the early tornadoes of 2012.    Unusual extreme weather connected with global warming?  There is no reason to believe this is true.   Backing for this statement comes from a comprehensive report of the Intergovernmental Panel on Climate Change (IPCC) on extreme weather events, found here.  To quote the IPCC report: "There is low confidence in observed trends in small spatial-scale phenomena such as tornadoes and hail."
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It is somewhat embarrassing for me to admit this, but part of the problem is that a small minority of my colleagues--people who should know better-- are feeding the extreme-weather/climate hype in the mistaken belief that by doing so they can encourage people to do the right thing--lessen their carbon footprint.

So that my coverage of Cliff's post is "fair and balanced," I wish to include his final thoughts even though Cliff and I, to an extent, disagree:

I believe the science is fairly clear...the impacts of global warming due to human-enhanced greenhouse gases will be be very significant, that the effects will increase gradually at first, but then accelerate later in the century. 

For our (literally) of thousands of new readers the last two weeks, the evidence shows -- on balance -- human beings warm the earth to a small extent. There is zero evidence of "acceleration" of the warming at the present time (the earth's temperature has been remarkably stable the last fifteen years) and no evidence that this is a major problem any time in the next couple of decades.  I my view, there are far more important and urgent environmental problems than global warming.

Because the sun's behavior in recent years gives some (but hardly conclusive) evidence that it may be starting to act to cool the earth, which might balance or overcome humans effect on climate, I recommend doing nothing in terms of mitigating global warming at this time.

So, the next time you hear about heat waves, cold waves, floods, droughts, and tornadoes being caused by global warming, just let it pass. There will always be extremes of weather.


Hat tip: Roger Pielke, Jr.

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