The Colorado River supplies water to seven states, including New Mexico, before crossing the border into Mexico. Then—theoretically, nowadays—it reaches the Sea of Cortez. Demands from cities and farms, along with climate change, strain the river and affect its flows. Now, a new study shows that even though annual precipitation increased slightly between 1916 and 2014, Colorado River flows declined by 16.5 percent during that same time period. That’s thanks, in large part, to “unprecedented basin-wide warming.” Warming reduces snowpack and increases the amount of water plants demand.
The signs of rising temperatures are obvious across New Mexico right now, from the mountains to the river valleys, and from rangelands to suburban backyards. “Climate change for the Southwest is all about water,” said Jonathan Overpeck, who has spent decades studying climate change and its impacts in the southwestern United States. Warming affects the amount of water flowing in streams, and the amount of water available to nourish forests, agricultural fields and orchards. There’s also the physics of the matter: A warmer atmosphere holds more moisture, demanding more from land surfaces. Plants need more water, too.
Over the next week, New Mexico Political Report will be reporting from…not New Mexico. Instead, we’ll be taking a closer look at the Colorado River. The Colorado delivers water to more than 36 million people in seven states and two countries. Its waters carved the Grand Canyon and, far more recently, allowed the growth of Sunbelt cities like Phoenix and Tucson. (No, neither is near the Colorado.