Rising global temperatures have prompted a flurry of investigations into large-scale geoengineering efforts that could potentially help keep Earth cool. One proposed strategy is solar geoengineering, which would most likely involve the release of aerosols into the atmosphere to reflect solar radiation back into space, preventing it from heating the planet.
Theoretically, a single country—or group of countries—could unilaterally decide to deploy solar geoengineering, resulting in worldwide climate effects. Thus, some may wish to develop countergeoengineering strategies to thwart others’ efforts. Although this idea is not new, Parker et al. now present the first serious academic analysis of countergeoengineering, exploring its potential development and political effects.
There are many potential circumstances that might prompt countries to counter solar geoengineering. For instance, some countries could face harmful climate effects resulting from another country that lowered temperatures below a certain threshold. Others might object to solar engineering out of concerns that it could disincentivize efforts to reduce carbon dioxide emissions, leaving its harmful effects—like ocean acidification—to increase unchecked. A country might even seek to deliberately harm another through geoengineering.
To understand these dynamics, the researchers first examined what technologies to counter solar geoengineering might look like. Such techniques might consist of substances released into the atmosphere to directly neutralize reflective aerosols, or they could take the form of greenhouse gases or aerosols that have warming effects, indirectly opposing solar engineering. According to the researchers, it would be challenging to develop such technologies, but it is theoretically possible.
Using a simplified game theory approach, the researchers demonstrate how the threat of countergeoengineering from one country could theoretically deter another country’s use of solar geoengineering. Similar to nuclear arms, geoengineering and countergeoengineering technologies would not actually need to be used in order to have a significant influence on policy making.
Deployment of these technologies likely would be very gradual, however, compared, for example, to the immediate destruction unleashed by a nuclear weapon; this would allow more time for complex international negotiations. The researchers also outline the possibility of a dangerous, escalating arms race between warming and cooling efforts, which could result in environmental risks for people around the world.
Given the practical challenges and the expense of countergeoengineering technologies, their future development would likely stem, in part, from the failure of countries to cooperate in efforts to mitigate climate change. For that reason, the researchers express hope that these technologies will never be pursued. Nonetheless, a time may come when detailed assessment of different countergeoengineering proposals is possible and necessary. (Earth’s Future, https://doi.org/10.1029/2018EF000864, 2018)
—Sarah Stanley, Freelance Writer