Diego Azubel/epa/Corbis

A dried-up section of the Jialing River, Chongqing, China, March 2007

2009 may well turn out to be the decisive year in the human relationship with our home planet. By December, when the world’s leaders plan to gather in Copenhagen to sign a new global accord on global warming, we’ll know whether or not our political systems are up to the unprecedented challenge that climate change represents. So far the signals are mixed at best—and as I’m writing those words, the news flashes up on my screen that a huge new chunk of the Antarctic ice sheet has collapsed into the sea.

In any event, Nicholas Stern’s new book provides the best scorecard we have for keeping track of this drama as it unfolds. Stern is a member of the House of Lords, and has been a top-drawer economist for many years. He was chief economist at the World Bank at the beginning of the decade, and then served as head of the UK Government Economics Service between 2003 and 2007. It was during those years that British leaders asked him to undertake a large-scale review of the economics of climate change. When he started out, he writes, “I had no special knowledge, beyond that of a concerned citizen anywhere, of the science of climate change.” He began, as any inquiry into this problem must, by looking at what science can tell us about the dangers we are courting by pouring carbon into the atmosphere:

The first thing that struck me…was the magnitude of the risks and the potentially devastating effects on the lives of people across the world. We were gambling the planet.

But because he was an economist, he was able to put those risks into financial terms—at the time the Stern Report was published in October 2006 the most widely quoted calculation was that global warming could exact an economic price larger than the Great Depression and a world war combined. In this new book he uses an example closer to the moment:

The magnitude of risks involved in climate change is vastly greater than, for instance, the disruption that would be caused to people were the Western financial system to collapse.

In one way, that seems obvious. Even a new depression would last only for a generation, while climate change promises irreversible degradation across geological time scales. The problem, of course, is that the collapse of financial systems happens quickly, and so our political systems respond by throwing piles of money into the breach; global warming happens just slowly enough that political systems have been able to ignore it. The distress signal is emitted at a frequency that scientists can hear quite clearly, but is seemingly just beyond the range of most politicians.

Stern’s great contribution was tuning the receiver of the economics profession so it could pick up the signal too. It wasn’t easy—previously, too many economists managed to minimize the danger of global warming, arguing that we would soon be so much richer that we’d be able to absorb the costs of a warming world. But the response to Stern’s report signaled a change—it was hailed by such Nobel Prize winners as Joseph Stiglitz, Amartya Sen, James Mirrlees, and Robert Solow, who wrote,

If the world is waiting for a calm, reasonable, carefully argued approach to climate change, Nick Stern and his team have produced one. They outline a feasible adjustment policy at tolerable cost beginning now.

The Stern plan, and the emerging outlines of a Copenhagen agreement, are based on several premises. One is that dealing with climate change is technologically possible—Stern describes the list of possible technologies, including nuclear energy, carbon sequestration, solar energy, and windmills. Another is that these are affordable. He cites, for instance, the widely circulated report produced by the New York–based consultants McKinsey and Co., which shows that a great many already available conservation technologies such as high-efficiency lighting could be deployed at little cost, and in many cases with quick positive returns. Stern writes that achieving concentrations of carbon dioxide in the earth’s atmosphere of 500 parts per million (ppm) “might cost 2 percent of world GNP per annum over the next half-century.”

Taking 500 ppm as the maximum limit for the future—we’re currently at 387 ppm—is roughly the target that federal and global legislation is designed to hit. Without any action, in what scientists call a “business-as-usual” scenario, we’d see concentrations of carbon in the earth’s atmosphere rise past 700 ppm before century’s end. Stern’s review of the scientific data indicates that stabilizing concentrations at the 500 ppm level would be about enough to limit temperature increases to roughly 2 or 3 degrees Celsius, which he believes would be dangerous but not catastrophic. Those numbers are not hard and fast—and as we shall see later, the latest science suggests that they are highly optimistic. But since they will form the backdrop to legislative and treaty negotiations, they are important to consider.


Stern focuses on the potential economic costs of the shifts required to meet those goals. “There is some uncertainty” about the potential figures, he concedes, “perhaps plus or minus 3 percent, but we know enough about the relevant technologies and investments to make reasonable estimates.” On the one hand, it’s a large price—2 percent of current global GDP is about a trillion dollars. But if growth resumes, “such a one-off cost would imply that the world economy would take roughly an additional six months in reaching the level of world income it would otherwise reach by 2050.” Paying for this technological transformation, in other words, is like paying for preventive health care—going to the dentist each year costs something, and it hurts a little, but it’s worth it if you can prevent a root canal a decade or two later.

So the question for Stern becomes: how can we persuade the nations of the world to make a serious commitment in Copenhagen this December, and then to keep it? Stern currently spends much of his time at the international conferences and private conclaves preparing the ground for the Copenhagen talks, and his assessment of the state of play can be taken as authoritative. The deal now being discussed would look something like this:

• The planet agrees to cut emissions at least by half from their 1990 levels by 2050.

