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Instead of using actual CO2 measurements made prior to 1959, the IPCC uses proxy measurements from air bubbles trapped in ice cores -- even though these are not accurate for CO2 measurements.
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Some scientists believe ice core measurements understate CO2 as one goes back in time studying deeper and deeper ice (the deeper the ice, the more pressure it is under, the more CO2 levels are understated) … so the measurement errors automatically create a rising CO2 trend over time !
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Pettenkofer method measurements are ignored by the IPCC simply because they do not show a smooth rising trend in the past two centuries (see chart below).
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Infra-red spectroscopy measurements of CO2, made at Mauna Loa, Hawaii since 1959, shows CO2 levels today that are similar to the 1935 to 1945 CO2 levels from Pettenkofer measurements.
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The IPCC makes no attempt to explain this difference, or why they ignore real-time CO2 measurements in favor of inaccurate proxy measurements.
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The IPCC ignores real time Pettenkofer CO2 data, the most accurate CO2 measurements before 1959.
The IPCC also ignores NASA weather satellite temperature data, the most accurate average temperature measurements since 1979.
An organization like the IPCC that ignores the best available CO2 level and average temperature data is practicing politics, not science !
Note: gray on the chart is the estimated error range of the Pettenkofer data::
