For the people who eke out an existence in Africa's semiarid Sahel region south of the Sahara, a shift in climate is nothing short of disastrous. What makes the Sahel so unstable, and why is it shifting?
Though not everyone agrees why the Earth is getting warmer, temperatures are inching up worldwide. A couple of degrees doesn't seem like such a big deal. What difference can a subtle change make? See more »
Some scientists think that the ocean is a potentially enormous storage ground for carbon dioxide. Could thousands of aquatic tubes help sequester carbon, or is it all just a pipe dream? See more »
Our big cars and big appetites are taking a big toll on the environment. Overconsumption contributes to the depletion of Earth's resources, and some countries are taking more than their share. See more »
We humans like to trade one problem for another. We give up drinking only to take up smoking. Will we also exchange a reliance on dwindling fossil fuels for a food shortage caused by ethanol production? See more »