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Encyclopedia > Sea level rise
Sea level measurements from 23 long tide gauge records in geologically stable environments show a rise of around 20 centimeters per century (2 mm/year).
Changes in sea level since the end of the last glacial episode

Sea-level rise is an increase in sea level. Multiple complex factors may influence this change. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... This tidal gauge is ready to be installed underwater in a marina. ... Image File history File links Post-Glacial_Sea_Level. ... Image File history File links Post-Glacial_Sea_Level. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ...


Sea-level has risen about 130 metres (400 feet) since the peak of the last ice age about 18,000 years ago. Most of the rise occurred before 6,000 years ago. From 3,000 years ago to the start of the 19th century sea level was almost constant, rising at 0.1 to 0.2 mm/yr.[1] Since 1900 the level has risen at 1 to 2 mm/yr; since 1993 satellite altimetry from TOPEX/Poseidon indicates a rate of rise of 3.1 ± 0.7 mm yr–1 [2]. It is very likely that 20th century warming has contributed significantly to the observed sea-level rise, through thermal expansion of sea water and widespread loss of land ice [3]. Church and White (2006) found a sea-level rise from January 1870 to December 2004 of 195 mm, a 20th century rate of sea-level rise of 1.7 ±0.3 mm per yr and a significant acceleration of sea-level rise of 0.013 ± 0.006 mm per year per yr. If this acceleration remains constant, then the 1990 to 2100 rise would range from 280 to 340 mm,[2]. Sea-level rise can be a product of global warming through two main processes: expansion of sea water as the oceans warm, and melting of ice over land. Global warming is predicted to cause significant rises in sea level over the course of the twenty-first century. This article is about the unit of length. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ... For other uses, see Satellite (disambiguation). ... The TOPEX/Poseidon satellite altimeter is a science project to measure the ocean surface topography. ... In physics, thermal expansion is the tendency of matter to increase in volume or pressure when heated. ... Sea water is water from a sea or ocean. ... This article is about water ice. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... In physics, melting is the process of heating a solid substance to a point (called the melting point) where it turns into a liquid. ...

Contents

Overview of sea-level rise

Local and eustatic sea level

Water cycles between ocean, atmosphere, and glaciers.

Local mean sea level (LMSL) is defined as the height of the sea with respect to a land benchmark, averaged over a period of time (such as a month or a year) long enough that fluctuations caused by waves and tides are smoothed out. One must adjust perceived changes in LMSL to account for vertical movements of the land, which can be of the same order (mm/yr) as sea level changes. Some land movements occur because of isostatic adjustment of the mantle to the melting of ice sheets at the end of the last ice age. The weight of the ice sheet depresses the underlying land, and when the ice melts away the land slowly rebounds. Atmospheric pressure, ocean currents and local ocean temperature changes also can affect LMSL. Diagram of water cycle with emphasis on glacial mass balance. ... Diagram of water cycle with emphasis on glacial mass balance. ... Animated map exhibiting the worlds oceanic waters. ... Air redirects here. ... This article is about the geological formation. ... The Ocean Waves, see I Can Hear the Sea Ocean waves Ocean surface waves are surface waves that occur in the upper layer of the ocean. ... This article is about tides in the Earths oceans. ... Isostasy is a term used in Geology to refer to the state of ice above stasy and is angravitational equilibrium between the Earths lithosphere and asthenosphere such that the tectonic plates float at an elevation which depends on their thickness and density. ... Earth cutaway from core to exosphere. ... An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² (19,305 mile²).[1] The only current ice sheets are in Antarctica and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much... Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ... Ocean currents (1911) Ocean currents (1943) An ocean current is any more or less continuous, directed movement of ocean water that flows in one of the Earths oceans. ... For other uses, see Temperature (disambiguation). ...


Eustatic” change (as opposed to local change) results in an alteration to the global sea levels, such as changes in the volume of water in the world oceans or changes in the volume of an ocean basin. It has been suggested that this article or section be merged with sea level. ... Oceanic basin can also refer to the river basins flowing into an ocean. ...


Short term and periodic changes

There are many factors which can produce short-term (a few minutes to 14 months) changes in sea level.

