First you should be aware "Years before Present" on those charts is usually from the 1950's.
Second the CO2 coalition is a fossil funded propaganda organisation that has no interest in the truth.

"The CO2 Coalition, a group that downplays the risks of climate change, has received significant funding from conservative foundations and energy industry figures. In its first four years, the coalition received over $1 million in contributions. Specific examples include the Charles Koch Institute donating $33,283 and the Lynde and Harry Bradley Foundation donating $50,000. The George C. Marshall Institute, the coalition's predecessor, received $662,409 from Koch foundations between 1997 and 2017"

Third more importantly this is the referenced work of Jouzel et all

(No doubt the CO2 coalition misrepresent their work)
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Orbital and Millennial Antarctic Climate Variability over the Past 800,000 Years

Jouzel, Jean; Masson-Delmotte, Valerie (2007): EPICA Dome C Ice Core 800KYr deuterium data and temperature esimates [dataset]. PANGAEA

https://doi.pangaea.de/10.1594/PANGAEA.683655with an abstract here:
https://www.science.org/doi/10.1126/science.1141038

We suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records.

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We know of the past history of glacial periods, there is nothing new about this. We know the cause: Milankovitch We have an idea of CO2 levels during these cycles and how this amplified (and at times suppressed) the effects.

The chart also shows the temperature difference between peak warm periods and the ice ages of around just 4C, which should put into context how extreme the warming of 1.5C post industrial is. What we can't see clearly from this chart is the rates of change which are in the order of thousands of years for these 4C changes.