Even without any help, most of the carbon dioxide humans have emitted would eventually turn to stone, via a natural process known as chemical weathering. But “eventually” here means hundreds of thousands of years, and who has time to wait for nature? At Hellisheiði, Aradóttir and her colleagues were speeding up the chemical reactions by several orders of magnitude. A process that would ordinarily take millennia to unfold was being compressed into a matter of months.
Arádottir had brought along a rock core to show me the end result. The core, which was roughly two feet long and a couple of inches in diameter, was the dark color of the lava fields. But the black rock—basalt—was pocked with little holes, and these holes were filled with a chalky white compound—calcium carbonate. The white deposits represented, if not my own emissions, then at least somebody’s.
A basalt core with pockets of calcium carbonate
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When, exactly, people began altering the atmosphere is a matter of debate. According to one theory, the process got under way eight or nine thousand years ago, before the dawn of recorded history, when wheat was domesticated in the Middle East and rice in Asia. Early farmers set to clearing land for agriculture, and as they chopped and burned their way through the forests, carbon dioxide was released. The quantities involved were comparatively small, but, according to advocates of this theory, known as the “early Anthropocene hypothesis,” the effect was fortuitous. Owing to natural cycles, CO2 levels should have been falling during this period. Human intervention kept them more or less constant.
“The start of the switchover from control of climate by nature to control by humans occurred several thousand years ago,” William Ruddiman, a professor emeritus at the University of Virginia and the most prominent proponent of an “early Anthropocene,” has written.
According to a second, more widely held view, the switchover only really started in the late-eighteenth century, after the Scottish engineer James Watt designed a new kind of steam engine. Watt’s engine, it’s often said, anachronistically, “kick-started” the Industrial Revolution. As water power gave way to steam power, CO2 emissions began to rise, at first slowly, then vertiginously. In 1776, the first year Watt marketed his invention, humans emitted some fifteen million tons of CO2. By 1800, that figure had risen to thirty million tons. By 1850 it had increased to two hundred million tons a year and by 1900 to almost two billion. Now, the figure is close to forty billion tons annually. So much have we altered the atmosphere that one out of every three molecules of CO2 loose in the air today was put there by people.
Thanks to this intervention, average global temperatures have, since Watt’s day, risen by 1.1° Celsius (2° Fahrenheit). This has led to a variety of increasingly unhappy consequences. Droughts are growing deeper, storms fiercer, heat waves deadlier. Wildfire season is getting longer and the fires more intense. The rate of sea-level rise is accelerating. A recent study in the journal Nature reported that, since the 1990s, melt off of Antarctica has increased threefold. Another recent study predicted that most atolls will, in another few decades, become uninhabitable; this includes entire nations, like the Maldives and the Marshall Islands. To paraphrase J. R. McNeill paraphrasing Marx, “Men make their own climate, but they do not make it just as they please.”
No one can say exactly how hot the world can get before out-and-out disaster—the inundation of a populous country like Bangladesh, say, or the collapse of crucial ecosystems like coral reefs—becomes inevitable. Officially, the threshold of catastrophe is an average global temperature rise of 2°C (3.6°F). Virtually every nation signed on to this figure at a round of climate negotiations held in Cancún in 2010.
Meeting in Paris in 2015, world leaders had second thoughts. The two-degree threshold, they decided, was too high. The signatories of the Paris Agreement committed themselves to “holding the increase in the global average temperature to well below 2°C…and pursuing efforts to limit the temperature increase to 1.5°C.”
In either case, the math is punishing. To stay under 2°C, global emissions would have to fall nearly to zero within the next several decades. To stave off 1.5°C, they’d have to drop most of the way toward zero within a single decade. This would entail, for starters: revamping agricultural systems, transforming manufacturing, scrapping gasoline- and diesel-powered vehicles, and replacing most of the world’s power plants.
Carbon dioxide removal offers a way to change the math. Extract large amounts of CO2 from the atmosphere and “negative emissions” could, conceivably, balance out the positive variety. It might even be feasible to cross the threshold of catastrophe and then suck enough carbon out of the air to keep calamity at bay, a situation that’s become known as “overshoot.”
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If anyone can be said to have invented “negative emissions,” it’s a German-born physicist named Klaus Lackner. Lackner, who’s now in his late sixties, is a trim man with dark eyes and a prominent forehead. He works at Arizona State University, in Tempe, and I met up with him one day at his office there. The office was almost entirely bare, except for a few New Yorker cartoons on the theme of nerd-dom, which, Lackner told me, his wife had cut out for him. In one of the cartoons, a couple of scientists stand in front of an enormous whiteboard covered in equations. “The math is right,” the first scientist says. “It’s just in poor taste.”
Lackner has lived in the United States for most of his adult life. In the late 1970s, he moved to Pasadena to study with George Zweig, one of the discoverers of quarks, and a few years later, he moved to the Los Alamos National Laboratory, to do research on fusion. “Some of the work was classified,” he told me, “some of it not.”
