This photograph was taken at Biosphere2 near Oracle, Arizona where experiments on the reactions of plants to a carbon dioxide enriched atmosphere were conducted in the 1990s, by then owner Columbia University. The original project was to allow people to live in a self contained and auto-sustaining environs.

Biosphere II, Tucson, Arizona: J. Siry, January 8, 2000.

The Biosphere 2 experiment failed due to a rapid accumulation of carbon dioxide and decreasingly low levels of oxygen. Because the facility was sealed to simulate conditions in space no exchange with Earth's oxygen rich atmosphere was taking place. Over time the level of oxygen dropped even though plants in the facility generated oxygen for photosynthesis.

In hindsight the problem was the rapid removal of oxygen from the biosphere chamber because the concrete was still drying and oxidizing as it dried and hardened. That means the concrete was combining with the available oxygen in the facility and robbing the occupants of the oxygen they required to breathe.

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