Let's do a little math to see why. The Energy Information Administration, an arm of the U.S. government, forecast last year that, all things being equal, world energy consumption would increase 50 percent by 2030. That's a good round number, summing up the desire of people across the world for refrigerators, televisions, ice cubes, hamburgers, motorbikes, and maybe even a little air-conditioning in the tropics.
But it's not at all clear where that energy can come from, because we happen to be alive at the moment when the oil is starting to run out. In November 2008 the International Energy Agency estimated that production from the world's mature oil fields was declining 6.7 percent a year, a rate that is expected to get even worse over time. Offsetting this decline will require finding a new Kuwait's worth of output every year, or somehow squeezing that much more from existing fields. Many observers think we've already passed the peak of oil production. An optimist in this world is someone who thinks it might still be a matter of years. But there's little question where the future lies, which is why the cost of a barrel of oil spiked to $147 last year. It took the prospect of a Great Recession to bring it back down to $40. Curbing high gas prices with recurrent economic slumps is probably not the smartest of remedies.
What are the options? There are the other fossil fuels. But natural gas will last us only so long. The obvious substitute is coal, of which we have quite a bit—except that coal brings us squarely to the other horn of this dilemma. It's the dirtiest of our fuels: Burn it and you automatically release lots and lots of carbon dioxide into the atmosphere, and that carbon dioxide is the culprit behind global warming. Which, like peak oil, is happening rather faster than we might like.
In the summer of 2007, for instance, the Arctic melted. By the end of the summer, there was 22 percent less sea ice than ever observed before. A comparable melt the following summer briefly opened the Northwest and Northeast Passages simultaneously, very likely offering human beings their first chance to circumnavigate the Arctic on open water. This melt was 30 years ahead of the computer forecasts about global warming. It confirmed that we were warming the planet. There was no other explanation on offer. Worse, it was one of a number of feedback loops that would amplify that warming: Instead of the nice, white sheet of ice covering the Arctic, a mirror that reflected 80 percent of incoming solar radiation back out to space, we all at once had big pools of blue water, which absorb 80 percent of those rays of the sun. We'd kicked off the warming, but now nature was taking over and doing the job on her own. And that wasn't the only such feedback. As permafrost thawed in northern tundra, for instance, carbon dioxide and methane, another greenhouse gas, began to seep out into the atmosphere. The warmer seasons we were producing led to the spread of various pests that killed tens of millions of acres of trees across the North American West—and the fires all that dead wood fueled added new clouds of carbon to the atmosphere. We weren't producing it directly, but it all led back to us. Our cars and factories had clearly triggered a worldwide reaction, which in retrospect shouldn't surprise us. After all, we were taking millions of years' worth of stored carbon—all those old ferns and plankton—and pouring it into the atmosphere in the course of a few generations. Why wouldn't it cause problems?