In the 1860s, a restless young adventurer named Jack Swilling spent years in the unforgiving American Southwest engaged in one of the country’s favorite pastimes: running from his past and trying to get rich. After years of rough living, he made an unusual discovery that would alter both his life and the destiny of the region.

Scouting through the Salt River Valley, Swilling glimpsed faint markings and mounds of earth that stretched for miles across the arid Arizona landscape. He followed the paths, accidentally discovering the remains of a colossal water transfer system — an advanced irrigation network that rivaled the Roman aqueducts in both scope and engineering precision.

The Hohokam civilization, once the region’s predominant power, had begun meticulously forging this sinuous system of miles and miles of waterways across the arid desert as early as the 1st century C.E. With water sourced from the distant Salt River, the Hohokam perhaps cultivated more than 10,000 acres of arid land. The capillaries of their sprawling water infrastructure allowed them to tower over neighbors, amassing tributes and military support from surrounding tribes. Engineering and maintenance of their vast agriculture system required a despotic, centralized order that flourished for hundreds of years.

And then around 1500 C.E., it disappeared with barely a trace. The exact causes of the collapse remain unsolved, but to the best of historians’ understanding, it was due mainly to drought that even the Hohokam irrigation system couldn’t manage.

For Swilling, however, the remains of this water infrastructure became an opportunity. He founded the Swilling Irrigation and Canal Company and set out to rebuild the Hohokam canal network. By 1867, streams of liquid gold flowed from the Salt River more than 200 miles away to nourish a nascent agricultural industry. The oasis required a fitting name. Among Swilling’s ensemble of entrepreneurs and criminals, the Englishman Darrell Duppa proposed the name “Phoenix.” According to Duppa, “A great race once dwelt here, and another great race will dwell here in the future. I prophesy that a new city will spring, phoenix-like, from the ruins and ashes of the old.”

A century and a half later, the American Southwest is sweltering under another harsh drought. Last year, 1,000-foot wells dug deep underground by residents of Rio Verde, a community on the outskirts of Phoenix, started coming up dry. The neighboring city of Scottsdale stepped in to help, hauling water to Rio Verde homes in trucks. Then in January of 2023, those were halted too.

In the meantime, Phoenix has become one of America’s fastest-growing cities, a trend bolstered by preferential tax schemes and the growth of the (very water-hungry) semiconductor industry. The city now has America’s largest manufacturing capacity for advanced chips.

But the deep drought across the parched landscape haunts citizens and local politicians. The once unthinkable prospect of running out of water has become thinkable. One Arizona resident noted, “Hell yes, there’s a panic. We’re on the front lines of the panic. As it looms and gets closer, of course now more people are opening their eyes going, ‘Oh my gosh, this is actually a real thing.’”

The cause — and perhaps solution — of the multi-decade megadrought stifling the American Southwest on a scale not seen in more than a millennium is tied in surprising ways to another desert, one on the other side of the world. Seven thousand miles away, in the Taklamakan Desert, dust is blown into the jet stream that links western China to the Western United States. This Asian dust, scientists have found, contributes to rainfall in America, a reminder of the planetary equilibrium the two countries are intimately enmeshed in. In this precarious symbiosis, discoveries by both nations in understanding and mitigating the plight of drought may forge a powerful bridge across divided deserts.

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Ecological Mythmaking

In both China and the United States, ecological myths have played a key role in shaping national identity. Whether it be the American frontier and the veneration of national resources or China’s geological transformations and the quest to control tumultuous nature, these myths have evolved into a vital source of political legitimacy. In both countries, leaders have imbued nature with religious overtones, rendering it an essential basis of the political environment — “Build Back Better” in the U.S and “ecological civilization” in the People’s Republic.

Chinese legends tell of a time in ancient history when 10 suns simultaneously shone on the Yellow River Civilization (黃河文明), leading to an apocalyptic drought followed by a great flood. Yu the Great (大禹), a mythical engineer-king, used clay stolen from the gods to build dikes and dams, quelling the raging river and inaugurating dynastic rule in China that lasted for thousands of years.

For much of Chinese history, emperorship was tightly bound to successful water resource management. Unlike Biblical or Greek mythologies, natural catastrophe was rarely seen as divine retribution for sins, but rather a constant possibility in an anthropic universe that bureaucrats must always anticipate. The collapse of political order and dynastic transitions have been intimately tied to natural disasters, especially on the Yellow River, throughout China’s history.

Starting around 1048 C.E., flooding on the Yellow River caused the deaths of over a million people and contributed to the demise of the Northern Song Dynasty. In the 1600s, cataclysmic flooding and the destruction of dikes took the lives of an estimated 300,000 people, striking a critical blow to the already struggling Ming Dynasty. Between 1851 and 1855, massive floods resulted in hundreds of thousands of deaths and contributed to the causes of the Taiping Rebellion, the deadliest civil war in human history. Even today, China’s political and economic future remains dependent on the predictable and consistent flow of its two most vital rivers, the Yangtze and the Yellow.

