If computer models can be shown to accurately represent past climates, they can then be used to predict future climates. With increasing confidence, researchers can use the simulations to determine what will happen given various scenarios involving increasing levels of greenhouse gases. Recent studies have produced some surprising results. Climatologists once thought global changes in temperature occurred over many thousands of years. They are now finding that significant change can occur over much shorter periods, Cravens said.
Many scientists now believe climate can change dramatically over just one decade.
The Associated Press reported hundreds of scientists in a recent United Nations sponsored study predict the earth's mean temperature will increase by between 3 and 11 degrees Fahrenheit over the next 100 years. A change of 7 to 10 degrees is the equivalent of making Montreal feel like Miami, Cravens said.