clear over time or at least less black and white. >> the other thing you learn is certain questions about global warming that remain deeply uncertain and happen to be the ones that matter most to people. how hot is it going to be, the range has not changed since 1979, before i wrote my story, the range of warming from a doubling of c02 in the atmosphere has been about the same. >> projected rain. >> known unknowable. don't assume that five more years of science -- >> yeah. >> too complicated. it's about cloud particles and things that are beyond understanding and looks like they are beyond -- kind of like there's a chapter on weather forecasting, a forecast beyond 14 days is basically impossible. new-- numerically impossible. conrad lauren -- no, ed lawrence at mit, '62.