Future Tense

Farm the Oceans to Help Stop Global Warming

It’s a controversial idea—but it’s already happening anyway.

Great pods of thousands of whales once fertilized aquatic plant life as they traveled.

Eitan Abramovich/AFP/Getty Images

This essay is excerpted from The Unnatural World: The Race to Remake Civilization in Earth’s Newest Age by David Biello, published by Scribner.

On Wednesday, Nov. 16, David Biello will discuss The Unnatural World in Washington, D.C., at a happy hour event hosted by Future Tense—a partnership of Slate, New America, and Arizona State University. For more information and to RSVP, visit the New America website.

The Southern Ocean is a forbidding place, mostly unvisited by humans. Winds of more than 120 kilometers per hour wreak havoc, and waves routinely wash up and over the bow of any ship that dares to venture so far south, drenching the decks in ice-cold sea spray that instantly freezes. Worse, rare freak waves can build to towering heights and flip a ship in place. Looming icebergs can fatally wound an unwary or unarmored vessel. Beyond this storm-tossed sea lies Antarctica, locked in deep freeze by a current that reaches 4,000 from sea surface to ocean bottom and spans thousands of kilometers in its endless encircling moat. And the Southern Ocean is where the mustachioed marine biologist Victor Smetacek, like any good scientist with a plan to change the world, hopes to change the sky with the power of the sea.

Since the 1980s, Smetacek has ventured aboard the Alfred Wegener Institute for Polar and Marine Research’s sturdy icebreaker Polarstern to study plankton in their native habitat: the Southern Ocean. It is there that phytoplankton show their full diversity. One family, the diatoms, their elaborate shells made of the same element as sand—baroque twisting nets, thistles and thorns, even pod-shaped landing craft—guard the ocean-drifting cells as they busily turn carbon dioxide into food using the energy in sunlight. Like a jumble of children’s blocks of all shapes and sizes, a sample of seawater turns up countless thousands of the most abundant life form on the planet and the base of the global food chain. And some scientists argue that phytoplankton can change the world, given enough nutrients. “Give me a half tanker of iron, and I will give you an ice age,” the oceanographer John Martin growled at a lecture at the Woods Hole Oceanographic Institution in 1988.

Plankton and their ancestors were the first geoengineers—large-scale manipulators of the entire planet and its biological, geological, and chemical processes. Some 2.4 billion years ago, photosynthetic bacteria began to bubble out oxygen. By 1.7 billion years ago, oxygen made up 10 percent of the atmosphere—a massive change in the chemical composition of the air. Slowly at first, but steadily, the atmosphere became dominated equally by geology and biology, off-gassing from volcanoes, and emanations from life combining to wreath the planet in a particular mix of gases.

Now the burning of untold eons’ worth of this captured and fossilized sunshine—otherwise known as coal, oil, and natural gas—has changed that mix of gases again. Carbon dioxide piles up in the sky, swathing Earth in a slightly different mix of opaque gases that prevent the planet from shedding back to space some of the sun’s ceaseless heat. To throw off that greenhouse gas blanket, why not simply copy nature? Use photosynthesis to bind that excess CO2 in carbohydrates and then bury that food beneath land or sea. Given that the plankton of the sea produce 70 percent of the oxygen in the atmosphere, these prolific tiny plants seemed a good place to start. Scientific experiments and even accidents of industry have shown that plankton blooms can be reliably induced with the addition of extra trace nutrients like nitrogen, phosphorus and, in the case of Smetacek’s work, iron. That’s Smetacek’s grand scheme: fertilize the ocean with iron. This is the Anthropocene as direct action, turning the wildest wilderness into a kind of farm.

But not everyone supports the idea, or even experiments to see whether it would even work. And that’s thanks to the efforts of a peripatetic citizen-scientist named Russ George who tried to turn plankton blooms into gold.


Back in 2007 George formed Planktos Inc. and raised funds for an expedition to the Galápagos Islands to dump iron in the water. He would sell the rights to the CO2 sucked in by any subsequent plankton bloom. This is the core idea of an “offset”: You reduce CO2 by, say, fertilizing a plankton bloom, and then sell the credit for that sucked-up CO2 to someone emitting a lot of CO2, like the owner of a coal-fired power plant. And Planktos wasn’t alone in trying to sell the idea: At the time, San Francisco–based Climos had a similar plan, as did Virginia-based GreenSea Venture. (Both companies seem to be defunct now.) The schemes attracted investors including Elon Musk, wunderkind of electric cars and space travel these days but not shy of geoengineering then or now. The scheme promised a forestry of the sea, but it really was more like boosting sapling growth by dumping a ton of fertilizer on otherwise degraded land in the hopes that something green would grow faster and more abundantly.

