Geoengineering the Global Climate: Pax Climatica?
July 09, 2009
The Obama administration's commitment to re-engage the international community on climate change has kindled hopes that negotiations in Copenhagen later this year can hammer out a new agreement on combating global warming to succeed the expiring Kyoto Protocol. Yet regardless of the outcome in Denmark, building pressures on the climate system risk overwhelming developments in the diplomatic arena. World greenhouse gas (GHG) emissions now surpass the highest scenarios anticipated by the Intergovernmental Panel on Climate Change, and observed temperature changes to date are already climbing beyond their previously projected range, suggesting that the chance of significant negative impacts is appreciably higher than foreseen just a few years ago.
Alarmed by this mounting danger, a growing number of analysts are urging policymakers to undertake the scientific and policy spadework necessary to prepare geoengineering measures against global warming. Geoengineering entails intentional, large-scale intervention in the mechanics of the climate system, either by removing greenhouse gases from the atmosphere or by reducing the solar radiation that reaches the Earth. Strategies in the first category include proposals to chemically filter CO2 from the air and sequester it underground or to fertilize the oceans with nutrients to encourage the growth of carbon absorbing phytoplankton. Strategies in the second category include launching space-based mirrors into orbit or injecting reflective particles into the stratosphere to block a portion of the incoming solar energy.
Proponents advance two related arguments for contemplating such alternatives. First, despite the guarded optimism engendered by the shift in America's stance, recent analysis of current emissions trajectories underscores the increasing improbability of restraining global warming below the 2oC threshold that many experts consider dangerous. Reversing these trends will require a radical de-carbonization of the global economy and root-and-branch restructuring of the world energy system, an arduous process that has been compared to turning around a supertanker in a sea of syrup. Geoengineering approaches, by contrast, necessitate neither such fundamental societal transformations nor the associated economic costs. Relying on the targeted application of specific technologies, many already available, geoengineering could potentially stabilize the climate in as little as a few months rather than several decades.
The halting progress of international negotiations toward collective emissions reductions commitments underlies the second reason for policymakers to consider geoengineering options. Global emissions mitigation demands broad participation to be effective. Geoengineering measures, on the other hand, needn't wait upon the cumbersome machinery of international coordination. Such policies could allow a small group of nations or even single state possessing the requisite technical capacities to provide a stable climate system for all, much as Britain earlier supplied the 19th century stability of the Pax Britannica.
For its supporters, then, geoengineering can furnish a bulwark against catastrophic climate change, a backstop option that should be developed in case global warming proves more severe than expected or global diplomacy less effective than hoped. Critics, however, contend that pursuing such approaches perversely undermines incentives for countries to reduce their GHG production, knowing geoengineering technologies can offset their emissions. Moreover, deliberately meddling with the climate system to counteract our prior inadvertent interference could have disastrous unintended side effects. Consequently, no country would readily accept that another state (or group of states) might unilaterally move to control the climate. Advocates respond that this is precisely why governments should move now to test potential strategies in advance and forge preliminary understandings to govern their use. Geoengineering technologies, they argue, should be part of a portfolio of solutions, including collective emissions cuts. Rather than as an emergency switch to be thrown to stop all climate change, geoengineering should be treated as a knob to be turned up as needed to complement other measures and buy time for them to work.
Unfortunately, such a carefully calibrated approach would likely prove supremely difficult to carry off. If initial research and testing indicates that geoengineering strategies would be successful and safe, tremendous struggles will ensue over how vigorously to turn the knob. In the countries actually developing and deploying the technologies, it will be very challenging for governments to argue to their own constituents - much less to citizens of other countries - that, although geoengineering could effectively roll back the climate threat from greenhouse emissions, publics everywhere must nevertheless continue to bear the burdens of rapidly retooling the global economy away from fossil fuels. For the rest of the world, it will matter less how far the advanced countries turn the dial than that some countries could unilaterally determine the climate for all the others. Whatever level of control the geoengineers attempt, different nations will feel disparate impacts and will hold the geoengineering states responsible for the results. It is hard to imagine what preliminary understanding besides an unlikely international consensus could smoothly resolve this problem. If initial research and testing gives more equivocal results, suggesting that geoengineering strategies can work but carry a meaningful risk of negative consequences, then these debates will be all the more contentious.
Geoengineering options should not be ignored. They cannot be accurately evaluated if they are not first effectively explored. Nevertheless, decision makers would do well to think through the political as well as the climatological scenarios that could arise from recourse to these technologies. Rather than providing policymakers a possible path around the worst thickets of global climate diplomacy, adopting geoengineering alternatives appears likely to cast them directly into the thorniest international issues.
 Joel B. Smith et al., "Assessing Dangerous Climate Change Through an Update of the Intergovernmental Panel on Climate Change (IPCC) 'Reasons for Concern'," Proceedings of the National Academy of Sciences, vol.106, no.11 (2009).
 Kevin Anderson and Alice Bows, "Re-Framing the Climate Change Challenge in Light of Post-2000 Emissions Trends," Philosophical Transactions of the Royal Society A, vol.366, no.1882 (2008).
David Michel is a Research Fellow with the Stimson Center's Regional Voices: Transnational Challenges project.