The Best American Science and Nature Writing 2010

by Tim Folger

  Hansen has now concluded, partly on the basis of his latest modeling efforts and partly on the basis of observations made by other scientists, that the threat of global warming is far greater than even he had suspected. Carbon dioxide isn't just approaching dangerous levels; it is already there. Unless immediate action is taken—including the shutdown of all the world's coal plants within the next two decades—the planet will be committed to change on a scale society won't be able to cope with. "This particular problem has become an emergency," Hansen said.

  Hansen's revised calculations have prompted him to engage in activities—like marching on Washington—that aging government scientists don't usually go in for. Last September, he traveled to England to testify on behalf of anticoal activists who were arrested while climbing the smokestack of a power station to spray-paint a message to the prime minister. (They were acquitted.) Speaking before a congressional special committee last year, Hansen asserted that fossil fuel companies were knowingly spreading misinformation about global warming and that their chairmen "should be tried for high crimes against humanity and nature." He has compared freight trains carrying coal to "death trains," and he wrote to the head of the National Mining Association, who sent him a letter of complaint, that if the comparison "makes you uncomfortable, well, perhaps it should."

  Hansen insists that his intent is not to be provocative but conservative: his only aim is to preserve the world as we know it. "The science is clear," he said, when it was his turn to address the protesters blocking the entrance to the Capitol Power Plant. "This is our one chance."

  The fifth of seven children, Hansen grew up in Denison, Iowa, a small, sleepy town close to the western edge of the state. His father was a tenant farmer who, after World War II, went to work as a bartender. All the kids slept in two rooms. As soon as he was old enough, Hansen went to work, too, delivering the Omaha World-Herald. When he was eighteen, he received a scholarship to attend the University of Iowa. It didn't cover housing, so he rented a room for twenty-five dollars a month and ate mostly cereal. He stayed on at the university to get a Ph.D. in physics, writing his dissertation on the atmosphere of Venus. From there he went directly to the Goddard Institute for Space Studies—GISS, for short—where he took up the study of Venusian clouds.

  By all accounts, including his own, Hansen was preoccupied by his research and not much interested in anything else. GISS's offices are a few blocks south of Columbia University; when riots shut down the campus, in 1968, he barely noticed. At that point, GISS's computer was the fastest in the world, but it still had to be fed punch cards. "I was staying here late every night, reading in my decks of cards," Hansen recalled. In 1969 he left GISS for six months to study in the Netherlands. There he met his wife, Anniek, who is Dutch; the couple honeymooned in Florida, near Cape Canaveral, so they could watch an Apollo launch.

  In 1973 the first Pioneer Venus mission was announced, and Hansen began designing an instrument—a polarimeter—to be carried on the orbiter. But soon his research interests began to shift earthward. A trio of chemists—they would later share a Nobel Prize—had discovered that chlorofluorocarbons and other man-made chemicals could break down the ozone layer. It had also become clear that greenhouse gases were rapidly building up in the atmosphere.

  "We realized that we had a planet that was changing before our eyes, and that's more interesting," Hansen told me. The topic attracted him for much the same reason Venus's clouds had: there were new research questions to be answered. He decided to try to adapt a computer program that had been designed to forecast the weather to see if it could be used to look further into the future. What would happen to Earth if, for example, greenhouse-gas levels were to double?

  "He never worked on any topic thinking it might be any use for the world," Anniek told me. "He just wanted to figure out the scientific meaning of it."

  When Hansen began his modeling work, there were good theoretical reasons for believing that increasing CO2 levels would cause the world to warm, but little empirical evidence. Average global temperatures had risen in the 1930s and '40s; then they had declined, in some regions, in the 1950s and '60s. A few years into his project, Hansen concluded that a new pattern was about to emerge. In 1981 he became the director of GISS. In a paper published that year in Science, he forecast that the following decade would be unusually warm. (That turned out to be the case.) In the same paper, he predicted that the 1990s would be warmer still. (That also turned out to be true.) Finally, he forecast that by the end of the twentieth century a global-warming signal would emerge from the "noise" of natural climate variability. (This, too, proved to be correct.)

