Under a White Sky: The Nature of the Future

by Elizabeth Kolbert

As a result of yet another biocontrol effort gone awry, Australia is besieged by a species of giant toad known familiarly as the cane toad. In keeping with the recursive logic of the Anthropocene, researchers at AAHL were hoping to address this disaster with a further round of biocontrol. The plan involved editing the toad’s genome using CRISPR.

“The classic thing people say with molecular biology is: Are you playing God? Well, no. We are using our understanding of biological processes to see if we can benefit a system that is in trauma.”

While carp are a problem in the United States because nothing eats them, cane toads are a menace in Australia because just about everything eats them.

Cooper next turned her attention to “breaking” the toads’ toxicity. Cane toads store their poison in glands behind their shoulders. In its raw form, this poison is merely sickening. But toads can, when attacked, produce an enzyme—bufotoxin hydrolase—that amplifies the poison’s potency a hundredfold. Using CRISPR, Cooper edited a second batch of embryos to delete a section of the gene that codes for bufotoxin hydrolase. The result was a batch of detoxified toadlets.

Spot was mostly brown, with one yellowish hind leg; Blondie was more richly variegated, with whitish hind legs and light patches on his forelimbs and chest. Cooper reached a gloved hand into the tank and pulled out Blondie, whom she’d described to me as “beautiful.” He immediately peed on her. He appeared to be smiling malevolently, though I realized, of course, that wasn’t actually the case. He had, it seemed to me, a face only a genetic engineer could love.

Since the 1960s, it’s been a dream of biologists to exploit the power of gene drives—to drive the drive, as it were. This dream has now been realized, and then some, thanks to CRISPR.

If CRISPR confers the power to “rewrite the very molecules of life,” with a synthetic gene drive, that power increases exponentially.

And there’s nothing special about color in fruit flies. Just about any gene in any plant or animal can—in principle, at least—be programmed to load the inheritance dice in its favor. This includes genes that have themselves been modified or borrowed from other species. It should be possible, for example, to engineer a drive that would spread a broken-toxin gene among cane toads. It may also be possible one day to create a drive for corals that would push a gene for heat tolerance.

With a synthetic gene drive, the normal rules of heredity are overridden and an altered gene spreads quickly.

In a world of synthetic gene drives, the border between the human and the natural, between the laboratory and the wild, already deeply blurred, all but dissolves. In such a world, not only do people determine the conditions under which evolution is taking place, people can—again, in principle—determine the outcome.

GBIRd wanted Thomas’s help designing a very particular kind of mouse drive—a so-called “suppression drive.” A suppression drive is designed to defeat natural selection entirely. Its purpose is to spread a trait so deleterious that it can wipe out a population. Researchers in Britain have already engineered a suppression drive for Anopheles gambiae mosquitoes, which carry malaria. Their goal is eventually to release such mosquitoes in Africa.

Mathematical modeling suggests that an effective suppression drive would be extremely efficient; a hundred gene-drive mice released on an island could take a population of fifty thousand ordinary mice down to zero within a few years.

If the Anthropocene’s clearest geological marker is a spike in radioactive particles, its clearest biological marker may be a spike in rodents. Everywhere humans have settled on the planet—and even some places they’ve only visited—mice and rats have tagged along, often with ugly consequences.

ship rats (Rattus rattus),

The house mouse (Mus musculus) originated on the Indian subcontinent; it can now be found from the tropics to very near the poles. According to Lee Silver, author of Mouse Genetics, “Only humans are as adaptable (some would say less so).”

Gene-drive technology has been compared to Kurt Vonnegut’s ice-nine, a single shard of which is enough to freeze all the water in the world. A single X-shredder mouse on the loose could, it’s feared, have a similarly chilling effect—a sort of mice-nine. To guard against a Vonnegutian catastrophe, various fail-safe schemes have been proposed, with names like “killer-rescue,” “multi-locus assortment,” and “daisy-chain.” All of them share a basic, hopeful premise: that it should be possible to engineer a gene drive that’s effective and at the same time not too effective. Such a drive might be engineered so as to exhaust itself after a few generations, or it might be yoked to a gene variant that’s limited to a single population on a single island.

It has also been suggested that if a gene drive did somehow manage to go rogue, it might be possible to send out into the world another gene drive, featuring a so-called CATCHA sequence, to chase it down. What could possibly go wrong?

The strongest argument for gene editing cane toads, house mice, and ship rats is also the simplest: what’s the alternative? Rejecting such technologies as unnatural isn’t going to bring nature back. The choice is not between what was and what is, but between what is and what will be, which, often enough, is nothing.

The issue, at this point, is not whether we’re going to alter nature, but to what end?

The tree, once common in the eastern United States, was all but wiped out by chestnut blight. (The blight, a fungal pathogen introduced in the early twentieth century, killed off nearly every chestnut in North America—an estimated four billion trees.) Researchers at the SUNY College of Environmental Science and Forestry, in Syracuse, New York, have created a genetically modified chestnut that’s immune to blight. The key to this resistance is a gene imported from wheat. Owing to this single borrowed gene, the tree is considered transgenic and subject to federal permitting. As a consequence, the blight-resistant saplings are, for now, confined to greenhouses and fenced-in plots.

under an obligation. Of course, the argument against such intervention is also compelling. The reasoning behind “genetic rescue” is the sort responsible for many a world-altering screwup. (See, for example, Asian carp and cane toads.)

The history of biological interventions designed to correct for previous biological interventions reads like Dr. Seuss’s The Cat in the Hat Comes Back, in which the Cat, after eating cake in the bathtub, is asked to clean up after himself: Do you know how he did it? WITH MOTHER’S WHITE DRESS! Now the tub was all clean, But her dress was a mess!

Kingsnorth has also observed, “Sometimes doing nothing is better than doing something. Sometimes it is the other way around.”

As power stations go, geothermal plants are “clean.” Instead of burning fossil fuels, they rely on steam or superheated water pumped from underground, which is why they tend to be sited in volcanically active areas. Still, as Aradóttir explained to me, they, too, produce emissions. With the superheated water inevitably come unwanted gases, like hydrogen sulfide (responsible for the stink) and carbon dioxide. Indeed, pre-Anthropocene, volcanoes were the atmosphere’s chief source of CO2.

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.

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.

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.

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.

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.

God help us

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.

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.

mind boggling

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.”

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.

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.

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.)

“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.”

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.

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.

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.

Declining emissions and rising atmospheric concentrations point to a stubborn fact about carbon dioxide: once it’s in the air, it stays there.

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.

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.

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.

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.

“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.’

Burning fossil fuels generates energy. Capturing CO2 from the air requires energy. So long as this energy comes from burning fossil fuels, it will add to the carbon that has to be captured.