I read an interesting story recently that talked about the levels of carbon dioxide (CO2) in the air. What made it so interesting is that the story mentioned how the one station in Antarctica that measures CO2 levels in the Earth's atmosphere finally reached the level of 400 parts per million (ppm). This particular station, was the very last station in the entire world to hit this level, and it was the first time in 4 million years that the surrounding area did so. However, there was something even more interesting than that. In the story, which you can read by either clicking here or following the link at the bottom, there is a link to a YouTube video that shows just how CO2 increases in density and flows around the world. As the dead of winter kicks in, the video shows the CO2 levels at its absolute highest, becoming as what appears to be as dense as the clouds can during a rainstorm. However, keep in mind that this density is still fairly small, as it is essentially 400 milli...