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Posted at 11:50 AM ET, 08/07/2008

Freedman: Achenbach Off on Weather & Warming

On Sunday, the Washington Post ran an opinion piece on climate change by Joel Achenbach, a Post reporter and fellow washingtonpost.com blogger. While he made several good points about the perils of attributing individual extreme weather events to long-term climate change, Achenbach unfortunately left the mistaken impression that somehow climate and weather are two distinct realms. In fact, they are intricately related.

"Somewhere along the line, global warming became the explanation for everything," Achenbach wrote, lamenting that this has taken attention away from other more certain (in his view) environmental problems. This is not a novel criticism, by the way, since it's been aired by everyone from Danish economist Bjorn Lomborg on down to my barber. Achenbach decries the sensationalist media coverage that climate change often receives in the popular press.

Keep reading for more on the connection between weather events and climate change. For local weather, see our full forecast into early next week, SkinsCast for Saturday's preseason Redskins home opener, and our Virgin Mobile Festival forecast.

But while Achenbach criticizes other reporters for conclusively tying a single extreme weather event to global climate change, he instead commits the opposite error by making it seem like scientists cannot make any meaningful connections between trends in weather events and climate change in general. He underplays the links between extreme weather and climate change to such an extent that he may cause as much confusion among the public as when reporters hype up the issue.

"Seems to me that it's inherently impossible to prove a causal connection between climate and weather -- they're just two different things," Achenbach wrote. This point is accurate in the sense that the climate does not cause individual weather events, but it clouds the issue at hand.

Climate is the average of weather, which means that climate trends reflect weather trends. As the climate warms it increases the likelihood of certain weather events, such as bouts of extreme precipitation or temperature. According to the work of the U.N. Intergovernmental Panel on Climate Change and the U.S. Climate Change Science Program, journalists are on solid scientific ground when they bring up climate change in the context of extreme weather events.

But for Achenbach, the lack of conclusive causal connections between a single weather event and climate change means that journalists and activists should focus instead on other environmental concerns, and base their climate change worries on other aspects of the voluminous scientific literature on the subject.

"This caused that: It would be nice if climate and weather were that simple," he wrote [his emphasis]. Here Achenbach neglects to make an important point, which is that when the average of a dataset changes, that means some of the individual data points have shifted. Since climate is the average of weather, this means that climate change is also about weather change. And scientists have said that weather extremes may shift noticeably in response to warming from human emissions of greenhouse gases.

I've previously compared the role that greenhouse gases, such as carbon dioxide, play in day-to-day weather to the role that steroids may have played in boosting baseball slugger Barry Bonds' home run record. Steroids increase the odds of hitting home runs but don't cause an individual shot over the left field wall. Similarly, greenhouse gases can't be blamed for causing a particular extreme weather event, but over time they can compound the likelihood of more such events.

Achenbach would have done a greater service to the Post's readers had he gone on to explain what the relationship between climate change and weather extremes actually is, rather than what it isn't. Instead he missed the opportunity, and seemed content to state that climate doesn't cause weather and move on to other topics ranging from population growth to economics.

As a result, the piece didn't fully reflect the scientific understanding of where weather extremes fit into the long-term climate change picture.

Two prominent bloggers in the climate change arena also had strong, but very different, reactions to Achenbach's piece. Roger Pielke Jr. of the University of Colorado praised the story for its "nuanced" approach, while Joe Romm of Climate Progress came out swinging at Achenbach, calling his piece, "a typically uninformed journalistic 'backlash' piece, whereby a reporter creates a straw man and then sets it on fire."

In the end, perhaps Achenbach is doing something right if he is generating such strong reactions?

By  |  11:50 AM ET, 08/07/2008

Categories:  Climate Change, Climate Change

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