Basically the bright white of ice in the arctic bounces sunlight off it really effectively. With less ice cover that sun light that used to be reflected away is now absorbed into the ocean, the hot water then releases heat that rises into the atmosphere.
alykat
commented
1 year ago
Check out slides 25 and 26 here: https://docs.google.com/presentation/d/1CH3HLokQZSBZ5MuE2eS7jhT3oqwXK-QlKZcXhOgK45k/edit#slide=id.g20fc77a20b2_0_132
Basically the bright white of ice in the arctic bounces sunlight off it really effectively. With less ice cover that sun light that used to be reflected away is now absorbed into the ocean, the hot water then releases heat that rises into the atmosphere.
Priority-wise, this ranks between #67 and #86