With Too Much of a Good Thing, Europe Tackles Excess Nitrogen

In Germany, the Netherlands, Denmark and other countries, European governments are beginning to push farmers, industry, and municipalities to cut back on fertilizers and other sources of nitrogen that are causing serious environmental harm.

Only seconds after Claudia Wiedner drops the metallic rod into the gray waters of Lake Scharmützel, 30 miles southeast of Berlin, the probe starts sending signals back to her computer. On a cold, foggy day in March, Wiedner, a limnologist at the Brandenburg University of Cottbus-Senftenburg, and a research technician are out on the water in their small vessel to investigate nitrogen pollution.

The water samples they pull up tell an encouraging tale — at least in this lake. “We have been measuring reactive nitrogen and phosphorus in this lake since 1993 and what we see is a change for the better — levels have dropped considerably,” Wiedner says. Her colleague, Ingo Henschke, an avid diver and former fisherman, can attest to this, saying that better sewage treatment and a decrease in nearby farming have significantly improved water quality.

collecting phytoplankton
Scientists use a net to collect plankton in the waters of Lake Scharmützel in Germany. CLAUDIA WIEDNER

“I was able to document a return of large swaths of stoneworts algae and the rich water life they sustain,” Henschke says.

But Scharmützel Lake is an exception in Germany — it serves as a kind of gold standard for positive changes. For like the rest of Europe and much of the world, Germany’s waterways are suffering from a surplus of nitrogen that is spread across fields as fertilizer, pours off of farms where livestock and chickens are raised, or flows out of factories, sewage systems, and wastewater treatment plants. The result is harmful algal blooms in lakes, dead zones in oceans, and an impoverishment of terrestrial and aquatic biodiversity — problems that the European Union is now trying to address.

“We are observing a wide range of severe negative changes in the environment due to excess reactive nitrogen,” says Wiedner, who is the project coordinator of a flagship research project called “NITROLIMIT.” She says there is growing concern among European environmental scientists and agencies that nitrogen pollution has been ignored for far too long. NITROLIMIT, funded by the German federal government, includes 30 researchers from six institutes. The team has studied 370 lakes in northeastern Germany, but only one quarter were classified as being ecologically healthy.

The farming lobby is working hard to stop legislation to constrain the release of nitrogen.

Throughout Germany, up to 600,000 metric tons of ammonia — a nitrogen molecule concentrated in liquid manure from animal farming — finds its way into streams and lakes each year, according to Ulrich Irmer, head of water policy at Germany’s Environmental Protection Agency. Earlier this year, the agency warned in a report that urgent changes are needed to reduce nitrogen pollution, including farmers managing their fertilizer use much more efficiently and consumers eating less meat.

In the basin of the Untere Havel, a river that runs through western Berlin, researchers from the NITROLIMIT project determined that nitrogen pollution would have to be reduced from 6,500 tons annually today to 3,500 tons in order to restore a sound freshwater ecosystem. Implementing the necessary changes, such as boosting organic farming along the river and building retention ponds for urban stormwater, would cost more than 60 million euros.

But all over Germany, from the Untere Havel basin in the east to meat-producing North Rhine-Westphalia in the west, the farming lobby is working hard to stop legislation that would constrain the release of nitrogen into the environment. Being able to dump manure in the landscape is a key factor in producing cheap pork and other meats for the domestic and Asian markets.

In Europe, politicians concerned about the environment tend to be preoccupied with carbon emissions and climate change. But the environmental consequences of nitrogen are increasingly difficult to ignore. The German Advisory Council on the Environment, Chancellor Angela Merkel’s central body of experts, sounded the alarm bell in January with a scathing report. It said that while Germany prides itself on its high recycling rates and its “Energiewende” — its aggressive transition to a nuclear-free renewable energy supply — nitrogen pollution remains largely unchecked.

Germany ‘can’t keep claiming to be a leader in green policies if it does not address the nitrogen problem.’

“The country can’t keep claiming to be a global leader in green policies if it does not address the nitrogen problem,” says council member Heidi Foth, a toxicologist from the University of Halle. According to the council’s report, one quarter of Germany’s groundwater bodies are contaminated with excess nitrogen and half of all terrestrial habitats are negatively affected by it. Across Europe, the problem of nitrogen pollution is especially acute in areas with intensive industrial animal farming, in particular the so-called “pig belt” that stretches from Denmark, across northwest Germany, to the Netherlands.

Nitrogen is a chemical element all living beings need to grow and sustain their bodies in a form that chemists call “reactive.” Until the early 20th century, the supply of reactive nitrogen was limited by nature. Farmers could only fertilize their fields with the nitrogen that circulated between soil, air, plants and animals, or add a little guano dung imported at high prices from remote Pacific islands.

This changed fundamentally when, around 1910, German chemists Fritz Haber and Carl Bosch found a way to extract the gas most abundant in the atmosphere — nitrogen in its “non-reactive” form — and turn it into fertilizer and other useful chemicals on an industrial scale. That’s when modern agriculture took off. Today, a third to a half of all humans are fed thanks to this “Haber-Bosch process.”

