People love to debate whether CO2 leads or lags temperature, based on ice core graphs. The whole discussion is a farce. You can make CO2 appear to lead or lag by how you position the two graphs on the Y-axis.
CO2 appears to lag.
CO2 lags temperature rises in ice core data
Same graph with the Y-axis shifted. Now CO2 appears to lead.
CO2 changes as a response to ocean temperature. Warmer water (and beer) can hold less CO2, so it outages CO2 to the atmosphere. Cold water holds more CO2, and removes it from the atmosphere. This is one of the first things geology students learn.
via The Deplorable Climate Science Blog
April 6, 2019 at 10:10AM
Iowa Climate Science Education 
RE: “The whole discussion is a farce”
I don’t think that it is a “farce” to study this or ask the question.
It is a good question, and should be a good teaching moment for undergraduate studies of climate and climate cahnge.
Learning to articulate an answer might help students understand other graphed relationships.
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