The 'Consensus' View: Kevin Trenberth's Take On Climate Change


hide captionKevin Trenberth is a distinguished senior scientist at the National Center for Atmospheric Research.

Rich Crowder/Corbis



In some ways Kevin Trenberth personifies that consensus. He's been part of the IPCC since its early days in the 1990s and is outspoken in defense of the science.

And it turns out that his own research bears directly on one of today's major talking points by climate skeptics. His studies, at the National Center for Atmospheric Research in Boulder, Colo., seek to explain why the global air temperature hasn't increased over the past 15 years.

Trenberth is the most prominent denizen of the research center — its distinguished senior scientist. You'd never guess he's 68 years old, either by his spry appearance or his scientific productivity.


"Jim Hansen famously went before Congress and declared that the drought was due to global warming, essentially," Trenberth says. "And I wrote a paper along with two others that appeared in Science magazine which basically said that it wasn't."


Understanding Global Temperature Changes



So will the oceans come to our rescue?

"That's a good question, and the answer is maybe partly yes, but maybe partly no," he says.



"They probably can't go on much for much longer than maybe 20 years, and what happens at the end of these hiatus periods, is suddenly there's a big jump [in temperature] up to a whole new level and you never go back to that previous level again," he says.


"When the natural variability or when the weather is going in the same direction as global warming, suddenly we're breaking records, we're going outside of the bounds of previous experience, and that is when the real damage occurs," Trenberth says.




And a few years ago, Trenberth was lamenting to his colleagues in an email that the Earth observing system still didn't give them all the data they needed to fully explain the ups and downs of global temperatures.

"I said it was a travesty that we couldn't account for, essentially, the global warming in some sense," Trenberth says.


"That email was taken completely out of context and misused in many respects," Trenberth says.

An Expanding Role For Scientists

Trenberth readily acknowledges that there are still some gaps in understanding the Earth's overall heat balance. But that doesn't undercut the basic observation that carbon dioxide and other gases from human activity are driving up the Earth's temperature in the long run.

Indeed, the last decade was the warmest on record, even though temperatures didn't keep climbing during that period. The 1990s were warmer than the 1980s. And the 1980s were warmer than the 1970s.




"If you play the right kind of role, then other countries will follow," he says.

You could argue that's simply wishful thinking, or you could argue that China and India would be even less likely to address climate change if the United States wasn't even going to try.


"Some of the human-induced changes are occurring 100 times faster than they occur in nature," Trenberth says. "And this is one of the things that worries me more than climate change itself. It's actually the rate of change that's most worrying."





Support comes from: