Humans now annually add more biologically available nitrogen to the Earth’s land surfaces than do all natural processes. For 3 billion years, available nitrogen had been the major limiting currency for life on Earth. The recent human disruption of the global nitrogen cycle is causing major environmental harm, including water and air pollution, marine dead zones, 10% of global greenhouse gas emissions, and species extinctions. Three major ways to solve this nitrogen problem are: (1) much more efficient global use of nitrogen fertilizers; (2) shifts to lower-meat and healthier diets; and (3) halting the conversion of food crops into biofuels, such as US corn ethanol used for transport. Series: "CARTA - Center for Academic Research and Training in Anthropogeny" [Humanities] [Science] [Show ID: 37910]