The Great Acceleration, post WWII humanity forcing the earth system, is charging ahead at exponential speed, including record temps year-after-year-after year-after year and on and on it goes, relentlessly.
Fatally, many parts of the world become uninhabitable with a 2°-4°C increase in temps, too hot for human physiology. Under the circumstances, the human body cannot get rid of bodily heat fast enough. People die. Will worldwide average temps increase by 2°-4° and if so, how fast? Nobody knows for sure, but the outlook is lousy.