It’s Time to Plan for Drier Western Rivers

Three recent studies highlight how climate change will jeopardize the water supply from Western rivers. The best antidote, researchers say, is to drastically reduce greenhouse gas emissions. | Illustration by Maddy Olson

A strange thing happens during particularly wet winters in California: farmers flood their fields. Never mind that crops are dormant and soil is already saturated — these farmers are more concerned about what lies beneath their land. Aquifers are the last line of defense against drought conditions. By flooding their fields in January, farmers hope to fill these underground reservoirs with water they can use in August.

If a trio of recent studies prove accurate, one can expect to see this method deployed more regularly. Combined, the reports paint a bleak picture: Amid one of the worst droughts of the last 1,200 years, we’re seeing less reliable snowfall, which could dramatically affect agriculture in three key Western basins. Warmer temperatures mean winter precipitation will come more often as rain than snow — a change our current irrigation regime wasn’t built to withstand.

But don’t toss this information into your coronavirus-era heap of gloom. Now is the time for water managers to utilize these projections and make sound investments in resiliency.

“The main thing is proactively planning and bringing climate change and changes in snowmelt into the conversation,” said Nathan Mueller, an assistant professor at Colorado State University and an author of one of the studies. “We want people to be thinking about the core issue.”

The first thing to account for is that large swaths of the West are experiencing historic aridity. By analyzing tree-ring data, a team of researchers from Columbia University, the University of Idaho, and other institutions determined that we’re in the middle of a drought that’s downright biblical — and it might last for a long time. The study, published in the journal Science, concluded that 2000-2018 was the second-driest 19-year period in the Southwest in the last 1,200 years.

“We now have enough observations of current drought and tree-ring records of past droughts to say that we’re on the same trajectory as the worst prehistoric droughts,” lead author Park Williams, a bioclimatologist at Columbia University, said in a release.

Just four dry spells during the 1,200 year period researchers focused on lasted a full 20 years, putting our current predicament in rare company […]

Full article: It’s Time to Plan for Drier Western Rivers