Greenhouse gases naturally blanket the Earth and keep it about 33 degrees Celsius warmer than it would be without these gases in the atmosphere. This is called the "Greenhouse Effect". Over the past century, the Earth has increased in temperature by about .5 degrees Celsius and many scientists believe this is because of an increase in concentration of the main greenhouse gases: carbon dioxide, methane, nitrous oxide, and fluorocarbons. People are now calling this climate change over …showed first 75 words of 2729 total…

…showed last 75 words of 2729 total…emit greenhouse gases when burned. Coal emits high amounts of greenhouse gases, and the world may be supplied with enough of it to last over 100 years. Oil emits high amounts of greenhouse gases and also other types of air pollution harmful to the environment. The world's oil supply is also estimated to last over 100 years. Natural Gas is the lowest of all fossil fuels in greenhouse gas emissions; supplies are projected to last over 100 years.