A hot summer, plus drought in parts of the U.S. has renewed longstanding concerns about the atmospheric greenhouse effect and spawned both doomsday scenarios and legislative proposals to stabilize the climate. As usual, we are dealing with a mixture of fact and fancy. These molecules, because of their inherent radiative properties, enhance the normal greenhouse effect of the atmosphere that relies mainly on existing water vapor and carbon dioxide. The enhanced greenhouse effect should increase the earth's average temperature provided that all other factors remain the same . Aside from these facts, all the rest is theory at best, speculation at worst.
More research is needed on atmospheric physics and on modeling and atmosphere-ocean system.
More can observations over the past century positively disentangle climate fluctuation from long-term trends. Observed trends do not agree with expectation from greenhouse theory. A large temperature increase of 0.6 degree Celsius, or about 1 degree Fahrenheit occurred between 1880 and 1940, well before human influences were important. In fact SST exhausts are likely to counteract the damaging effects of CFCs on ozone. Only a few years ago, it was thought that acid rain could be reduced just by cutting smokestack emissions of sulfur dioxide.