People can stop it.
Each day, the typical American puts carbon in the air simply by waking to an electric alarm clock, switching on a coffee maker and turning up the heat. During the course of a year, each American on average puts more than 5 tons of carbon out there, not counting what he or she exhales. That's the most per capita of any nation on Earth. In the form of diamonds, this represents enough carbon to fill nearly two dozen 20-gallon garbage cans. Humans produce it as carbon dioxide, the most abundant heat-trapping greenhouse gas.