“Green” fertilizer in Africa: no substitute for an agroecological transition

Synthetic fertilizers in Africa

In the 20th century, the Haber-Bosch process or ammonia synthesis enabled a dramatic increase in crop yields in many parts of the world. However, artificial fertilizer use remained low on the African continent. Since the early 2000s however, the increase in the use of synthetic fertilizers in agriculture across the African continent has been a key element for implementing the so-called African green revolution. The most crucial agreement was the Abuja Declaration of 2006, in which member states of the African Union agreed to increase fertilizer use to an average of 50 kilograms per hectare. Consequently, at least 10 African countries subsidized the supply of artificial fertilizers, spending large shares of their agricultural budgets on this area of financial support for farmers. A key player in this wave of support for synthetic fertilizer use was – and still is – the Alliance for a Green Revolution in Africa (AGRA), founded by the Bill and Melinda Gates Foundation and the Rockefeller Foundation, collaborating closely both with African states and multinational agricultural corporations like the Norwegian nitrogen fertilizer producer, Yara.

In May 2024, the African Fertilizer and Soil Health Summit took place in Nairobi, Kenya. During the summit, the 10-year Fertilizer and Soil Health Action Plan was launched, calling for increased investments in the local production and distribution of both mineral and organic fertilizers as well as biofertilizers and biostimulants. Despite this progress in the narrative, civil society networks like the Alliance for Food Sovereignty in Africa (AFSA) still hold major reservations and call for a focus on agroecology, the promotion of biofertilizer production and a phase out of imported chemical fertilizers.

Fossil fuel-based synthetic fertilizers: Not compatible with net zero by 2050

As efforts to mitigate climate change intensify, the fertilizer industry, and particularly nitrogen fertilizer producers, have come under increasing pressure to take accountability for the carbon footprint of their product. The life cycle of nitrogen fertilizer production accounts for more than 2 percent of global greenhouse gas emissions. This is due to the energy intensive Haber-Bosch process; the methane emissions associated with extracting, processing, and transporting the fossil gas that is the primary feedstock for fertilizer production; as well as the emission of nitrous oxide during and after application. 

In response, the fertilizer industry is investing in the development of so-called “green” fertilizer, where renewable energy is used to generate “green” hydrogen, which in turn is used to produce “green” ammonia. Yara claims these fertilizers have a 75-90 percent lower carbon footprint, in comparison to the same fertilizers made with fossil gas. However, so called “green” fertilizers also pose major risks and challenges. These cannot be ignored if the continent intends on taking a path that recognizes the importance of looking beyond short-term gains in order to achieve resilient and sustainable agriculture systems.

Risks of “green” fertilizers

Before producing “green” ammonia and “green” fertilizer, “green” hydrogen needs to be produced. The main problem regarding the production of “green” hydrogen is that it requires large areas of land – for example, for photovoltaic systems or wind farms – and a large quantity of water. If the production of “green” hydrogen, ammonia and fertilizer are not properly managed, and lead to land and fresh water grabs or aquatic dead-zones (due to the inadequate disposal of by-products of the desalinization process), they could threaten the livelihoods of farmers, pastoralists and fisher folk. While these threats can all be managed, their regulation requires strong governance institutions, which may not be the current reality in many of the countries and regions on the continent.

Another risk is linked to the use of synthetic nitrogen fertilizer. When nitrogen fertilizer – whether it be fossil fuel-based or “green” fertilizer – is applied to agricultural fields, usually only some of the nitrogen is fixed in the plants and soil. A portion of the excess nitrogen is emitted as nitrous oxide – a greenhouse gas 300 times more potent than CO₂. Excess nitrogen can also cause overstimulation of growth in aquatic plants and algae (known as algal blooms), which in turn, can clog water inlets, use up oxygen while decomposing, and block light to deeper waters. Excessive nitrogen in drinking water can cause cancers, reproductive problems, hypothyroidism and other serious conditions. In 2023, leading environmental scientists studied different planetary boundaries, nitrogen being one of them. They concluded that nitrogen is one of the six (out of nine) planetary boundaries that have already been transgressed globally, meaning that more nitrogen is applied to the agricultural system than plants and soils can absorb.

Furthermore, synthetic nitrogen fertilizers based on ammonia dramatically accelerate soil acidification. Among other problems, soils that are particularly acidic are less able to absorb phosphorus. This poses a major problem because phosphorus is a critical and non-substitutable resource. Regarding soil biodiversity, it has been proven that intensive fertilization and the use of chemical pesticides result in a decrease in the diversity and number of soil microorganisms. Without a healthy microbial community, plants are unable to access essential nutrients, resulting in increased risk of pests and diseases, and the production of poor quality fruit and vegetables.

Questioning the correlation between nitrogen fertilizer application and food security

It is often stated that using more fertilizers boosts yields and therefore enhances food security. However, it should be noted that the correlation between nitrogen fertilizer application and food security is not clear cut. In 10 out of 13 member countries of the Alliance for a Green Revolution in Africa in which the use of synthetic fertilizers was promoted particularly strongly since 2006, the number of undernourished people actually increased between 2004-2006 and 2016-2018 – from a total of 100.5 million to 131.3 million people. The reason is that higher agricultural productivity in certain crops does not automatically result in improved access to food – political conflict, food waste, food affordability, and other factors are critically important in addressing hunger and malnutrition. The political economy of food systems, that is who has access to land and water, what food is produced, and for whom, significantly impacts food security, as shown by ongoing hunger in regions that grow food for export. 

Recommendations

“Green” hydrogen-based nitrogen fertilizers should in no way impede the necessary transition to sustainable, just and resilient food systems, based on the concept of agroecology. Therefore the political priorities should be the following:

1. Fossil fuel-based nitrogen fertilizers should be completely phased out. Investments in fossil fuel-based fertilizer production on the continent should be strongly discouraged. 
2. The use of biofertilizers and cultural methods to improve soil fertility must be prioritized. In the medium-term, agricultural design must shift towards diversified agricultural systems.
3. “Green” hydrogen-based nitrogen fertilizers should only be used for limited periods in nitrogen deficient situations, if at all, with the aim of avoiding the lock-ins and dependencies that result from synthetic fertilizer use. 

This text is a shortened and updated version of the policy paper “Resilient Agriculture on the African Continent: The Proof will be in the Soil. Recommendations on fossil fuel-based and «green» fertilizer production and use in Africa” edited by Heinrich Böll Foundation offices in Abuja, Berlin, Capetown and Nairobi in May 2024. 

Further reading & listening

Heinrich Böll Foundation (2024): “Rethinking Agriculture: Soil Health for Sustainable Farming in Africa”

Alliance for Food Sovereignty in Africa (2024): “AFSA Statement on the African Fertilizer and Soil Health Action Plan 2023-2033”.

Heinrich Böll Foundation, TMG (2024): “Soil Atlas: Facts and figures about a vital resource”.

Böll Europe Podcast – “Soil Atlas 2024 (Part 1): The fertiliser trap”.