You gather your most expensive people into a room to make your most important decisions. Then, somewhere in the second hour, the room quietly gets worse at making them. Not the people. The room.

I now travel with a portable CO2 monitor. Outdoors it reads around 400 parts per million. In a closed meeting room with a handful of people in it, I have watched it climb past 2,000. The photo here is a real reading: 2,143.

That number matters more than it looks. Researchers at Lawrence Berkeley National Laboratory put people in a chamber and varied only the CO2. At 1,000 ppm, performance dropped significantly on six of nine decision-making measures compared with a clean-air baseline of 600. At 2,500 ppm, seven of the nine fell substantially, some into a range they called dysfunctional. A separate study out of Harvard found cognitive scores declining as CO2 rose, with the steepest losses in exactly the domains you called the meeting for: strategy, planning, and using information under pressure.

Continue reading on my blog because it's too long for here. https://blog.mikebowler.ca/2026/07/03/co2-and-decision-making/