While perusing the arguments on global warming, I happened across an article by Lorne Gunter that claims that “30 years of warmer temperatures go poof.” The article asserts that because recent global temperature anomalies went down to around the 0 mark, the temperature rise claimed by global warming researchers has been erased and all the global warming concerns have been much ado about nothing. To support this claim, Mr. Gunter uses this graph of this data from UAH:
The graph shows a “Global trend line” through the data, but this trend line is incorrectly drawn. See the graph below, made from the same data set:
In this second graph, a couple of things are clear. First, a correctly drawn trend line (in this case a 100-month moving average) shows a flattening but no significant decline. Second, the data in the second graph goes a few months further into 2008, where the temperature anomaly as risen, thus “regaining” about 20 years of the supposed 30 that were lost. The fallacy of the claim is thus clear: The temperature anomalies move in fairly wide swings. What is important is the rising mean temperature anomaly, not what the level is at any given month.
Mr. Gunter, unfortunately, is widely known for his outlandish claims. For a wonderfully detailed and well-linked analysis of other errors in the aforementioned Gunter article, see this greenfyre post.