sea ice is also responsible for another feedback mechanism through insulation

This would result in less sunlight being absorbed,and lead to a cycle of cooling,as in previous ice ages.Arctic sea ice is also responsible for another feedback mechanism through insulation.By forming a layer on the ocean's surface,the ice acts as a buffer between the frigid arctic air and the relatively warmer water underneath.But when it thins, breaks, or melts in any spot,heat escapes from the ocean,warming the atmosphere and causing more ice to melt in turn.Both of these are examples of positive feedback loops,not because they do something good,but because the initial change is amplified in the same direction.