Scientists More Outspoken on Exteme Weather-Climate Links

Recent extreme weather events, from the Midwestern drought to Hurricane Sandy, have people paying attention to climate change. Post-Sandy polls have shown a spike in concern about the climate among Americans. Some scientists have been emboldened to connect these events directly to human-caused global warming.

One of them, NASA's James Hansen, who heads NASA's Goddard Institute for Space Studies in New York and is a climate science pioneer. He was in San Francisco this month to receive the Stephen Schneider award for climate communications. As it happened, he had just written an opinion column for The Guardian newspaper, which  drew some pretty straight lines from global warming to Sandy:

"The chances of getting a late October hurricane in New York without the help of global warming are extremely small. In that sense, you can blame Sandy on global warming."

Previously few scientists were willing to link any specific weather events to climate change. In a recent studio interview for KQED Science, I asked Hansen if that's changing.

Hansen: Well, yes, it's changing in the sense that the climate dice are now noticeably loaded. But in the case of Sandy, the waters in the Atlantic Ocean were a few degrees warmer than normal, so it kept that storm amped up. And, of course, the warmer atmosphere also holds more water vapor, so you get more rainfall and therefore you've got heavier floods. But, in addition, sea level has gone up a measurable amount over the last several decades, and that contributes too. The climate dice are now loaded, and they're becoming more loaded. And it's reaching a level that the public should notice -- that the frequency of extreme events is greater than it used to be.

CM: The public, I think is noticing. We've certainly noticed here in California. Just recently, we had one of these multi-day, multi-wave storms referred to as a "Pineapple Express." Are there climate change fingerprints on that type of event, too?

JH: Well, there is a fingerprint on extreme rainfall. So if you look at the record rainfalls -- the extreme events --  those are affected by global warming, because the atmosphere holds more water when it's warmer. And the relationship is quite a strong one. So storms -- thunderstorms, hurricanes, tornadoes -- those storms that are driven by a latent heat of water vapor are going to be stronger. The extreme ones are going to be stronger and that's simple physics. But, you can't blame any single event [on warming], so the analogy that was recently drawn of a baseball player on steroids -- that's a good example. He'll hit more home runs, but you can't say that particular home run was because he was on steroids. But you can clearly see there's an impact.

Hansen has also not minced words about California's newly-established cap-and-trade program. At the Commonwealth Club, he drew surprised laughs from the audience when he paused briefly, apparently searching for words, and then blurted out, "Because it's not -- it's half-assed."

Back in our studios, he explained why he thinks so.

JH: California is very useful in providing an example of how you can have a good economy, compared to the rest of the country, and still have low emissions and hopefully go still lower. But, frankly, Cap-and-Trade is not the way to do it. What you need is an honest, flat carbon fee across the board that covers coal, oil, and gas, is collected from the fossil fuel companies, and the money that's collected should be distributed to the public, so that the person who does better than average will actually get more in their dividend than they pay in increased prices. That way, the public would allow this price to go high enough to phase out fossil fuels. And that's what we have to do. But a cap-and-trade system--you have to go big. We tried that with the Kyoto protocol. Most countries just laughed. China and India just laughed at us when we asked them. They're not gonna put a cap-and-trade system on. But if we have this carbon fee, it can be made global.

CM: The oil and gas industry and others are still pushing back hard against even the market-based cap-and-trade system here in California. Of course a carbon fee--or tax--would be politically even more difficult to achieve. What do you think the chances of that would be?

JH: Well, I don't think it is politically more difficult if it's explained to the public. It should be salable--but of course there's no salesman for it. Politicians have not yet been willing to recognize that we can't burn all the fossil fuels. They're allowing, and even encouraging, fossil fuel companies to go after every fossil fuel they can find. Tar sands, tar shale, fracking, mountaintop removal. It's crazy because our children are going to have to figure out a way to suck that CO2 back out of the atmosphere, or they're going to get problems that will be monumental.

As Hansen and I were talking, negotiators from 194 countries were wrapping up UN climate talks in Quatar. They made scant progress toward an agreement to cut carbon emissions that, if finalized, wouldn't be in place until 2020. Meanwhile, 2012 will likely go down as America's warmest year on record, with worldwide carbon emissions reaching a record high.

Happy New Year.