So, let's be honest the global climate is warmer and is going to be even much warmer no matter what. This causes glaciers to melt and more water to move to the oceans, and rising sea levels. This also cause the water in the ocean to be warmer, and as such when above 4°C it takes up more space due to dilatation. (Even though in the 0°C-4°C range it's the other way around).
Many people live at low altitude, and relocating all those people somewhere else would be an incredibly huge human population movement that is not really foreseeable. Also the sea level is used for measuring altitude, and if it rises more than 1m it will be very annoying to measure altitude, because we would have to know against which time period's sea level the altitude is measured.
Instead it seems like a better idea to somehow prevent the sea level from moving, even though the climate is warm. So far, warming has already been very observable, but sea levels doesn't seems to have risen much yet, so I have good hopes it's going to be possible. There is several ways this could be accomplished
- Use Netherlands-style dams to protect populations in low-altitude sea coasts
- Use evaporation so that water is in vapor form as opposed to liquid form (but this causes even more greenhouse effect!)
- Create artificial lakes everywhere possible to stock more water outside the sea. Also refill Aral Sea and Dead Sea who had been drying up.