• The developed countries agree to go first, slashing emissions 20 to 40 percent by 2020, and committing to reductions of at least 80 percent by 2050. In so doing, they quickly demonstrate “that low-carbon growth is possible and affordable.”

• The developing countries pledge that if the rich nations actually meet their commitments, they will agree to their own targets, no later than 2020.

• Everyone agrees that rich nations can meet some of their own reduction targets by funding projects in poor nations—i.e., if it’s cheaper for Con Ed to build a windmill in Mongolia than retrofit the big boilers in Astoria, they do so, on the grounds that it’s both economically efficient and that it moves new technology to places that need it.

• Rich countries pay poor countries for the “extra costs of development” that come from using renewable technologies or expensive carbon sequestration equipment instead of simply burning their piles of coal, and also to help them adapt to climate changes we are starting too late to prevent.

These basic principles, of course, have to be extracted from mountains of tedious but crucial details, and much of the negotiation now underway is about those details. Environmentalists and industry lobbyists are assessing them to try to make sure that they don’t contain (or do contain) loopholes that could eliminate emissions reductions, lead to widespread deforestation, and so on. But lay aside those particulars for a moment, and ask yourself, as Stern does, whether the major nations can be brought together around those principles. He identifies China, India, the EU, and the United States as critical to an agreement, and treats each at some length.

Europe is relatively easy: the main powers of the European Union have been in the vanguard of climate politics for two decades. “The course in Europe,” Stern writes,

seems to be well set and many interesting instances of practical progress exist, whether they be onshore wind for electricity generation in Germany or Denmark, or tighter regulations on car emissions.

India, by contrast, has barely engaged the issue of global warming. Its emissions are only a third of China’s or America’s, but they are increasing quickly. India has a third of the world’s poorest people too, and the government is committed to rapid economic growth in order to improve their lives. But India is also particularly vulnerable to the effects of climate change: the Himalayan glaciers that supply its major rivers are melting with astonishing speed; the rise in sea level threatens its crowded coasts; and many new analyses suggest that the timing and intensity of the crucial monsoons are apt to change in a warming world. The issue hasn’t, Stern notes, been fully brought “into the broad political domain” of the world’s biggest democracy, something that must happen very quickly.

Meanwhile, in the world’s biggest nondemocracy, the Chinese are inching their way toward the outlines of a deal. They understand that they too face enormous climate threats, and that moving away from coal would be helpful in cutting back carbon emissions and in many other ways; however, the economic downturn has made Beijing’s attempt to keep its citizens under control all the harder, and hence the need for economic growth unchecked by higher energy prices has become all the more imperative. A disturbing recent story in The New York Times finds that the Chinese have returned to fast-track approvals of cement plants and other polluting industries in the midst of their economic downturn. Stern finds consolation in the fact that many of the Chinese leaders are engineers by training, and so “technological issues have a very high profile.” They are, he hints, most interested in the transfer of renewable energy technology and other advanced engineering that could come with a climate deal.


That leaves the United States, which has had an outsized role in climate change from the beginning. For one thing, it is far and away the biggest source of the problem: though China passed the US last year as the largest carbon emitter, we’ve been at it far longer—the residence time of CO2 molecules in the atmosphere is over a century, meaning it will be many more decades before we’re supplanted as the biggest carbon culprit. But our politics have also prevented us from taking any part in the solution to the problem, and that, in turn, has made it almost impossible for the rest of the world to take action. The conservative movement in America has been able to block every proposal to do anything serious about global warming. Perhaps because of the movement’s ties to the fossil fuel industry but also because of a free-market absolutism, it has vehemently opposed not only the regulation of carbon but also the scientific consensus on the need for action. The question is whether that has changed with the election of Barack Obama and a Democratic Congress.


Gideon Mendel for Action Aid/Corbis

Residents of the flooded village of Salempur, in India’s Bihar province, August 2007. The devastating levels of recent monsoon flooding have been linked by scientists to global warming.

On the one hand, the atmosphere in Washington is clearly different. In ten weeks Obama has done more to deal with global warming than all the presidents of the last twenty years combined, including allowing California to set its own limits on emissions from cars, a decision that will do more than any “car czar” to rewrite the rules for Detroit. He has appointed a strong team of scientists and talented bureaucrats who know the issue deeply: it includes the former EPA head Carol Browner as his chief climate sounding board, Harvard’s John Holdren as the science adviser, the admirably frank physicist Steven Chu as energy secretary, and the eloquent activist Van Jones as a “special adviser for green jobs, enterprise, and innovation.”

Moreover, Obama himself has continued to mention global warming at every turn, and in commendably strong terms. In Strasbourg during his recent European journey, for instance, he said:

We all know that time is running out. And that means that America must do more. Europe must do more. China and India must do more. Rolling back the tide of a warming planet is a responsibility that we have to ourselves, to our children, and all of those who will inherit God’s creation long after we are gone. So let us meet that responsibility together. I am confident that we can meet it. But we have to begin today.

