ok here we go. the earths population is increasing at a massive rate, and as we get bigger we have more energy requirements. now where do we get our energy from? for our cars etc. fossil fuels! now what happens when we burn fossil fuels, for the people among us who didnt study science, we get Carbon Dioxide (CO2). now CO2 is a green house gas and that is fine, but we are having an excess amount of CO2 being emmitted and this is causing an excess amount of said gas in our atmosphere, along with the depletion of ozone due to the reaction with the Chlorine molecule (Cl2), we are causing an increase in the greenhouse effect, thus increasing the temperature and there we have global warming.