Thursday, January 20

‘Truly an emergency’: How the drought returned to California and what lies ahead | Climate crisis in the American West


JJust two years after California celebrated the end of its last devastating drought, the state is facing another. The snow cover has came down to almost nothing, the 1,500 reservoirs of the state are at just 50% of its average levels, and federal and local agencies have begun imposing water restrictions.

Governor Gavin Newsom has declared a drought emergency in 41 of the 58 counties in the state. Meanwhile, temperatures rise As the region prepares for what is expected to be another unprecedented fire season, scientists are sounding the alarm on the state’s preparedness.

“What we are seeing right now are very severe dry conditions and in some cases and in some parts of the west, the lowest inflows to the reservoirs on record,” says Roger Pulwarty, senior scientist at the National Oceanic and Atmospheric Administration. (Noaa) from the physical sciences lab, adding that while the system is designed to withstand dry spells, “much of the slack in our system has already been used up.”

How do we get here?

A progressive trend

Drought is not unnatural for California. Its climate is predisposed to wet years interspersed with dry ones. But the climate crisis and rising temperatures are aggravating these natural variations, turning cyclical changes into crises.

Drought, as defined by the National Weather Service, is not a sudden appearance of characteristics, but rather a progressive trend. It is classified after a period of time, when the prolonged lack of water in a system causes problems in a particular area, such as damage to crops or supply problems. In California, dry conditions began to develop in May of last year, according to federal monitoring systems.

Dry banks rise above the water in Lake Oroville on Sunday, May 23, in Oroville, California.
Dry banks rise above the water in Lake Oroville on Sunday, May 23, in Oroville, California. Photograph: Noah Berger / AP

The effects really began to show in early spring 2021, when the annual winter rainy season failed to replenish the parched landscape and a hot summer further removed moisture from the environment. In March, conditions were dire enough for US Secretary of Agriculture Tom Vilsack to appoint most of California as a primary disaster area. Just two months later, 93% of the Southwest and California suffered from drought, with 38% of the region ranked at the highest level.

“When there are droughts with warm temperatures, the system dries up much faster than expected,” says Pulwarty, adding that climate change can make droughts more severe and harder to recover. “It’s not just about the amount of precipitation you get, it’s also about whether or not it remains as water in the soil.”

Waning water, rising temperatures

The state’s previous drought lasted about seven long years, from December 2011 to March 2019, according to official estimates. But some scientists believe that it never really ended. These researchers suggest that the west is trapped by an emerging “mega drought” that could last decades. A 2020 study that analyzed tree rings for historical weather clues concluded that the region may be entering the worst prolonged period of drought found in over 1200 years and attributed about half of the effects to human-caused global warming.

Meanwhile, California has warmerand 2020 brought some of the highest temperatures ever recorded. In August of last year, Death Valley reached 130 ° F (54 ° C) and a month later, an area in Los Angeles County recorded a day of 121 ° F (49.4 ° C), the hottest in its history.

Heat changes the water cycle and creates a thirstier atmosphere that accelerates evaporation. That means less water is available for communities, businesses, and ecosystems. It also means that there will be less snow, on which California depends approximately 30% of your water supply.

“Snow cover, in the context of the western United States and specifically in California, is really critical to our water supply,” says Safeeq Khan, a professor at the University of California, Merced, who researches the climate crisis and sustainability. of the water. “The snow cover settles on the mountain and melts in the spring and early summer. That provides the buffer to overcome the extreme heat of summer, ”he explains.

But in recent years, even during wet winters, he says, the snow cover wasn’t as strong as it used to be. This year, even before summer, it’s almost over. The melt has also produced less runoff than expected, meaning less was dripped into streams, rivers and reservoirs.

“Years like this, when we don’t have the snow cover, it really puts our water system under tremendous pressure,” says Khan. He doesn’t think that’s going to change anytime soon, adding that while drought is not new in the West, “the type of drought that we are experiencing is new. The impact is much greater than in the past. “

What will be the impact?

Drought disasters are among the costliest, according to the U.S. National Centers for Environmental Information, with an average of of $ 9.3 billion in damages and losses. Dry conditions are also expected to fuel another potentially devastating wildfire season. In 2020, flames consumed an estimated 4.1 million acres, tens of thousands of buildings burned, and 31 people lost their lives.

Darkened slopes and dying trees not only increase the risk of ignition, but also make fire behavior more extreme when flames erupt, according to Scott Stephens, a fire ecologist at the University of California at Berkeley. “We will probably reach typical fire season humidity levels six weeks earlier this year due to the drought,” he said as part of a series of interviews for the California Institute of Public Policy.

Along with wildfire risks, water shortages are putting enormous pressure on the state’s agricultural industry, which grows more than a third of the country’s vegetables and supplies two-thirds of the fruits and nuts in the US Farmers are already slaughtering crops and fallow fields in anticipation of water shortages. Karen Ross, California Food and Agriculture Secretary, told the California Chamber of Commerce that she expected 500,000 acres would have to lie idle this year.

Stagnant, shallow water covers 'Channel A' in Klamath Falls, Oregon, on Tuesday.
Stagnant, shallow water covers ‘Channel A’ in Klamath Falls, Oregon, on Tuesday. Photograph: Dave Killen / AP

The federal government has already announced a drastic reduction in water allocations for farmers in California’s Central Valley, while further north, tensions rise in the Klamath Basin, where a federal canal serving 150,000 acres of agricultural land will dry up. for the first time in 114 years.

Cities and other urban regions will also receive less water, and residents are asked to conserve where they can.

“We really are in an emergency situation,” Rick Callender, executive director of the Santa Clara Valley Water District, which supplies water to 2 million residents south of the San Francisco Bay Area, told Mercury News this week. pass. The agency enact mandatory countywide restrictions, adding that the public should anticipate that the cuts will increase as the situation escalates. “We are going to pursue everything we can do to address this emergency.”

The worsening drought will also exacerbate the long-standing problems of the Central Valley population, which has suffered from shortages of water for drinking, cooking and sanitation. During the previous drought, the wells dried up and never recovered. More than a million Californians still do not have access to safe water.

Low water levels also have the potential to affect the state power grid, which depends on hydroelectric plants, reported the Los Angeles Times. Lake Oroville is expected to drop below 640 feet, the level state officials say is required to operate a plant, by August. At the moment, is just above 700 feet.

How prepared is the state?

California has already invested billions to prepare and has learned key lessons from the latest round, when the state experienced its driest four-year period in history. In 2014, the state also passed the Groundwater Management Law, a landmark legislation that requires communities to monitor groundwater basins and develop plans to protect them. But implementation is still in its early stages.

Newsom has proposed an investment of $ 5.1 billion over the next four years to respond to the disaster and improve infrastructure. Cal Fire, the state firefighting agency, has also added 1,400 new firefighters to its ranks, in addition to picking up new helicopters and fire trucks.

“California has done an extraordinary job,” says Pulwarty, but adds that more ambitious solutions are still needed.

“There are innovations that we need to scale up,” he says, from urban conservation and reuse to increasing agricultural efficiency and creating land reserves that will help regions to be more resilient when drought disasters strike.

Others caution that the state must take a long-term view, as drought conditions are likely to worsen before they improve.

“If we’re concerned about this year, we’re really playing the short game,” says Doug Parker, director of the California Water Resources Institute. “It’s next year that I think is more important.”

The water system, he says, is designed to handle short-term shortages. “When you go into three, four or five years of drought in a row, that’s when things really start to get serious. We all want to know what will happen next winter. “


www.theguardian.com

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