Synthetic Nitrogen Fertilisers Major Contributor of GHG

2022-01-10, 10:33pm Agriculture


Fertiliser waiting to be spread. Creative Commons.

New research provides the first estimate of the global climate impacts of synthetic nitrogen (N) fertilisers. The production and use of synthetic N fertiliser accounts for 2.4% of global emissions, responsible for 1 out every 40 tonnes of greenhouse gases (GHGs) currently pumped into the atmosphere. The synthetic N fertiliser supply chain was responsible for estimated emissions of 1,250 million tonnes of CO2e in 2018, roughly 21.5% of the annual direct emissions from agriculture (5,800 million tonnes).

The majority of emissions from synthetic N fertilisers occur after they are applied to the soil and enter the atmosphere as nitrous oxide (N2O), a persistent greenhouse gas. But what is less discussed is that almost 40% of the greenhouse gas emissions of synthetic N fertilisers occur in production and transport, largely in the form of CO2 caused by the burning of fossil fuels during manufacture.

Agro-chemicals are controlled by a small number of global corporations that wield enormous political clout. The market for synthetic N fertilisers alone is worth over US$70 billion. Worldwide use of synthetic N fertilisers is set to increase by over 50% by 2050. The new research, however, finds no evidence that programmes to increase efficiency have had any significant impact. Another key driver behind today’s excessive use of N fertilisers is the ongoing decoupling of crops and livestock. Farms now growing feed crops utilise synthetic N fertilisers rather than the animal manure.

If the world stands a chance of effectively dealing with the climate crisis, industrial farming systems that depend on synthetic N fertilisers and other chemical inputs must be replaced with agroecological farming systems that do not use chemicals and local food systems in which animals and feed sources are fully integrated. Change has to come from revitalising and supporting farmer-based seed and knowledge systems that are best able to provide seeds and practices adapted to local conditions and able to produce nutritious and abundant food without chemicals. Similarly, farmer knowledge of organic fertilisers and alternatives to building soil fertility needs to be rebuilt, shared and implemented so that the current dependency on chemical fertilisers can be overcome. A global phase-out of synthetic N fertilisers must also be accompanied by a phase-out of industrial livestock which is also a huge source of greenhouse gas emissions and a major driver of forest and biodiversity loss.

- Third World Network