By Carl Pope, Bloomberg View

California is not unique in experiencing a destructive feedback loop in which declining water resources are devoted to energy production, and energy is required to transport water where it is increasingly scarce. Throughout much of the U.S. and the world, we manage water and energy as if they were unrelated. In reality, they are Siamese twins.

Utility executives in Washington State are concerned that low snowpack threatens reservoirs that generate much of the state’s power. Legislators in Texas, who are normally reluctant to acknowledge the existence of climate change or to spend tax dollars, approved billions of dollars in new water projects to deal with a seemingly endless drought. Nevada water officials worry that they will no longer be able to withdraw water from behind Hoover Dam if the water level continues dropping. (Meanwhile, upstream Glen Canyon Dam, which loses up to 10% of its water to evaporation and seepage under the best circumstances, remains commissioned to generate electricity.)

The energy-water feedback loop is even worse in emerging economies, where energy production siphons more water, and water delivery requires more power. Mining and burning coal, and refining oil, use 20% of China’s water supply, and an even higher proportion in the nation's arid Northwest. As a result, China has been forced to use very expensive and inefficient “dry cooling” technology in many of its coal-power plants. Having devoted too much water to mining coal, China recently abandoned many efforts to extract natural gas from shale because the shale is located in regions that lack the water required for hydrofracking.

Desperately needing energy, Pakistan has nonetheless been unable to agree on proposals to dam the Indus River for hydropower because some proposals would create irrigation potential in Sind Province, and others in the Punjab, threatening civil war. Pakistan's upstream rival, India, dams its own tributaries of the Indus, reducing the flow and fueling the conflict between the two South Asian neighbors.

India spends 25% of its electricity on highly inefficient irrigation systems that waste both power and water. (Solar pumping would be cheaper, increase crop yields and conserve huge amounts of water—a virtuous cycle. But solar infrastructure in India is nowhere near critical mass.) At the same time, the Indian state of Maharashtra has had to shut down its coal-fired plants in recent summers; the state cannot spare the water necessary to cool the plants.

Africa, too, is struggling to balance competing demands of water and energy. Kenya allowed its forest to be cut for charcoal fuel, which degraded the watersheds and led to dramatic declines in hydroelectric capacity and supplies of electricity. Chad’s major water body, Lake Chad, shrank 95 percent over the past four decades as declining rainfall was exacerbated by increased consumption. Oil production has intensified the unsustainable withdrawal of groundwater as Exxon Mobil and other oil companies drill ever-deeper wells.

In the Limpopo region of South Africa, efforts to mine the Makhado coal reserves have provoked a virtual water war between mining companies and locals. Eskom, South Africa’s primary electrical utility, already uses 2 percent of the nation’s water to generate power. A Greenpeace study showed that even the most modern of South Africa’s coal plants, Kusile, would use 173 times as much water per kwh as wind energy would. South Africa is already utilizing a higher percentage of its total precipitation than any country on earth—40 percent; it has none left to spare for energy development.

When water runs out, stressed regions turn to desalination, which is extremely energy intensive, requiring about 15,000 kwh for every million gallons. In fact, energy generally accounts for about half the cost of desalinated water. To mine and burn coal for electricity, China depleted its fresh water supplies on the North China Plain. Now, China proposes to use much of that electricity to desalinate sea water. The United Arab Emirates use enormous amounts of energy to desalinate their water, about 70 percent of which is expended on urban gardens.

Humans can live in a variety of climates, including hot, dry ones. But the scale of modern human civilization depends on populations and industries with access to reliable, cheap water. If the rest of the world didn’t pay a premium for oil, places like Saudi Arabia and the United Arab Emirates would not be able to support their present populations—water scarcity requires them to import too much food. And they certainly wouldn’t be able to support their luxurious living standards. The desert wouldn't allow it.

The cycle of waste can be arrested in much of the world, however. Wind and solar energy not only reduce carbon emissions, they reduce the amount of water devoted to energy production. Efficient drip irrigation systems should be paired with efficient solar pumps to reduce demand for fossil fuels and the water required to extract them. New buildings should be optimized to be both carbon- and water-neutral, linking passive solar architecture with rainwater harvesting. Finally, groundwater must be carefully protected and overdrafts restricted. During wet years— and there will be wet years even in a changing climate—water must be stored and preserved beneath the earth. We will need it for the droughts to come.