Heres another angle for you to this question since you got me interested in playing with some math .specifically as it relates to the thermal expansion of water.
A temperature of 39.2 happens to be the point where water is the most dense (8.3452 lb/gallon). This also happens to be very close to what various scientists have determined is the overall average temperature of the oceans. Lets assume the ocean average temperature climbed 0.8 degree to an even 40 degrees F. At this temperature, the weight of the water would be 8.3450 lb/gallon or to put it another way, if a gallon of water was originally at 39.2 degrees F and it was allowed to warm to 40 degrees F, it would occupy a volume that is approximately 1.00002 x larger than its original volume of one gallon. The average depth of the ocean per NOAA is 12,080 feet. Lets say the entire ocean went up in temperature by 0.8 degrees F. This would increase the volume such that it would rise to an average height of 12,080.24 feet .. in other words, about 3 inches. This of course does not take into account that any rise in water would be spread out so it actually would be less.
Great analysis! How much would you have to tweak it, to account for the weird way water behaves between 32*F and 39.2*F? (Or whatever the corresponding figures are for sea water.)