Hi there Brian!

First of all, my apologies for not answering back then.

Second, I encourage you the read of this study by NOAA that will explain you in a very detailed way why is the ocean heating if glacial water is melting.

https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content#:~:text=Rising%20amounts%20of%20greenhouse%20gases,over%20the%20past%20few%20decades.

Basically, as I state in this article, the ocean is absorbing monstrous amounts of heat from greenhouse gases at a higher rate than the ice is melting.

Thanks for asking again, hope this time I got the proper answer back to you!