By Donella Meadows
–September 24, 1992–
The first media reports were glowing. There was Biosphere 2, a huge greenhouse in the Arizona desert, containing a miniature ocean, a rainforest, a savanna, a desert, a farm, and eight people who will live there, sealed in, for two years. A gee-whiz, hi-tech, Green experiment. All air, water, and food cycling and recycling through natural processes. A test site for space travel, or for learning to live sustainably on Biosphere 1: the earth.
The next reports swung the pendulum the other way. Biosphere 2 is a fake. They’re sneaking in fresh air at night. It’s not solar powered. Underneath is a throbbing engine room, using a steady flow of natural gas to provide cooling, rain, wind in the enclosed atmosphere, waves in the mock ocean. Furthermore the experiment is failing. The air in Biosphere 2 is unstable. The people are starving. Birds and frogs locked into the simulated ecosystems are dying.
Whenever the media paint a picture all white or all black, you know the truth is probably somewhere in the middle. Biosphere 2 is not pure science, not total theater, but some of both. It is not working perfectly. But it’s astonishing that it’s working at all. It is producing fascinating lessons about humanity and Planet Earth, and that, after all, is its purpose.
The eight Biospherians were closed into their 2.5-acre world just a year ago. They had little time to prepare for a winter that turned out to have, because of an El Nino shift in Biosphere 1, one-fourth less sunshine than normal in Arizona. That meant a sharp slowdown in the motor of any biosphere — the photosynthesis of plants. Because the plants were taking in less carbon dioxide and putting out less oxygen, the carbon dioxide content of the enclosed atmosphere soared. Because plant growth was slow, food production lagged. The Biospherians began to lose weight.
They responded to this difficulty in a way that only humans, of all creatures in Biosphere 1, can do. They began to think a new way. They came to see “sunfall” as their most precious resource. Hungrily, they watched where light fell in their domain as the sun circled the sky, and they made sure it hit a green leaf at every opportunity. They stuck plants on cliffs. They planted lower-story vegetation in the forest to soak up whatever sun got through the trees.
Helpers of photosynthesis. Harvesters of sunfall. An interesting way for human beings to see themselves!
In the spring the sun returned and the food problem improved, but the atmosphere continued to shift. Now its oxygen content is down to 16 percent, as opposed to a normal 21 percent for Biosphere 1. (That is evidence, by the way, that Biosphere 2 has no significant air leaks.) The oxygen unbalance can’t be explained by failure of photosynthesis. Rather, the Biospherians believe, it comes from something to which humanity normally pays little attention — soil chemistry.
Soil is more than stuff to hold plants up. It is a constant flux of chemical and microbial action, exchanging molecules with the air and water that flow through it. Apparently the soils in Biosphere 2 were not stable, not in equilibrium with the atmosphere. They have been drawing in oxygen and depositing it as calcium carbonate, ferric oxide, or other oxidized minerals. The Biospherians hope that this process is now nearly complete. So far their bodies have adjusted to the oxygen-poor atmosphere. It’s like living at high altitudes. They can do it — but only up to a point.
Of all the dire forecasts I heard from scientists about what could go wrong with Biosphere 2, I never heard anyone mention soil-air chemistry. Another useful lesson: soil is a dynamic part of the planetary balance!
Mark Nelson, one of the Biospherians, calls his new home an “eco-boomerang.” Anything you do comes right back to you in your air or water or food. You check the air analysis before you open a can of glue. Whatever you throw down the sink or toilet will soon, after biological purification, be watering your food — or you. You learn on a literal gut level to be grateful to the microbes and other scavengers that break down wastes and turn them back into nutrients.
That same eco-boomerang exists for us all on Biosphere 1, of course. Because our world is bigger, the feedbacks take much longer, but they work the same way.
No one who knows anything of earth science expected Biosphere 2 to work perfectly. It was not an exercise to create a human-designed world, but an exercise to reveal the complex interdependencies of the world we already have. It serves its purpose by teaching useful ideas — such as the fact that sunfall is a resource, or that soil is an active part of the system, or that everything we dump comes back to us.
By this criterion the experiment is already a stunning success. The nature of the success suggests a use for Biosphere 2 that was never intended by its designers. It should be a training module not just for scientists or astronauts, but for world leaders. Let’s put them in there for awhile, and then have another Earth Summit.
Copyright Sustainability Institute 1992