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May 21, 2009

Man-made plans to engineer the climate may sound crazy, but so does a planet too hot to support life.

By Tara Kyle

Two decades ago, the movie version of The Avengers pitted John Steed and Emma Peel against Sir August de Wynter, a villain trying to destroy the world by using a machine to control the weather.
Fast forward to today: man-made methods of altering the climate have become a subject for serious scientists and foreign policy experts. In order to halt global warming, some of our leading thinkers are developing strategies to blow sulfur into the stratosphere, seed clouds and rocket millions of tons of tiny mirrors into space.

Welcome to the World of Geo-Engineering

“There has been a traditional sense that this is a topic not to be thought about; it is just too irresponsible and outlandish,” says John Steinbruner, director of the Center for International and Security Studies at the University of Maryland.
“There still are some people who would like to categorically declare it to be taboo, but that looks to me like it will be impossible. The mainstream people are beginning to say we can’t afford to take that attitude, we have to look at it.”
That’s not to suggest that those same mainstream people are prepared to advocate for these ideas.
“My initial reaction was ‘gee, we ought to make a ban on this in the same way that we’ve got a ban on, for example, chemical or biological weapons,’” says Granger Morgan, director of Carnegie Mellon’s Climate Decision Making Center.

Fooling with Mother Nature

But the cat is already out of the bag, since at least some geo-engineering projects are technically feasible and could be relatively inexpensive.
These factors make it conceivable that a single nation—or even a single company—could attempt to change the climate.
The result is that mainstream organizations from the Council on Foreign Relations to Britain’s Royal Society are looking at the possibilities and implications of geo-engineering. At the National Commission on Energy Policy, geo-engineering is “an issue we’re starting to pay attention to in a much more serious way,” says research director Sasha Mackler.
The commission has yet to take a formal position on the matter, and Mackler cautioned that he is not “particularly happy about the idea of diving deep into geo-engineering.” But he acknowledges that directly manipulating the climate could play a role alongside mitigation (the act of directly reducing CO2 emissions) and adaptation efforts to help humans cope with global warming.
Most geo-engineering strategies aim either to remove greenhouse gases from the air through direct carbon capture or to reduce their effects by increasing the amount of heat reflected away from the Earth.
And while the issues with carbon capture have to do primarily with large-scale economic feasibility, tackling the problem by increasing the amount of sunlight that is reflected by the Earth and its atmosphere—called the albedo—could be cheap.
“If a couple billionaires in the world decide to fund this thing, they could do it,” says Juan Moreno-Cruz, a doctoral student working on geo-engineering and economic growth at the University of Calgary.
It’s just that no one seems sure what the full array of consequences could be.
First off, projects that are beneficial for one country or region might change temperatures, rainfall or wind patterns in a way that is detrimental to another.
Furthermore, each geo-engineering method has its own potential pitfalls. For example, injecting sulfur, a known pollutant, into the stratosphere could adversely impact respiratory health.
That’s why Ken Caldeira, a scientist with the Carnegie Institution for Science’s Department of Global Ecology and a ten-year veteran of geo-engineering research, doesn’t see these systems as part of a routine solution to climate change.
“If there’s a knob to turn on how much you are going to engineer the planet…different knob settings are going to affect people in different ways,” he says. “I think most countries are not going to want to deal with that.”
However, Caldeira believes geo-engineering could function as an emergency back-up plan. He imagines a catastrophic event occurring in 2020 or 2040, such as the sinking of Greenland or the release of huge amounts of methane gas from under melting permafrost in Siberia. In those scenarios, a global effort to achieve a quick fix might make sense.
But there’s another reason scientists are hesitant to use geo-engineering unless absolutely necessary: they believe once a project is started, it could be hard to stop. And since so many variables exist with different geo-engineering methods, that’s a big chance to take.

Is Anyone in Charge?

Steinbruner worries that no agreement is in place mandating that individual countries “don’t mess around with the global environment.” He and many scientists see few systems in place to develop even a rudimentary level of oversight to monitor experiments that could get underway within the next few years.
Yet with dire environmental scenarios in the public consciousness, geo-engineering seems unlikely to go away.
“There is some risk that sooner or later someone is going to start talking seriously about doing this,” says Morgan. “It’s much better to be thinking and talking and understanding what the potential pros and cons are—which we don’t understand and won’t until we’ve mounted a significant research program—than to just pretend it doesn’t exist.”

Ideas to Save the Earth

Cloud Seeding

The Brainstorm: Boats would spray seawater into the troposphere in order the increase the whiteness of cloud formations. This proposal, explored by The Royal Society, would cause the clouds themselves to reflect more sunlight, thus increasing the Earth’s albedo.
The Lowdown: “The idea is pretty,” says Moreno-Cruz, who notes that it would be expensive in terms of both dollars necessary to build the boats and energy bills necessary to blow up the seawater. And Caldeira cautions that while seawater spraying sounds benign, “it is a step down a slippery slope toward climate control.”

Ocean Fertilization

The Brainstorm: Seeding the ocean with nutrients like iron should cause a bloom in the population of phytoplankton, which eat carbon. Although most of this carbon returns to the atmosphere when the plankton die, around 10 percent falls to the sea floor in a natural form of carbon sequestration. So more plankton should mean more carbon sink.
The Lowdown: “This is a lesson for everyone,” says Moreno-Cruz of a recent experiment by a team of Indian and German scientists. Turns out more plankton can also mean more crustaceans…which would eat all the plankton. “It was one of those technologies that seemed like an obvious bet it was going to work, and then it didn’t for a reason that nobody thought of before.”

Mirrors in Space

The Brainstorm: Deflect sunlight away from the Earth before it hits the atmosphere by placing 20 million tons of thin refracting discs or “flyers” at the Lagrange Point (L1). This spot, 1.5 Gm away from the Earth and 150 Gm from the sun, is gravitationally stable.
The Lowdown: As proposed by the University of Arizona’s Roger Angel, this system could cost around $5 trillion and would be difficult to take down once in place. “That’s all kind of far out,” says Morgan. “Putting something at the L1 point is nontrivial.”

Converting Landscapes

The Brainstorm: Replace dark forests with more reflective grasslands. Since dark shades absorb much more sun than lighter ones (fresh snow has an albedo of about 90 percent, while charcoal’s albedo is about 4 percent), this should increase the Earth’s average albedo.
The Lowdown: “It’s not very rational,” says Moreno-Cruz, because “land is a very, very scarce resource, and you would need to use a lot of it for it to have a good effect.” Given other demands on land use, such as agriculture and timber, Moreno-Cruz doesn’t see any free space of sufficient size outside of the Sahara, which is already light enough to reflect plenty of sun (about 40 percent).

Direct Air Capture

The Brainstorm: Use big turbines to effectively suck carbon from the air. While power plants are already starting to work with cost-effective carbon capture systems, the University of Calgary is among the institutions working on turbines that can do this from anywhere on Earth.
The Lowdown: This technique, sometimes considered outside the parameters of geo-engineering, “could prove to be an enormously important part of the portfolio of tools we use to try to deal with climate change,” says Mackler. Unlike albedo modification strategies, it would actually remove some of the C02 created by diffuse sources, like cars and airplanes, which contribute to over half of greenhouse gas emissions.

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