Once more about Climate Change..

[Beaker]

(06-13-2017, 09:55 PM)Stewy Wrote: So while it is absolutely true that CO2 levels are high, it is also true that things like the Vostok Ice Cores do not measure CO2 from the past, but measures O18/O16 ratios which are a temperature indicator, the levels of past CO2 are estimates based upon those temperatures suggested by the O Isotope ratios.  So we must rely upon a foundation of Geology which is Uniformitarianism or "the Present is the key to the past" to make estimates of CO2 levels, but they are NOT direct measurements. 

Isotope ratios are indeed one method, but direct measurement of CO2 levels trapped in bubbles in the ice is used also. One example of this is at the Bern Labs where they crush samples under vacuum conditions and then measure the amounts of C02 via gas chromatography. This is also done at the Grenoble labs (to provide more than one example). So to say that direct measurements of CO2 do not occur and all we are going by are indirect estimates is not the case. The fossilized stomata method is an indirect estimate based upon correlation. That is one of the methods used to take us farther back than the ice cores.
This is one of the sites that Trump is cutting off. You can see their notice at the top of the page. But it gives more detail to the outline I provided above:
http://cdiac.ornl.gov/trends/co2/ice_core_co2.html