University of California Institute on Global Conflict and Cooperation

International cooperation depends on conditional commitments between states. We examine the politics of conditional commitments in climate change using three experiments in ten major carbon-emitting countries. We specifically investigate whether public pledges of conditional action made by national governments increase public support for ambitious climate action in other countries. We find that only unconditional pledges increase public support for policy ambition in foreign countries. Additionally, countries seeking financial and technical transfers only gain foreign support for transfers when they combine conditional pledges with ambitious unconditional pledges. We also observe that the public in most countries only favors making part of their country’s climate pledge conditional on other countries’ actions when their home country makes an unconditional commitment at or above the average level necessary to prevent dangerous warming. Overall, public preferences are unconditionally aligned with addressing the climate problem. Conditional commitments are more aligned with increasing domestic support for climate policy than unlocking more ambitious settlements between countries.