Aridification Spreading in North America a New Study Finds

Winding Road Photography

As we expand our understanding of climate change, scientists have begun to focus on the growing role warming temperatures are playing as a potent driver of greater aridity–which is different than drought.

As NOAA describes it, drought is “a period of abnormally dry weather sufficiently long enough to cause a serious hydrological imbalance”. Aridity is measured by comparing long-term average water supply (precipitation) to long-term average water demand (evapotranspiration)…aridity is permanent, while drought is temporary.

A recent study from the University of Michigan and Colorado State reveals that aridity is already a clear trend across the western United States and human-caused warming is also driving increased aridity eastward across North America, with no end in sight.

Why This Matters: As study co-author Jonathan Overpeck explained,

The impact of warming on the West’s river flows, soils, and forests is now unequivocal. There is a clear longer-term trend toward greater aridification, a trend that only climate action can stop.”

Increasing aridity doesn’t just affect an isolated region, it has the ability to disrupt precipitation patterns and ecosystems in nearby regions as well. The threats climate change already poses are being compounded by aridity and the only way to slow this trend is to take drastic action on climate change.

Why is Increasing Aridity a Problem? Aridity drives water scarcity and can wreak havoc on soils and their ability to produce crops by altering soil bacteria.

As Phys explained, aridity in the Western United States is typically framed in terms of episodic drought.

  • Many water and land managers, as well as the general public, implicitly assume that when returning rains and snowfall break a long drought, arid conditions will also fade away. But that’s not the case if Western states.
  • Additionally, warmer air can hold more water vapor, and this thirsty air draws moisture from water bodies and land surfaces through evaporation and evapotranspiration—further drying soils, stressing plants and reducing streamflow.
  • But the atmosphere’s increased capacity to hold water vapor also boosts the potential for precipitation; rain and snow amounts are, in fact, rising in many regions of the United States outside the Southwest.
  • However, the frequency and intensity of dry spells and droughts are expected to increase across much of the continent in coming decades, even if average annual precipitation levels rise

But in the West specifically, warming is also contributing to widespread tree death and more severe wildfires. 

Real Time: As reported, despite a rainy April for Southern California, Northern California’s snowpack continues to thin while the ongoing drought worsens.

Additionally, America’s longest river was recently drier than during the Dust Bowl. And it’s bound to happen again.


Up Next

Wildfire Smoke Undoes Years Of Air Quality Improvement

Wildfire Smoke Undoes Years Of Air Quality Improvement

by Amy Lupica, ODP Staff Writer A new study from Stanford University and the University of California, San Diego reveals that plumes of smoke from wildfires in recent years threatens to undo 40 years of air quality improvements in the American West and is just as deadly as heat-related health threats.  In 2020, a record-breaking […]

Continue Reading 614 words
One Cool Thing: GM Makes an EV Splash at Consumer Electronics Show

One Cool Thing: GM Makes an EV Splash at Consumer Electronics Show

GM unveiled big plans at this year’s Consumer Electronics Show for electric vehicles — driverless “shuttle” vans and even – imagine this – flying cars.  CEO Mary Barra, the keynote speaker, unveiled a new company logo and highlighted innovative new vehicles.  The company has created a new unit called BrightDrop that will sell its EV600 […]

Continue Reading 98 words
Top Ten Stories of 2020: EVs Charge Ahead

Top Ten Stories of 2020: EVs Charge Ahead

This year two “EVs” repeatedly made headlines — environmental voters and electric vehicles.  When we look back in 2035, by which time we should have converted completely to renewable energy, 2020 could be seen as the year when the auto industry fully committed to the transition to electric vehicles and trucks.

Continue Reading 463 words

Want the planet in your inbox?

Subscribe to the email that top lawmakers, renowned scientists, and thousands of concerned citizens turn to each morning for the latest environmental news and analysis.