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Over geologic time sea level has fluctuated by more than 300 metres, possibly more than 400 metres. The main reasons for sea level fluctuations in the last 15 million years are the Antarctic ice sheet and Antarctic post-glacial rebound during warm periods. The current sea level is about 130 metres higher than the historical minimum.
The sea-level curve (also known as the eustatic curve) is the representation of the changes of the sea level relative to present day mean sea level as gleaned from the stratigraphic record 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 ...
Earth's radius at sea level is 6,378.137 km (3,963.191 mi) at the equator. It is 6,356.752 km (3,949.903 mi) at the poles and 6,371.001 km (3,958.756 mi) on average. [ 4 ] This flattened spheroid, combined with local gravity anomalies, defines the geoid of the Earth, which approximates the local mean sea level for locations in the open ocean.
With 0.5 m sea level rise, a current 100-year flood in Australia would occur several times a year. In New Zealand this would expose buildings with a collective worth of NZ$12.75 billion to new 100-year floods. A meter or so of sea level rise would threaten assets in New Zealand with a worth of NZD$25.5 billion.
Older Peron warm and wet, global sea levels were 2.5 to 4 meters (8 to 13 feet) higher than the twentieth-century average 3900: 5.9 kiloyear event dry and cold. 3500: End of the African humid period, Neolithic Subpluvial in North Africa, expands Sahara Desert 3000 – 0: Neopluvial in North America 3,200–2,900: Piora Oscillation, cold ...
These data are compared to the reference (or datum) level usually called mean sea level. [3] While tides are usually the largest source of short-term sea-level fluctuations, sea levels are also subject to change from thermal expansion, wind, and barometric pressure changes, resulting in storm surges, especially in shallow seas and near coasts.
The global average and combined land and ocean surface temperature, show a warming of 1.09 °C (range: 0.95 to 1.20 °C) from 1850–1900 to 2011–2020, based on multiple independently produced datasets. [8]: 5 The trend is faster since the 1970s than in any other 50-year period over at least the last 2000 years. [8]: 8 .
Plotted is the extinction intensity, calculated from marine genera. The Late Devonian extinction consisted of several extinction events in the Late Devonian Epoch, which collectively represent one of the five largest mass extinction events in the history of life on Earth. The term primarily refers to a major extinction, the Kellwasser event ...