Bingo.
Runaway heating caused by greenhouse gases increased cockpit temperature to the point where the pilot's sweaty hand slipped onto the button turning off the transponder and he was no longer able to maintain control of the yoke, causing the aircraft to pitch and climb to 45,000 ft.
Crazed by the temperature change, the pilots decided to make a dramatic statement against climate change "deniers" by plunging the aircraft into the Indian Ocean.
Lol