As for Congress, he has a strong ally in California’s Henry Waxman, head of the House Energy and Commerce Committee. He replaced Michigan’s John Dingell in a rare congressional coup designed to let him take on the global warming issue, and earlier this winter, with Massachusetts Congressman Ed Markey, he introduced a comprehensive bill to do on a national basis pretty much precisely what Stern recommends for the globe: caps on carbon, a system by which companies and utilities would get permits to emit steadily decreasing amounts of carbon with each passing year. If they exceeded their reduction targets, they’d be able to sell the rest of their allowance to some other firm having trouble meeting its goals. The bill aims to cut carbon emissions 20 percent by 2020 and 80 percent by 2050, and Waxman has promised to get the bill out of committee and onto the House floor by Memorial Day.

Hearings began on the bill on April 21, during Earth Day week, and proponents seemed confident that their legislation could pass the House. Still, there are a few caveats: it is extraordinarily complex—hundreds of pages of text that is hard to understand and easy to pick apart provision by provision. The possibility of a defeat, recalling the disaster of the Clinton health care plan, can’t be discounted. That’s especially true since the Republicans are deprived of most other targets by Obama’s popularity and the scale of the mess Bush left behind. But here they will focus on the cost to the taxpayers of increased energy prices—they are already (using greatly inflated estimates) going on about the $3,100 “light switch tax.” And they will argue that the money will go to support pork—an “Al Gore wish list,” as one opponent put it.

For a country still suspicious of big government, and currently fearful of a depression, it could be a messy fight, one that might end in a very watered-down bill.* And if Congress doesn’t pass something plausible, then it’s very hard to see how the Copenhagen talks could come out well. Especially since conservatives will be on the lookout for anything that resembles a “giveaway” to China or the rest of the developing world—that is, precisely the kind of adaptation funding that Stern recommends.

Something else could go wrong too, however, even if everyone accepted Stern’s advice and we reached the kind of agreement that he envisions. That is, the planet itself may not be following the path he outlines.

Stern begins his account with a scientific interpretation based largely on the Intergovernmental Panel on Climate Change (IPCC) reports issued in the winter of 2007 and based on research from the first few years of the decade. It supports his decision to use targets like 500 parts per million of carbon as the eventual goal. (He unfortunately muddies the argument by using a more arcane formula, “CO2 equivalents,” which also counts other gases like methane. Though methane, black soot, and the like do contribute to climate change, other gases offset their effect, and since CO2 remains the main driver in any event, arguments emphasizing the threat of other sources unnecessarily complicate an already eye-glazing topic.)

His basic calculation is that the largest dangers still lie some ways in the future—that the world, with some difficulty, can deal with two or three degrees Celsius of temperature increase, and hence we have a couple of decades for emissions to continue growing, at least in the developing world, before they start coming down. “Temperature increases of 4–5 degrees C and above are likely to be catastrophic,” he writes. And indeed they are. The problem is, the latest science shows that temperature increases of one degree Celsius, which is what we have, are already proving catastrophic. The world’s high-altitude glaciers—the “water towers” in the Himalayas and the Andes that irrigate so much of the world—are already on the way out; the Arctic is already melting; drought is already spreading with wicked speed.

In the short span since the last IPCC report, a growing number of climatologists have decided that its conclusions underestimated both the scale and pace of global warming. An “emergency summit” of scientists in Copenhagen in March reported that new data across many fields showed dramatically faster change than they had earlier forecast. Sea level, for instance, is now predicted to rise much faster than we thought just a few years ago. NASA’s James Hansen, perhaps the world’s foremost climatologist, has offered an estimate to define the new science: 350 parts per million CO2, his team reported, was the maximum amount of carbon in the atmosphere consonant with the planet “on which civilization developed and to which life on earth is adapted.”

That’s a very strict number—since we’re already at 387 parts per million, it implies that this is a dilemma not for the near future but for right this moment. It implies that tough as negotiating Stern’s agreement will be, the resulting effort won’t be tough enough to handle climatic disruption. It implies that we’d need much more dramatic action much sooner—by Hansen’s calculation, the entire world needs to be out of the business of burning coal by 2030, and the Western world much sooner. Since coal supplies half of America’s electricity, and much more of China’s, that represents political trouble of a different order of magnitude.

A couple of things might change the political climate. One is a genuine grassroots movement asking for swift action—to date, climate has been the province mostly of experts, which is why some of us have mounted a campaign ( in the hope of rallying public opinion behind more dramatic action. Another is the wild card of weather—polling data leaves no question that powerful heat waves or hurricanes remind voters of what’s coming. And the world now has a globally popular leader who could decide to conduct the kind of high-profile campaign that might summon us to rise to the occasion.

Stern cautions against pushing for lower carbon targets. It could, he says, “disrupt the possibility of an agreement in the very near future…. We risk appearing to ask for the impossible.” It’s a good point. But it presumes that the negotiations are being conducted between human beings—between industry and environmentalists, between Chinese and Indians and Americans and Germans. That is true to an extent—indeed, these are the most delicate negotiations that the world has ever engaged in. But the real negotiation is between humans on the one hand and chemistry and physics on the other. And chemistry and physics, unfortunately, don’t bargain.

—May 12, 2009