Deserts , worldwide, expand by about 50.000 square kilometres per year, and desertification threatens the livelihoods of a billion people in 110 countries. In Europe, Spain is particularly affected.
Desertification is a particular problem in China.
One Chinese study suggests that soil becomes prone to erosion for the following reasons
- Overgrazing (30%)
- Excess land reclamation of unsuitable soil (27%)
- The collection of firewood (33%)
- Water misuse (10%). Excessive irrigation can make soil salty and infertile.
The solution is to be found by
- planting trees,
- managing grassland better and
- conserving water in river basins.
The world population is now 7 billion and will eventually reach 9 billion. We cannot afford to lose fertile food producing land if we are to avoid famine.
We have also got to conserve water, because water demand is increasing rapidly. Urban societies consume more water than rural ones. Meat production requires much more water than grain production, but as people get richer they eat more meat.