Tucson, Arizona — Deadly heat waves have become the summertime norm in Arizona and much of the Southwest in recent years. But this year, those heat waves are coming months before the height of summer. As an atmospheric “heat dome” planted itself over much of the U.S. West, temperatures outside Phoenix reached 101 degrees on the first day of spring, making Arizona the hottest place on Earth.
The heat dome continues to shatter temperature records this week. What crucial snowmelt that remained in desert mountains quickly dissipated, all but guaranteeing water shortages and another violent forest fire season later this year.
A groundwater crisis decades in the making has already slowed the otherwise rapid expansion of suburban sprawl around Phoenix, leaving entire housing developments sitting empty in the desert. That water shortage hasn’t stopped state officials from offering lucrative tax breaks to companies building AI data centers that guzzle huge amounts of freshwater and electricity. Arizona Gov. Katie Hobbs, a Democrat, has called for curtailing tax incentives for such data centers but faces an uphill battleagainst the GOP-controlled legislature.
All signs point to intense stress on the natural systems that make much of the Four Corners region farmable and livable. The most famous example of this stress is the decades-long battle between Western state governments over access to water from the Colorado River Basin. Record heat, even before this latest “heat dome,” has reduced mountain snowmelt that feeds the Colorado River, threatening water supplies for hydroelectric power plants, Grand Canyon wildlife, vast swaths of farmland, and about 35 million people.
Projections show that critical lakes and reservoirs in the Colorado River Basin could reach catastrophically low levels by mid-2027, according to Taylor McKinnon, the southwest director at the Center for Biological Diversity.
“We’ve got record low water storage basin-wide, an unprecedented heat wave decimating a record low snowpack, and decades of flow declines attributable in part to human-caused climate change,” McKinnon told Truthout.
McKinnon pointed to Lake Powell on the border of Utah and Arizona, a major reservoir in the Colorado River system that is at increasing risk of reaching so-called “minimal pool,” or levels so low that vital environmental life and infrastructure — including the Glen Canyon Dam, or endangered species such as the humpback chub in the Grand Canyon — would be put a risk in order to keep water moving downstream to millions of consumers in the lower basin.
“There is a raft of attributions to anthropogenic climate change that underpins the Colorado River crisis that is now throwing the greater Southwest into water turmoil,” McKinnon said. “I wouldn’t say that we’re in full blown water crisis yet, because it’s likely to worsen.”
Negotiations between Western states over a new, federally approved water reclamation plan to bolster supplies in the Colorado River Basin have stalled as the Interior Department scrambles to rework water systems amid the deepening impacts of climate change, according to Jennifer Pitt, director of the Colorado River program at the National Audubon Society.
“For a long time, the expectation was that the seven U.S. states sharing the river (Arizona, California, Colorado, New Mexico, Nevada, Utah and Wyoming) would develop a consensus-based proposal for [water] Reclamation, but that hasn’t happened and talk of litigation has increased,” Pitt reported on March 20.
As the specter of another lengthy legal battle over the Colorado River looms over the region, there’s plenty of blame for the Southwest’s water woes to go around. Ranchers and farmers require large amounts of water for irrigation, and dozens of data centers already operating in Arizona and across the Sun Belt also need massive amounts of water to cool servers. However, one culprit stands out among the rest: the burning of fossil fuels and the spiraling climate crisis.
Daniel Swain, a climate scientist at the University of California Agriculture and Natural Resources, said extreme heat waves are the “most slam-dunk type of event when it comes to thinking about extremes and climate change.” As Western states prepared for the current heat wave, Swain accurately predicted it would be, “in a climatological and statistical sense, record-shattering.”
“I’m using that language intentionally because we’re not just breaking records — we’re breaking long-standing records by enormous margins,” Swain told NPR on March 16. “Essentially to a point where it would be almost impossible to have heat waves of this kind of magnitude if it weren’t for the warming that’s already occurred.”
Research linking the heat dome currently smothering the West to climate change is ongoing, and scientists are increasingly able to link extreme weather events to specific sources of greenhouse gas pollution. A study recently published in Nature found that global warming driven by fossil fuel emissions made 213 heat waves reported between 2000 and 2023 more intense and more likely to occur. Climate change made heat waves recorded between 2010 and 2019 about 200 times more likely, the study found, and 26 percent of all heat waves globally over the past two decades would have been virtually impossible without climate disruption.
The world’s top fossil fuel polluters — half of which are large oil and gas firms and cement producers — contributed “substantially” to the increase in heat waves globally, the study found. Just a handful of nations and private companies are responsible for the majority of climate-warming emissions; the study specifically names several Big Oil firms, including ExxonMobil, Chevron, BP, Saudi Aramco, Shell, and Russia’s Gazprom.
Additionally, McKinnon added, “it’s looking more and more likely that declines in rainfall in recent decades are attributable in part to human-caused climate change.”
McKinnon said media outlets often inaccurately describe the crisis in the Southwest as “drought.” Droughts are temporary and often caused by a lack of rainfall and snowpack. The Southwest is undergoing a much more permanent change known as aridification, a long-term process in which a region becomes increasingly dry and waterless, which is distinct from a temporary drought.
“Droughts are temporary. Aridification is permanent due to the physics of hotter air,” McKinnon said. “These are conditions that are here, they are worsening, and they will be with us.”