Fusion is the process that powers the stars and, closer to home, thermonuclear bombs. When Lackner was at Los Alamos, it was being touted as the energy source of the future. A fusion reactor could generate essentially limitless quantities of carbon-free power from isotopes of hydrogen. Lackner became convinced that a fusion reactor was, at a minimum, decades away. Decades later, it’s generally agreed that a workable reactor is still decades away.
“I realized, probably earlier than most, that the claims of the demise of fossil fuels were greatly exaggerated,” Lackner told me.
One evening in the early 1990s, Lackner was having a beer with a friend, Christopher Wendt, who’s also a physicist. The two got to wondering why, as Lackner put it to me, “nobody’s doing these really crazy, big things anymore.” This led to more questions and more conversations (and possibly also more beers).
The two came up with their own “crazy, big” idea, which, they decided, wasn’t really so crazy. A few years after the original conversation, they produced an equation-dense paper in which they argued that self-replicating machines could satisfy the world’s energy needs, and, more or less at the same time, clean up the mess humans had created by burning fossil fuels. They called the machines “auxons,” from the Greek αυξάνω, meaning “grow.” The auxons would be powered by solar panels and, as they multiplied, they’d produce more solar panels, which they’d assemble using elements, like silicon and aluminum, extracted from ordinary dirt. The expanding collection of panels would produce ever more power, at a rate that would increase exponentially. An array covering three hundred eighty-six thousand square miles, an area as large as Nigeria but, as Lackner and Wendt noted, “smaller than many deserts,” could meet all the globe’s electricity demands many times over.
This same array could also be put to use scrubbing carbon. A Nigeria-sized solar farm would, they calculated, be sufficient to remove all the carbon dioxide emitted by humans up to that point. Ideally, the CO2 would be converted to rock, much the same way my emissions had been converted in Iceland. Only instead of little pockets of calcium carbonate, there’d be whole countries’ worth of it—enough to cover Venezuela in a layer a foot and a half deep. (Where this rock would go,
the two did not specify.)
More years went by. Lackner let the auxon idea slide. But he found himself more and more interested in negative emissions.
“Sometimes by thinking through this extreme endpoint you learn a lot,” he told me. He began giving talks and writing papers on the subject. Humanity, he said, was going to have to find a way to pull carbon out of the air. Some of his fellow scientists decided he was nuts, others that he was a visionary. “Klaus is, in fact, a genius,” Julio Friedmann, a former deputy energy secretary who now works at Columbia University, told me.
In the mid-2000s, Lackner pitched a plan for developing a carbon-sucking technology to Gary Comer, a founder of Lands’ End. Comer brought to the meeting his investment adviser, who quipped that what Lackner was looking for wasn’t so much venture capital as “adventure capital.” Nevertheless, Comer put up $5 million. The company got as far as building a small prototype, but just as it was looking for new investors, the financial crisis of 2008 hit.
“Our timing was exquisite,” Lackner told me. Unable to raise more funds, the company folded. Meanwhile, fossil-fuel consumption continued to rise, and along with it, CO2 levels. Lackner came to believe that, unwittingly, humanity had already committed itself to carbon dioxide removal.
“I think that we’re in a very uncomfortable situation,” he told me. “I would argue that if technologies to pull CO2 out of the environment fail, then we’re in deep trouble.”
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Lackner founded the Center for Negative Carbon Emissions at ASU in 2014. Most of the equipment he dreams up is put together in a workshop a few blocks from his office. After we had chatted for a while, we walked over there.
In the workshop, an engineer was tinkering with what looked like the guts of a foldout couch. Where, in the living-room version, there would have been a mattress, in this one was an elaborate array of plastic ribbons. Embedded in each ribbon was a powder made from thousands upon thousands of tiny amber-colored beads. The beads, Lackner explained, were composed of a resin normally used in water treatment and could be purchased by the truckload. When dry, the powder made from the beads would absorb carbon dioxide. When wet, it would release it. The idea behind the couch-like arrangement was to expose the ribbons to Arizona’s thirsty air, then fold the device into a sealed container filled with water. The CO2 that had been captured in the dry phase would be released in the wet phase; it could then be piped out of the container and the whole process restarted, the couch folding and unfolding over and over again.
Lackner told me he’d calculated that an apparatus the size of a semi-trailer could remove a ton of carbon dioxide per day, or three hundred and sixty-five tons a year. Since global emissions are now running around forty billion tons a year, he observed, “if you built a hundred million trailer-sized units,” you could more or less keep up. He acknowledged the hundred-million figure sounded daunting. But, he noted, the iPhone has only been around since 2007, and there are now almost a billion in use. “We are still very early in this game,” he said.
The way Lackner sees things, the key to avoiding “deep trouble” is thinking differently. “We need to change the paradigm,” he told me. Carbon dioxide, in his view, should be regarded much the same way we look at sewage. We don’t expect people to stop producing waste. “Rewarding people for going to the bathroom less would be nonsensical,” Lackner has observed. At the same time, we don’t let them shit on the sidewalk. One of the reasons we’ve had such trouble addressing the carbon problem, he contends, is the issue has acquired an ethical charge. To the extent that emissions are seen as bad, emitters become guilty.
