This is a good overview on the growth of C02 in the atmosphere and the implications for climate change. Scientists have been able to measure the concentration change by comparing current measurements with measures of gas trapped in ice bubbles hundreds of thousands of years ago. There is no question that C02 concentration has increased dramatically since the industrial revolution. The great majority of climate scientists believe that the C02 acts as blanket which traps the heat in the atmosphere and that is responsible for the observed increase in average global temperature.
I suppose that everyone who believes that the earth is only 10,000 years old will question the data obtained from air bubbles that are 100,000 years old. The article also includes the comments of a scientist from MIT who questions the conclusions of the great majority of the scientific community on the warming effect of C02.
It was interesting, but rather discouraging, to read the comments by those who read the article. The author intended that the article alert the reader to the potential for catastrophic changes in the earth's climate. Some concluded that the evidence was ambiguous because there is always some dissent in the scientific community about any complex issue. It was very clear, however, that the science of climate change has become primarily an issue of political affiliation for many Americans.