Since the 1970s, a prominent strand of the environmental community has warned of imminent energy shortage, hoping to persuade people to conserve resources and shift to alternative fuels that pollute less. This has often worked for a time: in the 1970s, for example, fears of scarce oil and environmental damage combined to prompt strong efforts that cut fuel consumption and directed government money toward renewable power. Yet initiatives in this vein have inevitably faltered. Worries about vanishing resources have reliably spurred rising prices, which, in turn, spark exploration and innovation that reveals ever-larger sources of fossil fuels. That new abundance does not only challenge the economics of alternative energy sources - it also invariably erodes their foundation of political support.
Charles Mann's fascinating essay recounts the most recent turn in this cycle, and gives a glimpse at what the next twist might be. Shale gas and tight oil, he reports, have again eviscerated expectations that a transition to clean energy will driven by fossil fuels' scarcity. And methane hydrates, still an esoteric and far-from-commercial prospect, might eventually dwarf that, giving the world the option to use fossil fuels forever - and by driving climate change, fry the planet in the process.
Mann is right about one big thing: geology isn't going to save us from having to take tough political steps if we're going to seriously confront climate change. But he needn't have invoked shale gas or methane hydrates to do that. A paper published in Nature Climate Change last year pointed out that if all the coal in the world were burned, it would likely warm the planet by an unimaginable 27 degrees Fahrenheit. (International negotiations typically focus on keeping warming to 3.6 degrees or less.) Alas the world has become more coal-dependent, not less, in recent years. In mid-April, the International Energy Agency (IEA), an intergovernmental organization with 28 members including the United States, reported that despite surging investment in renewable power, "the average unit of energy produced today is basically as dirty as it was 20 years ago". The culprit is the inexorable rise of coal.
Indeed that rising coal consumption makes our predicament considerably more troubling than many of those who celebrate the rise of natural gas appear ready to admit. In Mann's telling, natural gas will move us beyond coal, leaving only the (admittedly large) challenge of spurring a final move to zero-carbon fuels. In practice, the world has already sunk huge sums of money into thousands of coal-fired power plants, and operating those plants remains cheap; and, despite the U.S. shale boom, more coal plants are being built. Even if the natural gas boom were to eventually spread from the United States to the rest of the world, coal-fired power could well continue to dominate much of the global energy system for decades.
So natural gas doesn't let us off the hook for a decade or two while we figure out how to make zero-carbon energy thrive. Indeed it doesn't even give the United States a pass. In May 2012, fracking briefly spurred gas to pass coal as the top source of U.S. electricity. But as natural gas prices recovered, coal regained its top rank, a position most expect it to retain for decades to come. That won't cut it if we're going to seriously tackle climate change. To be certain, cheap gas makes it less expensive to cut our emissions, by shifting away from traditional coal. But we'll still need governments to step in and tip the balance, whether through new regulations or a price on carbon that gives gas an advantage over coal.