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Responding to the CO2 Coalition's "Fact #15" on Eemian Warmth

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CO2 Coalition 's " Fact #15 " wants us to believe that temperatures even 8°C warmer than today would be just fine for humanity. In order to make that claim, they need to perform a few tricks. The first trick is to make that 8°C Greenland temperatures instead of global temperatures. The second trick is to redefine  "today" as "the mean of the past millennium." Here's how they say it The results revealed that the Eemian interglacial warm period, between 130,000 and 115,000 years ago, was much warmer than previously thought. In fact, it was, 8°C (14.4°F) warmer than today. Their source for this is Dahl-Jensen 2013[1], which details the results of the new North Greenland Eemian (NEEM) Ice Drilling ice core. The paper concludes: NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer i...

Review of Inconvenient Facts, Part 2 - Temperature

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Pages 2K Reconstruction of Global Temperatures Replicating MBH98/99 In a previous post , I wrote an initial review of Gregory Wrightstone's Book, Inconvenient Facts. We began to see that Mr. Wrightstone's book was pretty low on facts and high on convenience - that is, Wrightstone's claims would be very convenient for us if we believe him, since if there is no problem, we have no compelling reason to fix a non-existent problem. That post covered only the first two chapters of his book. Chapter 3 is supposed to contain more inconvenient facts about temperature, but what we get is a lot of misinformation about temperature based on 1) the rejection of scientific evidence about temperature and 2) the confusion of global temperatures with local temperatures, including 2a) Central England and 2b) the Greenland summit, and 3) the misuse of a terrible proxy reconstruction. Confusion About Proxies Mr. Wrightstone (somewhat) correctly observes that, if global (or Northern Hemisphere)...

Misuse of the GISP2 Ice Core

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Central Greenland Temperature Reconstruction In 2000, R. B. Alley published the results of a proxy analysis of a single ice core in Central Greenland as part of the GISP2 project.[1] The resulting time series reconstructs local temperature fluctuations over the last 50,000 years. The graph above includes only the last 15,000 years; you may see versions of this graph showing the last 10,000 or 12,000 years. The proxy reconstructs temperatures at the Greenland Summit (the GISP2 project) using the ratio of two different oxygen isotopes: 18O and the more abundant 16O. Lower the 18O/16O ratio indicates lowers temperatures, since as temperatures decrease, a more 18O precipitates out at lower latitudes, making the 18O/16O ratio smaller over Greenland. Alley's time series ends 95 years BP, or 95 years before 1950, so the last data point in this analysis is 1855. The IPCC and other organizations are interested in modern warming frequently consider modern warming as measured against the 1850...