Scientists Sound Alarm on Climate

Early in his career, a scientist named Mario J. Molina was pulled into seemingly obscure research about strange chemicals being spewed into the atmosphere. Within a year, he had helped discover a global environmental emergency, work that would ultimately win a Nobel Prize.

Now, at 70, Dr. Molina is trying to awaken the public to an even bigger risk. He spearheaded a committee of the American Association for the Advancement of Science, the world’s largest general scientific society, which released a stark report Tuesday on global warming.

The report warns that the effects of human emissions of heat-trapping gases are already being felt, that the ultimate consequences could be dire, and that the window to do something about it is closing.

(Read More in the New York Times)