John Rockhold's Public Library

So professionally I’m a pig when it comes to carbon.

To me the most compelling evidence is the fact that the stratosphere—the upper atmosphere—is cooling while the lower atmosphere and the land surface are warming. That’s a sign that greenhouse gases are trapping energy and keeping that energy close to the surface of the earth. I mentioned that in ocean acidification, you actually see animals that should make shells unable to make shells anymore. You could demonstrate the same kind of effect in a bell jar in the lab. There is a level of certainty about it.

First, with regard to your due diligence as a publisher, why hasn’t DISCOVER published a compelling account of the other side? Because there isn’t any. That’s a pretty good reason. There are a lot of things in that speculative and competing explanations category, but there is no preponderance, and that is what is compelling to me. For example, take the evidence that Robin cited. If you were a cynic and you asked about the probability of the ice sheet in the north going up, it’s 50 percent. Going down? Fifty percent. And the South Pole going up? Fifty percent. Going down? Fifty percent. Probability they are both going together? Twenty-five percent. What’s the probability of the stratosphere cooling while the earth gets warmer? Again, assuming we knew nothing, 50 percent. Troposphere warming? Fifty. The probability that one will go up while the other goes down? Twenty-five percent. Same thing for other patterns, like the way high-latitude continents are warming more than low-latitude ones are. With any single line of evidence, you can say, “Oh, well, there’s still a 25 percent chance it’s random,” but what happens when you put all these events together? The probability of all these events’ lining up the same way is pretty darn low unless we are dealing with global warming.

We’re highly incentivized to show that all our colleagues are wrong. If we could come up with good evidence that they’re wrong, we would be out there publishing it. The evidence just doesn’t exist.

We will have to raise the food supply another two times to feed all of the people that we think will be alive by the latter third of the 21st century.

Climate change is such a huge issue that people tend to feel paralyzed by it. Stephen, you’ve framed it in a helpful way as a problem of risk management. What does that mean?