No one can say with any assurance what the dollar value of damages would be from the highly uncertain climate changes that might accompany a planet earth that is steadily warming.

Paul Solman: Are headlines trumpeting the fact that carbon dioxide levels in the earth’s atmosphere have now passed 400 parts per million for the first time in something like three million years unduly alarmist? Or are they a timely warning?

I asked noted environmental economist Martin Weitzman to address the question.

An expert on the Soviet economy in the ’70s and ’80s, Weitzman first made news in 1984 with the publication of a book called The Share Economy, an argument for profit sharing instead of fixed wages. Fourteen years later came his paper Recombinant Growth, which revolutionized how some of us understood the enormous potential of technology.

But for many years, Weitzman has also been working on environmental economics and most recently, in a series of widely cited academic papers, on the economics of global warming; the most famous, on the “Economics of Catastrophic Climate Change.”

Weitzman’s central idea is not unlike the legendary bet proposed by the 16th century Catholic French philosopher Blaise Pascal. One way to interpret Pascal’s argument: even if you think the likelihood of God’s existence is vanishingly small, the cost if you’re wrong — eternal damnation — is infinitely high. An infinite cost times even a tiny probability is still … an infinite cost.

So you make a finite investment by believing in God and acting accordingly in order to avoid an infinite cost. To put it another way, you’re obliged, mathematically, to make the investment in belief.

You might keep Pascal’s argument in mind while reading Weitzman. Or think of the “Black Swan” argument of Nassim Taleb: certain events, however unlikely you think they may be, could have such enormous