I stumbled across a blog posting two days ago that was quite interesting: CO2, Temperatures, and Ice Ages. The analysis as presented contains some serious errors and misconceptions. I posted comments to that effect, but it seems that "skeptics" are intolerant of dissenting opinions, and my comments were never added to the blog. That's too bad, and a bit funny since this is behaviour of which climate scientists are often accused (just read the voluminous comments on the posting; the ones which were published of course). That does not make for good science. Well, good thing I have my own blog. Maybe the authors of the other blog will stumble across it. So, take a look at the blog posting, and then read my (re-created) comments below...
The analysis are presented is flawed. The method of aggregating the data over several glacial-interglacial cycles, apparently by averaging estimated temperature values and carbon dioxide values invalidates the analysis. The cycles cannot be treated as independent replicates of a single process; they are serially correlated data. Moreover, the lag between temperature change and carbon dioxide concentrations is well known, and has absolutely nothing to do with carbon dioxides effectiveness as a greenhouse gas nor its role in the Pleistocene cycles. Our current regime of glacial-interglacial cycles was initiated approximately 2.4 million years ago, and temperature and carbon dioxide are reasonably well synchronized in the early cycles. Carbon dioxide however is intimately connected with the rest of the carbon cycles, and is affected noticeably by other processes such as fluctuating rates of carbonate deposition (which itself is intimately tied to global oceanic temperatures), carbon burial rates in the deep ocean, orogenic (mountain-building) processes, and erosion. To look at the data in the simplistic manner in which you did, and within such a narrow window, cannot be used to support a hypothesis of no role for carbon dioxide in global warming. And, very importantly, the implication that somehow prior interpretations of these data have been contrived to support arguments of current anthropogenic warming is nonsense. These data have been known and studied for decades (no, it did not all begin with a few ice cores), well before we became generally aware of the issue of modern climate crisis.