When you think of agriculture and climate change, you likely think of last summer’s crippling drought: dried corn stalks, thirsty cattle and rising food prices. Or of floods—with harvests delayed, crops and pastures submerged and killed, and produce spoilt. While the effects of climate on agriculture are clear, less well known is the great potential for agriculture to be a source for substantial climate solutions.
Agriculture is the nation’s largest source of nitrous oxide, a potent greenhouse gas. Each year, US farmers apply around 12 million metric tons of synthetic nitrogen fertilizer to crops. The problem is that only about half of the fertilizer that is applied is used by the crop, with the rest released to soil and water, mostly in the form of nitrate, and to the atmosphere, mostly in the forms of nitrous oxide and ammonia. This leads to harmful impacts, not just on our climate, but on air and water quality, human health and biodiversity.
What is the upside to this inefficient use of fertilizer? Real room for improvement. If current practices and technologies were more widely applied, we could reduce nitrogen losses from farm and livestock operations by 30% to 50%, including reductions in emissions of the heat-trapping and ozone-destroying gas, nitrous oxide. A largely unrecognized aspect of climate change and agriculture is how nitrogen pollution compounds climate change, and vice versa. The good news is that we have several proven solutions, such as planting winter cover crops to absorb excess nutrients, better timing of nutrient applications relative to when the crops need them, and re-integrating livestock and manure management with crop management. The challenge is to make these practices more economically viable and low-risk for farmers to adopt.
The Global Partnership on Nutrient Management, in collaboration with the International Nitrogen Initiative (WHRC President and Senior Scientist Eric Davidson is the North American Coordinator of the International Nitrogen Initiative), recently drafted a special report to the United Nations Environment Programme (UNEP) entitled Global Overview on Nutrient Management, which identifies ten key actions that would help maximize nutrient benefits for humanity, while minimizing the many threats of pollution. The report’s subtitle clearly states the issue at hand: The Challenge to Produce More Food and Energy with Less Pollution. Improving nutrient use efficiency across the full food supply chain, from the farmer’s field to the dinner plate, is identified as a shared challenge that links these key actions, while contributing to the Green Economy in all countries. In addition to improved nutrient use efficiency on the farm, the report also discusses how food wastage can be reduced and how dietary choices, such as portion sizes of meat, also are part of the problem and the solution.
The report highlights that there is still no intergovernmental framework to address the multiple challenges for nitrogen, phosphorus and other nutrients. A blueprint for such a framework is outlined and considers the institutional options. The potential for net economic benefits is illustrated by estimating the consequences of meeting a common aspirational goal to improve nutrient use efficiency by 20% by the year 2020.
Most farmers want to avoid waste of expensive fertilizers and they want to be good stewards of their land, but more outreach and economic incentives are often needed for adoption of some of the most effective measures to increase the efficiency of fertilizer use and to avoid nutrient losses to the air and water.