Climate scientists - and Stephen Schneider of Stanford - spoke about avoidable and unavoidable climate impacts. Schneider said we have to get on with the job.
Geoengineering is intentionally altering Earth's climate. But creating a means to cool down the climate - even temporarily - is fraught with potential for unintended consequences.
Oceanographer Eddie Bernard said progress has been made in understanding tsunamis since the one that struck southeast Asia in 2004. But, he said, the science of predicting earthquakes is still unreliable.
Limiting carbon emissions might lead to economic opportunities, said Carnesale of U.S. National Academy of Sciences committee on America's Climate Choices.
Kathleen Tierney of the Natural Hazards Center at the University of Colorado talks about what you can do to be prepared if you live in an earthquake-prone area.
Baker said a slowdown of ocean circulation, caused by global warming, could mean less heat brought by the oceans to Earth's high latitudes. And that means, in a warming world, Europe could get cold.