We’ll be seeing a lot of this nonsense over the next two days.
It was not a good year for people, weather and climate. The winter was strangely warm in many places and the summer ridiculously hot. As a large fraction of the country suffered through extreme or even extraordinary drought many folks naturally wondered, “Is this climate change?” Then along came a presidential election in which the words “climate change” disappeared from the dialogue. Now, just a week or so before voting day, the convergence of westbound Hurricane Sandy with a eastbound cold front is creating a massive storm, a Frankenstorm even, that is threatening millions of Americans. Weird weather is making yet another appearance in our lives and once again we ask, “Is this climate change?”
The hyper-charged political landscape we are crossing now creates its own sparks when trying to answer that question. In a world looking for “wake-up calls” and “smoking guns,” how do scientists address the thorny issue of attribution? Did anthropogenic climate change cause the storm that rained out your picnic yesterday? Is it causing the terrifying storm crawling up the East Coast now? There are deep, powerful and potent issues here that touch on both science and the relationship between science and politics.
Let’s start with the science.
For years, most climate scientists would say it’s impossible to link an individual weather event with climate change. That, in fact, is the difference between weather and climate. Climate is all about long-term trends — not the 5-day forecast.
Recently, however, some researchers have taken the issue of attribution seriously. Using a variety of techniques, they are attempting to quantify the role human-driven climate change plays in particular events. This is science at the bleeding edge, where framing their questions correctly so that they might lead to meaningful answers is still a hot issue.
Researchers like Randall Dole of NOAA, for example, might ask what percentage of an extreme event’s magnitude came from a changing climate. Peter Stott of the UK Met Office frames the question differently. He looks at the odds for a given extreme weather event to occur given human-driven climate change. Kevin Trenberth of NCAR takes a third view, asking: Given a changed background climate, how should we expect weather to change?