How has the carbon dioxide levels been affected?
A major player in the controversy is the amount of carbon dioxide in the air. (See carbon dioxide graph.) Plants use carbon dioxide and give off oxygen as a “waste product.” Animals, on the other hand, use this discarded oxygen in respiration and give off carbon dioxide as a “waste product.” The graph shows that our atmosphere has increased about 100 parts per million in the last 250 years, mostly the years since the Industrial Revolution. The increase might be even greater if it was not for the phytoplankton in the oceans using some of the excess carbon dioxide. Is there a relationship between increased burning of fossil fuels and the increase in temperature and carbon dioxide? Most scientists who have studied the phenomenon would say yes. However, there are those who say the increase is not caused by mankind’s activity but by a natural swing in environmental norms. Looking back in geological time at the cycles that have occurred before, there have been times when temperatures on the
