'Mann's Hockey Stick shows that temperatures have risen about half a degree over the last 1000 years. Let's assume for the sake of argument that he is correct. Ice core data shows that temperatures regularly vary by about 12C,and that current CO2 levels are unprecedented for hundreds of thousands of years'
Climate activists don't like seeing heatwaves in the 1930s hotter by far than any heatwaves today according to Biden's EPA. So a concerted effort is being made led by Prof. Andrew Deslser, to revise the inconvenient data & cool the past compared to today's temps. The climate campaigners erased the Medieval Warm Period previously and they erased the temperature pause.