Climate modeling is the inverse of weather prediction. The further away from the present a weather event is going to occur, the harder it usually is for meterologists to predict—as anyone who has ever tried to rely on a 10-day extended forecast should know. But in climate change, modelers can have meaningful confidence in how increased concentrations of greenhouse gases in the atmosphere will warm the planet and change the climate. What they can’t do—not yet—is look at a recent event and figure out precisely what role artificial climate change might have played. So we know that heat waves will become more common in a warmer planet—but it’s hard to say whether a recent heat wave was actually due to climate change, or rather to the sort of natural weather variations that led to oppressively hot days well before human beings began digging up and burning all the dead dinosaurs in the Earth.
Case in point, as it turns out: the brutal 2010 Russian heat wave. The unusual and lasting heat killed nearly 11,000 people in Moscow alone and led to devastating wildfires throughout much of Siberia. More than a third of the country’s grain harvest was lost—a disaster that has helped feed record global food prices. Temperatures in the upper 90s to above 100 F hit western Russia for more than a month, and in Moscow the daily average temperatures for July was 87 F—20 F higher than the norm. For many environmentalists—and for Russians especially—the heat waves were visceral evidence that climate change was real and that it was already having an effect on the planet. As my Ecocentric colleague Eben Harrell wrote last August:
But even if it’s impossible to say whether current heatwaves would have occurred without climate change, there’s nothing like feeling extreme heat in the bones to change people’s minds about whether climate change will pose a serious threat in the future. As TIME reported earlier this month, even Russian president Dmitri Medvedev was inspired to finally make bold public statements about the need to tackle the causes of global warming.
A new study by government scientists at the National Oceanic and Atmospheric Administration (NOAA), however, concluded that the heat wave was chiefly driven by natural weather variation, as opposed to greenhouse gases. From NOAA:
The team — led by Dole, Hoerling, and Judith Perlwitz from the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder — sifted through long-term observations and results from 22 global climate models, looking for trends that might help explain the extraordinarily high temperatures in western Russia during the 2010 summer. They also ran atmospheric models that used observed global sea surface temperatures, Arctic sea ice conditions and atmospheric carbon dioxide concentrations in 2010 to assess whether such factors might have contributed to the heat wave.
How unusual was that Russian heat wave? Look at a map of temperature anomalies from last July:
That bright red angry territory over much of Russia really stands out. But according to the NOAA researchers, it was essentially a fluke, caused by stalled air:
The heat wave was due primarily to a natural phenomenon called an atmospheric “blocking pattern”, in which a strong high pressure system developed and remained stationary over western Russian, keeping summer storms and cool air from sweeping through the region and leading to the extreme hot and dry conditions. While the blocking pattern associated with the 2010 event was unusually intense and persistent, its major features were similar to atmospheric patterns associated with prior extreme heat wave events in the region since 1880, the researchers found.
As Randall Dole, deputy director of research at NOAA and a lead author of the paper, said in a briefing today:
To be sure, it was a rare event. But rare events happen and rarity alone doesn’t imply cause.
So does this mean humanity is off the hook, that we don’t need to worry about cutting carbon or adapting to warming? Far from it. As the study pointed out, the Russian heat wave may not have been chiefly caused by climate change, but it is a harbinger of what we can expect if we don’t reduce carbon emissions soon. Attempting to attribute individual weather attempts to climate change makes for fascinating science, but it’s much less important than understanding the totality of what living through a warmer world will be like. (And if there are any scientists or environmentalists out there who still believe that perfectly attributing a flood or a heat wave to climate change will finally break through skeptics, well, forget it.)
With or without climate change, disasters will happen—and because there will be climate change, they’re likely to be worse. There’s a role for cutting carbon, but the more immediate need is adaptation—both through development and through smarter governance. We need to close the disaster gap that seems to be widening between rich and poor countries. Yes, the Russian heat wave was unprecedented—but there’s no reason that a modern, developed city like Moscow should lost 11,000 people to heat. Not that such human wreckage can occur only in Russia—Chicago shamefully lost more than 700 residents during the great heat wave of 1995. It’s going to be hard to attribute extreme weather events of the future to carbon and other greenhouse gases—but when people die needlessly, we’ll have no trouble attributing it to lack of preparation. We’ve certainly had enough warning.
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