Biosphere 2 has stood amid the paloverde, mesquite, and ocotillo southwest of Oracle, Arizona, for less than 20 years, yet it looks decidedly aged. Its skin is mostly glass and lacks window-washing tracks, so the hundreds of panes had to be cleaned by workers hanging on ropes like rock climbers. At one time seven people were employed to do this; today there are none. The desert wind deposits dust on the structure and the rain washes it downward, forming parallel streaks. The rain forest inside pushes against the glass. In 2003 there were about 150 employees on the site. Less than a third remain. Dry leaves collect against the air handlers by the main doorway; whiptail lizards skitter over the concrete paths, and javelinas trot around the grounds at night. A note on a whiteboard in the operating engineer’s office tallies the number of poisonous reptiles encountered on the site, which is greater than the number of maintenance people left to encounter them: “Rattlesnakes: 17.”

The café is closed, the mission control building deserted, and inside the row of clear plastic sheds where plants were readied for installation in the main structure, towering exotics—Panama hat palm, angel’s trumpet—stand bleached and lifeless where they perished when the water was turned off. A monochrome monitor displays the last numbers it ever knew, burned into its dead screen. On the shelf below is the 1986 manual for the environmental monitoring system to which it was connected. Nothing ages faster than the future.

Constructed between 1987 and 1991, Biosphere 2 was a 3.14-acre sealed greenhouse containing a miniature rain forest, a desert, a little ocean, a mangrove swamp, a savanna, and a small farm. Its name gave homage to “Biosphere 1”—Earth—and signaled the project’s audacious ambition: to copy our planet’s life systems in a prototype for a future colony on Mars. A May 1987 article in DISCOVER called it “the most exciting scientific project to be undertaken in the U.S. since President Kennedy launched us toward the moon.” In 1991 a crew of eight sealed themselves inside. Over the next two years they grew 80 percent of their food, something NASA has never attempted. They recycled their sewage and effluent, drinking the same water countless times, totally purified by their plants, soil, atmosphere, and machines. It wasn’t until 18 years later, in 2009, that NASA announced total water recycling on the International Space Station. At the end of their stay, the Biospherians emerged thinner, but by a number of measures healthier.

Despite these successes, the media and the science establishment seized upon the ways in which the project had failed. Chief among these was an inability of Biosphere 2’s atmosphere to sustain human life. As was true outside, the problem was signaled by rising carbon dioxide. By 1996 Biosphere 2 had passed into the hands of Columbia University, and later the University of Arizona took over. Both used it to run scenarios of global climate and atmospheric change. In its later life, “instead of trying to model utopia, Biosphere 2 would actually model dystopia—a future plagued by high carbon dioxide levels,” wrote Rebecca Reider, author of a definitive history of the project. But while most research on impending environmental disaster relied on computer models, Biosphere 2 represented a fascinating alternative mode in which large-scale analog experiments employed real organisms, soil, seawater, and air.

The man behind Biosphere 2 was John Allen, a Colorado School of Mines–trained metallurgist and Harvard MBA. In 1963, after two hallucinogenic experiences on peyote, Allen looked out of the Manhattan office building in which he was working and realized he could not open the window. He felt trapped like a bug inside glass—an ironic epiphany for a man who would work so hard to seal up a handful of his followers three decades hence. So he sailed from New York aboard a freighter and traveled the world, seeking wisdom. By 1967 he had become a self-styled esoteric teacher in Haight-Ashbury-era San Francisco, delivering weekly lectures to a group of mostly younger followers and cohabitants. In 1968 he and his students went to New York to set up a theater company, and from there to New Mexico, where they started a commune near Santa Fe. If most such counterculture experiments yielded to entropy and poverty, Allen’s Synergia Ranch is a notable exception. The Synergians were a very hardworking bunch.

In 1974 a lanky young Texan and Yale dropout named Ed Bass wandered up the driveway to Synergia Ranch. Like Allen, Bass had a strong interest in the environment. Unlike Allen, he was the billionaire heir to an oil fortune. Later that year Allen and his followers drove an old school bus to Berkeley, California, where they built an 82-foot sailboat. None of them had ever built even a rowboat. In 1975 they began sailing the Heraclitus around the world. They took her up the Amazon River, dove coral reefs in the tropics, and sailed her to Antarctica to do research on whales.

With John Allen’s big dreams and Ed Bass’s big money, the Synergians began taking on bigger things. They acquired a huge cattle ranch in Australia, started a sustainable forest in Puerto Rico, built a hotel and cultural center in Kathmandu, and took on other projects in Nepal, the United Kingdom, France, and the United States. Now calling themselves the Institute for Ecotechnics, they began hosting international meetings on ecology, sustainable development, and then space colonization. At a conference in Oracle in 1984, Allen announced his plan to build a prototype Mars colony on Earth before the decade was out. The destiny of human beings was to seed Earth’s life into space, and the first stop would be a working colony on Mars.

The principals of the institute broke ground for Biosphere 2 in January 1987. If some of them lacked academic qualifications for the jobs they held, they enlisted real experts to execute the design. Walter Adey, a geologist at the Smithsonian Institution, was in charge of the ocean. The rain forest was the domain of Sir Ghillean Prance, then director of the New York Botanical Garden. These and other experts installed 3,800 species of life inside, even as cranes lifted great sections of white superstructure into place overhead. The majesty and complexity of the project entranced the press, touching on myth and religious narrative, Rebecca Reider wrote. Time called it “Noah’s Ark: The Sequel.” This created expectations that would be hard to meet.

