Smart nitrogen management can strongly reduce pollution

The scientists show that if smart abatement measures were implemented on global croplands, these global changes could generate $476 billion in societal benefits for food supply, human health, ecosystems and climate, at a net abatement cost of only $19 billion. “However, these measures and technologies are seldom fully implemented by farmers due to many constraints, such as a high heterogeneity of best practices on the local scale and high implementation costs for farmers,” says lead-author Baojing Gu of Zhejiang University, China.

“The most important barrier is yet that many of the benefits of reducing nitrogen pollution are not seen by the farmers themselves, but only pay off for the society as a whole – in the form of clean and healthy air, clear lakes, and a biodiverse and resilient nature,” explains Benjamin Bodirsky from Potsdam Institute for Climate Impact Research, co-author of the study. Even more, farmers who spend time and efforts for reducing their nitrogen pollution to very low levels have difficulties competing against those who do not care, as they usually get the same market price for their grains but get no compensation for lowering the pollution for the environment.

Policies could yet correct this market failure. “The most elegant solution for the German context would be a nitrogen surplus tax,” says Benjamin Bodirsky. “It is like a tax on all the nitrogen that the crops have not taken up and which ends up polluting the environment. Such a tax would give sustainable farmers a competitive advantage instead of disadvantage, and would strongly reduce nitrogen pollution and the connected damages to human health and ecosystems.”