Water
During the part past century,while world population gas tripled,the use of fresh water for human consumption,agriculture,and other activities has increased sixfold.Some rivers that Formerly reached the sea no longer do so all of the water is diverted to human use before it reaches the river's mouth.Half the world's wetlands have disappeared in the same period,and today20percent of freshwater species are endangered or extinct.Many important aquifers are being depleted,and water tables in many part of the world are dropping at an alarming rate.Worse still,world water use is projected to increase by about50 percent in the next 39 years.It is estimated that ,by2025