  Later, Hansen became even more specific. In 1990 he bet a roomful of scientists that that year or one of the following two would be the warmest on record. (Within nine months, he had won the bet.) In 1991 he predicted that owing to the eruption of Mt. Pinatubo, in the Philippines, average global temperatures would drop and then, a few years later, recommence their upward climb, which was precisely what happened.

  From early on, the significance of Hansen's insights was recognized by the scientific community. "The work that he did in the seventies, eighties, and nineties was absolutely groundbreaking," Spencer Weart, a physicist turned historian who has studied the efforts to understand climate change, told me. He added, "It does help to be right."

  "I have a whole folder in my drawer labeled 'Canonical Papers,'" Michael Oppenheimer, a climate scientist at Princeton, said. "About half of them are Jim's."

  Because of its implications for humanity, Hansen's work also attracted considerable attention from the world at large. His 1981 paper prompted the first front-page article on climate change that ran in the Times—STUDY FINDS WARMING TREND THAT COULD RAISE SEA LEVELS, the headline read—and within a few years he was regularly being invited to testify before Congress. Still, Hansen says, he didn't imagine himself playing any role besides that of a research scientist. He is, he has written, "a poor communicator" and "not tactful."

  "He's very shy," Ralph Cicerone, the president of the National Academy of Sciences, who has known Hansen for nearly forty years, told me. "And, as far as I can tell, he does not enjoy a lot of his public work."

  "Jim doesn't really like to look at anyone," Anniek Hansen told me. "I say, 'Just look at them!'"

  Throughout the 1980s and '90s, the evidence of climate change—and its potential hazards—continued to grow. Hansen kept expecting the political system to respond. This, after all, was what had happened with the ozone problem. Proof that chlorofluorocarbons were destroying the ozone layer came in 1985, when British scientists discovered that an ozone "hole" had opened up over Antarctica. The crisis was resolved—or, at least, prevented from growing worse—by an international treaty phasing out chlorofluorocarbons, which was ratified in 1987.

  "At first, Jim's work didn't take an activist bent at all," the writer Bill McKibben, who has followed Hansen's career for more than twenty years and who helped organize the anticoal protest in D.C., told me. "I think he thought, as did I, If we get this set of facts out in front of everybody, they're so powerful—overwhelming—that people will do what needs to be done. Of course, that was naive on both our parts."

  As recently as the George W. Bush administration, Hansen was still operating as if getting the right facts in front of the right people would be enough. In 2001 he was invited to speak to Vice President Dick Cheney and other high-level administration officials. For the meeting, he prepared a detailed presentation titled "The Forcings Underlying Climate Change." In 2003 he was invited to Washington again, to meet with the head of the Council on Environmental Quality at the White House. This time he offered a presentation on what ice-core records show about the sensitivity of the climate to changes in greenhouse-gas concentrations. But by 2004 the administration had dropped any pretense that it was interested in the facts about climate change. That year NASA, reportedly at the behest of the White House, insisted that all communications between GISS scientists and the
outside world be routed through political appointees at the agency. The following year, the administration prevented GISS from posting its monthly temperature data on its website, ostensibly on the ground that proper protocols had not been followed. (The data showed that 2005 was likely to be the warmest year on record.) Hansen was also told that he couldn't grant a routine interview to National Public Radio. When he spoke out about the restrictions, scientists at other federal agencies complained that they were being similarly treated, and a new term was invented: government scientists, it was said, were being "Hansenized."

  "He had been waiting all this time for global warming to become the issue that ozone was," Anniek Hansen told me. "And he's very patient. And he just kept on working and publishing, thinking that someone would do something." She went on, "He started speaking out, not because he thinks he's good at it, not because he enjoys it, but because of necessity."

