Once more about Climate Change..

[Stewy]

(06-14-2017, 09:33 AM)Beaker Wrote: 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

I was speaking more of the Vostok Ice Cores specifically.  My understanding is that they don't use the methods above just just the Isotope ratios.  I misunderstood what you were trying to say.  I thought you were specifically speaking of the Vostok Ice Cores directly measuring CO2.  It would be interesting to see the direct measurements of CO2 vs. the estimated ones from other methods and compare the correlation.

As an aside:
I found no published articles linking all these methods, except a post from a noted "climate denier" (they basically just call him a geologist who makes blog posts.  I guess being a geologist makes you a climate denier) here - https://wattsupwiththat.com/2010/12/26/co2-ice-cores-vs-plant-stomata/

Without getting into the details, it appears very well written and covers most methods of CO2 analysis.  I don't have time to niggle the details of it, but he references many published articles and quotes many of the methods mentioned here and more.  Read it and decide for yourself.