"shut the gate, that'll do me.So the earth sudenly has zones of different gravity and aggregate atmospheric pressure and water doesn't find it's own level ??
strewth, next you'll be telling me the water in your bath tub isn't level due to global warming.you are a waste of space, iggyland for you, goodbye."
Tide gauges[edit]Between 1993 and 2018, the mean sea level has risen across most of the world ocean (blue colors).[33]Another important source of sea-level observations is the global network of tide gauges. Compared to the satellite record, this record has major spatial gaps but covers a much longer period of time.[34] Coverage of tide gauges started primarily in the Northern Hemisphere, with data for the Southern Hemisphere remaining scarce up to the 1970s.[34] The longest running sea-level measurements, NAP or Amsterdam Ordnance Datum established in 1675, are recorded in Amsterdam, the Netherlands.[35] In Australia record collection is also quite extensive, including measurements by an amateur meteorologist beginning in 1837 and measurements taken from a sea-level benchmark struck on a small cliff on the Isle of the Dead near the Port Arthur convict settlement in 1841.[36]
This network was used, in combination with satellite altimeter data, to establish that global mean sea-level rose 19.5 cm (7+3⁄4 in) between 1870 and 2004 at an average rate of about 1.44 mm/yr (1.7 mm/yr during the 20th century).[37] Data collected by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia show the current global mean sea level trend to be 3.2 mm (1⁄8 in) per year, a doubling of the rate during the 20th century.[38][39] This is an important confirmation of climate change simulations which predicted that sea level rise would accelerate in response to climate change.
Some regional differences are also visible in the tide gauge data. Some of the recorded regional differences are due to differences in the actual sea level, while other are due to vertical land movements. In Europe for instance, considerable variation is found because some land areas are rising while others are sinking. Since 1970, most tidal stations have measured higher seas, but sea levels along the northern Baltic Sea have dropped due to post-glacial rebound.[40]
