Abstract

To fit the magnificence of this setting in Beijing’s Great Hall of the People, and the honor of giving the 2007 Sir John Crawford Memorial Lecture, it is well to have a subject of suitable proportions. I have chosen one of global size and urgent time frame: our climate crisis. We only have one future and one global climate–and now it looks as if we only have one chance to rescue our civilization from collapse and prevent a mass extinction of species during the 21st century. Unless you have been keeping up with climate science for the past twenty-five years, you likely do not know how serious the matter has become. The notion that we might slowly get into serious trouble by mid-century has been conveyed by the media and understood by at least some political leaders. But that scenario depends on somehow avoiding sudden shifts in climate in the meantime, instant setbacks at a time when we lack maneuvering room. An abrupt shift in drought area occurred in 1983 and we had a near-miss of a mass extinction of Amazon species in 1999. It is easy to appreciate that one more degree of global warming will seriously reduce crop yields in the tropics, but in the words of climate scientist Claudia Tebaldi 1, “It’s the extremes, not the averages, that cause the most damage to..