For the last century, ammonia has been hailed as a miracle chemical. A key component of synthetic fertilisers, it has become central to the food system and driven an agricultural revolution. 

In recent years, the colourless gas has also been widely promoted by industry in ‘clean’ power generation and as a ‘sustainable’ shipping fuel – prompting plans for massive growth in the sector. 

Yet, this boom poses major risks. Ammonia production and use currently account for five percent of all global greenhouse gas emissions – more than those from commercial shipping and aviation combined – and over 99 percent of ammonia is produced from fossil fuels. 

Over the last 100 years, pollution linked to the chemical has also pushed many ecosystems to the point of collapse. Ammonia-based fertilisers are a key driver of nitrogen pollution, which is causing a major crisis for rivers and oceans around the world. 

How is Ammonia Used?

Ammonia is produced using the Haber-Bosch process, a reaction between nitrogen from the atmosphere and hydrogen that is generally derived from natural gas. 

Since the process was discovered in the early 1900s, it has transformed farming. By allowing massive production of cheap synthetic fertilisers – chemical compounds used for rapid plant growth – it enabled a huge acceleration in crop production, as well as the advent of large-scale, monoculture farms, producing nitrogen-hungry crops such as wheat and corn. Nowadays, over 70 percent of ammonia is used for fertilisers.

In the last decade, the industry has begun expanding into other markets. Ammonia stores large amounts of energy – meaning that it can be burnt to run ships or help fuel power plants. At the point of combustion, it does not release carbon dioxide emissions, and is therefore promoted by industry as a ‘clean’ fuel. 

Demand for ammonia is expected to boom in the coming decades. The International Energy Agency (IEA), an intergovernmental organisation working on climate modelling, says that ammonia production could increase by almost 40 percent over the next 25 years.

Fossil Fuel Lock-in

Ninety-nine percent of ammonia is currently produced from fossil fuels, mainly from natural gas. In 2021, ammonia production accounted for five percent of all natural gas consumption worldwide. 

As demand grows, it therefore risks locking in fossil fuel use for decades to come, according to legal and advocacy organisation the Center for International Environmental Law (CIEL). 

In 2024, CIEL published a report that found if all proposed new ammonia plants went ahead in the U.S. – one of the world’s largest ammonia producers – it would quadruple the country’s production, with 95 percent of the expansion based on the use of fossil fuels.

Decarbonising Production?

The industry claims that it is possible to decarbonise this ammonia production using carbon capture, utilisation and storage (CCUS) – a process by which carbon emissions are trapped and then used for industrial processes or stored underground. Ammonia produced with CCUS is called ‘blue ammonia’, and is widely promoted by the industry and some experts as a ‘low-carbon’ product. 

However, CCUS is currently far from operating at anywhere near the scale that would be required to dent global emissions. Research by DeSmog has shown that many large CCUS projects have failed to meet their promised potential, and so far, most captured carbon dioxide has been pumped underground in order to squeeze remaining oil or gas out of depleted fields, so that it can be extracted and used. 

Even if CCUS were successful in capturing emissions from ammonia plants, it does nothing to address those from extracting the fossil fuels, a process that releases the potent greenhouse gas methane – which has 28 times the warming potential of carbon dioxide.

Ammonia can also be produced from renewable energy. Known as ‘green ammonia’, this form is the lowest carbon option available, and experts say it will be vital for decarbonising the sector. 

However, campaigners and academics also warn that if ‘green’ production booms, it could use vast amounts of land, water and renewable energy. A 2022 report by industry-led coalition Mission Possible Partnership estimated that by 2050 green ammonia production could require between 3,500-7,000 terawatt-hours of wind and solar power annually – up to 700 times more electricity than Kenya consumes each year.  

Green ammonia production hubs are planned globally, from affluent regions like Australia and the U.S. to places like Mauritania and Namibia – countries where only around half the population currently has access to electricity. 

All three forms of ammonia production are expected to grow over coming years. Under current government policies, the IEA projects that the amount of ammonia produced with CCUS will almost double by 2050. However, it predicts that ammonia production from fossil fuels without any efforts to capture emissions will also grow, remaining responsible for around 70 percent of total production. Renewable-based ammonia would only provide around one percent of the total, according to the projections. 

Under this scenario, emissions from ammonia would only fall by ten percent by 2050 – way below the 70 percent needed to meet international climate goals. 

Potent Greenhouse Gas

While the industry widely promotes emissions savings from switching production processes, the majority of emissions from ammonia currently arise during its use. 

