Humanity is currently faced with two global crises, one financial and one environmental. Although ostensibly distinct, these crises are in fact interlinked. Unsustainable consumption, at the heart of the environmental crisis, is driven to a large extent by unsustainable debt, which creates financial instability. If these underlying issues are tackled, and investment is directed into environmental initiatives through a 'green new deal', then the ultimate outcome of the financial crisis could be the mitigation of the environmental crisis. If, conversely, economic hardship is used as a justification for delaying action on critical environmental issues and economic growth remains at the centre of government policy, then the ultimate outcome of the financial crisis could be the deepening of the environmental crisis. The relationship between the two crises therefore provides both opportunities and threats to achieving long-term economic and ecological sustainability.