Earth is now at the peak of one of its passing warm spells. It started in the 17th century when there was no industrial influence on the climate to speak of and no such thing as the hothouse effect. The current warming is evidently a natural process and utterly independent of hothouse gases.
The real reasons for climate changes are uneven solar radiation, terrestrial precession (that is, axis gyration), instability of oceanic currents, regular salinity fluctuations of the Arctic Ocean surface waters, etc. There is another, principal reason—solar activity and luminosity. The greater they are the warmer is our climate.
Astrophysics knows two solar activity cycles, of 11 and 200 years. Both are caused by changes in the radius and area of the irradiating solar surface. The latest data, obtained by Habibullah Abdusamatov, head of the Pulkovo Observatory space research laboratory, say that Earth has passed the peak of its warmer period, and a fairly cold spell will set in quite soon, by 2012. Real cold will come when solar activity reaches its minimum, by 2041, and will last for 50-60 years or even longer.
http://en.rian.ru/analysis/20080103/94768732.html
