Unsuccessful crop security
The world's cropland area stopped increasing at the beginning of 1980s. Water is becoming scarce and it will constrain the growth and food production in some parts of the world. Deforestation sets in motion a chain of events that leads to the gradual deterioration of the soil fertility: 24 billion tons of top soil is lost each year to soil erosion. The gradual increase in the average temperature of the earth affects food production more than any other environmental change. Even if the land productivity could be raised during the nineties as high as 0.9% a year, the growth in food output will be about half the projected rate of world population growth.