WATER
It's as vital to life as air. Yet fresh water is one of the rarest resources on Earth. Only 2.5 percent of
Earth's water is fresh, and of that, the usable portion for humans is less that 1 percent of all fresh
water, or 0.01 percent of all water on Earth. Water is constantly recycling through
Earth's hydrologic cycle. But population growth and pollution are
combining to make less and less available per person
per year, while global climate change adds new
uncertainty. Availability of fresh water
varies tremendously around the
world, inevitably triggering
conflicts over water
resources.
GLOBAL IRRIGATED AREAS AND WATER WITHDRAWALS
Since 1970 global water withdrawals have correlated with
the rise in irrigated area. Some 70 percent of withdrawals
are for agriculture, mostly for irrigation that helps produce
40 percent of the world's food.Water Resource Problems 253