All of the evidence shows none of the natural cycles which have caused warming in the past such as solar variability are responsible.
However – one variable which is known to cause planetary warming – ie. an increase in the concentration of atmospheric CO2 IS occurring. And the increase in atmospheric CO2 is being cased by emissions from fossil fuel burning.
It is pretty stupid to ignore the obvious cause and try to pretend that some mysterious unknown “natural cycle” is responsible.
If you saw somebody get hit by a bus – would you be thinking that that persons death was caused by some unseen “natural cycle”? Or do you think perhaps that being run over by a bus might have something to do with it?
We know that atmospheric CO2 is increasing due to anthropogenic emissions.
We know that the concentration of atmospheric CO2 is directly related to global temperature.
We know that the global temperature has been increasing.
We know that there has been a drop in the outgoing radiation from the earth in the wavelength bands that CO2 and CH4 absorb radiation.
It is pretty stupid to go trying to attribute the observed temperature increase to some mysterious, unknown “natural cycle” when the evidence is overwhelming to the contrary.
Source: http://answers.yahoo.com/question/index?qid%3D20100510194747AAMuSrZ