The concept of “hydraulic despotism,” first coined by historian and political theorist Karl August Wittfogel in 1957, is deeply rooted in this historical context. Wittfogel argued that centralized control of water resources served as the foundation for the creation and maintenance of many global empires, particularly in China. According to his theory, the bureaucratic requirements needed to govern unpredictable rivers and nurture fragile agriculture allowed China’s leaders to centralize and retain power for thousands of years. Water management was so imperative in Chinese society that it dominated all other aspects of life, determining property rights, political power and economic development.

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Distant Desert Dust

At the same time as Rio Verde residents were drinking the last sips of their well water, China was sweltering under a stifling drought of its own. A devastating 11-week heatwave pushed the Yangtze, the world’s third-longest river and a source of drinking water for 400 million people, to its lowest recorded level. In Anhui Province in eastern China, the government started hauling water by truck to help struggling citizens.

A few years ago, China and the U.S. might have worked together to overcome these crippling environmental conditions. In 2013, the two countries announced a collaborative effort to curb emissions and collaborate on climate solutions. It was an ambitious agreement between the top two polluters.

Such cooperation is less likely today. The Trump administration dismantled Obama-era climate commitments, and the Biden administration has not yet fully revived them. Global environmental cycles and rhythms remain poorly understood, and collaborative research is urgently needed.

The Cold War-colored glasses of the rivalry between the world’s two biggest economies obscure the reality that both are on a path of environmental destruction, one bounded by planetary chemistry and shared infrastructural history. The history of the American West has been consistently shaped by a history of cyclical droughts, a fact well-recorded by the region’s tree rings. But the ongoing megadrought, the worst in 1500 years, has been the most severe, heavily influenced by an unprecedented lack of rainwater.

Emerging research over the last decade suggests that the source of the prolonged and uncontrollable American drought may be intricately linked to the Taklamakan Desert. Depending on the year, approximately 20 atmospheric rivers — jet streams that bring rain — pass across the U.S. West Coast annually. Together they supply more than half the precipitation that falls in California, and much of what the Southwest gets as well. Atmospheric scientists have long puzzled over why some clouds drop more water than others. We might now have the answer.

In the early 2010s, researchers compared two atmospheric rivers that were practically identical in temperature and water content. But one contained dust from the Taklamakan Desert that it had picked up after a sandstorm and carried across the Pacific. It released almost 40% more water — a difference of 1.5 million acre-feet of water, more than in the entirety of California’s largest water reservoir — than the one that had no desert dust.

In order for clouds to drop rain, water particles must coagulate and ice over. The icing can be accelerated with certain minerals, like the artificial silver iodide used for cloud seeding. In 2013, scientists discovered a group of minerals called potassium feldspars were natural cloud seeders; their crystal structure offers an extremely convenient scaffolding for water molecules to bind to. While K-feldspars, as they are known, make up a tiny proportion of dust on a global scale, they are abundant in the Taklamakan. The desert — “Place of No Return” in the local folk history — is encircled by the Kunlun, Pamir and Tian Shan mountain ranges, which formed a reserve of finely ground dust with nowhere to go but north, toward the Siberian jet stream. More than 400 million tons of sand from the Taklamakan and other Asian deserts are blown over the Pacific every year.

Perhaps even more importantly, the Taklamakan dust that ends up in the American West carries “hitchhikers” — desert microbes like bacteria whose biological structure is designed to survive in the hot desert and also protect them on a winding journey across the Pacific. Dust also can carry viruses, which (unlike bacteria) are often protected by a solid protein casing, a lattice figure of alternating positive and negative charges that water molecules easily latch onto.

Similar winds bring sand from the Sahara to feed the Amazon rainforest and from the Mojave to the Colorado Plateau. Every day, minerals and microorganisms journey across the planet, wafted aloft into the atmosphere among the clouds, maintaining vast and elaborate planetary relationships. These winds have shaped the rise and fall of empires and influenced pivotal political developments, all unbeknownst to humans.

In recent decades, atmospheric wind connections between the U.S. and China have shifted considerably. The frequency of dust storms in northern China has decreased, partly due to China’s Great Green Wall initiative that aims to plant millions of acres of forest to hold back the desert. Taklamakan dust is also not as effective in the presence of air pollution, which has increased significantly along the U.S. West Coast and throughout northern China.

This particular planetary relationship between sand and rain began more than 25 million years ago, during the Oligocene Era’s tectonic uplift of the Tibetan-Pamir Plateau, which enclosed the area that became the Taklamakan Desert. This geochemistry does not have political borders or allegiances. Simultaneously, our anthropogenic world of international relations is agnostic to these geological epochs, which to its detriment misses something fundamental in the distinction between “geopolitics” and “politics.” The drying of cities such as Phoenix and San Diego, for example, is linked to the anti-desertification measures in Kashgar, one of China’s westernmost cities. Planting more trees there, paradoxically, could mean less rainfall halfway across the world.

