Back in the 1980s, when concern about a possible nuclear winter was at its height, the conservative columnist William Rusher jokingly referred to the tendency of catastrophists like the late Carl Sagan to talk "lip smackingly" about the end of the world. Those were the days when concerns sparked by a new U.S.-Soviet arms race were at their height, and scientists were warning that an all-out nuclear war would produce so much soot, the world would be plunged into a multi-year winter making life for the survivors virtually unsustainable. Sagan was among the leading scientists drawing attention to this dire scenario.
Given the satisfaction Rusher took from mocking those who liked to roll up every conceivable disaster into one irresistible package, he'd probably enjoy the report that is being posted today by the Proceedings of the National Academy of Sciences, "Massive Global Ozone Loss Predicted Following Regional Nuclear Conflict." The article postulates that a regional nuclear war involving India and Pakistan would kick so much soot up into the stratosphere, heating of ambient gases would accelerate the chemical reactions that break down ozone as high as 60 kilometers up. The result here on the surface of the earth: a thinning of ozone north and south of 20 degrees latitude--everywhere north of Mexico City, for example, or south of Rio--to levels characteristic of the Antarctic ozone hole that has caused such serious concern in recent decades.
Michael Mills, the atmospheric scientist at the University of Colorado, Boulder, who is lead author of the PNAS paper, says the ozone thinning would lead to much higher rates of skin cancer and cataracts, and have drastic effects on plant ecology during the five to eight years it persisted.
For those able to contemplate catastrophe scenarios with cool objectivity--without smacking their lips--a recent study estimating the chances of nuclear war will be of interest in this context. That risk analysis, described in the current issue of IEEE Spectrum, finds that the odds of nuclear war during the Cold War years might have been as high as 5 in 1000 per year. Similar odds might hold in situations like the India-Pakistan stand-off.