Short-term (periodic) causes Time scale
(P = period)
Vertical effect
Periodic sea level changes
Diurnal and semidiurnal astronomical tides 12–24 h P 0.2–10+ m
Long-period tides    
Rotational variations (Chandler wobble) 14 month P
Meteorological and oceanographic fluctuations
Atmospheric pressure Hours to months –0.7 to 1.3 m
Winds (storm surges) 1–5 days Up to 5 m
Evaporation and precipitation (may also follow long-term pattern) Days to weeks  
Ocean surface topography (changes in water density and currents) Days to weeks Up to 1 m
El Niño/southern oscillation 6 mo every 5–10 yr Up to 0.6 m
Seasonal variations
Seasonal water balance among oceans (Atlantic, Pacific, Indian)    
Seasonal variations in slope of water surface    
River runoff/floods 2 months 1 m
Seasonal water density changes (temperature and salinity) 6 months 0.2 m
Seiches
Seiches (standing waves) Minutes to hours Up to 2 m
Earthquakes
Tsunamis (generate catastrophic long-period waves) Hours Up to 10 m
Abrupt change in land level Minutes Up to 10 m

The Chandler wobble is a small variation in Earths axis of rotation, discovered by American astronomer Seth Carlo Chandler in 1891. ... ... “Vaporization” redirects here. ... For discussion of land surfaces themselves, see Terrain. ... For other uses, see Density (disambiguation). ... Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ... The Southern Oscillation refers to an oscillation in air pressure between the southeastern and southwestern Pacific waters. ... This article or section is in need of attention from an expert on the subject. ... For other uses, see River (disambiguation). ... Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ... Annual mean sea surface salinity for the World Ocean. ... A seiche (pronounced saysh) or an underwater wave is a standing wave in a body of water. ... This article is about the natural seismic phenomenon. ... For other uses, see Tsunami (disambiguation). ...

Longer term changes

Sea-level changes and relative temperatures

Various factors affect the volume or mass of the ocean, leading to long-term changes in eustatic sea level. The two primary influences are temperature (because the volume of water depends on temperature), and the mass of water locked up on land and sea as fresh water in rivers, lakes, glaciers, polar ice caps, and sea ice. Over much longer geological timescales, changes in the shape of the oceanic basins and in land/sea distribution will affect sea level. Sea level history during late Quaternary, with corresponding relative temperature. ... Sea level history during late Quaternary, with corresponding relative temperature. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Mass (disambiguation). ... For the village on the Isle of Wight, see Freshwater, Isle of Wight. ... For other uses, see Lake (disambiguation). ... This does not cite any references or sources. ... An icebreaker navigates through young (1 year old) sea ice Nilas Sea Ice in arctic Sea ice is formed from ocean water that freezes. ... The table and timeline of geologic periods presented here is in accordance with the dates and nomenclature proposed by the International Commission on Stratigraphy. ...


Observational and modelling studies of mass loss from glaciers and ice caps indicate a contribution to sea-level rise of 0.2 to 0.4 mm/yr averaged over the 20th century. A view down the Whitechuck Glacier in North Cascades National Park in 1973 The same view as seen in 2006, where this branch of glacier retreated 1. ...


Glaciers and ice caps

Each year about 8 mm (0.3 inch) of water from the entire surface of the oceans goes into the Antarctica and Greenland ice sheets as snowfall. If no ice returned to the oceans, sea level would drop 8 mm every year. Although approximately the same amount of water returns to the ocean in icebergs and from ice melting at the edges, scientists do not know which is greater — the ice going in or the ice coming out. The difference between the ice input and output is called the mass balance and is important because it causes changes in global sea level. This page is about the form of precipitation. ... For other uses, see Iceberg (disambiguation). ... Global glacial mass balance in the last fifty years, reported to the WGMS and NSIDC. The downward trend in the late 1980s is symptomatic of the increased rate and number of retreating glaciers. ...


Ice shelves float on the surface of the sea and, if they melt, to first order they do not change sea level. Likewise, the melting of the northern polar ice cap which is composed of floating pack ice would not significantly contribute to rising sea levels. Because they are fresh, however, their melting would cause a very small increase in sea levels, so small that it is generally neglected. It can however be argued that if ice shelves melt it is a precursor to the melting of ice sheets on Greenland and Antarctica[citation needed]. Ross Ice Shelf An ice shelf is a thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. ... For other uses, see North Pole (disambiguation). ... An ice cap is a dome-shaped ice mass that covers less than 50,000 km² of land area (usually covering a highland area). ... An icebreaker navigates some through young (1 year) sea ice Sea ice is formed from ocean water that freezes. ...

