This is an excellent article and warrants saving and reading.
Carbon Dioxide or Solar Forcing?
By: Nir J. Shaviv
Natural or Anthropogenic? Which mechanism is responsible for global warming over the 20th century? According to the common perception, the temperature over the 20th century has been warming, and it is mostly anthropogenic in origin, with greenhouse gases (GHGs) being the dominant driver. Others, usually called "skeptics", challenge this view and instead claim that the temperature variations are all part of natural variability.
As I try to demonstrate below, the truth is probably somewhere in between, with natural causes probably being more important over the past century, whereas anthropogenic causes will probably be more dominant over the next century. Following empirical evidence I describe below, about 2/3's (give or take a third or so) of the warming should be attributed to increased solar activity and the remaining to anthropogenic causes.
Like many others, I was personally sure that CO2 is the bad culprit in the story of global warming. But after carefully digging into the evidence, I realized that things are far more complicated than the story sold to us by many climate scientists or the stories regurgitated by the media. In fact, there is much more than meets the eye.