Most ammonia is converted into fertilisers. When fertiliser is used on a field, only a small proportion is absorbed by the plant, and the rest runs off into waterways or the soil. This runoff reacts to create nitrous oxide, a potent greenhouse gas with almost 300 times the warming potential of carbon dioxide over a 100 year period. Two-thirds of emissions from fertilisers therefore come from their use.

As ammonia is increasingly used in other sectors, it could likewise react to create nitrous oxide, experts warn, if it does not burn properly, or it leaks or spills into the environment – for example when being transported for power generation or during an accident aboard a ship.¹EM, November 2024, ‘Risks, Benefits of Using Ammonia as a Shipping Fuel‘

Concentrations of nitrous oxide in the atmosphere are currently higher and rising faster than at any other time in the last 800,000 years. 

Major Pollutant

Pollution linked to ammonia is also already having major impacts around the world. 

The chemical contains large amounts of nitrogen, which is released into the atmosphere through its use in fertilisers. Nitrogen pollution is the world’s greatest driver of biodiversity loss, after habitat destruction and greenhouse gas emissions. 

When leaked into water, nitrogen pollution causes ‘eutrophication’ – a process where algae and other organisms rapidly grow, releasing toxins and depleting the oxygen needed for other plants and animals to survive. Such pollution has created numerous dead zones, from the Baltic Sea to the Gulf of Mexico – regions where fish and other aquatic life cannot survive.

While nitrogen exists and naturally cycles between the air, the oceans, and soil, human activity has massively increased the amount of nitrogen in the biosphere, releasing as much each year as all natural sources combined. By overloading these nitrogen cycles, humans have pushed them way beyond safe operating limits.

As ammonia use expands, the risk of nitrogen pollution from leaks, industrial disasters and spills could also increase. Nora Wissner from German research institute Oeko-Institut warns that if leaked when used as a shipping fuel, for example, it could cause major harms to marine life.²Nora Wissner, ‘Ammonia as a Marine Fuel: A Closer Look from an Environmental Perspective’, in EM, November 2024, ‘Risks, Benefits of Using Ammonia as a Shipping Fuel’

Safety Concerns

This growing demand for ammonia is also raising safety concerns for workers and fenceline communities.

Ammonia is toxic to humans, and can burn or corrode tissues in the body, with significant exposure potentially resulting in death or permanent brain damage.

Some experts warn that use of ammonia as a shipping fuel in particular could therefore have dire consequences. Paul Martin, an independent consultant with Spitfire Research, who specialises in decarbonising the chemical industry, says that it would result in deaths of entire crews. Other experts say that major safety precautions must be put in place to enable use. ³EM, November 2024, ‘Risks, Benefits of Using Ammonia as a Shipping Fuel’

Ammonia could make up between 35 and 45 percent of the marine fuel mix by 2050, according to analysts’ projections. 

Greenwashing Power? 

Ammonia is also being championed as a ‘low-carbon’ energy source for power production. 

In countries like South Korea and Japan, ammonia is increasingly burnt alongside coal in existing power plants in a process called ‘co-firing’. Industry and the countries’ governments say that this can help decarbonise power production. 

However, plants currently only use up to 20 percent ammonia in the mix, meaning that 80 percent of coal emissions remain. In the 2023 run up to the intergovernmental G7 summit, the UK and Canada challenged Japan on its dependence on ammonia as an energy source in its climate plans. 

Ammonia can also be an indirect energy source. The chemical contains large amounts of hydrogen (H), and can therefore act as a ‘carrier’ for the element, which is increasingly being used as a ‘sustainable’ fuel for long-distance transport and heavy industry. 

Unlike hydrogen, ammonia can be liquified at relatively low pressures and moderate temperatures making it easy to transport, before the hydrogen is extracted at its end destination. 

Experts say that some forms of hydrogen could be used to reduce emissions in sectors that are difficult to decarbonise like the steel industry. But academics also warn that if hydrogen is used in the wrong scenarios it could produce more emissions than even the most polluting fossil fuels.

• 1
  EM, November 2024, ‘Risks, Benefits of Using Ammonia as a Shipping Fuel
• 2
  Nora Wissner, ‘Ammonia as a Marine Fuel: A Closer Look from an Environmental Perspective’, in EM, November 2024, ‘Risks, Benefits of Using Ammonia as a Shipping Fuel’
• 3
  EM, November 2024, ‘Risks, Benefits of Using Ammonia as a Shipping Fuel’