Are We Getting a Peek at Peak CO2 Emission?

Our planet is heating up. The cause is in some ways simple: Humans add a lot of carbon dioxide to the air every year, about 40 billion tons of it. CO2 is a greenhouse gas: It lets sunlight through to heat the ground, but the infrared light the ground emits gets absorbed, and cannot escape to space. That warms us up, slowly but inevitably. By every measure available to us, we see the effects of this increased heat. But there's hope, at least a hint of it. A new study has some hopeful news about g...