Freshwater is a critical resource and the supply is rapidly dwindling in an era of climate change. The demand for water far exceeds the rate of natural replenishment, leaving a seriously depleted water table and increased conflict over water rights in many regions. The bulk of our freshwater use is for cooling in power plants and irrigation in large-scale agriculture. In this discussion, John Rogers focuses especially on the problem of power plants. In the United States, 90 percent of electricity comes from conventional thermoelectric power plants' coal, nuclear, natural gas, and oil, and such technologies depend on freshwater cooling. Much of that freshwater is wasted. In a time of critical loss of freshwater, the deployment of alternative energy systems cannot be postponed.
