Global Warming is the gradual increase of atmospheric temperature that has been generally attributed to the increased levels of atmospheric carbon dioxide, chlorofluorocarbons, and other various gases that contain carbon compounds. The increase in atmospheric temperatures has caused in increase in temperature in Earth's air, land, and ocean ecosystems.

According to NASA, the Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat with abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era. Most of these climate changes are attributed to very small variations in Earth's orbit that change the amount of solar energy that the planet receives. However, the current warming trend noted by scientists is of particular significance because it is extremely likely (within 95% probability) to be the result of human activities since the mid 20th century.

The carbon footprint is the amount of carbon dioxide and other carbon compounds emitted due to the consumption of fossil fuels by a particular person or group of people. A carbon footprint measures the output of carbon output. Check out your carbon footprint here: http://www.nature.org/greenliving/carboncalculator/index.htm