There are a few important processes that cause observed sea level rise. In order, with IPCC estimates on the magnitude: - The ocean expands as it warms, which

There are a few important processes that cause observed sea level rise. In order, with IPCC estimates on the magnitude: - The ocean expands as it warms, which is the single largest contributor right now (1.1 mm/yr). - Mountain glaciers are next, as they are very rapidly melting (0.76 mm/yr, with large uncertainties). - Then Greenland, as mentioned by another poster (0.43 mm/yr).