A handful of landowners—about 500 farms in all—control the rights to 3.1 million acre-feet a year from the Colorado River. That’s equal to about a third of the water used by California’s cities, with 37 million people, where a four-year drought means neighbors report you if your lawn is green. Or, to measure another way, it’s half again as much water as Governor Jerry Brown aims to save under his April executive order, which set a February 2016 deadline for a 25 percent reduction in urban use. An acre-foot is about 326,000 gallons (1.2 million liters) and can supply the household needs of about 10 people for a year, though actual water use rates vary widely. ... Imperial Valley farmers know their water is precious and understand that to preserve a way of life that runs back a century they have to grapple with the needs of a drought-stricken state. Politicians, regulators, and lawyers have squeezed the valley before to get at its water. In 2003, the Imperial Irrigation District, under pressure from Senator Dianne Feinstein and other federal and state officials, controversially agreed to sell as much as 280,000 acre-feet a year to San Diego. Farmers here still discuss that episode at length, and emotions are still raw, because they believe similar water transfers are likely in the valley’s future. ... “People think transferring water out of the valley is a great sin,” he says. “Wasting water can be an even greater sin.” The neatly prepared field he’s inspecting is perfectly level—he uses lasers to make sure—and slightly lower than adjacent sections so water moves by gravity at an optimal speed. ... The most basic principle governing water use in the western U.S. is this: first in time, first in right. That’s why Imperial Valley farmers have so much water. They arrived early, building the first canal to withdraw Colorado River water and ship it to the valley in 1901. ... More than half the people who own land in the valley today live elsewhere.

An interest in big-clawed bears gave way to an interest in big-clawed cats, and for the past half decade, Rosen has spent almost all her time studying Panthera uncia, or the snow leopard, an animal whose life in the wild, owing to its far-flung habitat and fundamentally elusive nature, remains little known. ... So much remains unknown that scientists debate even the size of the snow leopard population itself: Some thought there were a thousand cats in the country, others put the number at 300. ... At 12,200 feet, the sage of the plains gave way to the middle reaches of the mountains, and the only other vehicles were trucks from a nearby gold mine. All around us was an ocean of unbroken snowpack; without sunglasses, it hurt to even open your eyes. At 15,000 feet, according to the altimeter on my satellite phone, the air began to feel painfully thin; my vision clouded at the corners with a gray haze, and my head throbbed. ... The snow leopard is a deceptively small beast: Males are 95 pounds, give or take, and light through the back and torso. They stand little more than 24 inches tall. (Female snow leopards are smaller still.) And yet as the late naturalist Peter Matthiessen, who wrote his most famous book about the snow leopard, once noted, there are few animals that can match its “terrible beauty,” which he described as “the very stuff of human longing.” ... Save for the pink nose and glimmering green or blue eyes, its camouflage is perfect, the black-speckled gray pelt a good blend for both snow and alpine rock. ... Data from the Snow Leopard Trust suggest that the cat will bring down an animal every eight to ten days—ibex or bharal or long-horned argali sheep, whichever large ungulates are nearby—and can spend three or four days picking apart the carcass. ... life of a male snow leopard is lonelier. He might stay with a female for a few days while they mate, but after that he’ll typically return to hunting and defending his territory in solitude. In Kyrgyzstan, he is often referred to, with reverence, as “the mountain ghost.”

Dead grass became a point of pride as state officials rolled out ad campaigns with slogans like “brown is the new green” and “going golden this summer.” With-it wealthier residents signaled their savvy by investing in beautiful, though dusty, re-landscaped eco-havens of olive trees, white-flowered chamise shrubs, and California golden violets with, perhaps, paths of decomposed granite wending through them. ... Turf Terminators, started by twentysomething entrepreneurs, pitched itself to people like Goldfarb who wanted to conserve but couldn’t afford to pay a landscape architect four or five figures. In less than two years, the company removed 16 million square feet of grass from 12,000 lawns. During that time, Turf Terminators was the veritable face of water-saving landscaping in and around Los Angeles, praised by government officials and some customers for providing a fast, affordable way to get rid of grass. ... The company’s short but profitable life span serves as an instructional fable for other cities that will inevitably face climate change-related infrastructure problems. The takeaway: Solutions are rarely simple or easy, so do a lot of research before throwing public money at the issues.

