Too much nitrous oxide in the atmosphere
Nitrous oxide is the third most harmful greenhouse gas. However, it rarely appears in the dialogue about the climate crisis. The increasing concentrations of N2O, which is mainly produced in agriculture, must be given greater focus.
17.06.2024 – Nitrous oxide (N2O), also known as nitrous oxide, is the most harmful greenhouse gas after carbon dioxide (CO2) and methane (CH4). In recent decades, the concentration of the greenhouse gas in the atmosphere has risen rapidly, according to an analysis by the Global Carbon Project. Agriculture is the biggest polluter, but nitrous oxide is also released when fossil fuels are burned.
A team of international researchers has evaluated millions of measurements from air, water and oceans since 1980. The 58 researchers from 15 countries are calling for more attention to the effect of nitrous oxide on global temperature rise.
10 percent more atmospheric nitrous oxide in four decades
Since 1750, the concentration of N2O in the atmosphere has increased by almost 25 percent, with around 10 percent occurring over the past four decades. Especially in the last decade, nitrous oxide has been accumulating: The growth rate of atmospheric N2O in 2020 was around 30 percent above the average of the years of the previous decade.
The increase in N2O thus exceeds assumed quantities of all scenarios of the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), according to the analysis. N2O emissions are also expected to continue to rise in the coming decades as demand for food, feed and industrial processes increases.
Less nitrous oxide in Europe, more in Asia
Nitrogen fertilizers and animal husbandry are the largest sources of N2O. Almost three quarters of all nitrous oxide emissions are caused by agriculture. Countries contribute to the global increase to varying degrees.
In Germany, N2O emissions have been declining since 1990, and nitrous oxide emissions from industry in particular have been reduced. This was mainly due to changes in processes in the production of adipic acid, a basic material for plastics. In the past four decades, emissions have been more than halved overall.
In Europe, too, emissions have been declining since 1980. This is due to a decline in emissions from industry and fossil fuels, as well as agriculture. In the latter sector, however, emissions have almost stagnated in the last two decades. N2O emissions increased most sharply in China and South Asia, with agriculture also the largest contributor.
Avoid hard-to-avoid emissions
Nitrous oxides are considered to be emissions that are difficult to avoid. In crop production, these come largely from fertilizers. They are formed when microorganisms break down nitrogen in the soil. However, the amount of nitrogen-containing fertilizers can often be significantly reduced without loss of yield. Instead, the use of fertilizer per hectare is still increasing globally, even though it hardly increases yields.
In Germany, nitrogen surpluses have been reduced in recent decades, according to the Federal Environment Agency. However, nitrogen efficiency remains low. Only about half of the nitrogen applied ends up in the targeted products. More precise analyses of nitrogen demand in agriculture therefore have the potential to reduce emissions that are difficult to avoid. jb