This effect raises the planet's natural average temperature from zero to about 60 degrees Fahrenheit. Without the effect, life would be impossible. This increase is directly linked to the burning of fossil fuels , the felling of forests and other human economic activities . Physics dictates that if you add more greenhouse gases to an atmosphere, you will trap more heat. The atmosphere of Venus is 97 percent carbon dioxide and its surface temperature is 900 degrees F. The Earth, however, has a complicated system in which heat is moved from the equator to the poles by winds and ocean currents .
Ecosystems interact with the atmosphere, adding and subtracting gases.
There are also naturally occurring swings and shifts in the system. One hundred million years ago, during the Mesozoic era , the average temperature was 20 degrees warmer and alligators lived in Alaska. All this makes divining what is happening to the climate a difficult exercise. As the researchers added carbon dioxide to the models, the temperature increased. F. The models, however, are only crude approximations of natural processes and there are some phenomena, such as cloud formation, that are poorly understood.