Environmental scientist David Keith proposes a cheap, effective, shocking means to address climate change: 
What if we injected a huge cloud of ash into the atmosphere to deflect sunlight and heat?

David Keith studies our climate, and the many ideas we've come up with to fix it. A wildly original thinker, he challenges us to look at climate solutions that may seem daring, sometimes even shocking.

Daniel Kammen, Director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley explains why renewable energy may take less time to see widespread incorporation than its critics have argued.

Also, watch the interview with Daniel Nocera, posted by MIT Tech TV.
MIT Tech TV is the video-sharing site for the MIT community. It supports community through the aggregation and distribution of science, engineering, and MIT-related video on the web.

The video interview describes how MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.