So, how much of an effect has that heat energy had on global sea ice. Well, let's have a look:
https://i2.wp.com/www.climate4you.com/images/NSIDC%20GlobalArcticAntarctic%20SeaIceArea.gif?ssl=1
It looks like the global sea ice extent has gone from 23,000,000 km^2 in 1979 down to 22,000,000 km^2...