Dwindling fresh water supplies worldwide will severely impact food security, aquatic ecosystems and political stability unless people begin protecting and conserving sources, says water issue specialist and author Sandra Postel.
Postel, director of the Amherst, Mass.-based Global Water Policy Project, spoke Thursday as part of the UNM Biology Department's 11th Annual Research Day. She said a growing trend toward treating water as an economic good has caused the world's growing population to ignore the negative environmental impact.
"The biggest challenge in this century will be figuring out how to satisfy the water needs of nine billion people while preserving wildlife habitats," she said.
Though fresh water is a renewable resource, its supply is limited and as population grows, the amount available for each person decreases, Postel said.
"Since 1950, we've seen the total renewable per capita supply down 50 percent," she said. "We're entering an unprecedented period of water stress."
Postel used a map of the world color-coded to represent areas of water stress, or places where fresh water supply is dangerously below the needs of the population. Severe shortages were indicated in the Southwestern United States, Mexico, Northern Africa, the Middle East, Central Asia and China.
Get content from The Daily Lobo delivered to your inbox
She added that political stability and peace in those areas has been increasingly threatened by competition between farming and urban areas, as well as between states and countries that share single water sources. She said food supplies also are threatened in areas of high irrigation, such Pakistan and China and India.
Postel stressed that the environmental impact to important aquatic ecosystems and farming soil has been devastating.
"Twenty years ago, this map looked very different," she said.
Postel said groundwater in these areas, as well as zones of heavy irrigation in the United States, is not being replaced fast enough to keep up with the demand.
"If the numbers are accurate, 8 percent of our food is grown with groundwater that is overpumped," she said. "That's the hidden subsidy with our food. No place has solved this problem. Just because the issues haven't shown in the global food price doesn't mean it's not a problem. You can still accelerate your car when the tank is empty."
She said the surge in worldwide population since 1950 has taken a huge toll on ecosystems. The number of large dams surged from 5,000 in 1950 to 45,000 today - an average of two dams a day, she said.
"That's a very large change in a short period of time," she said. "You're disconnecting that river from its channel. Each disconnection causes loss of ecological services, from fish to sediment movement. All these things depend on natural flows."
She said 20 percent of the world's freshwater fish are extinct or at extreme risk.
Postel added that she has hope that the problems can be solved, but that to do so would require a change of mindset nationwide. That attitude for the last century has been that the environment is just a residual and human needs come first, she said.
"But that piece of the pie gets smaller and smaller as the human part gets bigger," she said. "And the endpoint is devastation."
The new mindset, Postel said, would require that people place their water needs below those of the environment. By establishing the amount of water and flow patterns required by a source and capping the amount that humans can use to protect those requirements, the trends could be reversed, she added.
"We need to set aside water ecosystems' needs and basic human needs first," Postel said. "I think it's possible, but so far, there's been nothing but nibbling at the edges of what it will take to mitigate the problem."
