The American science enterprise may be facing its most significant challenges in a generation, with a new Congress possibly moving to cut research spending and open investigations into the federal stimulus program and the science of climate change, speakers said in a series of presentations at AAAS.

With nations incapable so far of taking drastic steps to cut emissions of heat-trapping greenhouse gases, many scientists and policy specialists have started talking more openly about geoengineering, the deliberate manipulation of the environment to reverse the effects of climate change.

For them, geoengineering may be “a bad idea whose time has come,” said Eli Kintisch, a reporter for Science, at a AAAS forum on the topic.