Growing interest in the social consequences of climate change has fueled speculation that global warming could lead to an increase in various forms of political violence. This article examines the effects of climate change on international conflict subsequent to the onset of European industrialization. Surprisingly, analysis at the system level suggests that global warming is associated with a reduction in interstate conflict. This naive relationship is suspect, however, as the increased consumption of carbon-based fuels is itself associated with changing patterns of politics and prosperity. In particular, economic development has been viewed as a cause of both climate change and interstate peace. Incorporating measures of development, democracy, cross-border trade, and international institutions reveals that systemic trends toward peace are actually best accounted for by the increase in average international income. The results imply that climate change, which poses a number of critical challenges for citizens and policymakers, need not be characterized as fundamentally a security issue, though climate change may have important security implications on the periphery of world politics. The analysis here also suggests that efforts to curb climate change should pay particular attention to encouraging clean development among middle-income states, as these countries are the most conflict prone. Ironically, stagnating economic development in middle-income states caused by efforts to combat climate change could actually realize fears of climate-induced warfare.