[Dr. Scott W. Tinker] Oil. It's so important that many feel we're too dependent on it. For 100 years, oil has made the world go 'round. Literally. Not only the cars, scooters, trucks, and buses that take us to work, school, and the store every day, but the global flow of commerce as well, bringing every product from where it's mined, made, or grown to where it's used, often a long journey powered by oil. The reason for this is that oil is a fantastic transportation fuel. It packs a huge amount of energy into a compact, lightweight liquid form. Easy to transport, easy to store, and easy to pump into a gas tank. And while it's mostly used for transport, it can also be used for heating, power production, and is an incredibly versatile chemical feedstock. Even today, it's still remarkably cheap, given the many social and economic benefits it provides. But there are other costs. The world's largest oil-consuming countries spend billions of dollars and huge political capital trying to stabilize oil regions each year. Then, there are environmental costs. Many small, and a few large, oil spills. Smog, local air pollution, and CO2 emissions come from the tailpipe. But the biggest challenge with oil is that it's virtually our only transport fuel. The vast majority of global transportation runs on it. This gives oil an excessive influence on the global economy. This can be good; low oil prices usually mean a booming economy. Or it can be bad. High oil prices are often followed by recession. And a shock to the global supply of oil, we've seen, can cripple the world economy. The solution, just like in a stock portfolio, is to diversify into other transportation fuels. As oil prices rise in the future, alternatives will become more competitive, and more will take hold in the market. Meantime, we need to hope that oil stays affordable long enough that we can make this transition smoothly. So oil is a miracle fuel that built the prosperity of the 20th century. Our success in the 21st will depend on expanding oil supply, increasing efficiency, and diversifying into other options. For more on oil and alternative fuels, see the film.