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The impact of Nitrogen on the Climate Change crisis

The Nitrogen Fix

Public awareness and desire for action to tackle climate change is growing. There’s plenty of focus on methane and carbon dioxide emissions, but rarely any talk about nitrous oxide which is 300 times more potent than carbon dioxide, and depletes the ozone layer.

The amount of reactive nitrogen in our environment has already breached safe limits, and it has a huge impact on biodiversity, and on plant and soil health as well as climate. We need to shine a spotlight on nitrogen.

Nitrogen in farming: Why do farmers use nitrogen?

As an organic farmer, managing nitrogen is key to everything I do. It is crucial to aid plant growth and is the primary determinant of crop yield. It is essential for farming, and for life on earth, but the overuse of nitrogen fertiliser is polluting our air, rivers, soils and seas.

Historically, nitrogen was supplied through the natural fixation of nitrogen by leguminous plants such as peas, beans and clover, and recycled through animal manures. The invention of synthetic nitrogen was one of the most significant innovations in the history of agriculture. It releases farmers from the constraints of rotational farming, allowing them to grow cereals and oilseeds year after year, without having to build nitrogen in the soil through restorative, nitrogen-fixing plants.

My father called synthetic nitrogen ‘sugar’, and it’s a good analogy. Just as sugar gives energy, but no nutrition, likewise with ‘bag’ nitrogen. Repeated doses sap vitality and create dependence. Plant immunity to disease is compromised.

Helen Browning on farm

What happens if farmers use too much artificial nitrogen?

Industrial manufacture of nitrogen fertiliser has scaled up in the face of pressure to increase the amount of food we can produce to feed a growing population. Despite its benefits to plant growth, excess artificial nitrogen use has a very detrimental impact on our environment. Greenhouse gas emissions are produced when manufacturing the fertiliser, and nitrous oxide emissions can take place when the fertiliser is applied to crops.

A dependence on synthetic nitrogen fertiliser has led to an excess of nitrogen in our environment. In the same way that we have released huge amounts of CO2 through burning fossil fuels, so have we released huge amounts of reactive nitrous oxide. This has both direct and indirect consequences. Find out more about the effects of nitrogen overuse in our nitrogen report.

nitrogen fertiliser spraying

Synthetic nitrogen versus naturally-fixed nitrogen

Unfortunately, it's not a simple case of synthetic nitrogen bad, naturally-fixed nitrogen good. If poorly managed, excess nitrogen from any source, and other nutrients too like phosphorous, can diffuse into waterways and the atmosphere.

All farmers need to manage nitrogen better. As an organic farmer, I have an especially strong commercial driver to do so. Retaining fixed nitrogen in the soil is crucial to the success of my cash crops such as wheat and barley. I have every incentive to manage it wisely, apply enough manure but not too much, and grow cover crops over winter to prevent nitrogen from leaching away.

What is the solution to the nitrogen problem?

There are many potential solutions to the nitrogen problem at the global, national and local level, and some of these require further debate and discussion. Our report outlines some key recommendations for the farming sector and policy makers to consider.

The Covid-19 crisis has created unprecedented disruption to our daily lives, our food system, and the national and global economy. The challenges we face in its wake are complex and interdependent and will require immediate and meaningful action on multiple fronts. We need the same vigorous approach that governments here and globally have demonstrated during the coronavirus pandemic, to tackling the much greater climate, nature and health crises we still face. As part of that response, we must fix the nitrogen problem.

The Climate Change summit in Glasgow next year, which will focus on both nature and climate, is the perfect platform for the UK to show leadership in this area, and to advocate solutions to this complex issue. One of them, of course, is to minimise the amount of synthetic nitrogen used by farmers, and to encourage further support for organic and similar systems.

Find out more about the nitrogen problem and our recommendations to the farming sector – download the report here.