We rarely have the luxury of being able to act on certainties; you’d be a fool if, credibly informed that unless you had an operation to repair an aneurysm you had a 99 percent chance of dying within a week, you responded that you only act when you’re certain.
Judge Richard Posner sits in for Larry Lessig this week and takes on a few lightweight issues, like global warming. It’s interesting to me how he frames the discussion in terms of what we don’t know, our (sciences’s) uncertainty, and how people reply with such certainty.
As I mentioned in a previous posting, the global climate equilibrium is fragile. In a period (known as the “Younger Dryas”) of only about a decade some 11,000 or 12,000 years ago, the earth’s temperature rose by 14 degrees Fahrenheit. The climate was very cold (it was the end of the last ice age) when the surge started, so no harm to human beings was done (rather the contrary); but imagine a similar surge today. Suppose the ice sheets that cover Greenland and Antarctica melted, raising ocean levels to the point at which most coastal regions, including many of the world’s largest cities, would be inundated. Or if the dilution of salt in the North Atlantic as a result of the melting of the north polar ice cap, the ice of which is largely salt free, diverted the Gulf Stream away from the continent of Europe. The dense salty water of the North Atlantic blocks the Atlantic currents from carrying warm water from the South Atlantic due north to the Arctic, instead deflecting the warm water east to Europe. That warm-water current is the Gulf Stream. If reduced salinity in the North Atlantic allowed the Gulf Stream to return to its natural northward path, the climate of the entire European continent would become like that of Siberia, and Europe’s agriculture would be destroyed.
Far-fetched? Perhaps. But what if it happened? What expanded market position or new product introduction is worth the destruction of a continent? Even if we differ on the certainty or even likelihood, what if the remote possibility comes to pass? This has one of my long-held arguments with nuclear power. The cancer and other health risks of coal or other fossil-fuel as poser sources might exceed that of nuclear power, if all goes well. But the worst-case scenario is far worse for nuclear power. If coal or gas-fired plant blows up, nothing prevents a new plant being built on the same spot as soon as the rubble is cleared. For an instructive example of what could happen with a nuclear plant, Chernobyl is still around and will be for thousands of years. (50,000 deaths have been attributed to this one accident: understanding that these accidents are caused by human error, either in design or failures of process and procedure, means we would see more of them, especially in privatized power plants.)