The authors of a new report commissioned by the United Nations Environment Programme (UNEP) have urged policy makers to roll out sustainable agriculture techniques, which they claim are "already available but typically not yet applied," and suggested consumers cut their meat intake to limit the damaging effects of modern farming on the environment.

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The report, Our Nutrient World, highlights how humans have massively altered natural flows of nitrogen, phosphorus and other nutrients. It shows that, while this has had huge benefits for world food and energy production, it has also created "a web of water and air pollution that is damaging human health, causing toxic algal blooms, killing fish, threatening sensitive ecosystems and contributing to climate change."

The study was carried out by over 50 experts from 14 countries and launched on Monday at a UNEP forum in Kenya. Lead author Professor Mark Sutton of the UK's Centre for Ecology & Hydrology (CEH) called on farmers, particularly those in western nations, to curb their use of inputs and increase use of sustainable techniques. He said, "Our analysis shows that by improving the management of the flow of nutrients we can help protect the environment, climate and human health, while addressing food and energy security concerns."

Sutton and his fellow researchers said their report makes a clear case for reducing nutrient use. They made recommendations based on their findings in no uncertain terms, addressing consumption patterns as well as food production; encouraging shoppers to improve their diets and reduce their meat intake. However, they stopped short of recommending new global legislation to control nutrient use. Instead, the researchers advise drawing up a "roadmap" to structure intergovernmental action, arguing that it may be easier to encourage action within frameworks and conventions which already exist at EU and global levels.

Professor Sutton explained, "One option is to extend and strengthen the mandate of an existing agreement called the 'Global Programme of Action for the protection of the marine environment from land-based activities' (GPA). By clubbing together to meet multiple global challenges for food, energy, water and air pollution, climate and health, a much stronger gravity to motivate action can be expected."

Reducing the impact of food production and consumption

The report looks at both production and consumption of food. Researchers found that, as a result of dietary shift towards greater consumption of animal products, around 80 percent of harvested nitrogen and phosphorus is consumed by livestock worldwide, rather than directly by people. The researchers concluded that "global nutrient supply and pollution are dominated by humans' choice to consume animal products."

Accordingly, they made a number of recommendations to address the challenges outlined in the report. In terms of production, they recommend improving nutrient management in agriculture (encompassing crop, livestock and manure management). CEH researchers suggested useful techniques which have yet to be rolled-out include precision agricultural methods such as 'planting' large fertiliser pellets into the ground, preventing ammonia emissions from escaping into the air, a technique which researchers said is "suitable for both developed and developing countries."

According to the international team of scientists, better waste water treatment could also have positive effects, alongside actions to improve nutrient recycling from arable and livestock farming.

As for consumption, they said that lowering meat intake in richer countries, where more animal products are eaten, would have the dual benefit of improving health and reducing strain on the environment. Researchers warned that rapidly increasing meat and dairy consumption in Asia and Latin America has "a huge potential to influence future levels of global nutrient pollution," unless patterns are altered in these countries and others where consumption is already high.  

However, although powerful industry groups in the UK and United States in particular have attempted to derail recommendations to curb meat consumption in the past, Dr Barnaby Smith of CEH assured that the Our Nutrient World authors, many of whom previously worked with industry stakeholders on the 2011 European Nitrogen Assessment, would relish the opportunity to engage with industry rather than working from an adversarial position.

He elaborated, "The [study's] results show industry stakeholders could make savings on many levels. It makes sense for industry to become more efficient, as there would be industrial, environmental and economic benefits from doing so."

Dr Smith elaborated that the report's release comes at an opportune time in the EU, coinciding as it does with the horsemeat scandal, which has sparked debate throughout Europe over the state of the food system. He continued, "The horsemeat issue has thrown into stark relief the long length of some of our food supply chains and the associated problems. Our Nutrient World advocates attempts to become more efficient by shortening supply chains; not necessarily making them more local, but most definitely simplifying supply chains, which would reduce complications and areas where things can go wrong."

However, another study co-author, Dr Bruna Grizzetti, based at CNRS/Université Pierre et Marie Curie (UPMC) in Paris, said, "The option of localising agricultural production is a really important one. Crop and livestock farming are often separated by many hundreds of kilometres. Localisation helps improve nutrient recycling, reducing nutrient losses, while bringing the production benefits and pollution responsibilities closer together."

Although the report shows that other industries responsible for pollution have begun to tackle the issue by reducing emissions from combustion and wastewater sources, agriculture is faring relatively poorly in comparison, as is consumer education. The authors recommend working with 'cluster points,' in "nutrient chains" where a few key individuals or communities exercise substantial control to address this; examples of these cluster points include governments and supermarkets.

The scientists behind the study also suggest that a 20 percent improvement in nutrient use efficiency by 2020 would reduce the annual use of nitrogen fertilizer by 20 million tonnes. They term this global aspirational goal "20:20 for 2020". Their analysis shows how this could provide a net saving worth an estimated £110 billion per year (albeit with a significant margin for error). The figure includes costs associated with implementing the new policy, financial benefits from reduced nitrogen use and improvements to the environment and human health from a reduction in use.