The prospect of human-induced climate change encourages drastic neomalthusian scenarios. A number of claims about the conflict-inducing effects of climate change have surfaced in the public debate in recent years. Climate change has so many potential consequences for the physical environment that we could expect a large number of possible paths to conflict. However, the causal chains suggested in the literature have so far rarely been substantiated with reliable evidence. Given the combined uncertainties of climate and conflict research, the gaps in our knowledge about the consequences of climate change for conflict and security appear daunting. Social scientists are now beginning to respond to this challenge. We present some of the problems and opportunities in this line of research, summarize the contributions in this special issue, and discuss how the security concerns of climate change can be investigated more systematically.