Last ice age was lethal to mammals in N America. Midwest was all covered with glacial ice higher than the tallest building in world ( 2,722 ft tall Burj Khalifa in Dubai, UAE).
If man can cause 0.01% more global warming than which the Sun causes due to its cycles, that would mean next ice age will be postponed by about 3 days. Extra 3 days for many mammals to enjoy life.
Where Chicago sits, had over a mile of ice on top of it.