In September 1991, four women and four men in NASA-style jumpsuits entered the air lock of Biosphere 2. Twelve days into the mission, Jane Poynter, a young Englishwoman in charge of the farm, put her hand in a threshing machine while winnowing rice. The group’s doctor sewed the tip of her middle finger back on, but the graft didn’t take and she was evacuated for surgery. She returned in only a few hours to serve out the two-year mission, but when she reentered the air lock, a duffel bag was placed inside with her. It contained nothing of substance, Poynter said—some circuit boards and a planting plan for the rain forest—but the media had a field day with it, along with the fact that someone had left and then reentered, which couldn’t have been done on Mars.

More ominous, signs of trouble with the internal atmosphere began within 24 hours. Each morning the crew had a breakfast meeting over bowls of home-grown porridge in Star Trek–style chairs around a polished black granite table. The morning after closure, the crew captain announced that carbon dioxide in Biosphere 2’s atmosphere had risen to 521 parts per million, a 45 percent increase above levels outside at the time. By the following day, the lowest it went was 826. Over the months that followed, the news at the morning meetings got worse. Crew members were feeling tired and began to pant when they climbed stairs.

In May 1992 in Palisades, New York, geochemist Wally Broecker got a phone call from someone at Biosphere 2, asking if he would be willing to consult on their atmosphere. Since the late 1970s, when he became the Newberry Professor of Earth and Environmental Sciences at Columbia University’s Lamont-Doherty Earth Observatory, Broecker had been sounding the alarm about a buildup of carbon dioxide in the big atmosphere. An elfish presence with a dried-apple-doll face and wild, tousled hair, he was already one of the great men of atmospheric-change research when he crossed the George Washington Bridge for dinner with John Allen at a Manhattan restaurant. The meeting had a cloak-and-dagger feel. Allen, a handsome, clean-shaven, broad-shouldered man who often wore a fedora, reminded Broecker of Indiana Jones. By Broecker’s account, Allen proffered a graph of the gas composition of Biosphere 2’s atmosphere, then nervously pulled it back, as if someone else might see it. A week later Broecker flew to Arizona and began collecting data.

Much attention had been focused on charismatic species when Biosphere 2 was put together. A biologist surveyed the world’s hummingbirds to find one with a bill the right shape to pollinate a variety of plants inside the structure, and without a mating display predisposing it to fatal collisions with the glass. But Broecker and his graduate student Jeffrey Severinghaus discovered that the culprits in the carbon dioxide problem were the tiniest organisms on board: soil bacteria.

The process of their subversion was respiration, in which living things release carbon dioxide into the atmosphere. Green plants absorb sunlight and carbon dioxide during photosynthesis, making carbohydrates and releasing oxygen, but they also do the reverse: Plants, too, respire (or breathe), burning carbohydrates to do work like making branches and roots. In the soil around their roots, billions of fungi and soil bacteria respire as well. In fact, the greater part of all “breathing” in terrestrial systems goes on underground.

Ever grand in their ambitions, Allen and his people intended Biosphere 2 to be used by rotating crews for 100 years. Feeling they had one shot to invest their world with life-giving nutrients, they had loaded their soils with compost and rich muck from the bottom of a cattle pond. (Agricultural chemicals used inside might end up in their air and water.) When the air locks closed, soil bacteria had a massive party, exhaling carbon dioxide and tipping the balance the wrong way.

As oxygen was converted to carbon dioxide, free oxygen in the atmosphere declined. By January 1993, Biosphere 2’s carbon dioxide levels were 12 times that of the outside, and oxygen levels were what mountaineers get at 17,000 feet. The crew’s doctor was having trouble adding up simple figures and disqualified himself from duty. So, a year and four months into the mission, tank trucks containing 31,000 pounds of liquid oxygen started driving up the access road to the site.

The story of fresh-faced idealists getting taken down a notch played well in the media. For two years the glass walls of Biosphere 2 were lined with TV cameras and tourists. The crew’s lives turned into reality TV. In fact, the producers of the world’s first reality TV show, Big Brother, which aired in the Netherlands in 1999, acknowledged Biosphere 2 as their inspiration. True to reality TV’s typical plotline, months cooped up together while struggling with their atmosphere and hunger and being filmed by well-fed people led to squabbles among the Biospherians. They emerged from the air lock in September 1993 in two groups of four who weren’t speaking. Organizational cracks opened between them and their advisory scientists and extended into their relationship with Ed Bass. Originally budgeted at $30 million, Biosphere 2 had already cost a reported $200 million. By the time a second crew took its place inside, Bass had had enough. On April 1, 1994, his bankers, accompanied by carloads of armed federal marshals and sheriff’s deputies, swept into the site with a restraining order. The second crew lingered inside Biosphere 2 for another five months and 16 days before terminating its mission.

Biosphere 2, it was widely reported, was a catastrophe. In 1999, when Time did its fin de siècle summary of the 20th century, it included Biosphere 2 in its list of the worst 100 ideas.

With the biospherians ejected from their eden, Bass’s people began looking for a new entity to operate the facility. Eventually they struck a deal with Columbia University. The new director of research was Wally Broecker, who had coined the term “global warming” two decades earlier. Here was a gigantic laboratory flask with a whole tropical forest and an ocean inside it—models of what many scientists suspected were the two biggest carbon sinks in the world. By 1995, when the deal was closed, Broecker was not alone in his sense of urgency.

Next page: Hot research site in a warming world