It’s a record we didn’t want to break. The carbon dioxide concentration in the atmosphere hits the 400 parts-per-million mark, a level which some scientists say is a point of no return for stopping climate change. A few days later, a leading newspaper prints an op-ed essay that claims CO2 is getting a bad rap: it’s actually good for the planet. The more the better.
Skeptic Phil Plait rebuts the CO2-is-awesome idea while a paleontologist paints a picture of what Earth was like when the notorious gas last ruled the planet. Note: humans weren’t around.