International governance of solar radiation management: does the ENMOD Convention deserve a closer look?

Anthropogenic climate change has warmed the planet to over 1°C above pre-industrial levels. The biophysical and social impacts of this warming are taking hold, with sea-level rise, melting of polar ice, more extreme weather events, drought, and wildfire. Solar radiation management (SRM) technologies are a set of ideas for increasing the reflectivity of the earth at various scales to offset the effects of anthropogenic climate change. The most ambitious SRM idea involves injecting aerosols into the atmosphere to cool the planet on a global scale. However, regional-scale SRM ideas are also being investigated to lessen climate impacts at regional and local scales. International governance of SRM research and development is a key issue for managing risk and building social license for these technologies. Despite this, there has been very limited international legal and institutional development on SRM. It may therefore be better to start working with existing rules and institutions of international law than wait for significant new treaty development to govern the issue. This article examines the potential of the ENMOD Convention - an overlooked Cold War arms control treaty on the use of environmental modification technologies - to contribute to international governance of SRM.