Climate cascades:IOs and the prioritization of climate action

International organizations (IOs) are rapidly reorienting around climate change, despite powerful principal states having divergent preferences on the issue. When and why do IOs prioritize climate change? We argue that they do so as a result of an endogenous process of staff learning and rotation. IO staff surveil and implement programs in target states. When working in climate-vulnerable countries, they come to see climate change as an issue warranting aggressive action. As these staff are rotated and promoted, interest in climate diffuses outwards and upwards through the institution. To test this theory, we introduce original data tracking the International Monetary Fund's attention to climate change and the career paths of key staff. We complement this with interviews of International Monetary Fund personnel. We find support for our theory.