CLIMATE CHANGE FROM A TO Z
The stories we tell ourselves about the future.
Physics Society meetings consisted of lectures on the latest scientific developments, many delivered by Arrhenius himself, followed by discussions that often lasted well into the night. The topics ranged widely, from aeronautics to volcanology. The society devoted several sessions to considering the instruments that would be needed by Salomon August Andrée, another early member of the group, who had decided to try to reach the North Pole via balloon. (Whatever the quality of his instruments, Andrée’s voyage would result in his death and the death of his two companions.)
A question that particularly interested the Physics Society was the origin of the ice ages. All over Sweden lay signs of the glaciers that had, for vast stretches of time, buried the country: rocks with parallel scrapings; strange, sinuous piles of gravel; huge boulders that had been transported far from their source. But what had caused the great ice sheets to descend, carrying all before them? And then what had caused them to retreat, allowing the rivers to flow once again and the forests to return? In 1893, the society debated various theories that had been proposed, including one linking the ice ages to slight variations in the Earth’s orbit. The following year, Arrhenius came up with a different—and, he thought, better—idea: carbon dioxide.
Carbon dioxide, he knew, had curious heat-trapping properties. In the atmosphere, it allowed visible light to pass through, but it absorbed the longer-wave radiation that the Earth was constantly emitting to space. What if, Arrhenius speculated, the amount of CO2 in the air had varied? Could that explain the glaciers’ ebb and flow?
The math involved in testing this theory went far beyond what was possible at the time. Arrhenius didn’t have a calculator, let alone a computer. He lacked crucial information about which wavelengths, exactly, CO2 absorbs. The climate system, meanwhile, is immensely complicated, with feedback loops nestled within feedback loops.
Arrhenius, who would later win a Nobel Prize for an unrelated discovery, plunged ahead anyway. On Christmas Eve, 1894, he began constructing a climate model—the world’s first. He assembled temperature data from around the globe and made ingenious use of a set of measurements that had been taken a decade earlier by an American astronomer, Samuel Pierpont Langley. (Langley had invented a device—a bolometer—for gauging infrared radiation, and had used it to determine the temperature of the moon.) Arrhenius performed thousands of computations—perhaps tens of thousands—and often labored over this task for fourteen hours a day. He was still calculating away as his marriage fell apart. In September of 1895, Rudbeck moved out. In November, without having seen Arrhenius again, she gave birth to their son. The following month, Arrhenius finished his work. “I should certainly not have undertaken these tedious calculations if an extraordinary interest had not been connected with them,” he wrote.
Arrhenius believed that he had unravelled the mystery of the ice ages, a riddle that had “hitherto proved most difficult to interpret.” He was at least partly right: ice ages are the product of a complex interplay of forces, including wobbles in the Earth’s orbit and changes in atmospheric CO2.
His model turned out to have another use as well. All across Europe and North America, coal was being shovelled into furnaces that were bellowing out carbon dioxide. By thickening the atmospheric blanket that warmed the Earth, humans must, Arrhenius reasoned, be altering the climate. He calculated that, if the amount of carbon dioxide in the air were to double, then global temperatures would rise between three and four degrees Celsius. A few quadrillion computations later, vastly more advanced climate models predict that doubling CO2 will push temperatures up between 2.5 and four degrees Celsius, meaning that Arrhenius’s pen-and-paper estimate was, to an uncanny degree, on target.
Arrhenius thought that the future he had conjured would be delightful. “Our descendants,” he predicted, would live happier lives “under a warmer sky.” The prospect was, in any event, distant; doubling atmospheric CO2 would, he reckoned, take humanity three thousand years.
It’s easy now to poke fun at Arrhenius for his sunniness. The doubling threshold could be reached within decades, and the results are apt to be disastrous. But who among us is any different? Here we all are, watching things fall apart. And yet, deep down, we don’t believe it.
On September 28, 2021, at the Youth4Climate conference, held in Milan, Greta Thunberg took the stage. Sitting near her was the city’s mayor, Giuseppe Sala, wearing a mask. Thunberg, who is five feet tall, could barely be seen over the lectern. She had removed her mask and was smiling.
