There's no such thing as an "inadvertent experiment". Experiments are done with the goal of testing theories.Ideally, experiments are done carefully, with conscious thought toward learning as much as possible. The poisoning of our atmosphere may be an inadvertent experiment, but it's an experiment nonetheless.
CO2 at atmospheric levels isn't poisonous; carbon dioxide is vital to life. People drink carbonated beverages with CO2 levels far higher than ever existed in the air; that's not poisonous either.And people of your ilk are forcing me to accept worsening poisoning every day.
For someone who claims to be a scientist, HSL sure doesn't understand the meaning of 'poisoning' or 'experiment'. I'm willing to bet, if he has a degree, it's in the social sciences, not physical science.I understand perfectly well how to run experiments, & have done plenty of them myself in the lab...