Trenberth: Hey, remember 1988, when James Hansen blamed CO2 for the drought and I said that was wrong?

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

And while these days he's a staunch advocate for the scientific consensus, his first foray into climate science was a cut across the grain. There was a devastating drought in 1988, which attracted the attention of one of the most renowned climate scientists.

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

Instead, he says the drought had to do with what at the time was an unappreciated part of the climate system: the El Nino warming phenomenon in the Pacific Ocean.
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Consider Hurricane Sandy. Trenberth figures the storm was maybe 5 or 10 percent more powerful as a result of global warming. And sea level is 8 inches higher than it was a century ago. That doesn't seem that dramatic, but he argues that made a huge and costly difference.

"I reckon that without climate change, we would not have exceeded thresholds that caused the flooding of the subways in Manhattan and the tunnels from Manhattan to New Jersey and to Brooklyn."
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"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."