One cause of Global Warming

One cause of global warming is the different human activity which releases CO2 from the fossil fuels, especially since the industrial revolution. The CO2 level in the air has been increased a lot comparing to 100 years ago. Most of the CO2 come from transportation which produces huge amount of CO2 into the air once its engines start working till it stop. In addition, Statistics show that 51% of CO2 emissions come from vehicles fossil fuels. Furthermore, co2 increases the ozone layer of the earth's atmosphere and it reduces the Oxygen proportion of the earth.