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Here's How Hot and Dry California Might Get by 2100

Researchers at UCLA predict a 'super summer' of an additional 60-90 days with temperatures over 95 degrees Fahrenheit by the end of the century if greenhouse gas emissions continue to rise.
Photo by Chris Carlson/AP

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Los Angeles will likely get a lot hotter and thirstier over the next century, but how much depends on what the world does right now.

If global greenhouse gas emissions remain constant, Southern California will be hit by a one-two punch of extremely hot temperatures and severe water shortages that might make the state's current climate conditions and ongoing drought seem quaint. The temperature increases may result in an entirely new season of hot, arid days, and depletion of surface and groundwater supplies might send the price of water skyrocketing for average users.


Researchers from the Department of Atmospheric and Oceanic Sciences at the University of California Los Angeles (UCLA) modeled the state's future climate under two different scenarios. The first, an optimistic one, predicts how much temperatures will rise if global greenhouse gas emissions are dramatically reduced. The second, more ominous, scenario predicts what will probably happen to the state if emissions continue to rise at their current rate.

Whatever actions we take, California's climate in 2050 is basically set in stone. By then, the number of "extremely hot days" — days when the temperature exceeds 95 degrees Fahrenheit — is expected to triple. Downtown Los Angles will experience about a dozen more extremely hot days than it did between 1981 and 2001; Riverside, Long Beach and the San Gabriel Valley will each have about twice as many.

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While California can no longer avoid this warm up over the next 35 years, there's still time to stave off the study's bleak forecast for 2100, when researchers predict California as a whole will experience 60-90 more extremely hot days — essentially resulting in a new super summer season — if greenhouse emissions are not cut. In this scenario, downtown Los Angeles could have up to 54 days a year with temperatures over 95 F. However, if emissions are reduced, temperatures should peak around 2050.


Alex Hall, one of the study's authors, told VICE News that while the emissions reductions needed to save California must stem from a global effort, the state could lead by example.

"California is now showing global leadership in adopting a cap-and-trade system that is already reducing the state's carbon emissions," he said, adding that while California cannot go it alone forever, "there is nothing wrong with California going first."

For Los Angeles County, the most populous county in the state, avoiding a hot future is necessary to avoid the compounding water woes it is already facing.

The researchers' findings were published in the Journal of Climate.

In another just released study, researchers from UCLA's Luskin Center for Innovation predicted that an increase in temperature will likely reduce precipitation and therefore the availability of surface water in Los Angeles County, where there are 228 separate community water systems. That will mean a greater reliance on imported water, which will send its price skyrocketing, said JR DeShazo, an author of the report.

"Beyond what is already allocated to [municipalities], they are going to have to pay $1,000 [per acre-foot of imported water] more than [they] used to," he told VICE News, adding that this would put more pressure on groundwater sources in metro areas, which already import huge quantities of water.

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Groundwater comes from aquifers deep underground, and they are difficult to replenish. If Los Angeles community water systems want to pump more groundwater, municipalities would have to invest hundreds of millions of dollars updating their water treatment facilities because nearly half of them rely on groundwater contaminated by decades of industrial waste. Those updates would require more revenue, which would hike up the price of water utilities. And that would have an especially painful impact on low-income households because water price increases will eat up a large percentage of their budgets.

But DeShazo also said he is hopeful Angelenos will change their behavior to avoid the worst.

"There's a huge push in the region to incentivize the removal of grass and lawns. That's going to continue into the future," he said.

DeShazo predicts that the state will soon begin allocating water in a way that takes pressure off groundwater sources, particularly in light of mounting public scrutiny of the agricultural sector, which accounts for 80 percent of the state's water consumption.

"There's no doubt there will be a push now to increase water trading [between] farmers [and municipalities]," DeShazo told VICE News. "I think we will see more pressure to do that and develop a formalized system to make that possible."

Follow Aaron Cantu on Twitter: @aaronmiguel_