The ice will melt. The sea will rise. Coastal cities will have only TWO choices - Build a dam against the rising sea or relocate the city inland. It will be impossible for a future President to ignore the coast of the USA.
Submarine sonar measurements indicate that ice thickness has decreased by 4 feet over the last 40 years. Satellite measurements indicate that the area of ice cover has decreased by 7% per decade over the last 30 years.