Carbon Dioxide is the evil green house gas. But it is part of a cycle, taken up by plants and converted into sugars, proteins and fats. These are then eaten by animals and once digested turn either into more animal ( about 10%) or respired directly into Carbon Dioxide. Eventually all the animals are eaten or die and this is then turned back into Carbon Dioxide and the cycle starts all over again.
The problem for us is using all the fossil fuels which take carbon taken out of the system millions of years ago and converts this into Carbon Dioxide.
This is a Green House gas which traps some of the Earths Heat and causes the Global Warming.
