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 curve data, and hence not independently verifiable. Because of this, there were later efforts to establish a sea-level curve based on non-commercial data. In 1987–1988 a revised eustatic sea-level curve for the Mesozoic and Cenozoic eras was published, now known as the Haq sea-level curve, in reference to the Pakistani-American Oceanographer Bilal Haq. Sea-level curve The sea-level curve is the representation of the changes of the sea level throughout the geological history. The first such curve is the Vail curve or Exxon curve. The names of the curve refer to the fact that in 1977 a team of Exxon geologists from