On Wednesday afternoon, a self-described whimsical scientist from Canada emerged from a sealed 3 meter (10 foot) by 3 meter cube constructed of plastic sheeting and plywood and filled with 200 leafy plants. Despite only lasting 15 hours in the structure before dangerously high CO2 levels forced him to exit, Kurtis Baute considers his experiment a success. His mission was to raise awareness about the dire threat of greenhouse gas emissions by documenting his experience on social media, and judging by the explosion of media coverage, he did just that.

In a series of Tweets and YouTube videos leading up to the event, Baute explained that he intended to spend up to three days in his
DIY “biodome” to illustrate – on a tangible, individual-level scale – how the human-driven processes of climate change affect all life on Earth. He hoped that by showing how his own life depended on sustaining an equilibrium between his respiration and the plants’ photosynthesis, people would be reminded that the Earth is also a self-contained system whose balance is currently in danger.

Baute, a science communicator who creates fun, educational videos on his YouTube channel, The Scope of Science, also shared many behind-the-scenes clips as he constructed the biodome in the backyard of his brother and sister-in-law’s British Columbia home.

After more than two months of research and preparation, Baute entered his biodome right after midnight on October 24. As he noted on his website last week, his original goal for staying in the sealed environment was amended after calculations suggested the gaseous balance could tip quickly if the conditions became less than ideal.

"I could probably survive in the [dome] three days," he wrote. "But my goal is not to just 'not die', my goal is to end this project without having turned blue, developed brain damage, gotten heat stroke, or just generally caused lasting harm to my body."

Once he was finally inside, Baute shared frequent updates on his blood oxygen and CO2 levels in the air and continued to engage his audience about climate science. 

"The messed up thing about my experiment is that some of my abort values (eg If CO2 is too high I escape) are just everyday experiences for many people on this planet. Everyone deserves clean air, but not everyone has it," he noted in a Tweet posted at 5:05 AM. Prior to that message, at the four-hour mark, he noted that he had been unable to fall sleep in the hammock set up inside, but that his blood oxygen levels were good.   

As the morning progressed, however, the CO2 levels began to rise, which Baute attributed to slower-than-expected plant metabolism caused by cloudy skies, meaning they couldn't keep up with the CO2 Baute was breathing out, just like all the photosynthetic organisms in the world can't keep up with our emissions.

At 6:30 PM, he reported that levels had gotten so high that it was beyond the range of both his sensors. According to a photo posted of his CO2 monitor, the concentration inside the biodome was more than 9,300 parts per million (ppm) right before he aborted. As of now, the global average outdoor concentration is 400 ppm, a significant increase from the 180 to 280 ppm present during much of the human era up to the Industrial Revolution.

Due to build-up from respiration, indoor levels can reach an alarming 1,000 to 5,000 ppm.

Scientists at Harvard, Lawrence Berkeley National Laboratory, and NASA have found evidence that our cognitive ability begins to decline in environments with 1,000 or more ppm, and the CDC reports that regular exposure to levels above 5,000 ppm are unsafe for one’s overall health.