California’s Drought is Over, But We Still Must Invest in Water Supply Projects

For the last 25 years, the US Drought Monitor (USDM), a collaborative effort by the University of Nebraska, NOAA, the USDA, and other experts throughout the country, has released a weekly map that shows the location and intensity of drought across the United States.

On January 8, for the first time ever, USDM’s weekly map showed the entire State of California to be drought free. The timing of USDM’s finding coincides with the release this week of a California Policy Center study, Statistical Review of United States Drought Monitor, that calls into question the objectivity of USDM’s reports. The USDM’s baseline assessment for the 20th century had California in a state of drought about 30 percent of the time, whereas their assessments for the first 25 years of the 21st century had the state experiencing drought more than 60 percent of the time. But our own analysis showed almost no change in drought frequency between this century and the last.

We based our conclusion on a statistical analysis of over a century of climate records from dozens of California-based monitoring stations. Variables we examined included precipitation, snowpack, temperature, relative humidity, dew point, and vapor pressure deficit. The post-2000 climate data show no substantial drying trend compared to prior 25-year periods in the 20th century. This undermines the credibility of USDM’s reports that find California to have entered a new, dramatically drier era with sharply heightened drought frequency.

What we observed from actual weather station data is corroborated by research presented at an event attended by water agency executives in Orange County in 2023 by Dr. John Christy, a Ph.D in Atmospheric Science who is a professor and Director of the Earth System Science Center at the University of Alabama. A native of California, Christy assured the audience that he has been giving our state special attention his entire life. He presented a series of slides that contradict the consensus that informs water policy in California. Its message might be summarized as follows: There may be some warming occurring over the past century in California, but it is not extreme, nor is it accompanied by unusually severe anything: droughts, extreme wildfires, heavy rainfall, diminished snowpacks, reduced river volumes, or drier air.

Whether or not the USDM’s findings are objective and reproducible, they have exercised enormous influence over water policy in California and throughout the U.S. But when even the USDM, which we allege is overstating the frequency and intensity of drought in California, says, for the first time in their 25-year history, that the entire state is currently drought-free, perhaps we should believe them.

In response to the USDM’s findings, UC climate scientist Daniel Swain, quoted in the Los Angeles Times, said “This is certainly a less destructive weather winter than last year was and than many of the drought years were, so it’s OK to take that breather and to acknowledge that, right now, things are doing OK. But as we move forward, we do expect to be dealing with increasingly extreme weather swings.”

Here’s where policies oriented to climate change go sideways. Let’s assume this unique moment for California to be completely drought free is not a return to normalcy but just an aberration on the road to a future of worsening weather whiplash. Let’s assume our future involves years of droughts followed by years that are too warm for a snowpack to form, but instead are characterized by torrential rains.

If this is truly what we face, why are water policies oriented to scarcity instead of abundance? Even if there is disagreement over whether or not climate change is a crisis, or whether or not the droughts we’ve experienced this century are worse than the droughts of the last century, most experts agree that in some form or another, there is going to be plenty of precipitation. Maybe we’ll have less snow, but we’ll have more rain. Maybe we’ll have some drier years, but we will also have wetter years. But policies oriented to scarcity will not give us the ability to adapt and prepare.

It may be a 20-year drought, or it may be an earthquake that liquifies the levees in the delta, allowing the Pacific Ocean to pour in and deny freshwater transfers south for years. Pick your disaster. But in a disaster scenario, the often heard refrain that “water conserved is water supplied” will be brutally debunked. Water is life. When there is nothing to conserve, life itself is the victim.

We examined the USDM’s methods and turned to core data to reproduce their findings, and we could not. So maybe things aren’t so bad, after all. But even if the USDM was understating a very real and severe long-term trend toward worsening droughts, the state’s policy response would be even more flawed. We should be investing in every possible way to harvest water. Wastewater recycling. Desalination. Urban runoff harvesting. Building better ways to safely remove additional millions of acre feet of water from the delta in wet years, storing it in off-stream reservoirs or underground.

These are the investments we should make. You can’t drink conservation.

“Weather whiplash” has been with us in California for a long time. In dry years, around 100 million-acre feet of rain fall onto in-state watersheds, and in wet years, the deluges exceed 300 million-acre feet. Living with and consuming surplus water, harvested from diverse and decentralized sources, and stored in extreme abundance, is how we should prepare for the next drought or the next disaster.