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certain_people t1_ja5zi0n wrote

The dating doesn't give you the gas levels or temperatures.

Instead separate samples are taken through an ice core, or a sediment core, or a rock sequence. Separate analyses are done on the samples to measure the greenhouse gas levels, temperatures, and ages.

Sediment samples might have carbon isotopes measured as a proxy for CO2, ice cores might have gas bubbles analysed, there's a whole suite of different measurements possible. The dating is totally separate and just puts some age pins on those measurements.


clamshellconundrum t1_ja6apou wrote

And those samples are compared to samples of similar age throughout the world to get a clear picture of global atmosphere levels during any one time.


SupernovaTheGrey t1_ja8hdwv wrote

How do they account for dissolved C02 and CO2 offgassing into the bubbles over time?


certain_people t1_ja8jhly wrote

Basically there are tests they can do to determine if that has happened, and where it has that data is dumped.