By 1870, the world was artificially producing a billion tonnes of CO 2 per year. By the late 1980s, we were up past 20 billion tonnes each and every year. And, at present, we're nearly up to 30 billion tonnes of CO 2 emitted annually. Out of this nearly 30 billion tonnes per year, the United States is responsible for about 6 billion tonnes of it. If -- as a world -- we don't cut our Carbon Dioxide production significantly, by 2030 we will have added as much Carbon Dioxide to the atmosphere as there was Carbon Dioxide in the atmosphere when we started!