Scientists weigh risks of climate 'techno-fixes'

Faced with the specter of a warming planet and frustrated by the lack of progress on this time-sensitive issue, some scientists have begun researching backup plans. They seek a way to give humanity direct control over Earth's thermostat.

Proposals run the gamut from space mirrors deflecting a portion of the sun's energy to promoting vast marine algal blooms to suck carbon out of the atmosphere. The schemes have sparked a debate over the ethics of climate manipulation, especially when the uncertainties are vast and the stakes so high. For many scientists, the technology is less an issue than the decisionmaking process that may lead to its implementation.

Environmental policy driven purely by cost-benefit analyses cannot, they say, effectively point the way on large issues like climate change. But even as many scientists caution against unintended, even catastrophic consequences of tinkering with climate, they concede that the more tools humankind has to confront a serious problem, the better.

Others wonder if the mere hint of a quick-fix solution will only provide a false sense of security and hamper efforts to address the root problem: carbon emissions from a fossil fuel-based economy. And then there's the trillion-dollar question: In a politically fractured world, how will technologies that affect everyone be implemented by the few, the rich, and the tech-savvy?

When scientists talk about geoengineering, they generally mean subtracting a fraction of the sun's energy from the earth equal to that trapped by human-emitted greenhouse gases. It is not a new idea, but only recently has it moved toward the scientific mainstream. In 2006, Nobel Laureate Paul Crutzen of the Max Planck Institute for Chemistry in Mainz, Germany, published a paper on injecting particles into the upper atmosphere to reflect incoming sunlight and cool the earth. Climate scientists have since run scenarios on climate models and first reports found that it might work. In November last year, NASA cohosted a conference on the topic.

It takes only a cursory look at this century's forecast to see the utility of a climate control switch. Currently at 380 parts per million, carbon-dioxide emissions are predicted to double their preindustrial rates, to about 500 ppm, by 2100. Last time there was that much CO2 in the air, palm trees grew in Antarctica and crocodiles sloshed about in the swamps of a tepid Greenland.

The Intergovernmental Panel on Climate Change predicts a temperature increase of 5.4 degrees F. by century's end. It also predicts that, assuming continued emissions, heat stored in the ocean will continue to warm the planet for a thousand years. This last point – that even if we stop all greenhouse-gas emissions tomorrow we're in for a certain amount of warming – is reason enough to look into geoengineering, says Jamais Cascio, a futurist and cofounder of the website worldchanging.com. "If you find yourself in a hole, the first step is to stop digging," he says. "But stopping digging isn't going to get you out of your hole."

By some estimates, geoengineering has the added allure of being cheaper than curbing emissions. Economists say that decarbonizing the economy will cost around 2 percent of the gross domestic product; putting reflective aerosols into the upper atmosphere will cost about one-thousandth of that, says Ken Caldeira, a climate scientist at the Carnegie Institution at Stanford University.

But others say the discussion over mitigation seems to have gotten ahead of itself. Why talk about fixing symptoms when we have the technology to address the root cause? "There's no getting around the fact that we're in a very desperate situation," says Bill McKibben, author of "The End of Nature" and more recently "Deep Economy." But "before geoengineering, let's do a little policy engineering first."

History seems to support Mr. McKibben's critique. The Clean Air and Clean Water Acts of the 1960s and 1970s, which cost more than the estimates for curbing emissions today, are seen in retrospect as absolutely the right thing to have done. That such costs are now viewed as untenable speaks to the shortcomings of the cost-benefit approach that has driven environmental policy for the past 25 years, says Frank Ackerman, director of research and policy program at the Global Development and Environment Institute at Tufts University in Medford, Mass.

Simply put, economic analyses can't deal with far-reaching, long-term problems like climate change or geoengineering, he says. There are too many unknowns. "Changing the earth's climate is an experiment we're going to do once," he says. "There are not going to be any do-overs."

For this reason, many call global warming a moral issue, not an economic one. There are certain relationships that cannot be assigned numerical values. "If you just looked at it from a cost-benefit point of view, Central Park is completely irrational," says Dale Jamieson, director of environmental studies at New York University. "Yet, nobody would think that the fact you can sell Central Park to Donald Trump is reason to do it."

Others point out that the mere mention of a techno-fix for climate change could have unintended consequences. If people know that someone will bail them out of catastrophe, they're more inclined to engage in risky behavior, says David Keith, director of an energy and environmental systems research group at the University of Calgary. Statistically speaking, those with flood insurance suffer the worst flood damage, he says. And because geoengineering may lead to greater risk-taking – in this case by continuing to emit copious amounts of CO2 – "it's clearly not, in some global sense, economically optimal," says Mr. Keith.

But Mr. Cascio points out that fail-safe technologies could also drive humanity in the other direction. If people understand that these technologies are a terrible last resort, the specter of their deployment may serve as a deterrent the way mutually assured destruction (theoretically) saved the world from a nuclear holocaust during the cold war. The parallel has to be made clear: "You are consciously trying to alter the complex systems that govern how our planet operates," he says. "Do that the wrong way, and you potentially kill everyone."

Not discussing these options could be worse, says Scott Barrett, professor of environmental economics at Johns Hopkins University in Washington, D.C. If scientists don't talk about geoengineering, the institutions and regulations governing its implementation will not be created. "The point may come where countries may experiment and there will be no international arrangements," Professor Barrett says.

We have to "bring this thing out into the open."

Because climate change has winners and losers – one country's breadbasket dries up while another's desert blooms – unilateral change becomes a sticky prospect. Manipulation – even if it's viewed as a corrective measure – will inevitably impinge on another's newfound good fortune. "Even if you're very confident that you can make things better, that doesn't necessarily give you the right to do that if, in fact, you're affecting other people's interests," says Professor Jamieson.

Ken Caldeira posits another possibility: "You could imagine some kind of arms race of geoengineering, where one country is trying to cool the planet and another is trying to warm the planet," he says.