If water is not managed better, today’s crisis will become a catastrophe. By the middle of the century more than half of the planet will live in areas of “water stress”, where supplies cannot sustainably meet demand. ... Where water is available, when and in what condition matters hugely. About 97% of the water on earth is salty; the rest is replenished through seasonal rainfall or is stored in underground wells known as aquifers. Humans, who once settled where water was plentiful, are now inclined to shift around to places that are less well endowed, pulled by other economic forces. ... As people get richer, they use more water. They also “consume” more of it, which means using it in such a way that it is not quickly returned to the source from which it was extracted. ... To make matters worse, few places price water properly. Usually, it is artificially cheap, because politicians are scared to charge much for something essential that falls from the sky. This means that consumers have little incentive to conserve it and investors have little incentive to build pipes and other infrastructure to bring it to where it is needed most. ... around a fifth of the world’s aquifers are over-exploited. This jeopardises future use by causing contamination. It also damages the layers of sand and clay that make up aquifers, thereby reducing their capacity to be replenished. ... People do not drink much water—only a few litres a day. But putting food on their tables requires floods of the stuff. Growing 1kg of wheat takes 1,250 litres of water; fattening a cow to produce the same weight of beef involves 12 times more. Overall, agriculture accounts for more than 70% of global freshwater withdrawals. ... estimated that agricultural production will have to rise by 60% to fill the world’s bellies. This will put water supplies under huge strain. ... Hydrologists expect that a warming climate will see the cycle of evaporation, condensation and precipitation speed up. ... There is no single solution for the world’s water crisis. But cutting back on use, improving the efficiency of that use and sharing out water more effectively would all help.

Perfecting the digital printout, he told me, had involved hundreds of hours of analog assessment: thousands of paint samples were mixed by hand, in Luxor, to match the tones in the original tomb, then compared with ink-jet outputs. Factum modified an enormous Epson printer so that it could make repeated passes over the gesso-like skin in perfect registration, allowing for fine tweaks. ... The only thing that was perceptibly modern was the absence of a musty odor. Lowe noted that the room’s sound wasn’t right, either. He hopes to enlist engineers to record the “acoustic signature” of Tutankhamun’s tomb, so that he can re-create it inside the facsimile. ... Factum began operations in 1998, when it was becoming clear that 3-D printing was a revolutionary tool. The workshop has made millions of dollars by fabricating sculptures for artists—Anish Kapoor, Maya Lin, Marc Quinn—who sometimes require technological assistance to realize their visions. Lowe appears to spend nearly all his profits on fanciful-seeming projects that, in aggregate, mount a serious case that the facsimile can play a central role in art conservation. ... Because an art work can be scanned without physical contact, the facsimile process makes traditional conservation efforts—from repainting to varnishing—seem like an exalted form of graffiti. A facsimile also allows the public to see objects that are nearly impossible to approach in person: Factum has recorded and reassembled everything from a Renaissance painting outside the Pope’s bedroom to rock carvings on a remote plateau in Chad.

If you were able to observe this creature in person, which is hard to do, given that they live in only a few places on earth, you would find it in a family network—a harem—with a dominant stallion watching over mares and their offspring, in groups of 5 to 15. For this to happen, you would have to be in Mongolia, Kazakhstan, China or Russia, the only places the horse lives anymore in the wild. ...  You don’t ride the takhi, or stable it, or—pony-like as the horse appears—saddle it up and perch children on it at birthday parties. The horse is too wild for that. While it has been captured and occasionally confined to zoos, it has never been tamed—it is the only truly wild horse in existence. Other horses that are thought of as wild are in fact feral. ... There are roughly 2,000 takhi in the world right now, and the largest number of them live at Hustai National Park, within 60 miles of Mongolia’s capital, Ulaanbaatar.

Eight years before, there were no sheep here. Then 21 ewes and five juvenile rams were transplanted to the Rocky Boy’s Reservation of the Chippewa Cree, which straddles part of the Bears Paw Mountains, an islandlike uprising on the plains. ... The herd quickly grew to 100, and 40 were relocated to South Dakota. It has again grown over 100, and another 40 are likely to be transplanted this spring, part of broad attempts to replant sheep populations that are a fraction of what they once were in the West. ... A man from Michigan had paid $100,000 for the year’s only chance to hunt one sheep in the herd on the Rocky Boy’s Reservation. ... In exchange, the Chippewa Cree tribe at Rocky Boy’s received the $100,000, which was used to fund two tribal game wardens overseeing wildlife on the reservation. ... It is a paradox of hunting, rarely so conspicuous as with wild sheep: The hunters are often the primary conservationists. ... widespread belief among serious hunters is that rams are the ultimate pursuit. ... That is for two reasons. One, opportunities to hunt sheep are scarce, and often prohibitively expensive. Two, the hunts are among the most difficult, often lasting weeks in some of the most remote regions on Earth.