A narrow hose made of composite fibers rises 18 miles over the Arctic. Supported by V-shaped balloons, it sprays 34 gallons per minute of sulfur dioxide into the earth’s stratosphere. Slowly, the aerosol reflects the sun’s rays back into space.
The temperature cools. The Arctic ice stops melting. Sea levels stabilize, no longer threatening to rise and wipe out coastal cities. Presto! No more global warming.
A crisis is an opportunity in disguise. And climate change, already linked this season to such things as monster blizzards in Alaska, mild weather in the Northeast, and killer tornadoes in the South, has started to attract engineering ideas like the StratoShield from a company called Intellectual Ventures, founded by the former chief technology officer at Microsoft and backed with money from Bill Gates.
Whether they ever work or not, these technologies acknowledge that the climate is already changing irreversibly, no matter how much the emission of greenhouse gases is reduced. And the next phase in the human response to global warming may be engineering a way to fix it, often in ways that sound like they come out of Hollywood or science fiction.
“The question is not, is there going to be climate change or isn’t there? It’s how much climate change are we going to tolerate,” says Roger Aines, who heads the geochemistry group at Lawrence Livermore National Laboratory, where he studies ways to bury carbon dioxide in the porous ground beneath Montana and Wyoming. “We spent the first 10 years trying to teach people about this, and now we’re entering a second phase where new ideas are going to be tried.”
Most of these so-called geoengineering proposals fall into two categories. The first entails scrubbing carbon dioxide from the atmosphere by, for example, building windmills that would pass it over an absorbent chemical, or planting fast-growing trees and microwaving them into charcoal to trap the CO2 they capture. The second involves reflecting solar radiation to cool the planet’s temperature by, say, spraying sulfur dioxide through those hoses or from fleets of 747s, launching billions of reflective balloons, firing sunlight-reflecting mirrors into space, or floating thousands of barges across the world’s oceans pumping salt spray into the atmosphere to swell the size of clouds that block the sun.
“We’re at the extremely early part of the discussion, but there are several groups of people who are beginning to think about this and wonder how it might work,” says Jane Long, associate director at Lawrence Livermore.
Long chaired an 18-member task force on geoengineering set up by the Bipartisan Policy Center, which added new momentum to the field with a report released in October urging coordinated research into these ideas.
The first and most important step, she says, “is to stop causing the problem” and reduce the emission of greenhouse gases. “But even if we stopped emitting tomorrow, we’ve already bought on climate change for the next thousand years. So we need to find a way to live with that. Very, very few scientists are advocating that we do these things yet, but we need to start thinking about it. We should have as many tools as we can if we need them.”
Critics worry that trying to manipulate the planet—which the Bipartisan Policy Center task force euphemistically called “climate remediation”—would do more environmental harm than good. But others are impatient.
“The sooner we take measures, the sooner they will start working,” says Victor Smetacek, a professor of biological oceanography at the Alfred-Wegener Institute in Germany who is experimenting with adding iron filings to the ocean to grow phytoplankton that “eats” CO2 and then sinks, effectively burying the carbon on the sea floor. Also called the Geritol project, the idea has been undergoing testing, but Smetacek’s journal article about his results is being held up by skeptical reviewers.
The pace of change will quicken, Smetacek says, when the effects of global warming become more evident. “If you get a couple of severe climate events, it will swing public opinion,” he says. “Everything will change when things get worse.”
Other, smaller solutions are—literally—more down to earth. Panels of scientists in South Florida are studying flood-control measures to protect its low-lying cities from rising sea levels. In California, work has begun on new ways to store water, making up for the disappearing snowpack that provides as much as a third of that state’s water supply. The British Institute of Mechanical Engineers has proposed painting roofs white to reflect heat. Scientists in Minnesota are working to improve the roots of trees to help them deal with anticipated droughts.
“Let’s say you now know that the city of New York is going to be exposed to a flood surge every year,” says Long. “All the subways are underwater. What are you going to do about it? Those are the kinds of engineering problems that are definitely amenable to competitive approaches.”
They’re also more realistic in the short-term.
“None of these are the single solution. That doesn’t mean we shouldn’t try to do them,” says Ken Buesseler, a senior scientists at the Woods Hole Oceanographic Institution. “I see them as small nudges that may make the planet better off.”
Photo courtesy of NASA