red-hot dice

August 6, 2012


James Hansen says droughts we have been experiencing can be linked to climate change.//photo by Tomas Castelazo/Wikimedia

Nothing like searing heat outside to focus the mind on a changing climate. Or warnings from NASA’s James E. Hansen, whose latest analysis indicates that climate change is already producing extreme weather.

In an op-ed in the Washington Post today, he discusses his and his colleagues’ analysis of the last six decades of global temperatures. Hansen, who first warned in 1988 about global warming brought on by the burning of fossil fuels, writes, “My projections about increasing global temperature have been proved true. But I failed to fully explore how quickly that average rise would drive an increase in extreme weather.” This latest analysis, to be published tomorrow in the Proceedings of the National Academy of Sciences, “shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change. To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.”

Again, as he did in 1988, Hansen uses dice to show our predicament. Fifty years ago, weather was variable but more predictable. Two sides of the die were colored white, or normal; two sides were blue, or cooler than normal; and two sides were red, or warmer than normal. “Rolling the die again and again, or season after season, you would get an equal variation of weather over time.”  Now, the dice are loaded, he said, with four sides colored red, or warmer than usual.

He says the heat waves in 2003 in Europe and 2010 in Russia, and the droughts last year in Texas and Oklahoma, “can each be attributed to climate change.” This hot summer “likely” will be as well. “These weather events are not simply an example of what climate change could bring — they are caused by climate change. The odds that natural variability created these extremes are minuscule, vanishingly small. To count on those odds would be like quitting your job and playing the lottery every morning to pay the bills,” he said.

Using bell curve graphs and big dice, Hansen also explains the analysis — and the implications — in an interview yesterday on PBS’ “NewsHour.” “What I didn’t think about at the time in the 1980s was that as we push the climate toward … these higher temperatures, the extremes, the highest temperatures, will be very extreme.” The temperature increase in the last few decades, he said, is enough to “change the frequency of these extreme events by a large amount” and has “now driven our climate outside the range that’s existed the last 10,000 years,” the time when human civilization developed. “It’s the large anomalies that have the practical impact,” such as in droughts, wildfires and heat waves.

According to the Guardian, scientists from the UN Intergovernmental Panel on Climate Change (IPCC) carried the same message when testifying Wednesday before the Senate Environment and Public Works Committee.

“It is critical to understand that the link between climate change and the kinds of extremes that lead to disaster is clear,” said climate scientist Dr. Christopher Field, a lead author of the IPCC report.

Dr. James McCarthy, professor at Harvard University and author of several IPCC climate studies, also said that as greenhouse gases continue to rise, natural events like El Niño cycles “will wreak even more havoc as they break old records for warm and wet conditions across much of the globe, because they will be occurring upon a higher baseline of warming.” The Washington Post and New York Times didn’t cover the hearing. The Baltimore Sun covered the hearing, with a focus on how Maryland must adapt to climate change.  (Reminder: Comments on the state’s draft Greenhouse Gas Emissions Reduction Plan are due Aug. 17 email: )

According to the Guardian, the hearing devolved into an exchange about whether global warming was a hoax — with Republican Sens. James Inhofe (Okla.) and Jeff Sessions (Ala.) on the hoax side, and Sens. Barbara Boxer (D-Calif.) and Bernie Sanders (I-Vt.) on the other. Sanders responded with a 40-minute speech to the Senate the next day, in which he urged Inhofe to reconsider his position.

“There is much more to be said [about global warming] because here on the floor of the Senate we are saying virtually nothing. …We look pretty dumb to the rest of the world by ignoring what many scientists believe is the major environmental crisis of our time, which, if we don’t get a handle on, will have profound impacts on the well-being of this country and countries throughout this world.”

elisabeth hoffman


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