The United States contains less than 5 percent of the world's population of 6.1 billion, but it consumes roughly 25 percent of the world's fossil fuel resources. Each American uses five times more energy than the average person in the world. In underdeveloped nations, individuals use 0 to 10 percent of the energy used by the average person in the world. As these areas become more developed, however, their inhabitants will require a larger share of the world's energy resources.

There is plenty of energy to go around, isn't there? Unfortunately, the answer is a definitive "No." The vast majority of the world's energy comes from burning fossil fuels. Fossil fuels are limited, nonrenewable resources, formed from the remains of ancient plants and animals that have undergone chemical reactions over the course of millions of years. Since fossil fuels are being consumed faster than they are produced, they are destined to run out.

As underdeveloped nations become industrialized and the global population continues to grow, the world's energy demands will continue to increase. Some energy experts estimate that the world will run out of oil and natural gas within the next forty years or so. Coal will remain available for up to a thousand years, but coal isn't the best solution. It is the "dirtiest" of the fossil fuels, producing significant pollution during mining and combustion.

Another issue is that fossil fuel consumption has been implicated in global warming. When carbon-rich fossil fuels are burned to release their energy, they also release carbon dioxide gas (CO₂). For each pound of carbon burned, almost four pounds of CO₂ gas enter the atmosphere. Carbon dioxide contributes to the greenhouse effect, which has been identified as a cause of global warming. Although scientists cannot predict all the effects of global warming or how severe they will be, they are fairly certain that ecosystems, human health, agriculture, climate, and sea level will all be negatively affected.