Ecosystems / Earth
Land, they say, is life. The earth beneath our feet transforms death into life, as the organic matter of decomposing plants, manure and animals is broken down by billions of micro-organisms. Mix this with particles of rock and minerals, as well as oxygen, nitrogen and carbon, and you have the rich but fragile ingredients of our planet’s skin, basic to human survival. For soil is not just the feeder of plants and thus of animals: it is the substratum of civilization.
Cultivating the land through agriculture has allowed humanity vastly to increase its population, and so to undertake great works of water and soil management. Today the world’s most productive land, which once supported a profusion of wildlife, is under human control.
But we have eroded our planet’s thin skin of soil at alarming rates, without understanding the need to replenish it. Clearing forests for land exposes soil to corrosive rainfall, and the poor, eroded earth that is left pushes cultivators ever further into the forests. Salination, deforestation, soil erosion and other abuses have led to famine, war and population crash. Chemical-based pesticides and fertilizers which in the 1960s increased food production are failing as pests develop resistance and toxic residues pollute soil, water, food and wildlife. In addition, chemical fertilizers require huge amounts of fossil fuels to manufacture and, used over the long term, deplete the quality of the soil.
Along with logging and agriculture, mining and oil/gas extraction are the largest assaults on the land. In the past 150 years we have drastically rearranged our landscapes, drilling and quarrying, beheading mountains and displacing communities. The results have been toxic sludge, dead rivers and silted waterways, floods and landslides.
Who controls the land – and whether it is exploited as a resource or stewarded for future generations, is a fundamental moral and political struggle.
EARTH – THE FACTS
• Farming may be the human endeavour most dependent upon a stable climate. Plant scientists from Asia have found that rising temperatures may reduce grain yields in the tropics by as much as 30% over the next 50 years.2
• More than half of all the synthetic nitrogen fertilizer ever used has been used since 1985. Human activities have now roughly doubled the rate of creation of reactive nitrogen on the land surfaces of the Earth and tripled the flow of phosphorus (also from fertilizer) into the oceans.1
• Africa is the only continent where food production per capita declined after 1960. This was due largely to soil erosion.3
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