Start here: https://skepticalscience.com/empirical-evidence-for-co2-enha...
Then proceed to intermediate and advanced. There are a TON of citations for your perusal. After your are done with that, the comments have some additional insights.
Have fun. This is quite the rabbit hole to dive into.
What was the CO2 ppm in the early Holocene? Why was the early Holocene so much warmer than today in spite of lower CO2 concentrations?
Early Holocene Temperature Oscillations Exceed Amplitude of Observed and Projected Warming in Svalbard Lakes
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...
Here's one of them from that page, chosen at random: https://www.tandfonline.com/doi/abs/10.5589/m04-044
A blog page linking a bunch of academic papers is as good as a hackernews comment linking a bunch of academic papers.
Your linked paper is about arctic temperatures, not global average temperatures.