The Haber-Bosch process has been declared the most important invention of the 20th century, more important than the computer, television, the mobile telephone and atomic energy. Without this process 40 % of the world population could not be fed today. In1900, 1.6 billion people lived on this planet - today 7 billion. In 1900, the yield of 1 hectare of land (100 x 100 meters) would not even feed two people. Today 4.3 people can live off the yield which is mainly being owed to nitrogen fertilizers. If, from one day to the next, we had to revert to the agriculture of 1900, famines of enormous proportions, major unrests and wars would ensue.

Not even with the worldwide food production doubling in the wake of the so-called Green Revolution in the years between 1965 and 2000, could synthetic fertilizers resolve the unequal distribution of foodstuffs. Areas under cultivation increased mostly at the costs of primeval forests.

Today, the Haber-Bosch process transforms the same amount of atmospheric nitrogen into reactive nitrogen as natural processes do. Fertilizers have a significant side effect since more is being employed than is needed by the plants. The excess finds its way through groundwater and rivers into the ocean where it keeps on fertilizing with unpleasant results. For example, today, the Mississippi carries, compared to 1900 four times the amount of nitrogen. The result is the an annual large algae bloom in the Gulf of Mexico and a frequent algae bloom in the Baltic Sea as can be seen in satellite images. For this, phosphate, another component of synthetic fertilizers, shares the responsibility with reactive nitrogen. The algae poison the water and deprive the water of oxygen when they perish - dead zones in the sea are the result. Besides over-fishing, the over-fertilization (eutrophication) is the greatest threat to the ecosystems in lakes, rivers and the sea. Fertilizers degrade into laughing gas which contributes to climate warming.

If the nitrate from well-fertilized fields finds its way into the groundwater and from there into wells, the contaminated poses a serious risk to the health of new-born infants and adults with impaired intestinal flora.


Reactive nitrogen also emanates from car engines and power plants, and even from ordinary gas boilers. Under high temperatures nitrogen and oxygen combine into nitrogen oxides. Especially in winter, the sweetish smell of the health-damaging nitrogen oxide can be smelled when cars drive by.


By now, yellow lichens are very widespread here. They are an indicator for the abundance of reactive nitrogen in the air. As a result of agricultural fertilization, the burning of heating oil or coal and car exhausts, tiny crystals and droplets of nitrogen compounds, as for example, ammonium nitrate float in the air. At high temperatures the oxygen in the air combines with atmospheric nitrogen to nitrogen oxide. As a consequence, every year in Germany, about 30 kilograms of reactive nitrogen descends on one hectare of land, and this not only in cultivated areas. Many ecosystems, moorland or heaths, for example, do not tolerate this fertilizer. Rare plants are supplanted by species which make better use of the aerial fertilizer and invade the terrain.


Synthetic fertilizers enabled us to cultivate in areas like moorlands or tropical rain forests, which before were not suitable for agriculture due to their nutrient-poor soils. All this happens at the cost of nature. At present, large areas of tropical rain forest in Africa, Southeast Asia, and Latin America are deforested by slash and burn to make way for arable land. Just between 2000 and 2006 an area of the size of the State of Hesse (21,000 square kilometres), was deforested in Amazonia each year, mostly for soybean cultivation. By now, pressure groups effect a slowdown in deforestation.