The only valid answer science can currently give is "insufficient data". There is WAY too much of the ocean floor unmapped to provide a statistically valid data set".
Yet we are told that the science is settled.
One aspect of global warming that always troubles me, is that, even if we accept the premise than man’s activity affects things, that there are obvious natural cycles occurring which are beyond our control or understanding.
For example, there have been numerous ice ages in earth’s history. Chicago was buried under a mile of ice during the last ice age. All that ice melted because of some natural climate changes which caused warming and melting. That ice didn’t melt because Cro Magnon man had coal fired power plants.