Contrarian - skeptic Sites:
As of 2007 there are still those who think there is no problem.
They point to normal waraming cycles (on the order of 100,000 years) and short term (decade) cycles in the north atlantic as the reason for the current changes. There are also warming effects from slight changes in the earth's orbit and solar cycles.

There are also natural checks and balances. e.g. More Carbon Dioxide (CO₂) has a fertilizing effect increasing the growth rate of plants which use CO₂ in photosynthesis; The increased plant growth absorbs more CO₂.

In a 2002 article "Climate Change: The Scientific and Historical Evidence:", Ken Schlichte stated:
"Several climatic phases during the last 11,000 years of the post-glacial period had temperatures which were warmer than present temperatures. These warmer temperatures have been correlated with increased sunspot activity and greater solar energy reaching the earth."

In the four interglacial warm periods prior to the present one the CO₂ never rose above 300 parts per million and CH₄ never went above 800 parts per billion. The current situation is that CO₂ is approaching 400 ppm and CH₄ is over 1700 ppb.

This is incontrovertible evidence that the present situation is not some natural phase but a massive climate change unprecedented in the past half million years.

Dr Gray, whose annual forecasts of the number of tropical storms and hurricanes are widely publicised, said a natural cycle of ocean water temperatures - related to the amount of salt in ocean water - was responsible for the global warming that he acknowledges has taken place.
He said his beliefs had made him an outsider in popular science.

However, he said, that same cycle meant a period of cooling would begin soon and last for several years.