[Dr. Scott W. Tinker] All energy has environmental impacts, from air to water to solid waste to land use and beyond. The key is managing these effectively and affordably into the future. The most discussed and debated environmental effect today is CO2 emissions. All fossil fuels, when burned, produce them. Nearly half of our CO2 emissions come from coal. More than a third comes from oil. Some countries are talking about reducing CO2 emissions. How much, and what effect that will have on the atmosphere, warming, and energy production is yet to be seen. There are other emissions we agree on more completely. Sulfur dioxide causes acid rain. Nitrogen oxides erode the ozone layer. Both of these, mostly from coal and oil, we control to some degree. But as a global society, we don't do a very good job of managing gaseous wastes, a big area for improvement. We're better with solid and liquid wastes. Most coal ash is captured. Large oil spills are rare. We've done a good job to date of keeping nuclear waste out of the environment, but we can improve here, too. Water use is becoming an increasingly big issue. In unconventional oil and gas production, for cooling power plants, even concentrating solar plants use a lot of water. While energy uses a small fraction compared to agriculture and industry, we'll likely see greater tension over water in the future. Good reason to work now to minimize quantities and improve recycling. Finally, there's land use. Renewable energies, wind, solar, hydro, biofuels, cover much larger areas than more concentrated energies, like nuclear and fossil fuels. How much land we're willing to use for energy in the future will likely depend on where the land is and what energy it's used for. In general, though, we've been reducing the environmental impacts of energy, but at a price. It's usually more expensive to make energy less impactful, and the cost gets passed along to consumers. As energy prices continue to rise, the key to a successful energy future is minimizing environmental impacts while keeping energy affordable, and using the prosperity that affordable energy brings to continue to invest in the environment.