Deliberate large-scale technological interventions in Earth's climate system — such as stratospheric aerosol injection or ocean iron fertilization — intended to counteract global warming. Debate weighs its potential as an emergency measure against profound risks and governance challenges.
If emissions reductions prove insufficient to prevent catastrophic warming, solar geoengineering might buy time to reduce suffering from climate impacts. Refusing to research it on principle is irresponsible when the costs of unmitigated warming are potentially civilization-threatening.
Geoengineering is a symptomatic treatment that does nothing about ocean acidification, which continues regardless of temperature management. It may also reduce political pressure for the emissions reductions that are the only lasting solution to climate change.
Stratospheric aerosol injection mimics the cooling effect of large volcanic eruptions, a well-understood natural phenomenon. Carefully calibrated small-scale deployment with monitoring could manage risks while building the knowledge base needed for larger applications.
Regional precipitation patterns, monsoon systems, and ozone chemistry would be affected in ways that models cannot predict with confidence. The losers from geoengineering's side effects — disrupted agriculture in Asia or Africa — may not be the same nations that deploy it.
Research into geoengineering does not itself reduce the incentive to cut emissions — the two are separate policy decisions. The moral hazard concern assumes that the mere existence of a backup plan will dominate political decision-making, which is unproven.
The availability of a technological 'fix' — even a risky one — relieves political pressure on fossil fuel interests and governments to undertake costly decarbonization. Geoengineering research and deployment can become the path of least political resistance.
International governance frameworks for geoengineering research and deployment — drawing on existing models from the IPCC, Antarctic Treaty, and nuclear non-proliferation regime — could ensure multilateral oversight and prevent unilateral deployment.
No effective governance framework for geoengineering exists, and creating one faces profound geopolitical obstacles. Any sufficiently wealthy nation or non-state actor could deploy stratospheric aerosols unilaterally, affecting the entire planet without global consent.