“Such a moral stance makes virtually everyone a sinner and makes hypocrites out of many who are concerned about climate change but still partake in the benefits of modernity,” he has written. Shifting the paradigm, he thinks, will shift the conversation. Yes, people have fundamentally altered the atmosphere. And, yes, this is likely to lead to all sorts of dreadful consequences. But people are ingenious. They come up with crazy, big ideas, and sometimes these actually work.
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During the first few months of 2020, a vast, unsupervised experiment took place. As the coronavirus raged, billions of people were ordered to stay home. At the peak of the lockdown, in April, global CO2 emissions were down an estimated seventeen percent compared with the comparable period the previous year.
This drop—the largest recorded ever—was immediately followed by a new high. In May 2020, carbon dioxide levels in the atmosphere set a record of 417.1 parts per million.
Declining emissions and rising atmospheric concentrations point to a stubborn fact about carbon dioxide: once it’s in the air, it stays there. How long, exactly, is a complicated question; for all intents and purposes, though, CO2 emissions are cumulative. The comparison that’s often made is to a bathtub. So long as the tap is running, a stoppered tub will continue to fill. Turn the tap down, and the tub will still keep filling, just more slowly.
To extend the analogy, it could be said that the 2°C tub is approaching capacity and that the tub for 1.5°C is all-but-overflowing. This is why the carbon math is so difficult. Cutting emissions is at once absolutely essential and insufficient. Were we to halve emissions—a step that would entail rebuilding much of the world’s infrastructure—CO2 levels wouldn’t drop; they’d simply rise less quickly.
Then there’s the issue of equity. Since carbon emissions are cumulative, those most to blame for climate change are those who’ve emitted the most over time. With just four percent of the world’s population, the United States is responsible for almost thirty percent of aggregate emissions. The countries of the European Union, with about seven percent of the globe’s population, have produced about twenty-two percent of aggregate emissions. For China, home to roughly eighteen percent of the globe’s population, the figure is thirteen percent. India, which is expected soon to overtake China as the world’s most populous nation, is responsible for about three percent. All the nations of Africa and all the nations of South America put together are responsible for less than six percent.
For the world to have a two-thirds chance of staying under 2°C without carbon dioxide removal, CO2 emissions would have to fall to zero within the next several decades. To stay under 1.5°C, emissions would have to fall much faster.
To get to zero, everyone would have to stop emitting—not only Americans and Europeans and Chinese, but also Indians and Africans and South Americans. But asking countries that have contributed almost nothing to the problem to swear off carbon because other countries have already produced way, way too much of it is grossly unfair. It’s also geopolitically untenable. For this reason, international climate agreements have always been based on the premise of “common but differentiated responsibilities.” Under the Paris accord, developed countries are supposed to “lead by undertaking economy-wide absolute emission reduction targets,” while developing countries are called on, more hazily, to enhance their “mitigation efforts.”
All of which makes negative emissions—as an idea at least—irresistible. The extent to which humanity is already counting on them is illustrated by the latest report of the Intergovernmental Panel on Climate Change, which was published in the run-up to Paris. To peer into the future, the IPCC relies on computer models that represent the world’s economic and energy systems as a tangle of equations. The output of these models is then translated into figures that climate scientists can use to forecast how much temperatures are going to rise. For its report, the IPCC considered more than a thousand scenarios. The majority of these led to temperature increases beyond the official 2°C disaster threshold, and some led to warming of more than 5°C (9° Fahrenheit). Just a hundred and sixteen scenarios were consistent with holding warming under 2°C, and of these, a hundred and one involved negative emissions. Following Paris, the IPCC produced another report, based on th
e 1.5°C threshold. All of the scenarios consistent with that goal relied on negative emissions.
“I think what the IPCC really is saying is, ‘We tried lots and lots of scenarios,’ ” Klaus Lackner told me. “ ‘And, of the scenarios which stayed safe, virtually every one needed some magic touch of negative emissions. If we didn’t do that, we ran into a brick wall.’ ”
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Climeworks, the company I paid to bury my emissions in Iceland, was founded by two college friends, Christoph Gebald and Jan Wurzbacher. “We met on the first day of starting university,” Wurzbacher recalled. “I think we asked each other in the first week, ‘Hey, what do you want to do?’ And I said, ‘Well, I want to found my own company.’ ” The pair ended up splitting a single graduate school stipend; each worked half-time on his PhD and half-time on getting their company off the ground.
Four of the IPCC’s “illustrative 1.5° C-consistent” pathways. All of the pathways require negative emissions and result in “overshoot.”
Like Lackner, the two initially faced a lot of skepticism. What the duo was trying to do, they were told, was a distraction. If people thought there was some way to draw carbon dioxide out of the atmosphere, they’d just emit even more of it. “People were fighting us, saying, ‘Well, guys, you shouldn’t be doing that,’ ” Wurzbacher told me. “But we were always stubborn.”
Wurzbacher, who’s now in his mid-thirties, is reed-thin, with a boyish mop of dark hair. I met with him at Climeworks’ headquarters in Zurich, which houses both the company’s offices and its metalworking shop. The place had some of the vibe of a tech start-up and some of the vibe of a bike store.
Under a White Sky Page 13
