Skip to main content

Sign up for our newsletter.

Quality journalism. Progressive values. Direct to your inbox.

A sign on a farm trailer reading "Food grows where water flows" hangs over dry, cracked mud at the edge of a farm April 16, 2009 near Buttonwillow, California. (Photo: David McNew/Getty Images)

A sign on a farm trailer reading "Food grows where water flows" hangs over dry, cracked mud at the edge of a farm April 16, 2009 near Buttonwillow, California. (Photo: David McNew/Getty Images)

Emerging Climate-Fueled Megadrought in Western US Rivals Any Over Past 1,200 Years: Study

"We now have enough observations of current drought and tree-ring records of past drought to say that we're on the same trajectory as the worst prehistoric droughts."

Andrea Germanos

The western United States is likely being gripped by an "emerging" megadrought partly fueled by the climate crisis, says a study published Friday.

Researchers claim the region's 19-year drought, from 2000–2018, already rivals that of any over the past 1,200 years.

"We're no longer looking at projections, but at where we are now," said lead author Park Williams, a bioclimatologist at Columbia University's Lamont-Doherty Earth Observatory, in a statement. "We now have enough observations of current drought and tree-ring records of past drought to say that we're on the same trajectory as the worst prehistoric droughts."

For the study, published in the journal Science, Williams and the other researchers looked at nine U.S. states, stretching from Oregon and Montana at the northern and southward through California and New Mexico. The researchers also included a portion of northern Mexico in the study.

Using tree ring data to infer yearly soil moisture and plot out the pre-modern data, the researchers documented four megadroughts—multi-decade droughts—beginning in 800 AD. 

The southwest's current drought was worse compared to the ones that took place in the late 800s, mid-1100s, and the 1200s. The most severe megadrought on recorrd began in 1575, though researchers said the difference between that Medieval one and the current was slight.

And while natural variability played a role in the current drought, the scientists estimate about half the blame—47%—lies with the Earth's heating, as warmer air is able to suck up more ground moisture.

In the Catalina Mountains in southern Arizona, forests struggle to keep up with recent increases in drought and wildfire activity, which are expected to continue due to human-caused climate change. (Photo: Park Williams/Lamont-Doherty Earth Observatory)
According to coauthor Benjamin Cook of Lamont and the Goddard Institute for Space Studies, "It doesn't matter if this is exactly the worst drought ever" but that "it has been made much worse than it would have been because of climate change."

Natural variability that can drive drought will likely continue, as will global warming, threatening further upheaval for a region already facing groundwater depletion.  

"Because the background is getting warmer, the dice are increasingly loaded toward longer and more severe droughts," added Williams.

"We may get lucky, and natural variability will bring more precipitation for a while," he said. "But going forward, we'll need more and more good luck to break out of drought, and less and less bad luck to go back into drought."


Our work is licensed under Creative Commons (CC BY-NC-ND 3.0). Feel free to republish and share widely.

We've had enough. The 1% own and operate the corporate media. They are doing everything they can to defend the status quo, squash dissent and protect the wealthy and the powerful. The Common Dreams media model is different. We cover the news that matters to the 99%. Our mission? To inform. To inspire. To ignite change for the common good. How? Nonprofit. Independent. Reader-supported. Free to read. Free to republish. Free to share. With no advertising. No paywalls. No selling of your data. Thousands of small donations fund our newsroom and allow us to continue publishing. Can you chip in? We can't do it without you. Thank you.

Under Pressure From Students, Three UK Universities Ban Fossil Fuel Recruiters

"It is vital that our universities show with actions, not words, that they are taking the side of climate justice, and not of the industries driving us deeper into a climate crisis," said one campaigner.

Julia Conley ·


Merkley Bill Aims to Dismantle Hedge Fund Stranglehold on Housing Market

Senate Democrat accuses Wall Street of "pouring fuel on the fire of the affordable housing crisis."

Jessica Corbett ·


'Donald Trump Has Finally Run Out of Places to Hide' as House Dems Get Tax Returns

"It's no longer a question of if he's hiding something big," one watchdog group asserted, "it's a question of what he's hiding."

Brett Wilkins ·


Democrats, Progressive Groups Push DOJ to Publish Database of 'Corporate Lawbreaking'

"The Corporate Crime Database Act will bring transparency to the corporate crime crisis so that the DOJ and other law enforcement agencies can better reckon with this greed-driven menace," said one advocate.

Kenny Stancil ·


As Corporations Enjoy Record-High Profits, Experts Urge Congress to 'Rein Them In'

"Today's record corporate profits mirror what we have been hearing on earnings call after earnings call: Corporations are gleefully reporting that their strategy to burden families with unnecessary price hikes is working."

Brett Wilkins ·

Common Dreams Logo