It’s time to let go of nitrogen fertiliser

In the first decade of the 20th century, two German chemists Fritz Haber and Carl Bosch, developed a way to produce synthetic nitrogen cheaply and on a large scale.

The agricultural industry fell in love with the chemical. Today, according to the United Nations, approximately 250 million tonnes of nitrogen are used around the world. Now, experts say, nitrogen, which is ubiquitous in synthetic fertiliser, could have catastrophic effects if the world doesn’t act fast.

Scientists at this year’s United Nations Environment Assembly (UNEA-4) which began yesterday in Nairobi, are warning that humans and the environment are faced with an existential threat if runaway nitrogen pollution continues. Consequently, the UN wants states to commit to reduce their use of synthetic nitrogen fertilisers as a means to reducing untold environmental damage.

“We’re in a fix. Over 80 per cent of the nitrogen we’re making is lost into the environment. And that is a serious pollution problem,” noted Environment Physicist from the Centre for Ecology and Hydrology Mark Sutton.

POLLUTION

The scientists spoke of close relationships between the excessive application of nitrogen fertiliser and environmental problems such as air pollution, eutrophication, the greenhouse effect, and acid rain.

“This pollution is contributing to the increased respiratory illnesses we witness today. If you drink water with too much nitrates in it then there is a risk of colon cancer, and nitrous oxide is the main cause of stratospheric ozone depletion,” Prof Sutton said an interview with Healthy Nation on the sidelines of the launch of the Frontiers report by UN Environment last week, ahead of UNEA.

Frontiers explores five of the most significant emerging global environmental issues. They include nitrogen pollution, synthetic biology, ecosystem connectivity, thawing permafrost peatlands and maladaptation to climate change.

Nitrate is one of the most common groundwater contaminants. If not regulated in drinking water, excess levels can cause “blue baby” disease.

“Every year an estimated $200 billion worth of reactive nitrogen is lost into the environment, where it degrades soils, pollutes air and triggers marine dead zones (when oxygen concentrations fall below the level necessary to sustain most animal life) and toxic algal blooms in waterways,” said UN Environment acting executive director Joyce Msuya.

“We know that algal blooms lead to the excessive growth of some species of aquatic life which causes an imbalance. And when the algae dies, it makes the water toxic, causes oxygen depletion, kills fish, leads to loss of biodiversity and makes drinking water unpalatable,” added Prof Sutton, giving Lake Victoria as a case study. He added that running the nitrogen cycle more efficiently would help fix the problem, which is prevalent in Africa, Eastern Europe, Central Asia, Latin America and the Caribbean – the highest consumers of nitrogen fertiliser.

Ms Msuya noted that a holistic approach to the global challenge of nitrogen management is beginning to emerge. “Some governments like China have started taking initiatives to prevent growth in synthetic fertiliser use by 2020. The European Union is encouraging the use of organic fertilisers and India is promoting natural farming. We are seeing promising new efforts to reduce losses and improve the efficiency of nitrogen fertilisers,” she said.