What would the earth be like if the solid phase of water ice did not float in the liquid phase?

Answer 1

Lets model your situation with every other variable kept constant. Basically, in this world, ice sinks water. We need to model for 2 bodies of water. Shallow bodies, like lakes and deep bodies like oceans. I'm going to ignore active volcanic activity. I'm also going to assume cases where the ambient temperature is sufficiently low enough to form ice. In our world, ice acts as incredibly good insulating layer(not much movement on the molecular level that allows the conduction of heat) due to its hydrogen and covalant bonding. Basically, it forms a packed, but evenly spaced, structure in which little moves. Its low density also inhibits the conduction of heat as nearby molecules are held at "arms length". In the case of a shallow body of water in the case of this world where ice sinks, we can also assume that geothermal and pressure heating due to depth is negligible. Hence, lacking this highly insulating layer, the warm water which rises would cool rapidly till freezing point, at which it would sink. And since cold water stays at the bottom, the ice would be melting very slowly. Therefore, ice builds from the bottom up and at a much faster rate than it would in our world. In a deeper body of water, its slightly harder to model due to geothermal heating. Very deep bodies of water might be able to retain some liquid water. In the case above, the ice sinks and it remains cold wherever it sinks to. However, when pressure and geothermal heating build up, the ice might be able to melt as it decends. In those places, there would be ice falling in the water, but there would not be any liquid ice floating on the surface. You basically get underwater snow. Fine snow if its not that cold/turbulent and a blizzard if it is. Lastly, im going to model your cup of soft drinks in which they love overfilling with ice, depriving you of the precious drink you pay for(at least over here). So here, your ice will stay at the bottom, which is already cold. Then since the top is warm and does not circulate down, it stays warm at the top but cold at the bottom. Hence, if u drink from the bottom, it will be colder than usual. But the average temperature will be higher. Also, assuming the same drinking rate, you will have more ice remaining and more of an incentive to ask for refunds, which you will not get anyway.