Do not focus so much on the ice extent as a switch to something new, Arctic sea ice decline is more like the most visible positive feedback from a warmer climate. Things already change drastically and less sea ice will make those changes more pronounced.
Think of the satellite observed sea ice loss since 1979 as a transition modulated by the amount of greenhouse gases. General understanding currently is that the jet stream (the polar vortex) becomes more meandered, resulting in more stuck weather patterns - due to slower moving Rossby waves, since the polar vortex jets expand farther south.
Interactions also to consider, rate of iceberg and freshwater discharge from Greenland and river runoff in the Arctic circle, Ocean currents, waves and coastal erosion, salinity/halocline in the Arctic Ocean, NAO (see for instance this
https://twitter.com/climate_ice/status/1150478225241305088).
General trend is temperature gradient in the northern hemisphere weakens, with the exception in the Greenland regions (see for instance Cold Blob anomaly), OR where cold Arctic air dives farther south, meets much warmer air, storminess increases (
Hansen: Frontal (cyclonic) storms with hurricane-like winds, which, with rising seas and storm surges, will devastate thousands of coastal cities) The planet is on a path to a warmer state, losing polar ice.
Implications are far reaching, negative for crop cultivation, biodiversity, ecosystems, atmospheric chemistry, profound on every level, and likely will last roughly 200,000 to 1,000,000 years - based on past such events in geological times.
However, our civilization can modulate the extent of change still, and maybe we develop more sophisticated negative carbon technologies - but at this time things like carbon capture and storage are not economically viable, remain largely untested, containments may leak over time.