No Se Nada had an interesting post last week claiming climate scientists are starting to worry that they’ve oversold climate change:

What I see is something that I am having a hard time labeling, but that I might call either a “hangover” or a “sophomore slump” or “buyers remorse.” None fit perfectly, but perhaps the combination does. I speak for (my interpretation) of the collective: {We tried for years – decades – to get them to listen to us about climate change. To do that we had to ramp up our rhetoric. We had to figure out ways to tone down our natural skepticism (we are scientists, after all) in order to put on a united face. We knew it would mean pushing the science harder than it should be. We knew it would mean allowing the boundary-pushers on the “it’s happening” side free reign while stifling the boundary-pushers on the other side. But knowing the science, we knew the stakes to humanity were high and that the opposition to the truth would be fierce, so we knew we had to dig in. But now they are listening. Now they do believe us. Now they say they’re ready to take action. And now we’re wondering if we didn’t create a monster. We’re wondering if they realize how uncertain our projections of future climate are. We wonder if we’ve oversold the science. We’re wondering what happened to our community, that individuals caveat even the most minor questionings of barely-proven climate change evidence, lest they be tagged as “skeptics.” We’re wondering if we’ve let our alarm at the problem trickle to the public sphere, missing all the caveats in translation that we have internalized. And we’re wondering if we’ve let some of our scientists take the science too far, promise too much knowledge, and promote more certainty in ourselves than is warranted.}

I was also at the AGU meeting, and here’s my take:

Some people do oversell climate change. Most of them are not scientists, but advocates in favor of polices to reduce greenhouse gas emissions (e.g., the Sierra Club, Greenpeace). Like all advocates, they use whatever arguments they think will win. To the extent overselling climate change helps them achieve their preferred policy goals, they do it freely and without regret.

They are balanced in the policy debate by advocates on the other side (e.g., CEI, Marshall Institute, Cato Institute), who distort facts in the other direction.

That’s political debate, folks. If you don’t like it, move to North Korea. The scientific community has no control over either group and should not be held responsible for them.

That said, there are perhaps a few dozen scientists (out of several thousand active climate scientists in the world) that could fairly be described as “selling” climate change to the general public. They are well-known to anyone who reads the paper: Jim Hansen, Michael Oppenheimer, Steve Schneider, et al. Some of their statements do, in my opinion, push the envelope of what the science can comfortably confirm. An example: Jim Hansen’s statement that we have 10 years to address climate change before we hit a tipping point.

But for every scientist or advocate that’s overselling, there’s one on the other side — a Bill Gray or Dick Lindzen or Pat Michaels. In my scientific opinion, the Grays and Lindzens misrepresent and distort the science far more egregiously than the Hansens and Oppenheimers.

For this reason, policymakers (and the general public) should never rely on individual scientists for their understanding of the state of scientific knowledge. Instead, they should instead turn to assessments.

Because assessments are written by literally hundreds of scientists, the biases of individual scientists tend to cancel out. As a result, they have shown themselves remarkably good reflections of the scientific consensus, and remarkably lacking in bias. For example, it is difficult to argue that the working group I report of the IPCC assessments has in any way oversold the science of climate change. The upper range of our climate predictions is indeed dire, but that, unfortunately, is what the data indicate — they have not been “sexed up” to push a preferred policy.

My view is that the statements of the scientific community (as represented by the IPCC assessments) are remarkably sound and not at all “oversold”. During the five days I was at the AGU, I did not encounter anyone who suggested otherwise — except for Dick Lindzen.