  • Scientists lack knowledge of changes in terrestrial storage of water. Between 1910 and 1990, such changes may have contributed from –1.1 to +0.4 mm/yr.
  • If small glaciers and polar ice caps on the margins of Greenland and the Antarctic Peninsula melt, the projected rise in sea level will be around 0.5 m. Melting of the Greenland ice sheet would produce 7.2 m of sea-level rise, and melting of the Antarctic ice sheet would produce 61.1 m of sea level rise.[3] The collapse of the grounded interior reservoir of the West Antarctic Ice Sheet would raise sea level by 5-6 m.[4]
  • The snowline altitude is the altitude of the lowest elevation interval in which minimum annual snow cover exceeds 50%. This ranges from about 5,500 metres above sea-level at the equator down to sea level at about 70° N&S latitude, depending on regional temperature amelioration effects. Permafrost then appears at sea level and extends deeper below sea level polewards.
  • As most of the Greenland and Antarctic ice sheets lie above the snowline and/or base of the permafrost zone, they cannot melt in a timeframe much less than several millennia; therefore it is likely that they will not, through melting, contribute significantly to sea level rise in the coming century. They can, however, do so through acceleration in flow and enhanced iceberg calving.
  • Climate changes during the 20th century are estimated from modelling studies to have led to contributions of between –0.2 and 0.0 mm/yr from Antarctica (the results of increasing precipitation) and 0.0 to 0.1 mm/yr from Greenland (from changes in both precipitation and runoff).
  • Estimates suggest that Greenland and Antarctica have contributed 0.0 to 0.5 mm/yr over the 20th century as a result of long-term adjustment to the end of the last ice age.

The current rise in sea level observed from tide gauges, of about 1.8 mm/yr, is within the estimate range from the combination of factors above[5] but active research continues in this field. The uncertainty in the terrestrial storage term is particularly large. This article is about the geological formation. ... Location of the polar regions Northern Hemisphere permafrost (permanently frozen ground) in purple. ... Antarctic Peninsula map Booth Island and Mount Scott flank the narrow Lemaire Channel on the west side of the Antarctic Peninsula. ... Outline Map of Greenland with ice sheet depths. ... A satellite composite image of Antarctica The Antarctic ice sheet is the largest single mass of ice on Earth. ... The West Antarctic Ice Sheet (WAIS) blankets the continent of Antarctica west of the Transantarctic Mountains, covering the area called Lesser Antarctica. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. ... There are very few or no other articles that link to this one. ... Altitude is the elevation of an object from a known level or datum. ... This article is about the geographical term. ... In geology, permafrost or permafrost soil is soil at or below the freezing point of water (0°C or 32°F) for two or more years. ... These pages contain the trends of millennia and centuries. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ... Runoff flowing into a stormwater drain Surface runoff is water, from rain, snowmelt, or other sources, that flows over the land surface, and is a major component of the water cycle[1][2]. Runoff that occurs on surfaces before reaching a channel is also called overland flow. ...


Since 1992 the TOPEX and JASON satellite programs have provided measurements of sea level change. Current data are available.[6] The data show a mean sea level increase of 2.9±0.4 mm/yr. However, because significant short-term variability in sea level can occur, this recent increase does not necessarily indicate a long-term acceleration in sea level changes.


Geological influences

Comparison of two sea level reconstructions during the last 500 Myr. The scale of change during the last glacial/interglacial transition is indicated with a black bar. Note that over most of geologic history, long-term average sea level has been significantly higher than today

At times during Earth's long history, continental drift has arranged the land masses into very different configurations from those of today. When there were large amounts of continental crust near the poles, the rock record shows unusually low sea levels during ice ages, because there was lots of polar land mass upon which snow and ice could accumulate. During times when the land masses clustered around the equator, ice ages had much less effect on sea level. However, over most of geologic time, long-term sea level has been higher than today (see graph above). Only at the Permian-Triassic boundary ~250 million years ago was long-term sea level lower than today. Image File history File links Phanerozoic_Sea_Level. ... Image File history File links Phanerozoic_Sea_Level. ... For the history of modern humans, see History of the world. ... Plates in the crust of the earth, according to the plate tectonics theory Continental drift refers to the movement of the Earths continents relative to each other. ... The thickness of the Earths crust (km). ... The Permian is a geologic period that extends from about 299. ... The Triassic is a geologic period that extends from about 251 ± 0. ...


