By Bruce Alberts

SAN FRANCISCO – Science provides an invaluable source of guidance to individuals and governments. This is true, in part, because scientists can often predict the future consequences of current actions.

For example, we know that someone who smokes two packs of cigarettes a day is likely to have a serious problem with cancer some 40 years later. And science predicts that, unless we severely constrain consumption of oil and coal around the world, the climate will continue to warm, increasing ocean volume and melting huge amounts of ice in the Arctic and Antarctic – thereby causing disastrous rises in sea level. …..