Covering an area of more than 50,000 square kilometres, farmers in California's Central Valley produce a quarter of the food consumed in the United States and almost half of the fruit, nuts and tree nuts that fill the shelves of the country's supermarkets. There are more than 250 crops, and agricultural activity in the area is estimated to generate revenues of 17 billion dollars a year (approximately 14.5 billion euros). At least, until now.

Rising temperatures, water scarcity, wildfires and periods of drought caused by the climate crisis are putting normal production rhythms under strain, forcing many farmers in the area to revise their plans.

Harvests at risk

The summer now drawing to a close has been among the hottest on record in California, with peaks of 54.4 degrees in Death Valley. The steady rise in temperatures is one of the main causes of the drought periods affecting the Central Valley, while heatwaves dry out the soil, reducing its fertility and making it unsuitable for certain categories of produce. During the summer, the worsening of environmental and working conditions forced a number of farmers to review their activities and, in some cases, change their production plans.

"Some business owners had left the dairy sector to move into farming, particularly almonds and pistachios," George Davis, vice-president of the California Farmers Union, tells us. "Now they find themselves having to abandon part of their crops, because there isn't enough water."

Even if the situation can vary across different parts of California, overall "farmers don't have as much water available as they would like," confirms Richard Waycott, president and CEO of the California Almond Board. For this reason, many are practising deficit irrigation, a process whereby the volume of water distributed across fields is carefully controlled in order to achieve the best possible result while using fewer resources than would normally be required.

For local business owners, the consequences are concrete. The New York Times reported on a rice farmer who decided to pause production in order to sell the water he would have used in his fields, considering this second option more profitable. Another farmer — also reported by the New York Times — is considering converting his almond fields to install a series of solar panels, and yet another has been forced to leave fallow a third of his melon fields. For the residents and business owners of the Central Valley, climate change, and the entire universe of phenomena connected to it, represents a concrete reality. The lack of water is a problem that can no longer be deferred.

Water shortage

Water is the most precious resource in the Central Valley: according to the United States Geological Survey (Usgs), a scientific agency of the US government, approximately 20 per cent of the groundwater used at national level comes from this territory, which is indeed the country's second-largest aquifer system.

In California, agriculture accounts for 80 per cent of total water consumption, but according to Davis the situation is now unsustainable: "You can survive one or two years of drought by using groundwater or reserves. But with temperatures continuing to rise, and extreme events becoming ever more frequent, there is no longer enough water," he states.

Against this backdrop, local authorities are struggling to reconcile the needs of farmers and residents. On 3 August, for example, the state's water control centre placed a limit on the water that farmers can draw from the state's two main rivers, the San Joaquin and the Sacramento, so as to ensure that 25 million people could continue to have access to drinking water. In the press release issued to announce the measure, the centre states plainly that the ongoing drought and rising temperatures are phenomena caused "by climate change".

Shortly before, in early July, California's Democratic governor Gavin Newsom had already issued an executive order calling on all residents to reduce their water consumption and cut waste by at least 15 per cent compared to 2020 levels. Newsom justified the decision by citing the "effects of global warming" — including "catastrophic wildfires", heatwaves and soil aridity — which "put at risk the health of our fellow citizens, the habitats of natural species and the economy."

Governor Gavin Newsom ✓ @CAgovernor

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During the last drought, we made water conservation a way of life & we can do it again.

Californians can step up again by voluntarily reducing water usage by 15%, saving 850,000 acre-feet of water - enough to supply more than 1.7 million households for a year.

♥ 43💬 3 8 lug 2021 · Apri su X →

According to Mike Wade, executive director of the California Farm Water Coalition, periods of water scarcity are nothing new in California, but in recent years there have been unexpected fluctuations that have disrupted the regular sequence of weather events: "Now the wet years are extremely rainy, and the dry years are extremely arid. This complicates the management of water reserves," he explains. "When we have several dry years in a row, reserves become depleted, and that is what is happening in the San Joaquin Valley," near San Francisco.

Possible solutions

Experts have different ideas about the possible solutions at play. George Davis, of the California Farmers Union, proposes a wide-ranging response: "In the long term, we will need to work to keep carbon in the ground. Its concentration in the air is now too high, and the seas can no longer reabsorb it. We have reached a critical point," he says, adding: "The only place carbon can stay is underground, that is where it belongs."

As regards the short and medium term, according to Mike Wade (California Farm Water Coalition) it is essential to improve water management over the medium term, so as to preserve water as much as possible in wet years and use it in dry ones. "There are particularly rainy periods, but at the moment we have no way of capturing that water," he points out.

Waycott is also convinced that in the future it will be essential to improve water management and transport systems in California. The president of the Almond Board cites as an example "intentional groundwater recharge", a mechanism whereby in particularly wet periods excess water is stored underground and used later. "It is a technique we have studied at length for almond fields — we can flood them in winter and allow the water to filter into the water table, from where it can then be extracted."

Even if technology and the efficiency of agricultural processes continue to improve in the future, the damage caused by climate change could have serious long-term consequences: "It is likely that the weight of the agricultural sector in California will decline," Waycott concludes. An enormous loss, brought about by the carelessness with which humankind has for too long treated the land around it.