Arctic sea ice: some scientists believe that the tipping point for the total loss of summer sea ice is imminent.
Greenland ice sheet: total melting could take 300 years or more but the tipping point that could see irreversible change might occur within 50 years.
West Antarctic ice sheet: scientists believe it could unexpectedly collapse if it slips into the sea at its warming edges.
Gulf Stream: few scientists believe it could be switched off completely this century but its collapse is a possibility.
El Niño: the southern Pacific current may be affected by warmer seas, resulting in far-reaching climate change.
Indian monsoon: relies on temperature difference between land and sea, which could be tipped off-balance by pollutants that cause localised cooling.
West African monsoon: in the past it has changed, causing the greening of the Sahara, but in the future it could cause droughts.
Amazon rainforest: a warmer world and further deforestation may cause a collapse of the rain supporting this ecosystem.
Boreal forests: cold-adapted trees of Siberia and Canada are dying as temperatures rise.
At my age I guess I'm lucky that I won't be around to see the shit hit the fan. There's no way we, as a fucked-up civilization, are going to be able to coordinate the development of a cooperative among nations to reduce/reverse global warming in a short enough time. Kids: you guys are screwed! Sorry.