Our early 21st century civilization is being squeezed between advancing deserts and rising seas.
Measured by the land area that can support human habitation, the earth is shrinking.
Mounting population densities, once generated solely by the addition of over 70 million people per year, are now also fueled by the relentless advance of deserts and the rise in sea level.
The newly established trends of expanding deserts and rising seas are both of human origin.
The former is primarily the result of overstocking grasslands and overplowing land. Rising seas result from temperature increases set in motion by carbon released from the burning of fossil fuels.
The heavy losses of territory to advancing deserts in China and Nigeria, the most populous countries in Asia and Africa respectively, illustrate the trends for scores of other countries.
China is not only losing productive land to deserts, but it is doing so at an accelerating rate. From 1950 to 1975 China lost an average of 600 square miles of land (1,560 square kilometers) to desert each year. By 2000, nearly 1,400 square miles were going to desert annually.