Solar geoengineering research faces geopolitical deadlock

Abstract

As a powerful potential lever on global temperatures, solar geoengineering—or solar radiation modification (SRM)—comes with formidable environmental and political risks. Assessments of SRM acknowledge that future governance of “direction, ownership and control” [(1), p. 45] is no optional extra: Outcomes achieved in modeling studies presuppose governance “to restrain harmful or unjust use of SRM…and assess and minimize any countervailing harms” [(2), p. 6]. But, although research is deemed urgent, the “guardrails” and institutions needed remain moot (3) or are deferred for later (4). Tentative efforts toward international cooperation and oversight collapsed most recently in February 2024. Drawing upon observations of the United Nations Environment Assembly (UNEA), we set out how clashing geopolitical interests and diverging knowledge politics are making even research controversial. Although the differences seem irreconcilable, we suggest that apparent consensus around nondeployment of geoengineering could be seized upon to provide some hope for coordinated and responsible SRM research.