I looked at several sources. Here is what I found.
There is a consencus that in the last 150 years there has been in increase in average global temprature of about .5 degrees centegrate, 2005 being either the warmest or in the top two with 1998.
Carbon dioxide has had about a 40% to 50% increase since the industrial age. The 2005 measurement was 375 ppm, the 1960 measurement was 313 ppm. The pre-industrial range has been between 180 ppm and 300 ppm.
Methane gas has had about a 150% increase since the industrial age. Methane occurs from the fermantation of organic matter. Currently it measures about 1800 ppb, compared to about 1,000 ppb pre-industrial age.
Without greehouse gases the earth would be on average 30 degree centegrate colder. However, no one has shown a quantitative link between carbon dioxide or greenhouse gases with temprature sensitivity due to other variables affecting the earths temprature.
There appears to be a legitimate debate on projected temprature increases (the assumptions used) and methods to control the increase in greenhouse gases.
For the naturalists - There was the Permian Triassic extinction event that wiped out about 70% of all land animals about 251 million years ago. One theory is that a release of massive amounts of methane gas from the oceans was the cause of about a 5 degree centegrate increase in the earths temprature. Methane gas by some is considered to have a much larger relative impact on global warming than other greenhouse gases. Whatever the cause, the earth's temprature went back into balance.
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