> I believe the current best guess is around 2 degrees C by 2050, > In short, the world of 2050 looks like it'll be almost unnoticeable warmer

The 2 degree C by 2050 projection is for if we stabilize CO2 emissions by 2020. Otherwise the projection is up to 5 C.

For reference, during the last ice age the world was 5 C colder, and Chicago was under two miles of ice.