Human-induced nitrogen emissions have surpassed natural emissions, damaging the environment and human health, says Mark Sutton, lead author of ‘Our Nutrient World’, a 2013 UNEP report
How is nitrogen pollution different from carbon emissions?
The attention to carbon is about climate change. Biology and life have other important elements. Amino acids, DNA and proteins are all nitrogen compounds central to life, and we need these to grow food. But in recent years, too much nitrogen has been used. A lot of it is leaking into our environment and has disturbed ecological and greenhouse gas balances.
Considering that we have exceeded limits for nitrogen pollution, how far can efficiency increase go in mitigating the threats?
My perspective is that we should embrace the link between the effects, the emissions and the efficiency. But we cannot forget about the threats themselves. If we only focus on efficiency, we will run into trouble because of what economists call the rebound effect—efficiency increases and brings down costs, which in turn increases the demand and consumption. It is important to think about sufficiency and consumption patterns—how much do we really need to eat? In Europe, 85 per cent of the nitrogen in agriculture is used to feed livestock while only 15 per cent reaches the people. We found that if Europeans were to halve their meat and dairy consumption, it would translate to a 40 per cent reduction in nitrogen pollution across Europe. But this is a very ambitious target.
How would mitigation play on a cost-benefit ratio?
Whenever you put a value to environmental threats, you get a big number where human life is involved although there is significant uncertainty. Of all the nitrogen inputs in the ground, only 20 per cent is available to humans. The rest is lost to the environment. We evaluated the net benefits if we improved efficiency of nitrogen use from 20 per cent to 25 per cent. That valuation was based on the amount of nitrogen saving in fertilisers, the environment and health threats and the cost of implementation. The cumulative benefit came to approximately US $170 billion of which the net benefit to the farmer was US $23 billion.
Why is it only now that there have been concerted efforts in scientific circles to address the problem of increasing nitrogen pollution?
Historically, scientists, researchers and policymakers have looked at their own part of the story within their disciplines, such as water, air and agriculture. In the end, the joined perspective is forgotten. At the International Nitrogen Initiative (INI, a group of scientists and researchers working to improve nitrogen efficiency), we are trying to show how that joined perspective can help motivate change once the entire picture is drawn up together.
How do governments factor into the equation?
The United Nations Economic Commission for Europe, comprising North America, Europe and Central Asia, has in the past discussed reduction of nitrogen pollution in the air. There was some progress as these discussions focused on transport with new engines and better exhaust systems to reduce emissions. But very little progress has been made when it comes to agriculture. So this remains a hot topic in Europe. But we have to look at the global scale. At INI, we are developing the International Nitrogen Management System which will support policy development and provide scientific assistance. We are also engaging with the United Nations Environment Programme and various intergovernmental bodies. Scientists are getting organised to deliver the science. Now governments have to get organised and work out how to link nitrogen-relevant policies.
Do you see that happening soon?
It’s a step-by-step process. At a 2012 intergovernmental meeting in Manila, many countries pushed to implement the 20 per cent improvement in nitrogen efficiency. No agreement was reached. The question is whether we are ready to reach an agreement in 2016 or 2017. We will be there to deliver the science, beyond that it would be the governments’ call.
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