George’s expedition actually set sail, embarking in the Weatherbird II on a self-declared “Voyage of Recovery” on Nov. 5, 2007, with plans to fertilize an area of ocean twice as big as Rhode Island off the Galápagos. But within the span of a few months, George went from testifying before Congress on the benefits of iron fertilization and carbon credit sales to being an international pariah. By December, the Weatherbird II had become a modern Flying Dutchman, homeless until the ship’s crew promised to suspend operations and docked in Madeira. By February 2008, the Voyage of Recovery had been indefinitely postponed.

But George was not done. He partnered with the Haida people of British Columbia to dump iron at sea in a bid to restore the salmon in 2012. George and a band of Haida fisherfolk set to sea in a rusting fishing vessel, dusting the sea. A bloom of some sort followed a few days later in satellite pictures from NASA. As word of the unexpected mini-geoengineering test leaked out, a global media frenzy kicked off. George had hacked the planet, perhaps to the rest of humanity’s chagrin. Was this an instance of villagers taking care of a problem in their backyard, as George argues, or a case of native peoples who long relied on a wild resource attempting to husband that resource back to health? Or was it rogue geoengineering?

If the latter, are the farmers of my native Midwest rogue geoengineers, given the annual dead zone in the Gulf of Mexico? Or are the cities of the world, the Detroits and Stockholms and Qingdaos, changing the planet by prompting “green tides” with sewage? Intention is all, apparently.

In the meantime, George’s machinations for “organic gardening” of the sea did have a lasting effect. Iron fertilization was seen as a crazy scheme. But we don’t know how dangerous (or not) ocean fertilization is—and we won’t know without experiments.

In some sense, iron fertilization is just the restoration of an old cycle. Great pods of thousands of whales once graced the global sea, fertilizing aquatic plant life as they traveled by defecating, their poop rich with iron from a steady diet of krill. “Krill is like a sponge,” Smetacek enthuses, “a reservoir of iron.” Whale poop fertilized the oceans like manure from cows and buffalo on land, only the whale’s liquid poop disperses in the water column, perfect to feed a plankton bloom and keep the cycle of life cycling. Here sperm whales play a key role—pooping out nutrients captured at depth and adding to the overall total, according to research Smetacek helped conduct. But people hunted out most whales decades ago, slowing this vital cycle. And the krill are disappearing, perhaps due to the loss of the whales, perhaps climate change, perhaps overfishing, perhaps all these insults and more.

Cut off from most continental dirt and dust, the plankton of the Southern Ocean cannot get enough iron to grow. Fertilizing these waters with the metal could promote blooms that then suck CO2 out of the air. When the microscopic creatures die, they sink in tens of millions to the bottom of the ocean and bury the carbon with them. In addition to helping combat climate change, such fertilization might ultimately even help whale populations rebound, abundance propagating from plankton to krill to blue whale, the world’s largest extant animal.

That’s because the tiny plants of the sea require 1 nanogram of iron per metric ton of water to grow, or roughly a paper clip’s worth in several hundred thousand Olympic-size swimming pools. And the subsequent blooms are quite natural: The waters nearer to Antarctica reliably turn pea-soup green at the end of the austral summer in November when the sea ice retreats.

In fact, Smetacek may not even have to do anything; the meltdown of Antarctica may do his work for him. As the glaciers dwindle, melting down as the globe warms under the blanket of greenhouse gases added by human pyromania, long-frozen iron fills the sea, fertilizing yet more blooms. But humans could also intervene more forcibly, boosting blooms or farming algae or trees to bury in the deep sea.

This is all a transition, in thinking as much as in reality. The sea is becoming a farm. Cages for rearing salmon crowd the waters from Scandinavia to Chile, and ponds for raising shrimp have replaced half the world’s coastal mangrove swamps.

Smetacek still has that drive to make the world right, or at least help people to think clearly about the challenges we now face. We are in a new age if some of us can contemplate intervening in the most powerful biological loop on the planet, one that has guided Earth for billions of years, through countless geologic epochs. Phytoplankton have nurtured the profusion of life on this planet, so now perhaps it’s time for them to be nurtured. “There’s no point in hanging on to things or saying it used to be like this. That’s changed, anyway,” he observes, with perhaps a tinge of regret in his voice. “We’ve changed everything.”

Excerpted from The Unnatural World: The Race to Remake Civilization in Earth’s Newest Age by David Biello. Copyright © 2016 by David Biello. Published by Scribner, a Division of Simon & Schuster, Inc. Reprinted with permission.

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