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Although our ancestors have struggled with water shortages from ancient Mesopotamia onward, the spreading scarcity of fresh water may be the most underestimated resource issue facing the world as it enters the new millennium. This can be seen both in falling water tables and in rivers that run dry, failing to make it to the sea. As world water use has tripled since mid – century, over – pumping has led to falling water tables on every continent.

China and India, the world's two most populous countries, depend on irrigated agriculture for half or more of their food supply. In China, water tables are falling almost everywhere that the land is flat. The northern half of the country is quite literally drying out. The water table under much of the north China Plain, a region that accounts for nearly 40 percent of China`s grain harvest, is falling by roughly 1.5 meters a year. Projections by the Sandia National Laboratory in the United States show huge water deficits emerging in some key river basins in China as the new millennium begins.

In India, the water situation may be deteriorating even faster. As India's population approaches the 1 billion mark, the country faces steep cutbacks in the supply of irrigation water. David Seckler, head of the International Water Management Institute in Colombo, the world's premier water research body, observes: "The extraction of water from aquifers in India exceeds recharge by a factor of 2 or more. Thus almost everywhere in India, fresh – water aquifers are being pulled down by 1-3 meters per year. " Secler goes on to speculate that aquifers are depleted, the resulting cutbacks in irrigation could reduce India`s harvest by 25 percent – in a country where food supply and demand are already precariously balanced and where another 600 million people are expected over the next half – century.

At present, 70 percent of all the water worldwide that is diverted from rivers or pumped from underground is used for irrigation, 20 percent is used for industry, and 10 percent goes to residences. The economics of water use do not favor farmers. A thousand tons of water can be used in agriculture to produce one ton of wheat worth $ 200, or it can be used to expand industrial output by $ 14,000-70 times as much. As the demand for water in each of these three sectors rises and as the competition for scarce water intensifies, agriculture almost always loses.

As the history of Easter Island suggests, wood has been essential to dozens of human civilizations, and the inability to manage forests sustainably has undermined and destroyed several of them. Today, we have a global forest economy in which the demands of affluent Japanese or Europeans are felt thousands of kilometers away – in tropical Africa, Southeast Asia, and Canada. Since mid – century, the demand for fuel wood has nearly tripled, while paper use has gone up nearly six times. In addition, forestlands are being cleared for slash – and – burn farming by expanding populations and for commercial crop production and livestock grazing. As population pressures intensify in the topics and subtropics, more and more forests are being cleared for agriculture