You asked about feedback in the Arctic!

Here are some of the feedback mechanisms (both positive + and negative -) that play a part in determining the extent of the ice:

Temperature – as temperature rises so does surface radiation from the atmosphere into space.
(-)

Water vapour increase – a rise in temperature means that more water vapour is held in the atmosphere and this can act like a blanket causing further temperature increase and a greenhouse effect
(+)

Melting snow and ice – as ice and snow melts the surface becomes darker and absorbs more heat and melting takes place more quickly. It becomes more difficult for ice to form and snow to lie on the ground. The amount of radiation reflected is called the albedo of a surface, light colours reflect heat darker colours absorb it
(+)

Cloud cover – more water vapour leads to more clouds and so heat is trapped
(+)

Cloud cover – clouds have a light colour surface so more heat from the sun is reflected back to space
(-)

Carbon dioxide biofeedback – increased carbon dioxide increases growth of plants which fix carbon and reduce the amount of carbon dioxide
(-)

Iceberg formation (this had better be over the sea!) as temperature rises ice sheets break up creating large number of icebergs which increase reflection
(-)

Iceberg formation – if all the icesheets and icebergs melt then the surface is darker and will absorb more heat.
(+)

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