Study finds global warming likely to be on hotter side of projections

Nov 18, 2012

The death and devastation caused by Hurricane Sandy and the Nor’easter that followed it, has brought the issue of climate change to the forefront. According to a new study published in the journal Science, we can expect global warming to be on the high side of current projections.

In the coming century will New York warm up by three degrees Fahrenheit and have a climate more like Richmond, Virginia? Or will it rise eight degrees and become like the state capital of Georgia, a city nicknamed “Hotlanta?”

That’s the range currently represented by more than two dozen different climate models, but new research shows the higher, hotter predictions are more likely to be accurate.

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 should expect that large changes will occur in the future and it’s a very qualitative description to say that New York will be more like Atlanta, Georgia. But certainly New York will warm up, as will cities throughout the world," Fasullo said. "We really just wanted to ask the naïve question, ‘Which model best reproduced what we saw in the satellite observations?'"

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 a lot of variation between climate models. He says, “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.”
 
He looked at the atmospheric dry zones in the subtropics, and found that most climate models fail to account for this dryness.

“You can kind of think of these dry zones as an iris of the climate system,” he said. “As the system warms up, the iris dilates and lets more sunlight into the system.”

And more warming can lead to more powerful storms, which draw on energy from warmer ocean temperatures.

Kevin Trenberth co-authored the study. He’s also a scientist at the National Center for Atmospheric Research.  He says, “the odds of this sort of thing happening, the odds of a strong storm are increasing.”

Hurricanes like Sandy occur naturally, but Trenberth says between 5 to 10 percent of their power can be attributed to manmade global warming.

“You know when you’re having storm surges that are flooding the subway system, 10 percent effect might be enough that if you didn’t have it, it wouldn’t have flooded,” he adds.

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 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 in 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,” Cuomo said.  

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 will be decades before the effects will 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.

For more on this and other stories, visit www.innovationtrail.org

The Innovation Trail is a collaboration between five upstate New York public media outlets. The initiative, funded by the Corporation for Public Broadcasting (CPB), helps the public gain a better understanding of the connection between technological breakthroughs and the revitalization of the upstate New York economy.