During the glacial/interglacial cycles over the past few million years, sea level has varied by somewhat more than a hundred metres. This is primarily due to the growth and decay of ice sheets (mostly in the northern hemisphere) with water evaporated from the sea.


The Mediterranean Basin's gradual growth as the Neotethys basin, begun in the Jurassic, did not suddenly affect ocean levels. While the Mediterranean was forming during the past 100 million years, the average ocean level was generally 200 meters above current levels. However, the largest known example of marine flooding was when the Atlantic breached the Strait of Gibraltar at the end of the Messinian Salinity Crisis about 5.2 million years ago. This restored Mediterranean sea levels at the sudden end of the period when that basin had dried up, apparently due to geologic forces in the area of the Strait.
The Mediterranean Basin refers to the lands around and surrounded by the Mediterranean Sea. ... The Jurassic Period is a major unit of the geologic timescale that extends from about 199. ... The Atlantic Ocean, not including Arctic and Antarctic regions. ... The Strait of Gibraltar as seen from space (on the left: Spain) A view across the Strait of Gibraltar taken from the hills over Tarifa, Spain The Strait of Gibraltar (Arabic: مضيق جبل طارق, Spanish: Estrecho de Gibraltar) is the strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Spain... // The Messinian Salinity Crisis, also referred to as the Messinian Event, is a period when the Mediterranean Sea evaporated partly or completely dry during the Messinian period of the Miocene epoch, approximately 6 million years ago. ... This article includes a list of works cited but its sources remain unclear because it lacks in-text citations. ...

Long-term causes Range of effect Vertical effect
Change in volume of ocean basins
Plate tectonics and seafloor spreading (plate divergence/convergence) and change in seafloor elevation (mid-ocean volcanism) Eustatic 0.01 mm/yr
Marine sedimentation Eustatic < 0.01 mm/yr
Change in mass of ocean water
Melting or accumulation of continental ice Eustatic 10 mm/yr
Climate changes during the 20th century
•• Antarctica (the results of increasing precipitation) Eustatic -0.2 to 0.0 mm/yr
•• Greenland (from changes in both precipitation and runoff) Eustatic 0.0 to 0.1 mm/yr
Long-term adjustment to the end of the last ice age
•• Greenland and Antarctica contribution over 20th century Eustatic 0.0 to 0.5 mm/yr
Release of water from earth's interior Eustatic
Release or accumulation of continental hydrologic reservoirs Eustatic
Uplift or subsidence of Earth's surface (Isostasy)
Thermal-isostasy (temperature/density changes in earth's interior) Local effect
Glacio-isostasy (loading or unloading of ice) Local effect 10 mm/yr
Hydro-isostasy (loading or unloading of water) Local effect
Volcano-isostasy (magmatic extrusions) Local effect
Sediment-isostasy (deposition and erosion of sediments) Local effect < 4 mm/yr
Tectonic uplift/subsidence
Vertical and horizontal motions of crust (in response to fault motions) Local effect 1-3 mm/yr
Sediment compaction
Sediment compression into denser matrix (particularly significant in and near river deltas) Local effect
Loss of interstitial fluids (withdrawal of groundwater or oil) Local effect ≤ 55 mm/yr
Earthquake-induced vibration Local effect
Departure from geoid
Shifts in hydrosphere, aesthenosphere, core-mantle interface Local effect
Shifts in earth's rotation, axis of spin, and precession of equinox Eustatic
External gravitational changes Eustatic
Evaporation and precipitation (if due to a long-term pattern) Local effect

The tectonic plates of the world were mapped in the second half of the 20th century. ... Age of oceanic crust. ... Isostasy is a term used in Geology to refer to the state of ice above stasy and is angravitational equilibrium between the Earths lithosphere and asthenosphere such that the tectonic plates float at an elevation which depends on their thickness and density. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Nile River delta, as seen from Earth orbit. ... Missing main definition------ someone add if you know it please. ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Łukasiewicz - inventor of the refining of kerosene from crude oil. ... The movement of water around, over, and through the Earth is called the water cycle, a key process of the hydrosphere. ... The asthenosphere (from an invented Greek a + sthenos without strength) is the region of the Earth between 100-200 km below the surface&#8212;but perhaps extending as deep as 400 km&#8212;that is is the weak or soft zone in the upper mantle. ... An animation showing the rotation of the Earth. ... For other uses, see Equinox (disambiguation). ... Gravity is a force of attraction that acts between bodies that have mass. ...

