purpose) is increasing the amount of combustion byproducts (including CO 2 ) in the air. Man uses energy. We create CO2 when we use energy. CO2 is the only gas in our environment that we make a substantial portion of. Man produces almost 7% of this gas. Much of this CO2 that we emit (over half) is to heat, cool and power our homes. Industrial activities have definitely contributed the most to the increasing levels of carbon dioxide in the air. Carbon dioxide is released when the factories are running and producing stuff. Burning of fossil fuels also cause it to rise. Every carbon-based life form (that includes every plant, animal, and human on earth) adds CO 2 to the atmosphere when it decomposes (or is burned). As agriculture developed, bigger and better plants cover more of the earth and an ever-increasing number of livestock are being raised. In addition, carbon from coal petroleum deposits that have been buried for millennia are being extracted and burned, releasing even more CO 2 into the air. Burning of fossil fuels and deforestation are the main causes of excess CO2... humans and other animals also increase carbon dioxide in the atmosphere since we breathe out CO2. Although, humans and other animals breathing is not the main cause of excess CO2 in the atmosphere. The most noteworthy changes in CO2 levels have always been due to temperature changes. we have seen mass shifts in Co2 levels due to natural temperature changes with CO2 consistently