40 Million Americans Depend On The Colorado River. That Could Be A Problem.

You’ve heard of the water cycle, right? You studied it in high school. Moisture evaporates into the atmosphere where it forms clouds. Those clouds produce precipitation which falls back to Earth as rain or snow, which creates lakes and rivers. Those lakes and rivers irrigate crops and meet the needs of humans and animals. Water is pretty important stuff. A human can go 20 days or more without food but only about 3 days without water.

Lake Powell and the Colorado River as seen from the International Space Station. Image credit: European Space Agency

40 million Americans depend on the Colorado River for drinking water and for growing crops. The deserts of Arizona bloom because of water diverted from the Colorado. The Imperial Valley in California — the source of much of America’s fruit and vegetables — is completely dependent on Colorado River water. The cities of Los Angeles, San Diego, Las Vegas, and Phoenix would shrivel and die were it not for the lifegiving water supplied by the Colorado.

But there’s a problem. The Colorado River now carries about 20% less water than it did a century ago. The Colorado originates in the Rocky Mountains, where it is fed by melting snow. Due to the changes in weather patterns attributable to a heating planet, not as much snow falls in those mountains today as in prior years. Less snow means the land in the upper elevations is warmed by the sun where previously the snow cover would reflect sunlight back into space, making the area hotter, which means that whatever snow falls melts sooner.

The result? There’s less water available. In fact, since 2000, water flow in the Colorado River has been reduced by 1.5 billion tons — enough to meet the needs of 10 million people — say Chris Milly and Krista Dunne of USGS. They attribute half of that loss to human activity.“The Colorado River Basin loses progressively more water to evaporation, as its sunlight-reflecting snow mantle disappears,” the researchers tell The Washington Post.

Image credit: USGS

Things are not likely to improve any time soon. Comparing the Colorado River’s historic flow between 1913 and 2017 to future conditions, Milly says, “That flow, we estimate, due to the warming alone would be reduced anywhere from 14 to 31 percent by 2050.” If that happens, there simply will not be enough water to sustain urban and agricultural areas in Arizona and southern California. Where will all those people go? No one has any idea.

Andrew Mueller, general manager for the Colorado River District, said in an email to The Washington Post that the findings provide “confirmation of significantly grim indicators about future flow in the Colorado River.” The amount of water that would disappear with another 1 degree C temperature rise is nearly five times what Las Vegas uses each year. “A decline in flows of this magnitude will present a significant challenge to all inhabitants in the Colorado River Basin,” he says.

The water in the Colorado River is shared between 7 states and Mexico, but the current agreement expires in 2026. The parties to the agreement are already negotiating the next agreement, but with less water to go around, hard choices will need to be made. And it doesn’t help that the current American government is doing nothing to address climate change and adamantly refuses to acknowledge there is a problem. US officials take the position that those who worry about a hotter planet are chumps who have been taken in by charlatans. Perhaps they will change their mind when the nearly $1 trillion in economic activity associated with the areas of the country that rely on the Colorado River begins to shrink.

Marlon Duke, a spokesperson for the US Bureau of Reclamation, which oversees the nearly quarter of million square mile watershed that feeds the river, tells The Post, “Reclamation works closely with ​leading scientists at the state and federal level, as well as universities to understand the potential impacts of climate change on the Colorado River. We will continue to use the best available science to manage the river to sustain reliable water far into the future.”

Such happy talk might be reassuring if the highest officials in the US government did not treat those same scientists as little more than crooks and liars. The prospects for the areas serviced by the Colorado are grim today and will likely be dire just 10 or 20 years from now as the US continues to twiddle its thumbs and dither about how to cope with an overheated planet. The two largest reservoirs along the 1,400 mile route of the Colorado River — Lake Mead and Lake Powell — are only half full today. In 20 years they are likely to be completely empty. That’s when today’s conservatives will throw up their hands and say, “Who knew?” and look for ways to blame Democrats for the looming catastrophe.