Nowadays, this effect is usually referred to as “rebound”—or, in cases where increased consumption more than cancels out any energy savings, as “backfire.” In a 1992 paper, Harry D. Saunders, an American researcher, provided a concise statement of the basic idea: “With fixed real energy price, energy efficiency gains will increase energy consumption above where it would be without these gains.”

In 2000, the journal Energy Policy devoted an entire issue to rebound. It was edited by Lee Schipper, who is now a senior research engineer at Stanford University’s Precourt Energy Efficiency Center. In an editorial, Schipper wrote that the question was not whether rebound exists but, rather, “how much the effect appears, how rapidly, in which sectors, and in what manifestations.” The majority of the Energy Policy contributors concluded that there wasn’t a lot to worry about. Schipper, in his editorial, wrote that the articles, taken together, suggested that “rebounds are significant but do not threaten to rob society of most of the benefits of energy efficiency improvements.”

I spoke with Schipper recently, and he told me that the Jevons paradox has limited applicability today. “The key to understanding Jevons,” he said, “is that processes, products, and activities where energy is a very high part of the cost—in this country, a few metals, a few chemicals, air travel—are the only ones whose variable cost is very sensitive to energy. That’s it.” Jevons wasn’t wrong about nineteenth-century British iron smelting, he said; but the young and rapidly growing industrial world that Jevons lived in no longer exists.

Most economists and efficiency experts have come to similar conclusions. For example, some of them say that when you increase the fuel efficiency of cars you lose no more than about ten per cent of the fuel savings to increased use. And if you look at the whole economy, Schipper said, rebound effects are comparably trivial. “People like Brookes would say—they don’t quite know how to say it, but they seem to want to say the extra growth is more than the saved energy, so it’s like a backfire. The problem is, that’s never been observed on a national level.”

But troublesome questions have lingered, and the existence of large-scale rebound effects is not so easy to dismiss. In 2004, a committee of the House of Lords invited a number of experts to help it grapple with a conundrum: the United Kingdom, like a number of other countries, had spent heavily to increase energy efficiency in an attempt to reduce its greenhouse emissions. Yet energy consumption and carbon output in Britain—as in the rest of the world—had continued to rise. Why?

Most economic analyses of rebound focus narrowly on particular uses or categories of uses: if people buy a more efficient clothes dryer, say, what will happen to the energy they use as they dry clothes? (At least one such study has concluded that, for appliances in general, rebound is nonexistent.) Brookes dismisses such “bottom-up” studies, because they ignore or understate the real consumption effects, in economies as a whole.

A good way to see this is to think about refrigerators, the very appliances that the World Economic Forum and Steven Chu cited as efficiency role models for reductions in energy use. The first refrigerator I remember is the one my parents owned when I was little. They acquired it when they bought their first house, in 1954, a year before I was born. It had a tiny, uninsulated freezer compartment, which seldom contained much more than a few aluminum ice trays and a burrow-like mantle of frost. (Frost-free freezers stay frost-free by periodically heating their cooling elements—a trick that wasn’t widely in use yet.) In the sixties, my parents bought a much improved model—which presumably was more efficient, since the door closed tight, by means of a rubberized magnetic seal rather than a mechanical latch. But our power consumption didn’t fall, because the old refrigerator didn’t go out of service; it moved into our basement, where it remained plugged in for a further twenty-five years—mostly as a warehouse for beverages and leftovers—and where it was soon joined by a stand-alone freezer. Also, in the eighties, my father added an icemaker to his bar, to supplement the one in the kitchen fridge.

This escalation of cooling capacity has occurred all over suburban America. The recently remodelled kitchen of a friend of mine contains an enormous side-by-side refrigerator, an enormous side-by-side freezer, and a drawer-like under-counter mini-fridge for beverages. And the trend has not been confined to households. As the ability to efficiently and inexpensively chill things has grown, so have opportunities to buy chilled things—a potent positive-feedback loop. Gas stations now often have almost as much refrigerated shelf space as the grocery stores of my early childhood; even mediocre hotel rooms usually come with their own small fridge (which, typically, either is empty or—if it’s a minibar—contains mainly things that don’t need to be kept cold), in addition to an icemaker and a refrigerated vending machine down the hall.

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The steadily declining cost of refrigeration has made eating much more interesting. It has also made almost all elements of food production more cost-effective and energy-efficient: milk lasts longer if you don’t have to keep it in a pail in your well. But there are environmental downsides, beyond the obvious one that most of the electricity that powers the world’s refrigerators is generated by burning fossil fuels. James McWilliams, who is the author of the recent book “Just Food,” told me, “Refrigeration and packaging convey to the consumer a sense that what we buy will last longer than it does. Thus, we buy enough stuff to fill our capacious Sub-Zeros and, before we know it, a third of it is past its due date and we toss it.” (The item that New Yorkers most often throw away unused, according to the anthropologist-in-residence at the city’s Department of Sanitation, is vegetables.) Jonathan Bloom, who runs the Web site wastedfood.com and is the author of the new book “American Wasteland,” told me that, since the mid-nineteen-seventies, per-capita food waste in the United States has increased by half, so that we now throw away forty per cent of all the edible food we produce. And when we throw away food we don’t just throw away nutrients; we also throw away the energy we used in keeping it cold as we lost interest in it, as well as the energy that went into growing, harvesting, processing, and transporting it, along with its proportional share of our staggering national consumption of fertilizer, pesticides, irrigation water, packaging, and landfill capacity. According to a 2009 study, more than a quarter of U.S. freshwater use goes into producing food that is later discarded.

Efficiency improvements push down costs at every level—from the mining of raw materials to the fabrication and transportation of finished goods to the frequency and intensity of actual use—and reduced costs stimulate increased consumption. (Coincidentally or not, the growth of American refrigerator volume has been roughly paralleled by the growth of American body-mass index.) Efficiency-related increases in one category, furthermore, spill into others. Refrigerators are the fraternal twins of air-conditioners, which use the same energy-hungry compressor technology to force heat to do something that nature doesn’t want it to. When I was a child, cold air was a far greater luxury than cold groceries. My parents’ first house—like eighty-eight per cent of all American homes in 1960—didn’t have air-conditioning when they bought it, although they broke down and got a window unit during a heat wave, when my mom was pregnant with me. Their second house had central air-conditioning, but running it seemed so expensive to my father that, for years, he could seldom be persuaded to turn it on, even at the height of a Kansas City summer, when the air was so humid that it felt like a swimmable liquid. Then he replaced our ancient Carrier unit with a modern one, which consumed less electricity, and our house, like most American houses, evolved rapidly from being essentially un-air-conditioned to being air-conditioned all summer long.