Historical models postulate that genocide cannot occur without the ideology and decisions of its authoritarian perpetrators and the indifference of bystanders. These models do not address genocidal risks from ecocide. Study objectives were to assess 1) the role of Malthusian pressures in recent genocides, 2) the role of ecocide and ecologic abuse in creating these pressures, and 3) strategies for prevention and deterrence. Analysis of reports, demographic studies, and time trends in recent genocides and recent ecocidal events from ecologic abuse suggests that Malthusian pressures and zero-sum rivalries over water, arable land, or natural resources by themselves do not lead to genocide. Such pressures may have exacerbated the political and socioeconomic predictors in Rwanda and Darfur, but not in former Yugoslavia. However, collapse of socioeconomic and governmental infrastructures following genocide can leave behind massive sustained damage to carrying capacity and sustainability. Surviving victims, if they return to their environments, will remain at risk for persecution. Ecocide--the large-scale destruction, depletion, or contamination of natural ecosystems--can result in widespread damage to health, survival, fertility, reproduction, and sustenance, and forced flight. International early warning and effective response systems are needed to deter or prevent political decisions to carry out genocide. Such systems must include long-term measures to resolve zero-sum conflicts over environmental resources and to prevent toxic risks to vulnerable populations and destruction of habitat by deliberate or wanton ecologic abuse, which itself should be redefined as a crime against humanity.