"Aridification" Comes For Western US

"Aridification" Comes For Western US

California and other parts of the US West are drying up, and the trend is expected to continue. This unprecedented dryness, dubbed "aridification” by scientists studying the phenomenon, will reshape the region. The interlinked, cascading effects of the climate crisis, beginning with pumping greenhouse gases (GHGs) into the atmosphere, have increased temperatures and destabilized rainfall patterns. These impacts have led to drier soil and scorching summers, making bark beetle outbreaks and wildfires more likely, possibly leading to a die-off of California's pine and cedar forests. That’s just one example among many -- from wildlife to agriculture to water supply -- that could happen to the region due to aridification.

"All the factors in the Southwest are leading to a drier and drier climate,” Jonathan Overpeck, co-author of a 2020 paper on aridification, told the Los Angeles Times. And because they are being driven by human-caused increases in greenhouse gases in the atmosphere, we expect this drying out to just get worse and worse until we stop.”

CBS: Megadrought in the West threatens energy and water security, May 5, 2022.

Guardian: The climate science behind wildfires | Why are they getting worse?, August 20, 2021.

CBS: What the megadrought means to the American West, July 18, 2021.

Why This Matters

Since aridification is "without a doubt” linked to human-caused climate change, it will only decelerate if there’s a decline in climate-damaging emissions, explained Matthew Kirby, a paleoclimatologist and professor at Cal State Fullerton, to the LA Times. That’s not the direction things are headed, with the setting of new record highs of atmospheric carbon, which surged past 419 parts per million last year.

While the region has experienced severe droughts in the past, they’ve never escalated as quickly or reached such extremes. That’s bad news for people, animals, and plants that now need to adapt to extremely dry conditions.

MSNBC: We Must Pay Attention To 'Urgent Crisis’ Of Extreme Heat Events, May 23, 2022.

ABC: Colorado River named country’s ‘most endangered,' April 18, 2022.

Water Runs Low

The country’s two largest reservoirs, Lake Powell and Lake Mead are at "critical [low] levels.” The Colorado River, which provides water for about 40 million people and around 5 million acres of farmland, is also alarmingly low. Climate change has fueled the extreme drought conditions, reducing river flows to record levels and threatening water supply for people and agriculture. It’s also putting the hydropower systems, built based on an assumption of water levels and flows, in a precarious place. In a worst-case scenario, the US Bureau of Reclamation estimates that Glen Canyon Dam could be non-operational by January.

PBS: ​​Megadrought causes perilously low water levels at Lake Mead, June 2, 2022.

CBS: What a drought has uncovered about Lake Powell, May 12, 2022.

CNBC: What Is The Future Of Hydropower?, May 28, 2022.

Much like the megadrought in the US West, the Iberian peninsula is experiencing its "driest climate in 1,200 years” and facing water shortages and restrictions. Computer modeling shows the drought cycles typical to Spain and Portugal increased by 30% between 1850 and 1980 and have almost doubled since 1980. Meanwhile, northern Italy is in the midst of its worst drought in 70 years, and due to heatwaves, low precipitation, and water shortages, the country has declared a state of emergency. Extreme heat has also reduced Alpine glaciers, specifically the Marmolada glacier in the Dolomites, which one study estimates has lost 90% of its volume over the past century. On Sunday, it collapsed, causing an avalanche that killed seven people, with five still missing.

DW: Italy in grips of severe drought as Po river dries up, July 3, 2022.

National Geographic: Global Water Wars (Full Episode) | Parched, July 29, 2021.

WW0: Newsmaker of the Week | Jacob Morrison, director of River's End, October 28, 2021.