The world's climate is changing at an unprecedented rate, largely as a consequence of human activity. This paper summarises the predicted impacts of these changes that are of greatest relevance to Oxfam. It focuses on the medium to long-term (25-50 years) dynamics in five key areas: water, food security, health, extreme events and political stability. It explains how the geopolitics of the historic responsibilities and future impacts of climate change are distinctly unequal - those countries with the greatest 'ecological debt' currently stand to suffer least from the consequences of their past activities. Without political action to mitigate and adapt, climate change threatens to widen global inequalities and undermine recent gains in social and economic development.