This short paper explores the security implications of climate change, focusing on the impacts on developing countries, particularly weak states. Security risks related to climate change will not be evenly distributed globally and will affect some kinds of governments more than others. While local and regional consequences of climate change remain very difficult to predict, three types of nations seem particularly vulnerable to the security risks of climate change: least-developed nations, weak states, and undemocratic states. Poor developing countries are the perhaps the most likely to suffer from climate change. These states lack the economic, governance, or technical capabilities to adapt to climate change. Failed and failing states—those with weak institutions of government, poor control over their borders, repressed populations, or marginal economies—stand a higher risk of being destabilized by climate change. The paper recommends a renewed emphasis on risk reduction and disaster preparedness with early warning systems that integrate meteorological risk with political risk.