Don't some scientists dispute the greenhouse effect?

Yes. Some argue that globe temperatures might stabilize or even decrease as the concentration of greenhouse gases increases. A hotter atmosphere, they say, would increase evaporation, sending u more water vapor that could condense into clouds. The increased cloud cover might reflect so much unlight that it would slow the rate at which the earth would be heated. Others contend that the increased evaporation would produce more rainfall. As it fell, the rain would cool the land and subsequently cool the air over the land.

Finally some researchers believe the geological record shows that large fluctuations in global temperature have always occurred independently of human activity, never as a result of it. these fluctuations are caused by such unpredictable event as variations in solar radiation, shifts in the earth's orbit and in ocean currents, meteoric activity, and volcanic eruptions.