The “mega-drought” sweeping the US Southwest has pushed water levels at the two largest reservoirs to record lows and forced unprecedented government intervention to protect water and electricity supplies in seven states.
Millions of Americans already struggling with critical water shortages are now facing power outages as energy demands grow during heat waves while hydroelectric supplies are strained. A US power regulator warned this week that much of the US is at risk of power outages, partly as a result of drought conditions limiting hydroelectric power supplies.
U.S. government climate scientists said more than half the country is suffering from drought conditions, while a separate study estimated the drought that hit southwestern states was the worst in 1,200 years after being exacerbated by human activity.
“This is by far the worst drought on record,” said Andrew Hoell, a drought-focused scientist with the US government’s National Oceanic and Atmospheric Administration (NOAA). “Why don’t you care about the worst drought in more than a millennium? We have to live through this.”
Water levels at Lake Mead, the largest US reservoir, and Lake Powell upstream of the Colorado River have dropped sharply, prompting federal officials to activate a drought emergency plan. Lake Powell’s water level is at its lowest since it was filled in in the 1960s.
As Lake Powell threatens to fall below the minimum level required for Glen Canyon Dam to operate, hydropower for an estimated 5.8 million homes in seven states is at risk.
US officials plan to divert water from another reservoir upstream in Utah to Lake Powell and release less water than usual downstream to Lake Mead. The actions would ‘prop up’ Lake Powell for an estimated 12 months.
“We’ve never taken this step before in the Colorado River drainage basin,” said Tanya Trujillo, an Interior Department official, referring to the emergency response.
Jason Smerdon, a climate scientist at Columbia University, described “scary” drought conditions in the southwestern states.
“All emission scenarios point to increased warming in the Southwest and thus increased drying,” he said. Although the drought was partly due to natural variations in rainfall patterns, he explained, it was exacerbated by a long-term trend of drought caused by human activities.
Noaa’s Hoell, a meteorologist who has tracked extreme weather and its relationship to climate change as part of annual studies, said: “The drought we are having right now has a high probability of being repeated in the future.”
Bart Miller, program director at Western Resource Advocates, a climate protection group, estimates that 14 million Americans depend on the Colorado River for their water, while about 5 million acres of farmland are irrigated with its water. “More and more people are beginning to understand that the path we are on is an uncertain one,” he said.
The nearby states of Nevada, Arizona, and California have all increased their efforts to limit water use. Las Vegas, Nevada’s largest city, has introduced restrictions, including caps on the size of golf courses, to reduce the amount of grass that needs to be watered. Farmers in parts of Arizona have also suffered cuts in the water they can use for irrigation.
In California, Gov. Gavin Newsom launched a $100 million ad campaign to save water. But when he asked residents in March to reduce their water use by 15 percent compared to 2020 levels, statewide use increased by almost 20 percent instead.
Kate Poole, senior director of the Natural Resources Defense Council’s water department, recommended further action to conserve water supplies, including reducing the amounts used in homes and urban areas, promoting efficient agricultural irrigation, and recycling and reusing water.
“We face a future with much less water and greater demand due to higher temperatures,” she said.
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