Past changes in sea level

Changes in sea level during the last 9,000 years

Description Sea level rise since the last glacial episode Sea level rise from direct measurements during the last 120 years This figure shows changes in sea level during the Holocene (last 10 kyr) based on data from Fleming et al. ... Description Sea level rise since the last glacial episode Sea level rise from direct measurements during the last 120 years This figure shows changes in sea level during the Holocene (last 10 kyr) based on data from Fleming et al. ...

The sedimentary record

For generations, geologists have been trying to explain the obvious cyclicity of sedimentary deposits observed everywhere we look. The prevailing theories hold that this cyclicity primarily represents the response of depositional processes to the rise and fall of sea level. In the rock record, geologists see times when sea level was astoundingly low alternating with times when sea level was much higher than today, and these anomalies often appear worldwide. For instance, during the depths of the last ice age 18,000 years ago when hundreds of thousands of cubic miles of ice were stacked up on the continents as glaciers, sea level was 120 m (390 feet) lower, locations that today support coral reefs were left high and dry, and coastlines were miles farther basinward from the present-day coastline. It was during this time of very low sea level that there was a dry land connection between Asia and Alaska over which humans are believed to have migrated to North America (see Bering Land Bridge). This article or section cites very few or no references or sources. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Nautical chart of Bering Strait, site of former land bridge between Asia and North America The Bering land bridge, also known as Beringia, was a land bridge roughly 1,000 miles (1,600 km) north to south at its greatest extent, which joined present-day Alaska and eastern Siberia at...


However, for the past 6,000 years (a few centuries before the first known written records), the world's sea level has been gradually approaching the level we see today. During the previous interglacial about 120,000 years ago, sea level was for a short time about 6 m higher than today, as evidenced by wave-cut notches along cliffs in the Bahamas. There are also Pleistocene coral reefs left stranded about 3 meters above today's sea level along the southwestern coastline of West Caicos Island in the West Indies. These once-submerged reefs and nearby paleo-beach deposits are silent testimony that sea level spent enough time at that higher level to allow the reefs to grow (exactly where this extra sea water came from—Antarctica or Greenland—has not yet been determined). Similar evidence of geologically recent sea level positions is abundant around the world. Narmer was an Egyptian pharaoh who ruled in the 31st century BC. Thought to be the successor to the predynastic Serket, he is considered by some to be the founder of the First dynasty, and therefore the first pharaoh of all Egypt. ... Some of the biodiversity of a coral reef, in this case the Great Barrier Reef, Australia. ... West Caicos is an island in the Turks and Caicos Islands. ...


Estimates

See IPCC TAR, figure 11.4 for a graph of sea level changes over the past 140,000 years.[7]

  • Sea-level rise estimates from satellite altimetry since 1992 (about 2.8 mm/yr) exceed those from tide gauges. It is unclear whether this represents an increase over the last decades, variability, or problems with satellite calibration.
  • Church and White (2006) report an acceleration of SLR since 1870. [2] This is a revision since 2001, when the TAR stated that measurements have detected no significant acceleration in the recent rate of sea level rise.
  • Based on tide gauge data, the rate of global average sea level rise during the 20th century lies in the range 0.8 to 3.3 mm/yr, with an average rate of 1.8 mm/yr.[8]
  • Recent studies of Roman wells in Caesarea and of Roman piscinae in Italy indicate that sea level stayed fairly constant from a few hundred years AD to a few hundred years ago.
  • Based on geological data, global average sea level may have risen at an average rate of about 0.5 mm/yr over the last 6,000 years and at an average rate of 0.1 to 0.2 mm/yr over the last 3,000 years.
  • Since the Last Glacial Maximum about 20,000 years ago, sea level has risen by over 120 m (averaging 6 mm/yr) as a result of melting of major ice sheets. A rapid rise took place between 15,000 and 6,000 years ago at an average rate of 10 mm/yr which accounted for 90 m of the rise; thus in the period since 20,000 years BP (excluding the rapid rise from 15-6 kyr BP) the average rate was 3 mm/yr.
  • A significant event was Meltwater Pulse 1A (mwp-1A), when sea level rose approximately 20 m over a 500 year period about 14,200 years ago. This is a rate of about 40 mm/yr. Recent studies suggest the primary source was meltwater from the Antarctic, perhaps causing the south-to-north cold pulse marked by the Southern Hemisphere Huelmo/Mascardi Cold Reversal, which preceded the Northern Hemisphere Younger Dryas
  • Relative sea level rise at specific locations is often 1-2 mm/yr greater or less than the global average. Along the US mid-Atlantic and Gulf Coasts, for example, sea level is rising approximately 3 mm/yr

