Scientist Tim Flannery explains the science of climate change for not only lay people but also policy makers, who, he hopes, will act to alleviate the problem. Flannery looks at climate changes over the last century and projects what the next century will bring--unless things change, and he is convincing when he tells us that weather is not a given, but is often the result of the actions of mankind. He goes on to explain and evaluate options such as solar, geothermal, and wind power sources, and urges actions that individuals and communities can take.