The paper describes and analyzes the responses of insurance companies to global climate politics. It shows how these responses failed to live up to the initial optimism of environmentalists and commentators about the potential of the involvement of insurers in climate politics. It then attempts to explain why insurers have disappointed environmentalist expectation. It shows that part of this is due to constraints and opportunities within the insurance business itself. But it then shows how much of the reason is to do with a simplistic understanding by environmentalists of the power of insurers. Examining the political-economic contexts in which insurance companies operate provides a clearer picture as to the limits to the role insurers can play in mitigating global warming.