The Great Plans

If the Taklamakan Desert’s most important export to the American West is dust, then the American West’s most important export to the Chinese desert is a modern hydrological imagination. The inspiration to control the Yangtze River, which has become the bulwark of the planet’s most important economic corridor and a key pillar in China’s anti-desertification fight, came from the American Southwest.

In the 1940s, Chiang Kai-shek hired the designer of the Hoover Dam, John L. Savage, to conduct a feasibility study for a similarly ambitious project in China. Surveys and estimates were carried out, and Chinese hydrologists and engineers came to the U.S. for training with the U.S. Bureau of Reclamation. Savage returned to the U.S. and published a proposal for the “Yangtze Gorge and Tributary Project” — or as he called it, “the dream dam.”

After the Communists triumphed over the Nationalists in China in 1949, Mao Zedong envisioned an elaborate infrastructural scheme to support China’s industry and hamper the desert’s northward spread by rerouting and damming the Yangtze. In 1956, he wrote a poem that reads in part:

Mao revived Savage’s vision, which, long after they had both passed on, became the Three Gorges Dam and the South-North Water Transfer Project. The former, completed in 2012, is the world’s largest hydroelectric dam. The latter, intended to be completed in 2050, will redirect 45 billion cubic meters of the Yangtze via three canals to the north. Last year, the river diversion’s price tag ballooned to $100 billion, making it the most expensive infrastructure project in human history. Also last year, parts of the Yangtze ran completely dry, forcing citizens to rely on water shipments until the rain returned in October.

The Colorado River, which served as the inspiration for the management of the Yangtze, has reached a similarly critical low point and is struggling to sustain the world it created. Annually, the river provides more than a quarter of the water consumed in Los Angeles, San Diego and Phoenix. It is essential for most of the country’s winter produce; its power illuminates Las Vegas. It is responsible for the boom of the American West, and it may become the bane of its existence.

In “Cadillac Desert” — a history of the water infrastructure that gave birth to the modern U.S. — Marc Reisner highlighted this conflicted legacy: “To some conservationists, the Colorado River is the preeminent symbol of everything mankind has done wrong — a harbinger of a squalid and deserved fate. To its preeminent impounder, the U.S. Bureau of Reclamation, it is the perfection of an ideal.”

The Hoover Dam was the largest in the world at the time of its construction: It rose more than 700 feet in the air and used enough about 6 million tons of concrete. Normally, it would take 100 years for that amount of concrete to harden. Savage’s cooling design — miles and miles of tubes running freezing water through the structure — brought the timeline down to less than two years.

Today, a drought lasting more than two decades could spell disaster for the Colorado River and its 40 million beneficiaries. As Reisner concluded: “One could say that the age of great expectations was inaugurated at Hoover Dam — a 50-year flowering of hopes when all things appeared possible. And one could say that, amid the salt-encrusted sands of the river’s dried-up delta, we began to flounder on the Era of Limits.”

Institutions For The Era Of Limits

Kimberly Prather discovered the connection between the Taklamakan Desert and rainfall in the American West only because her university, U.C. San Diego, had cooperated with China’s Ministry of Education. The collaboration led her to a ship off the coast of China where she collected data on dust aerosols and recognized the atmospheric link between the two countries.

Since the start of the recent tensions between Beijing and Washington, the majority of such transnational academic partnerships have ceased. Nevertheless, American and Chinese universities are currently conducting some of the most advanced research on droughts, and collaboration between both nations might be the only thing that can guarantee better insight into planetary rhythms.

Lanzhou University, in the capital of Gansu Province in China’s arid Gobi Desert, is home to the Center for Western Environmental and Social Development, which has led one of the planet’s most successful anti-desertification efforts. Across the Pacific, American institutions have been successfully investigating solutions to arid water management for decades — but the University of Arizona’s Water Resources Research Center and the Arizona State University’s Center for Hydrological Innovations’ discoveries remain notably isolated to the Southwest. 

In the last few years, despite national undulations, perhaps the most successful collaborative effort occurred between California and China, a partnership that allowed representatives of both governments to share policy insights, experience and funding. Starting in 2013, the collaborations — on carbon markets, clean transportation and electric vehicles, protecting biodiversity and reducing pollution — seem to have broad sticking power, lasting longer than the terms of several American presidents and California governors.

When one country’s desert forms another’s rain, then one’s dream is another’s peril. At the precipice of a new political epoch, interwoven ecologies of China and America may yet inspire a new era of bilateral relations, loftier than the most monumental of dams. Sharing knowledge and technology, and understanding the planetary connections between seemingly distant environments, is the only way to ensure mutual resiliency. In the communion of minds, divided terrains may mutually fortify one another, with forgotten borders dissolving into the sands from which they were birthed.