It's well known that Republicans base their climate change policy on scientific fallacy. But Democrats and the European Union do so, too—not of earth science, but social science. Their core belief—that a worldwide agreement to reduce emissions is the best policy to pursue—flies in the face of game theory and political science. Instead, we must seek solutions that do not require unprecedented international coordination and cooperation. One solution in particular should become a national priority: capturing carbon directly out of the air. 

The parties to the U.N. Framework Convention on climate change just finished their 20th annual meeting in Lima, having agreed on a historic multilateral emissions treaty to be finalized at a later date—specifically, at the annual meeting in Paris next year. But the treaty's success remains unlikely for the same reason an effective international agreement has eluded the world for the last 20 years. It is not world leaders’ lack of prudence or morality, but rather the nature of rational choice in the international system.

Climate change is what game theorists refer to as a “tragedy of the commons” or a multi-player “prisoner’s dilemma.” No state acting alone, even holding its emissions to zero, could prevent global temperature from rising 3.6 degrees Fahrenheit over the preindustrial average, the accepted (if somewhat arbitrary) tipping point, after which the most serious effects of warming emerge and become practically irreversible. As a result, it’s in each state’s rational self-interest not to reduce its emissions. If other states cooperate, even a non-cooperating state will receive the resulting benefits, but without having to pay the costs of reducing its own emissions. If cooperation fails instead, the state will not have wasted its resources pursuing those reductions. Ultimately, it’s optimal for a state to sign an agreement to spur others to action, but with no intention of ever upholding its own obligations. Since everyone shares this logic, it creates an environment of mistrust going into Paris. 

There are solutions to such collective action problems. The most effective is to force actors to keep their obligations by punishing free riders. This is what domestic governments do; but, of course, there is no global government.  The second-best solution is to “repeat the game.” Research shows that actors can learn to cooperate if they repeatedly experience the mutual destruction that their selfish behavior creates. Climate change, however, which worsens over a tipping point, presents no such learning opportunity. It’s a game we play one time. 

Game theory isn’t always right. There are counter-examples of truly international cooperation on climate change.  The 1987 Montreal Protocol, for instance, banned substances that interfere with the ozone’s absorption of UV rays. It was signed by every U.N. member and has been updated 10 times. But banning chemicals in aerosol cans and refrigerators is cheap, certainly by comparison to cutting emissions by 40 to 70 percent of 2010 levels by 2050, what the International Panel on Climate Change (IPCC) says is required to “likely” maintain warming below the temperature threshold. 

Beyond these economic obstacles, global politics demand that the U.S., as the most powerful nation and the second-biggest emitter, ratify any treaty. This means that it would have to pass a Republican-controlled Senate. What are the chances of that? Now consider the legitimate grievances of developing nations, who are asked to pay for the developed world’s 19th and 20th century emissions. When you add these economic and political barriers to the inherent limitations of international cooperation, basic social science—indeed, common sense—indicates that genuine success in Paris is improbable. We should still pursue it in earnest, but we ought to search for insurance policies. 

One solution is “air capture,” the process of taking carbon directly out of the air. It uses alkaline “sorbents” that bond naturally with the acidic carbon dioxide that is present in all air found anywhere on Earth. The CO2 can be stored safely—by, for example, converting it into rock—or it can be used for commercial purposes. Air capture’s future depends on its cost. In 2011, the American Physical Society estimated that it would cost $600 per ton of captured carbon. This is too expensive, given that humans emitted about 10 billion tons of carbon in 2013. But the science on which this estimate was based is already outdated, Klaus Lackner, the leading air capture researcher, explained to me. Lackner, who recently moved his lab to Arizona State from Columbia University, estimates that the technology he developed with Allen Wright, an “artificial tree” that absorbs carbon “passively” from the air, could capture carbon at $100 a ton. David Sholl’s group at Georgia Tech offers a similar estimate for their technology. Lackner believes that the limits for his current version, assuming mass production efficiencies, hover around $30 per ton.

Lackner and others in the field generally view their work as part of a future carbon market. But such markets are exceedingly complex, and require total global cooperation. They’re thinking too small. Air capture opens the door to straightforward (but massive) top-down solutions. If $30/ton were indeed possible, the U.S. government could construct huge forests of “artificial trees” in American deserts and absorb 30 percent of 2013’s carbon emissions for about $90 billion per year, probably sharing production and upkeep costs with the E.U., and possibly asking for payments from emitting nations and corporations. If, at the same time, worldwide emissions fell by only 10 percent, then you are nearing an answer.  

Technology like air capture takes us out of the “tragedy of the commons.” It does not require worldwide cooperation. A purely rational state or group of states would pay for it on their own, assuming their climate change costs outweighed project costs. That the world benefitted for free would not matter from a self-interested perspective. And from a moral perspective, it would be a good for the U.S. and the E.U. to clean up a mess we largely created. 

This technology is young. There have only been small demonstrations. But technological progress, while never guaranteed, is sometimes exponential.  Solar panels are almost 100 times cheaper than in the 1950s. The gas turbine engine continues to get more efficient. We don’t know how high these artificial trees will grow. The historic amount of funding for air capture research, in the tens of millions, needs to be increased dramatically. The IPCC itself envisions a huge role for carbon capture and storage, especially in the latter half of the 21st Century.

Air capture funding has been low not because the technology lacks promise, but because it has little value outside of government demand. There’s no real money to be made from collecting carbon from the air—unlike, say, collecting energy from the sun. For the technology to develop, the government must fund it. President Obama should diversify his climate change portfolio by funding a sort of Manhattan Project for air capture. We need to hedge our bets on Paris, the forecast for which, even after the groundbreaking agreement in Lima, remains cloudy.