12th December 2014

The world has 60 years of topsoil left

If present rates of degradation continue, all of the world's topsoil could be lost by 2075, according to a senior UN official.

Topsoil is the layer of soil that contains the greatest concentration of nutrients, organic matter and microorganisms. It is vital for maintaining a healthy root base and plant growth, enabling farmers to till and produce their food crops. To generate only 3 cm (1.2 in) of topsoil requires between 500 and 1,000 years through natural processes.

Modern agricultural techniques – requiring the soil to be ploughed and replanted each year, together with heavy use of chemicals – have resulted in the gradual erosion of topsoil. Deforestation and global warming also play a role. Worldwide, approximately one-third of topsoil has been lost since the Industrial Revolution. This is already harming the livelihoods of a billion people. If trends continue, all of the world's topsoil will be gone within 60 years, according to a United Nations statement on World Soil Day.

"Soils are the basis of life," said Maria-Helena Semedo, deputy director general of natural resources at the Food and Agriculture Organisation (FAO). "Ninety-five percent of our food comes from the soil."

With global population expected to surpass 9 billion by mid-century – along with huge increases in biofuel production – the amount of arable and productive land per person in 2050 will be only a quarter of the level in 1960, unless a radical transformation of agriculture occurs. In addition to providing food, soils play an essential role in the carbon cycle and water filtration. Soil destruction creates a vicious cycle, in which less carbon is stored, the world gets hotter, and the land is further degraded.

While the rate of degradation is not the same everywhere, "we are losing 30 soccer fields of soil every minute – mostly due to intensive farming," according to Volkert Engelsman, an activist with the International Federation of Organic Agriculture Movements, who spoke to the forum at the FAO's headquarters in Rome.

Organic farming can reduce toxic chemicals and carbon emissions, but requires more land. Vertical greenhouses can work for some crops, but their economic and technical feasibility have yet to be fully proven. In the 2030s, perennial wheat and corn could enable crops to be grown continuously for two or more years – offering a huge improvement over traditional annual crops. Hi-tech solutions might also emerge in the form of 3D-printed or laboratory-grown meat. In the more distant future, humans could upgrade their bodies to become partially or fully non-biological, drawing energy from sources other than food. Whatever solutions are eventually developed, this announcement from the UN is a sobering reminder of just how rapidly our world is changing.

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