When will global temperature reach equilibrium between melting ice and evaporating water.

Looking at the global warming postulation/theory (I cannot tell which yet), I note that the earth's surface is 71% water and 10% land. The amount of ice not floating in the water covers an estimated 10% of the land, making the comparative amounts of ice and water in the ratio of 71/2.9 (10% of 29%). Now I will conjecture that all of the ice on earth lies at latitudes greater than 60°, where solar radiation is reduced to the Cosine of the latitude which drops to ½ at that point. So calculating the radiation from the Sun, the liquid oceans are receiving 49 times as much radiation as the ice on the earth. Now the Heat of fusion of water is 80 calories per cu. cm. and the heat of vaporization is between 540 and 580 calories per cu. cm., depending on the water temperature. Lets call the average at 560 because it conveniently makes the ration 560/80 to be exactly 7 times the energy to vaporize the liquid phase than to melt the solid phase, which certainly mitigates the 49 times as much water exposed to evaporation as there is ice exposed to melting. The net difference is that the oceans should be evaporating 7 times as much liquid as the ice is melting into liquid, and therefore, Sea level should be dropping.

Since I believe that Sea Level is empirically measured rather than calculated, I am inclined to accept the claim of rising sea level, and that the reason that more ice is melting than ocean is evaporating is that the median temperature around the world is so much closer to 0°C. than it is to 100° C. I read somewhere on the Internet that the median temperature around the world is 52°F. which is 11.11°C. If that is the reason that sea level is rising rather than falling, it follows that there must be some temperature at which the melting and evaporating amounts reach some equilibrium. That temperature should be somewhere between 0° and 100°C, but closer to 0°C by virtue of the argument made in my first paragraph. I don't know how to calculate that equilibrium temperature but as an educated guess will seek a temperature that is 7 times closer to 0° as it is to 100°. That calculation, X = (100-X)/7 produces a temperature of 12.5°C or 54.5°F., not at all that far from the current temperature. Please, someone help me with a better calculation of the thermal equilibrium point or tell me where my reasoning is wrong. Likewise, if the increased volume of ocean water is due to thermal expansion, there still should be an equilibrium point at which evaporation matches thermal expansion plus melting.