Sea level the warmer water expands. For at least the last 100 years, sea level has been rising at an average rate of about per year. Most of this rise can be attributed to the increase in temperature of the sea and the resulting slight thermal expansion of the upper of sea water. Additional contributions, as much as one-quarter of the total, come from water sources on land, such as melting snow and glaciers and extraction of groundwater for irrigation and other agricultural and human uses. Pilots can estimate height above sea level with an altimeter set to a defined barometric pressure.
Sea level rise of the climate system. Of course, when the ocean gains heat the water expands and this represents a component of global sea-level rise. The thermal expansion of water increases with temperature and pressure of the water. Hence, cold Arctic Ocean water will expand less for a given increase in temperature compared to warm tropical water. Because different climate models have slightly different patterns of ocean heating, they do not agree fully on the predictions for the contribution of ocean heating on sea level rise. The large volume of ice on the Antarctic continent stores around 70% of the world's fresh