Massive energy consumption is having a negative impact on the planet. For example, in the summer of 2006, western Europe experienced some of the hottest weather on record. Moreover, this temperature increase is not an isolated occurrence. In fact, almost every credible scientist today believes that the earth is experiencing climate change due to the emissions of greenhouse gases from cars and coal-burning power plants. Ninety per cent of the energy used in the US comes from fossil fuels, oil, coal, and natural gas (Borowitz 43), but problems arise from other sources, too (e.g., nuclear power plants leave radioactive by-products, making storage difficult). Unfortunately, dams are not much better, as nearby populations must be relocated, and the surrounding habitat is destroyed.