In a previous post (part 3 of series is here), we examined the long-recorded (since 1659) central England temperature (CET) dataset and determined that the decade ending 2009 indeed had some of the warmest recorded temperatures for central England. But does that mean the decade also represents "unprecedented" warming? The preliminary analysis in the first post found very little to qualify as "unprecedented" temperature changes. What would a more detailed look find?
First, why do we even worry about "unprecedented" warming? As is well documented, global warming scientists associated with the IPCC and the publicly funded major climate research centers, along with the fanatical global warming activists, are claiming that human CO2 emissions since WWII are causing "unprecedented," exceptional, "tipping point" warming changes. The warming changes are so great, they say that..."The spectre of a 4C [degrees] warmer world, with alligators basking off the coast of Sweden..." Is there even a sliver of truth to these type of unprecedented claims? (click on images to enlarge)
In even more detail, the graph on the right looks at all the 60-year periods (starting with 1718, and ending with 2009, there are 292 periods shown) and right away one year stands out: 1938. Before any major human CO2 emissions, the 60-years ending in 1938 clocked a 2.76 degree temperature change. Towards the left side of the graph (the 18th century) there exist the majority of the largest temperature changes; whereas towards the right-side (the modern years) not too many large temperature changes. One should also note the incredible variability of temperatures throughout this extended range of 60-year periods, whether it be pre-1945 or post 1945 when the large human CO2 emissions began. Based on this graph, it would be fair to state that there was much greater variability prior to the era of "global warming" caused by CO2, which is directly opposite of what the consensus-favored, alarmist-loved AGW hypothesis proposes.
What does this say about the climate scientists, the politicians, and the activists stating that "unprecedented" warming change is happening due to human CO2? Well, nothing too good comes to mind other than thinking no sane person should ever believe a word they say, including, most recently, anything they say about melting glaciers. Amazing how one lie begets another.