Globally, human demand for freshwater is tremendous. We capture half of the available water flowing to the ocean. Several of the world’s greatest rivers—including the Nile, the Ganges, and the Colorado— are so tapped by human demands that they experience dry periods where they no longer flow to the sea.
Our rivers are fragmented by tens of thousands of huge dams—topped by China’s Three Gorges, a water impoundment system of epic proportions. Millions of smaller dams further divide our river ecosystems. Together, they block fish migrations and prevent a quarter of the sediment that rivers carry from reaching the sea.
As a result, river deltas on the Mississippi and the Nile, among others, are eroding and coastal fisheries are suffering from an imbalance of key nutrients.
Pollution now extends into the most remote corners of our planet and has reached unprecedented levels. We’ve overfished many lakes and rivers to the point where large-bodied fish species have vanished, leaving only smaller, less desirable species, to which we are now turning our hungry attention.
In the next few decades, human pressures on fresh waters will rise as our populations and economies grow. Already, inadequate water causes human suffering in many parts of the world. We can expect water shortages to spread and intensify, causing political instability.
In our quest to obtain water for drinking, agriculture, industry, and hydroelectricity, it seems unlikely that we will leave enough water for freshwater ecosystems and their inhabitants, extinguishing many of the thousands of freshwater species that are already endangered.
Somehow we must meet our need for fresh water while safeguarding the needs of the irreplaceable natural world we have been given, and the enormous benefits it can give us if we manage it wisely.
Photo, taken on December 30, 2009 in Clark County, Nevada, using a Canon EOS REBEL T1i, courtesy of Alan Stark via Flickr.
This script was adapted from a column by Dave Strayer that originally ran in the Poughkeepsie Journal. You can access the original article here – http://www.caryinstitute.org/ecofocus_2009-01-18.html.