“We have to get rid of the Medieval Warm Period!” – and they did take it out of all of their models. The models produce their famous “Hockey Stick” showing no global Warming or Cooling for 2000 years and predicting unlimited warming starting in the 1900s. No models needed? They blame human release of the trace gas CO2 – just 0.3% of Earth’s atmosphere.
Congressional Testimony on IPCC Global Warming Model