Drawing down N2O to protect climate and the ozone layer : a UNEP synthesis report

"This report addresses the benefits of drawing down nitrous oxide (N2O) emissions. N2O is now the most significant ozone-depleting substance emission and the third most important greenhouse gas released into the atmosphere. Global anthropogenic N2O emissions are rapidly increasing and are expected to almost double by 2050 unless mitigation action is accelerated. The continued build-up of N2O in the atmosphere will continue to deplete the stratospheric ozone layer and in so doing will to a degree undermine the achievements of the Montreal Protocol. The build-up of N2O will also make it more difficult to achieve climate targets. Two-thirds of current anthropogenic N2O emissions originate from agriculture and these can be reduced by boosting nitrogen use efficiency, especially by making the use of fertilizer, manure and feed more efficient. Improving nitrogen use efficiency can be accomplished through a wide variety of feasible options. This would bring added benefits of higher crop and livestock productivity, lower required agriculture inputs, as well as reduced air and water pollution due to decreased nitrogen losses to the environment. Small, but quick gains may also be possible by controlling emissions from just two chemical industries (adipic acid and nitric acid) that account for about 5% of global gross anthropogenic emissions." -- Executive summary, page ix