Describe in one complete paragraph how oil and natural gas compare in terms of predicted supply and carbon dioxide emissions.

Natural resources such as oil that are as yet undiscovered are very difficult to predict or estimate; this creates huge uncertainty and large errors in even the most rigorous scientific efforts to predict future supply. Changes in oil drilling and discovery technology can and will completely change the eventual results in the search for undiscovered resources. The controversy lies in the desire to eliminate oil from the world's energy mix in order to prevent a perceived but uncertain risk of global warming and the desire to encourage the use of alternative energy in order to reduce that risk, even though so far no alternative energy source other than natural gas, coal, and nuclear energy has been able to compete with oil economically.