“Climate change is not only a threat, it is above all an opportunity to create a healthier, greener, and cleaner planet which will benefit all of us,” she began. “We must seize this opportunity—we can achieve a win-win in both ecological conservation and high-quality development. . . . We need to walk the talk; if we do this together, we can do this.
“When I say ‘climate change,’ what do you think of?” she went on. “I think of jobs—green jobs.” This received a round of applause.
“We must find a smooth transition towards a low-carbon economy,” Thunberg said. “There is no Planet B. There is no Planet Blah—blah, blah, blah; blah, blah, blah.” Her listeners, including Sala, started to realize that they’d been had. The applause died down.
“Build Back Better—blah, blah, blah,” Thunberg continued.
“Green economy—blah, blah, blah.
“Net zero by 2050—blah, blah, blah.
“Net zero—blah, blah, blah.
“Climate neutral—blah, blah, blah.
“This is all we hear from our so-called leaders: words—words that sound great, but so far have led to no action,” Thunberg said. “Of course we need constructive dialogue, but they’ve now had thirty years of blah, blah, blah, and where has that led us?”
It was thirty years ago that the world’s “so-called leaders” gathered in Rio de Janeiro for the so-called Earth Summit. Everyone agreed that radical change was needed. To avert disaster, global CO2 emissions, which were then running at around twenty-two billion metric tons a year, would have to be reduced, eventually almost to zero. How this would happen, no one really knew. Still, the goal of preventing “dangerous” warming was enshrined in the United Nations Framework Convention on Climate Change, which President George H. W. Bush cheerfully signed.
“Some find the challenges ahead overwhelming,” Bush said. “I believe that their pessimism is unfounded.”
A follow-up conference of the parties, or cop, took place in Kyoto in 1997. By then, annual global emissions had risen to twenty-four billion tons. After much back-and-forth, it was agreed that something had to be done. The Kyoto Protocol, an addendum to the Framework Convention, laid out specific emissions-reduction targets for countries to meet.
“I am both determined and optimistic that we can succeed,” Vice-President Al Gore told the diplomats gathered in Japan.
After Kyoto, global emissions kept on rising, only faster. By 2009, they’d climbed to thirty-two billion tons a year. That fall, President Barack Obama flew to Copenhagen for yet another conference of the parties—cop15. “I believe that we can act boldly, and decisively, in the face of this common threat,” he declared.
By 2015, emissions had increased to thirty-five billion tons a year. At that year’s cop—No. 21—held in Paris, it was decided that, at last, really and truly, it was time to get serious. “The decisions you make here will reverberate down through the ages,” the United Nations Secretary-General, Ban Ki-moon, told the delegates. Nevertheless, emissions continued to rise. In the past thirty years, humans have added as much CO2 to the atmosphere as they did in the previous thirty thousand.
At some point during all the “blah, blah, blah”-ing—it’s hard to say when, exactly—climate change ceased to be a prospective problem and became a clear and present one. Since Rio, the Arctic ice cap has shrunk by two-fifths. Greenland has shed some four trillion metric tons of ice, and mountain glaciers have lost six trillion tons. Heat waves are now hotter, droughts deeper, and storms more intense. In some parts of the world, the wildfire season never ends.
One conclusion to draw from this pattern is that the world isn’t going to avoid “dangerous” warming. Global leaders will continue to gather at cops—this year’s, in Sharm el-Sheikh, just concluded—and to speak loftily about “net zero” and “a low-carbon economy.” But nothing will change, and, as a result, everything will change. There will be large-scale crop failures. The Greenland ice sheet will start to collapse—it may already be collapsing—and, owing to sea-level rise in some places and desertification in others, large swaths of the globe will become uninhabitable.
This conclusion is not, however, the one that Thunberg chose to draw when she spoke at the Youth4Climate conference. “Right now we are still very much speeding in the wrong direction,” she told the crowd in Milan. “But, of course, we can still turn this around—it is entirely possible.
“The leaders like to say, ‘We can do this,’ ” she went on. “They obviously don’t mean it, but we do—we can do this. I’m absolutely convinced that we can.”
Or, as Thunberg might put it, Blah, blah, blah.
What’s the matter here? Why has so little progress been made on climate change, even as the dangers have become ever more apparent?