And Alexandra McPherson of Greenpeace intone that America's energy needs in the 21st century can certainly be met by a few good windmill farms and solar-energy tracts. People like warmer climates. And sure, the program's admirable objectivity sometimes wavers. You'll see how scientists tease out ancient climate records from ice cores, tree rings, coral growth patterns, lake sediments and even monastic records. You'll find out why it's so hard to predict the effects of perplexing feedback systems.
Low clouds shade the planet and cool it.
High clouds trap heat and warm it. Watch that air space. Some effects appear contradictory. For example, burning fossil fuels puts plenty of carbon dioxide into the air. But it also generates a lot of sulfate aerosols that make clouds shinier and reflect more incoming sunlight back into space before it can hit the Earth.