In the coming century will New York warm up by three degrees Fahrenheit and have a climate like Richmond, Virginia?
Or will it warm by eight degrees and become more like the state capital of Georgia, a city with the nickname “Hotlanta”?
That’s the range currently represented by more than two dozen different climate models, but a new study published today in the journal Science shows the higher, hotter predictions are more likely to be accurate.
Bad weather
John Fasullo is a scientist at the National Center for Atmospheric Research (NCAR). He’s the lead author on the study, which analyzed the differences between 16 climate models.
“We really just wanted to ask the naïve question, ‘Which model best reproduced what we saw in the satellite observations?’” he says.
Fasullo was trying to work around the problem of clouds. They are key atmospheric indicators, but they can be tricky to observe with precision, and that can lead to variation between climate models.
“An easier way to approach the problem was to look at the environment in which clouds exist and ask the question, ‘Which models give the best representation of that environment?’” says Fasullo.
He looked at the atmospheric dry zones in the subtropics, and found that most climate models fail to account for this dryness.
The models that do tend to show the most warming in the future.
“You can kind of think of these dry zones as an iris of the climate system. As the system warms up, the iris dilates and lets more sunlight into the system,” he says.
More warming can lead to more powerful storms, which draw on energy from warmer ocean temperatures.
Kevin Trenberth is a senior scientist at NCAR and he co-authored the study.
“The odds of a strong storm are increasing,” he says.
Hurricanes like Sandy occur naturally, but Trenberth says between five to 10 percent of their power can be attributed to manmade global warming.
“When you’re having storm surges that are flooding the subway system, a 10 percent effect might be enough that if you didn’t have it, it wouldn’t have flooded.”
Changing political climate?
For years, these scientific warnings have come up against public skepticism and political apathy.
But that may be starting to change. In the aftermath of Hurricane Sandy, New York City Mayor Michael Bloomberg, an independent, gave a surprise endorsement to President Obama just before the election, praising his leadership on climate change.
Governor Andrew Cuomo also brought up the issue as he toured the devastation in the beachfront community of Breezy Point, Queens.
“I think there is climate change. I think that is a reality. I think if we don’t acknowledge it, then it’s just avoidance on our part,” says Cuomo.
Although the topic was noticeably absent from the presidential campaign, President Obama briefly mentioned it during his re-election acceptance speech early Wednesday morning: “We want our children to live in an America that isn’t burdened by debt, that isn’t weakened by inequality, that isn’t threatened by the destructive power of a warming planet.”
But Trenberth says he’s still worried that climate change isn’t high enough on the list of political priorities.
Carbon dioxide is retained for a long time in the atmosphere, so even if emissions were cut drastically today, it would be decades before the effects would be felt.
“By the time everyone recognizes that climate change is a major problem, it’s far far too late to do anything about it,” he says.