Human activities add more than 150 million tons of nitrogen to the biosphere each year.

But fertilizer is applied in such huge quantities on fields that it gets washed out into streams, lakes, and the oceans, where it severely impacts ecosystems. Cars and factories that burn fossil fuels add nitrogen, which had been stored underground for millions of years, to the atmosphere. Today, an estimated 150 million to 200 million tons of nitrogen are added to the biosphere through human activities each year. The total amount of nitrogen being cycled through ecosystems on land and in the oceans has doubled since preindustrial times.

According to a 2011 landmark study by Britain’s Natural Environment Research Council, damages from excessive reactive nitrogen in the environment cost the countries of the European Union between 70 billion and 320 billion euros per year due to air and water pollution, outweighing the direct economic benefits in agriculture.

Contrary to intuition, habitats with a shortage of nutrients, such as nitrogen and phosphorus, are richest in species. The shortage stops any one species from becoming dominant and facilitates a healthy competition between many species. Added nitrogen only helps a small number of species that can best metabolize it.

“If you add nitrogen to a species-rich ecosystem, a few plant species will thrive while a majority lose out,” says Peter Munters, who, from his base at the Netherlands’ Ministry of Economic Affairs, is in charge of an initiative to rein in nitrogen pollution. Munters said that diverse heathlands become monotonous grasslands, while bogs and dunes are overgrown by bushy vegetation. Rare species vanish. “Nitrogen is making our landscapes homogeneous,” Munters warns.

The Netherlands is one of the world’s nitrogen hotspots. Agriculture is extremely intensive, with vegetables, flowers, and meat being produced on an industrial scale. As a result, each hectare of agricultural land receives more than 200 kilograms of surplus nitrogen per year. The effects of intensive animal farming, fertilizer use in the Netherlands’ agricultural sector, and industrial nitrogen emissions have become so severe that the government has decided to act.

Obliged to protect its diversity of plants and animals under national and European law, the Dutch government launched a strategic plan this year designed to decrease the total amount of nitrogen deposition in the country’s 160 nature reserves protected within the European “Nature 2000” network. Munters says the government will spend 60 million to 80 million euros per year to reduce nitrogen deposition in the reserves and restore the sites.

The Dutch scheme includes some radical measures. From 2016 on, workers with excavators will move into some nature reserves to remove topsoil containing excess nitrogen, says Imke Boerma from Staatsbosbeheer, the Dutch agency in charge of nature reserves. He cautions that taking nitrogen out of nature reserve will only show effects if there is a sustained long-term effort.

For each of the five million people in Denmark, there are four pigs on Danish farms.

Denmark is another country with a huge nitrogen problem. For each of the five million Danes, there are four pigs on a Danish farm. Like Germany and the Netherlands, the Scandinavian country imports huge amounts of soy feed from South America to produce equally huge amounts of meat that then is exported, often to China. The meat leaves the country, but what stays in Denmark is the nitrogen from liquid manure that gets sprayed onto fields.

But Denmark has led the way in tackling the problems. It has decreed that farmers must apply fertilizer at least nine meters away from streams and lakes. Also, working with environmental agencies, farmers must establish strict nitrogen budgets, with fines for overuse of fertilizer. Nitrogen surplus per hectare fell from 170 kilograms in 1992 to 100 kilograms in 2010, according to data from the University of Aarhus.

“Our discharges into the Baltic Sea and the North Sea have dropped by approximately 50 percent over the past three decades as a result of numerous Danish action plans in agricultural areas and reducing output of nitrogen and phosphorus from households and industries,” says Stig Pedersen, chief adviser at the Danish Nature Agency.

But even at that lower level, ecological effects remain severe. In his office in downtown Copenhagen, Pedersen displays a map of Denmark showing where the country has not yet reached the “good ecological status” mandated by the EU’s water directive. Pederson acknowledges that most coastal waters in Denmark are still polluted by excess nitrogen.

In certain river basins, new wetlands are now being constructed to purify the water. Pedersen says that the 1,000 hectares of new wetlands that have been created in the Odense River basin alone act as an “ecological liver” that removes unwanted nutrients.

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“It takes time until you see what you get for your money,” says Pedersen. “But when excess nitrogen goes, life comes back.”

In Germany — Europe’s largest economy and most populous country — how reductions can best be achieved on a large scale is being hotly debated. The EU commission has already threatened to sue Germany for a lack of action over nitrogen pollution. Irmer, of Germany’s Environmental Protection Agency, points to new legislation that will require each of the 285,000 farms in Germany to submit a strict nitrogen-budgeting plan, beginning in 2018. The agency plans to establish nitrogen limits for water bodies based on ecological criteria.

The government’s Advisory Council on the Environment wants to go one step farther and reduce Germany’s massive consumption of meat, now at 60 kilograms (132 pounds) per capita per year. Advocates are seeking to remove tax advantages for animal products and to introduce tough fines for nitrogen pollution. They even want to change behavior at the thousands of canteens in ministries and other state-run institutions, requiring them to serve mainly vegetarian dishes or halved portions of meat.