The West is caught in a vicious climate change feedback loop

Almond trees are dying for lack of water at an orchard in Gustine, California.
CNN  — 

After a deadly, climate change-fueled heat wave smothered the Pacific Northwest at the end of June, historic heat threatens records once again, particularly in the drought-stricken Southwest region.

More than 30 million people are under heat warnings and advisories. The National Weather Service says the risk level for this heat wave is “very high” — dangerous for not just those with underlying health issues, but the entire population, especially those who work outdoors. The overnights, which in some places will only drop to the mid-80s, will bring little relief.

As temperatures climb to the triple digits, the sun will bake out what little moisture there is in the ground, worsening the West’s unprecedented drought. Scientists say heat and drought are inextricably linked in a vicious feedback loop that climate change makes even harder to break: heat exacerbates the drought, which in turn amps up the heat.

“As we’re getting these very extreme heat waves, it’s just making the drought even worse, even though drought is initially caused by the lack of precipitation,” Julie Kalansky, a climate scientist at Scripps Institution of Oceanography in San Diego, told CNN. “But during the dry months of much of the West, these heat waves just continue this drying throughout the summer and into the fall.”

More than 93% of the West is in drought this week, according to the US Drought Monitor, the largest area on record in that region. Nearly 60% of the west is in the two most-severe drought categories, extreme or exceptional.