Alexandra Cousteau is a spokesperson and supporter of the Dow Live Earth Run for Water and is the founder of Blue Legacy. The following post was written for Larry King Live.

From outer space it looks like we live on a blue planet. And we do – 70 percent of Earth is covered by water. But only a tiny percentage of that water is fit for human consumption. If you could fit all the water in the world into a gallon jug, less than a teaspoon of that would be available for our use. And as glaciers on all continents retreat, that teaspoon is shrinking.

Nearly every system that shapes the availability and quality of water on our planet is dramatically and historically out of balance. The past century of progress has largely ignored the simple principles of basic grade-school science: We share a single interconnected hydrosphere, one that puts us directly downstream from one another.

The consequences of our quest for progress and its impact on the rivers and everything that depends upon them – from rainfall patterns to wildlife to agriculture – will be disastrous. Ecosystems will collapse. Hundreds of millions of people will be displaced. And the steady rivers that once shaped the course of society and the soul of cultures will shift seasonally, delivering floods and landslides to some, and unimaginable drought to others.

This is “will,” not “might,” because this is not theory. It’s not opinion. It’s fact. Unless we do something, in less than a generation all of this will come to pass.

That’s why I’m so excited to be a part of the Dow Live Earth Run for Water. This event will bring people together around the world, raising awareness about the sources and consequences of the water crisis, locally and globally. It captures perfectly the interconnectedness of life on our water planet.

And it drives home the message that I hope each of you will take to heart: our water crisis is a global issue. A human issue. It isn’t going to be fixed by scientists or policymakers alone. It’s up to each us… to all of us.

In the end, our shared humanity and our shared history are written in water. And how the story ends is entirely up to us.

To learn more or how to participate in the Dow Live Earth Run for Water please visit liveearth.org.

Originally posted at http://larrykinglive.blogs.cnn.com/2010/04/14/cousteau-the-looming-water-crisis/.