  "When Jim makes up his mind, he pursues whatever conclusion he has to the end point," Michael Oppenheimer said. "And he's made up his mind that you have to pull out all the stops at this point, and that all his scientific efforts would come to naught if he didn't also involve himself in political action." Starting in 2007, Hansen began writing to world leaders, including Prime Minister Gordon Brown, of Britain, and Yasuo Fukuda, then the prime minister of Japan. In December 2008, he composed a personal appeal to Barack and Michelle Obama.

  "A stark scientific conclusion, that we must reduce greenhouse gases below present amounts to preserve nature and humanity, has become clear," Hansen wrote. "It is still feasible to avert climate disasters, but only if policies are consistent with what science indicates to be required." Hansen gave the letter to Obama's chief science adviser, John Holdren, with whom he is friendly, and Holdren, he says, promised to deliver it. But Hansen never heard back, and by the spring he had begun to lose faith in the new administration. (In an e-mail, Holdren said that he could not discuss "what I have or haven't given or said to the President.")

  "I had had hopes that Obama understood the reality of the issue and would seize the opportunity to marry the energy and climate and national-security issues and make a very strong program," Hansen told me. "Maybe he still will, but I'm getting bad feelings about it."

  There are lots of ways to lose an audience with a discussion of global warming, and new ones, it seems, are being discovered all the time. As well as anyone, Hansen ought to know this; still, he persists in trying to make contact. He frequently gives public lectures; just in the past few months, he has spoken to Native Americans in Washington, D.C.; college students at Dartmouth; high school students in Copenhagen; concerned citizens, including King Harald, in Oslo; renewable-energy enthusiasts in Milwaukee; folk music fans in Beacon, New York; and public health professionals in Manhattan.

  In April I met up with Hansen at the state capitol in Concord, New Hampshire, where he had been invited to speak by local anticoal activists. There had been only a couple of days to publicize the event; nevertheless, more than 250 people showed up. I asked a woman from the town of Ossipee why she had come. "It's a once-in-a-lifetime opportunity to hear bad news straight from the horse's mouth," she said. For the event, Hansen had, as usual, prepared a PowerPoint presentation. It was projected onto a screen beside a faded portrait of George Washington. The first slide gave the title of the talk, "The Climate Threat to the Planet," along with the disclaimer "Any statements relating to policy are personal opinion."

  Hansen likes to begin his talk with a highly compressed but still perilously long discussion of climate history, beginning in the early Eocene, some 50 million years ago. At that point, CO2 levels were high and, as Hansen noted, the world was very warm: there was practically no ice on the planet, and palm trees grew in the Arctic. Then CO2 levels began to fall. No one is entirely sure why, but one possible cause has to do with weathering processes that, over many millennia, allow carbon dioxide from the air to get bound up in limestone. As CO2 levels declined, the planet grew cooler; Hansen flashed some slides on the screen, which showed that between 50 million and 35 million years ago, deep ocean temperatures dropped by more than 10 degrees. Eventually, around 34 million years ago, temperatures sank low enough that glaciers began to form on Antarctica. By around 3 million years ago—perhaps earlier—permanent ice sheets had begun to form in the Northern Hemisphere as well. Then, about 2 million years ago, the world entered a period of recurring glaciations. During the ice ages—the most recent one ended about 12,000 years ago—CO2 levels dropped even further.

  What is now happening, Hansen explained to the group in New Hampshire, is that climate history is being run in reverse and at high speed, like a cassette tape on rewind. Carbon dioxide is being pumped into the air some ten thousand times faster than natural weathering processes can remove it.

  "So humans now are in charge of atmospheric composition," Hansen said. Then he corrected himself: "Well, we're determining it, whether we're in charge or not."

  Among the many risks of running the system backward is that the ice sheets formed on the way forward will start to disintegrate. Once it begins, this process is likely to be self-reinforcing. "If we burn all the fossil fuels and put all that CO2 into the atmosphere, we will be sending the planet back to the ice-free state," Hansen said. "It will take a while to get there—ice sheets don't melt instantaneously—but that's what we will be doing. And if you melt all the ice, sea levels will go up two hundred and fifty feet. So you can't do that without producing a different planet."

