The US Drought Monitor is a critical tool for the arid West. Can it keep up with climate change?

LOS ANGELES -- Known for its glowing swaths of yellow, orange and red, the U.S. Drought Monitor has warned farmers, residents and officials throughout the nation of impending water scarcity every week since 1999.

Backed by data on soil moisture, temperature, snow cover, meltwater runoff, reservoir levels and more, the map has become an essential instrument for determining the outlook of water supplies, declaring drought emergencies and deciding where and when government aid should be distributed, among other things.

But this critical diagnostic tool is also struggling to keep pace with climate change as longer and more persistent dry spells plague the American West and take an increasing toll on groundwater reserves and the Colorado River, according to a recent study published in the journal AGU Advances.

One problem, researchers say, is that the monitor was launched just as one of the driest periods in the history of the Southwest began, and it has never been adjusted for the region’s growing.