Emissions of nitrous oxide (N2O), also known as laughing gas, could double by 2050, threatening gains made in healing the ozone layer, the United Nations Environment Program warns in a new report.

Agriculture is by far the number one contributor to N2O emissions, accounting for some two-thirds, with other major sources including fossil fuel combustion, biomass burning and wastewater.

"Although not as prevalent in the atmosphere as CO2 in terms of mass, N2O ... is far from a laughing matter in respect to climate and ozone damage as it has a disproportionate impact on global warming because of its radiative properties and long lifetime in the atmosphere, which is 120 years on average," UN Under-Secretary-General and UNEP Executive Director Achim Steiner said in a statement.

According to the report, in the case of little or no mitigation efforts, levels of N2O emissions could increase by an average of 83 percent between 2005 and 2050. Moderate mitigation scenarios reduce this number to 26 percent and "concerted mitigation" to 22 percent.

Cutting down doesn't have to hurt, the researchers argue, citing an earlier report that found across-the-board improvemens in nitrogen use efficiency of 20 percent would cost the United States $12 billion annually, while saving it $23 billion each year in fertilizer costs. When taking into account environmental, climate and human benefits, this increases to as much as $160 billion annually, the report estimates.

Recommended actions to reduce emissions include:

  • Removing subsidies that encourage the overuse or misuse of nitrogen fertilizer and other products, while providing incentives for adopting best management practices that would improve nitrogen use efficiency;

  • Putting a price tag on nitrogen pollution through appropriate levies, incentives and tradable permits;

  • Encouraging research and development geared towards the development of innovative techniques to enhance nitrogen use efficiency as well as increased crop and animal productivity in agriculture and other sectors;

  • Increasing support for good nutrient management practices in crop and livestock operations through education, extension and outreach, especially to farmers in developing countries;

  • Setting clear targets for N2O emission reductions and for improving nitrogen use efficiency, and putting in place strategies for tracking progress.

"UNEP is working on a range of fronts to support the international efforts under the UN Climate Convention, from catalyzing the uptake of renewable energies and energy efficiency to adaptation projects in many parts of the globe," Steiner explained, noting that in order to be successful, the agency cannot act alone.

"We need all hands on deck to combat the serious and significant increases in N2O levels in the atmosphere."