Tragedy of the Commons in Dry California

The tragedy of the commons develops in this way. Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. Such an arrangement may work reasonably satisfactorily for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below the carrying capacity of the land. Finally, however, comes the day of reckoning, that is, the day when the long-desired goal of social stability becomes a reality. At this point, the inherent logic of the commons remorselessly generates tragedy.

As a rational being, each herdsman seeks to maximize his gain. Explicitly, or implicitly, more or less consciously, he asks "What is the utility to me of adding one more animal to my herd?" This utility has one negative and one positive component.

1) The positive component is the function of the increment of one animal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly +1.

2) The negative component is a function of the additional overgrazing created by one more animal. Since, however, the effects of overgrazing are shared by all the herdsmen, the negative utility for any particular decision-making herdsman is only a fraction of -1.

Adding together the component partial utilities, the rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another, and another ... But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit - in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all.

From one end of the valley to the other, 500,000 acres of new almond and pistachio trees have been added to the old trees over the past 10 years. This, in a period plagued by two of the worst droughts in California history or, grimmer yet, one epic drought interrupted by the record flood year of 2017. If the water-guzzling almonds demand less irrigation than the water-guzzling crops that feed the mega-dairies, the aggregate of their intensification is no less alarming. In Madera County, during this same scorched decade, the ground devoted to almonds has expanded by 60,000 acres. The trend makes selfish sense. Almonds ring up far more profits than the wine and raisin grapes they’re replacing. But it makes almost no communal sense. Almonds consume far more of everyone’s water....

Angell’s surveys of wells across the Madera sub-basin tell him that the underground water table that sustains 348,000 acres of cropland, cattle ground, and suburbia is bleeding out three feet of water from one harvest to the next. This amounts to 1 million acre-feet of overdraft each dry year. That’s water taken out of the earth and not returned by rain or snowmelt. That’s mining. All the houses and businesses of Los Angeles, by comparison, consume 580,000 acre-feet of water each year.

“I’ve been putting my camera down three wells a day,” he said. “I used to use the word unprecedented to describe what we’re doing to the land. Now I use the word biblical.

It took 170 years, but California finally decided, in 2014, to regulate groundwater extraction. Problem is, the law won’t actually reduce pumping for another 20 years. By granting growers such a long reprieve, the state set in motion a consequence that’s less unintended than expected: more pumping. Farmers developing new acres are trying to establish their legal possession before no more water can be grabbed. The state and the county, which lean libertarian in such matters, have no will to stop the drilling.