Many of the old threads here are about ice cores, isotopes, CO2 etc and the problems I see with those. There might be interest in a simple wrap up, what those problems are and rather than linking to old threads I think it might be an idea to use fresh words in an attempt to explain it. It may be known that the roots of the climate change hypotheses are in the research of paleo climate. See this elaborate work here. Especially: I intend to substantiate that the interpretation of indirect paleothermometers, especially isotopes to come to that conclusion is too simple.