Spring is starting to feel a lot like summer in California, as a record-setting heat wave punishes the parched state now in its fourth year of what is said to be the worst drought in a millennium.
Experts say the scorching spring days are part of a long-term warming pattern – driven largely by human activity – that is increasing the chances that future droughts will be as bad as this one. At fault is a warm and dry weather combination, which exacerbates the already dire drought conditions by drying soil, melting snow and driving up water usage.
“It’s like a one-two punch,” said Jeanine Jones, deputy drought manager for the state Department of Water Resources (DWR). “Not having enough water to fill our reservoirs and having the hot weather evaporate the little that we do have.”
According to the most recent US drought report, moderately below-average precipitation, coupled with extremely above-average temperatures, has maintained or worsened drought conditions in California. The consequences have been devastating, from shriveling reservoirs to vanishing groundwater, dying crops, thinning herds and raging wildfires.
California relies on a series of massive storms during the winter months to drop snow on the Cascades and Sierra Nevada mountain ranges. During the spring and summer months the snowpack, acting like a natural reservoir, melts as water demand rises.
But the recent extremely warm weather has caused precipitation to fall as rain rather than snow. The effect is dramatically less snowpack melt from the state’s mountain ranges, which can provide as much as a third of California’s water supply.
This year, the mountain runoff will likely be just a trickle. Snow on the mountains has fallen to 12% of average levels, from 28% last year. In March, data collected from parts of the Cascade and Sierra Nevada mountains indicated that some sites were for the first time snow-free by the first of the month. Jones said the 1 April snowpack measurements, which will be reported next week, are expected to be the lowest on record.
“That does not at all bode well for our depleted reservoirs,” Jones said.
Hotter temperatures are predicted to be the new norm in California, the result of rising temperatures under climate change. This month, for the first time since record keeping began in the late 1880s, the temperature in Los Angeles peaked in the 90s fahrenheit for six consecutive days, according to the Los Angeles Times.
Based on the current warming trajectory, the likelihood that low rain years will coincide with high heat years is almost a certainty.
“California is in a climate regime where are much more likely to get this kind of drought event again because of the role of temperature rise,” said Stanford University professor Noah Diffenbaugh, who led a study examining the role of warm temperatures in California’s droughts.
That study, published earlier this month in Proceedings of the National Academy of Sciences, found that historically, California’s worst droughts occurred when conditions were both dry and warm, and that those conditions had occurred more frequently in the past two decades than in the last century.
Diffenbaugh said global warming was increasing the risk that dry and warm years would coincide to almost ensure a drought similar to the present one. The researchers also found that in the early and mid-20th century, the warm and dry conditions occurred more or less independently.
“We’re heading into a regime where the temperature is essentially always conducive to drought,” he said.
With no foreseeable end to the drought in sight, policy makers at every level are scrambling to conserve the little water the state does have and avert dire predictions that the state could run out of a water soon, possibly in one year.
“This is a struggle,” California governor Jerry Brown said at a press conference earlier this month. “Something we’re going to have to live with. For how long, we’re not sure.”
On Friday, Brown signed into law a more-than-$1bn plan to fast-track emergency relief to drought-stricken cities and communities, including food aid and drinking water. The proposal also includes hundreds of millions of dollars to fund long-term projects, involving water recycling, conservation awareness and flood control projects. At the signing, Brown said the plan was part of a wider effort to prepare California for an “uncertain future”.
The legislation followed action by the State Water Resources Control Board(SWRCB) this month to pass what has been described as the most restrictive water conservation measures in state history. The plan limits the number of days residents can water their yards, and requires bars and restaurants to ask customers if they would like a glass of water before serving it.
“We are not seeing the level of stepping up and ringing the alarm bells that the situation warrants,” Felicia Marcus, the chairwoman of the SWRCB, said during the meeting this month. She said the measure was a first step, and that the board may consider even more stringent measures this spring.
Amir AghaKouchak, an assistant professor at the Department of Civil and Environmental Engineering, University of California, Irvine, said the $1bn water spending plan included “forward looking” measures that would help the state prepare for future dry spells. For example, the plan aims to improve infrastructure such as the state’s levees, which could help replenish underground aquifers, which have been drained by farmers drilling for groundwater to irrigate crops.
But he warned that there is still a lot scientists don’t know about droughts.
“We still don’t know a lot about how droughts develop, how they form, why they form,” AghaKouchak said. “If California wants to stay at the front of this, we have to consider science, and the best science. But it requires support.”
AghaKouchak said investing in “basic research” around water technology, water management and water harvesting could in the long-run improve strategies for responding to extreme weather. He also called for funding research to create better risk-assessment models to improve the predictability of droughts.
While there are conservation and planning policies that lawmakers can take now to conserve water and prepare the state for the next extreme weather event, California’s best hope lies ultimately in the willingness of the global community to confront climate change.
“This drought is not a local California issue,” AghaKouchak said. “This is a global issue. A single policymaker, or even all policymakers in California, alone cannot really do much about global temperature. This requires unprecedented international efforts and a truly global will to address these issues.”