A. Like many people, I used to think the scientific community was divided about climate change. Then in 2004, as part of a book I was doing on oceanography, I did a search of 1,000 articles published in peer-reviewed scientific literature in the previous 10 years.

I asked how many showed evidence that disagreed with the statement made in the Intergovernmental Panel on Climate Change’s report: “Most of the observed warming over the past 50 years is likely to have been due to the increase in greenhouse gas concentrations.” I found that none did. Zero.

That was astonishing, because if someone like myself had believed that the science was unsettled, what did the ordinary citizen think? I published my finding in Science. The article was called “The Scientific Consensus on Climate Change.”

It ignited a firestorm. I started getting hate mail. Letters arrived at my university demanding I be fired. At the same time, Al Gore talked about my paper in “An Inconvenient Truth.” Suddenly, I was a hero to the left because of Al Gore and a demon to the right because I was now part of the conspiracy to bring down capitalism. I thought I’d entered a parallel universe

WHAT ACTUALLY WAS HAPPENING?

I didn’t know it, but when I’d used the word “consensus,” I’d hit a land mine. For those who claim that climate change is a myth, the term “consensus” will — boom! — trigger a backlash. That’s because their strategy is based on spreading the idea that the science is still unsettled. Why? Because if you don’t know for sure there’s a problem, you can’t justify doing anything about it.