"Look here," Weber pointed at the screen, his finger sliding along the curve, "That nice data from last week was done on Saturday morning. On Saturdays, nobody's in the lab; no one opens doors, no one goes in and out, no one takes reagents, puts samples, chats, or makes calls. In short, the CO₂ concentration was stable for four hours. These three repetitions were done on weekdays. People from the lab next door frequently open doors, and the concentration is always fluctuating, like riding a roller coaster."
Yang Ping stared at the red curve for a full minute.
He slowly said, "So, your temperature exposure time might just be superficial. The real reason is the synergistic effect of CO₂ concentration fluctuations and temperature fluctuations. A single variable has limited impact; when both variables fluctuate simultaneously, they interact, producing an effect where 1+1 is greater than 2."
