Sourced of - 1ElisaPardo - https://www.youtube.com/watch?v=wYLmLW4k4aI Feeling guilty about your carbon footprint? You understand percent, which could be called parts per hundred. You're almost there to understanding parts per million, which is the way trace gases are described. You are in for a big surprise! Here is a link for total CO2 emissions from energy use, provided by US Department of Energy: http://tonto.eia.doe.gov/cfapps/ipdbp...