An additional 23 million tons of carbon dioxide came from California power plants in the last four years as a result of decreased hydropower – a 10 percent increase in CO2 emissions from the electricity-generating sector.

“One of the complications is that the drought has made it harder to meet the greenhouse gas targets that the governor has set,” said Gleick.

There are other reasons to be concerned, as well. “A linear trend fitted to the data shows that hydroelectricity generation has been declining over the past 15 years, largely due to drought conditions,” the report states.

“If you look at the last 15 years the trend is definitely down,” says Gleick. “I think an unresolved question is whether this is a long-term trend that is going to continue.” Is drought the “new normal” for California, as many have suggested?

A report published February 4 in Geophysical Research Letters found that droughts in the Southwest are likely to become more common as bigger storms have been occurring less frequently.

There are also other impacts that drought may have on energy. One of the consequences of the drought has been a massive increase in groundwater pumping to make up for a lack of surface water. Nowhere has this been more acutely felt than in the San Joaquin Valley, where overdrafting of aquifers has caused concern about falling groundwater levels, subsidence and consequences for farmers.

But, Gleick says, there is one major area that no one has studied yet and that’s how much energy is being used to pump that groundwater, which is increasingly being pumped from deeper depths.

“It is potentially very significant,” he said, but “we don’t have data on the volume of groundwater that’s actually been pumped or the depth from which it has been pumped and we’d need both of those to calculate the true energy cost of this additional energy cost.”

There are of course no easy fixes for increasing hydropower since any spot where you could put a hydroelectric dam already has one. But Gleick says there is still a lot we can do with water conservation and efficiency, wastewater treatment and reuse and stormwater capture.

“More effort is going into those three areas,” he says. “But I would argue not enough.”

This article originally appeared on Water Deeply. For weekly updates about the California drought, you can sign up to the Water Deeply email list.

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