  There's no precise term for the level of CO2 that will assure a climate disaster; the best that scientists and policymakers have been able to come up with is the phrase "dangerous anthropogenic interference," or DAI. Most official discussions have been premised on the notion that DAI will not be reached until CO2 levels hit 450 parts per million. Hansen, however, has concluded that the threshold for DAI is much lower.

  "The bad news is that it's become clear that the dangerous amount of carbon dioxide is no more than three hundred and fifty parts per million," he told the crowd in Concord. The really bad news is that CO2 levels have already reached 385 parts per million. (For the ten thousand years prior to the industrial revolution, carbon dioxide levels were about 280 parts per million, and if current emissions trends continue they will reach 450 parts by around 2035.)

  Once you accept that CO2 levels are already too high, it's obvious, Hansen argues, what needs to be done. He displayed a chart of known fossil fuel reserves represented in terms of their carbon content. There was a short bar for oil, a shorter bar for natural gas, and a tall bar for coal.

  "We've already used about half of the oil," he observed. "And we're going to use all of the oil and natural gas that's easily available. It's owned by Russia and Saudi Arabia, and we can't tell them not to sell it. So, if you look at the size of these fossil fuel reservoirs, it becomes very clear. The only way we can constrain the amount of carbon dioxide in the atmosphere is to cut off the coal source, by saying either we will leave the coal in the ground or we will burn it only at power plants that actually capture the CO2." Such power plants are often referred to as "clean-coal plants." Although there has been a great deal of talk about them lately, at this point there are no clean-coal plants in commercial operation, and, for a combination of technological and economic reasons, it's not clear that there ever will be.

  Hansen continued, "If we had a moratorium on any new coal plants and phased out existing ones over the next twenty years, we could get back to three hundred and fifty parts per million within several decades." Reforestation, for example, if practiced on a massive scale, could begin to draw global CO2 levels down, Hansen says, "so it's technically feasible." But "it requires us to take action promptly."

  Coincidentally, that afternoon a vote was scheduled in the New Hampshire state legislature on a proposal involving the state's largest coal-fired power plant, the Merrimack Station, in the town of Bow. The station's owner was planning to spend several hundred million dollars to reduce mercury
emissions from the plant—a cost that it planned to pass on to ratepayers. Hansen, who said he thought the plant should simply be shut, called the plan a "terrible waste of money." A lawmaker sympathetic to this view had introduced a bill calling for more study of the project, but, as several people who came up to speak to Hansen after his talk explained, it was opposed by the state's construction unions and seemed headed for defeat. (Less than an hour later, the bill was rejected in committee by a unanimous vote.)

  "I assume you're used to telling policymakers the truth and then having them ignore you," one man said to Hansen.

  Hansen smiled ruefully. "You're right."

  ***

  In scientific circles, worries about DAI are widespread. During the past few years, researchers around the world have noticed a disturbing trend: the planet is changing faster than had been anticipated. Antarctica, for example, had not been expected to show a net loss of ice for another century, but recent studies indicate that the continent's massive ice sheets are already shrinking. At the other end of the globe, the Arctic ice cap has been melting at a shocking rate; the extent of the summer ice is now only a little more than half of what it was just forty years ago. Meanwhile, scientists have found that the arid zones that circle the globe north and south of the tropics have been expanding more rapidly than computer models had predicted. This expansion of the subtropics means that highly populated areas, including the American Southwest and the Mediterranean basin, are likely to suffer more and more frequent droughts.

  "Certainly, I think the shrinking of the Arctic ice cap made a very strong impression on a lot of scientists," Spencer Weart, the physicist, told me. "And these things keep popping up. You think, What, another one? Another one? They're almost all in the wrong direction, in the direction of making the change worse and faster."