The fact that CO2 in the atmosphere can cause warming is fairly settled. The question is, how much? Is CO2 the leading driver of warming over the past century, or just an also-ran?
Increasingly, scientists justify the contention that CO2 was the primary driver of warming since 1950 by saying that they have attempted to model the warming of the last 50 years and they simply cannot explain the warming without CO2.
This has always struck me as an incredibly lame argument, as it implies that the models are an accurate representation of nature, which they likely are not. We know that significant natural effects, such as the PDO and AMO are not well modelled or even considered at all in these models.
But for fun, lets attack the problem in a different way. Below are two global temperature charts. Both have the same scale, with time on the X-axis and temperature anomaly on the Y. One is for the period from 1957-2008, what I will call the “anthropogenic” period because scientists claim that its slope can only be explained by anthropogenic factors. The other is from 1895-1946, where CO2 emissions were low and whose behavior must almost certainly be driven by “nature” rather than man.
Sure, I am just a crazy denier, but they look really similar to me. Why is it that one slope is explainable by natural factors but the other is not? Especially since the sun in the later period was more active than it was in the earlier “natural” period. So, which is which?
Note that these two are straight cut and pasts from this graph: