Greenhouse gas emissions and mitigation potential from fertilizer manufacture and application in India

Abstract

Synthetic nitrogen (N) fertilizers, by both very energy-intensive manufacture and inefficient N use in farm soils, contribute rationally to emissions of greenhouse gases (GHGs) and, thus, climate change. India consumes ∼14Mt of synthetic N per year, of which about 80 per cent is produced, and is the second-largest producer and consumer in the world, after China. We estimate that GHG emissions from synthetic N fertilizer in India reached ∼100Mt of carbon dioxide equivalent (CO2-e) in 2006/2007; about half of these emissions resulted from the 11Mt of synthetic N produced in the country that year (48Mt of CO2-e) and the other half resulted from the 14Mt of N applied to Indian farm soils in the same year (51Mt of CO2-e, ranging between 28 and 163Mt of CO2-e). Emissions from synthetic N fertilizers represent 6 per cent of India's total anthropogenic emissions, comparable to cement industry and to the whole road transport system. There is significant potential to mitigate these emissions: savings from increased N use efficiency and from shifting away from synthetic fertilizer could reduce total fertilizers emissions to 37Mt of CO2-e, and the contribution of fertilizers to India's emissions would drop from 6 to 2 per cent.