Global Importance and Progress of Reducing Anthropogenic Emissions of Nitrous Oxide.

Reducing anthropogenic emissions of carbon dioxide (CO₂) has dominated media, political, and scientific agendas in recent years. The atmospheric concentration of CO₂ has approximately doubled in the last 100 years due to rapid increases in the burning of nonrenewable fossil fuels. In addition to concerns of resource depletion, CO₂ is a greenhouse gas with the potential to increase global temperatures with a variety of potential catastrophic effects. Nitrous oxide (N₂O) is also a greenhouse gas, but it does not receive nearly as much attention due to anthropogenic emissions of CO₂ approximately ten-fold higher than N₂O. However, N₂O is a potent greenhouse gas with a warming potential ~300 times greater than that of CO₂ due to higher absorbtivity of infrared radiation and longer residence time in the atmosphere (~150 years for N₂O). Thus, more focus needs to be on reducing N₂O emissions. About two thirds of these N₂O emissions originate from agriculture—with the highest percentage from fertilization. Unlike CO₂, reducing N₂O emissions from fertilization is reasonably achievable without significant disadvantages. These reductions in N₂O emissions are achievable through promotion of a variety of best management practices (BMPs) for nitrogen (N), namely: applying the correct fertilizer source at the right rate, placement, and timing. These N management BMPs increase the percentage of N entering crop plants and reduce the amount lost to the environment. One such practice, the use of a controlled release fertilizer (polymer coated urea), has been shown to give the same or better crop yield/quality while exhibiting drastic reductions in N₂O emissions in many cases. Implementing use of polymer coated urea and other best management practices is vital to conserve natural resources used in the production of N fertilizer, volatilization of reactive N in the atmosphere, and to reduce the possible impacts of N₂O on global temperature.