To tell you the truth I think the information in your post is as much theoretic made up BS as the other side. I want to see the thermometers they found frozen in those ice cores.
They use the ratio of oxygen isotopes in the water frozen into the ice layers. The heavier oxygen isotope, Oxygen-18, does not evaporate as water (H2O-18) from the ocean surface as normal oxygen, Oxygen-16, water (H2O-16). As temperature increases more H2O-18 evaporates and the ratio of H20-18 to H20-16 in the ice changes. The ratio has been calibrated to temperature and is used as an estimate of surface air temperature. It is not perfect, but it is the best estimation tool at present. The time is determined by the lines in the core produced by differences in winter and summer.
Then you ignore the very core of what is science: That it is possible to determine by - often very, very - ingenious means what has taken place in the past, and what happens in the present, for that is fact, but it is impossible to measure (collect data of) what takes place in the future.
"Climate" is not some law of physics, as gravity or electromagnetic forces, that is well understood and defined so that we can say that if we drop a gold sphere off of the top of the Washingtom Monument tomorrow or in ten years hence it will takes x seconds to reach the ground.
"Climate" can be roughly described by an incredibly complex set of parameters that wholly relies on actual measurement. You cannot determine with any precision the climate of the future. See the first paragraph.
PS: Computer models simply are not science. Perhaps that is a point most do not understand.