This tidal gauge is ready to be installed underwater in a marina. ... Caesarea is the name of several Roman cities and towns, including: Caesarea Antiochia, properly Antioch in Pisidia, near modern Yalvaç, Turkey Caesarea Mazaca in Cappadocia, modern Kayseri, Turkey Caesarea Palaestina: modern Caesarea, in Israel Caesarea Philippi in the Golan Heights Iol Caesarea: modern Cherchell, in Algeria Caesarea Magna or Caesara... For the Italian commune, see Piscina (TO). ... Temperature proxies for the last 40,000 years The Last Glacial Maximum refers to the time of maximum extent of the ice sheets during the last glaciation, approximately 21 thousand years ago. ... Greek &#7936;&#957;&#964;&#945;&#961;&#954;&#964;&#953;&#954;&#8057;&#962;, opposite the arctic) is a continent surrounding the Earths South Pole. ... southern hemisphere highlighted in yellow (Antarctica not depicted). ... The Huelmo/Mascardi Cold Reversal (HMCR) is the name given to a cooling event in South America between 11,400 and 10,200 14C years BP. This cooling began about 550 years before the Younger Dryas cooling in the Northern Hemisphere, and both periods ended at about the same time. ... Northern hemisphere highlighted in yellow. ... Three temperature records, the GRIP one clearly showing the Younger Dryas event at around 11 kyr BP The Younger Dryas stadial, named after the alpine / tundra wildflower Dryas octopetala, and also referred to as the Big Freeze [1], was a brief (approximately 1300 ± 70 years [1]) cold climate period following...

U. S. Tide Gauge Measurements

U. S. Sea Level Trends 1900-2003

Tide gauges in the United States show considerable variation because some land areas are rising and some are sinking. For example, over the past 100 years, the rate of sea level rise varies from about an increase of 0.36 inches per year (10 mm per year) along the Louisiana Coast (due to land sinking), to a drop of a few inches per decade in parts of Alaska. The rate of sea level rise increased during the 1993-2003 period compared with the longer-term average (1961-2003), although it is unclear whether the faster rate reflects a short-term variation or an increase in the long-term trend.[9] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...


Amsterdam Sea Level Measurements

The longest running sea-level measurements are recorded at Amsterdam, in the Netherlands - most of which lies beneath sea level, hence the name. Records from 1700 onwards can be found at http://www.pol.ac.uk/psmsl/longrecords/longrecords.html. Since 1850, a rise of approx 1.5mm/year is shown here.


Australian Sea Level Change

The London Royal Society calculates net sea level rise in Australia at 1mm/yr[10] - an important result for the Southern Hemisphere. The National Tidal Center also graphs 32 gauges, some since 1880, for the entire coastline[11]


Future sea level rise

In 2001, the Intergovernmental Panel on Climate Change's Third Assessment Report predicted that by 2100, global warming will lead to a sea level rise of 9 to 88 cm. At that time no significant acceleration in the rate of sea level rise during the 20th century had been detected. [12] Subsequently, Church and White found acceleration of 0.013 ± 0.006 mm/yr². [2] IPCC is the science authority for the UNFCCC The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), to evaluate the risk of climate change brought on by humans, based mainly on... 2100 can refer to either: The first year of the 2100s decade. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ...


These sea level rises could lead to difficulties for shore-based communities: for example, many major cities such as London and New Orleans already need storm-surge defenses, and would need more if sea level rose, though they also face issues such as sinking land.[13] This article is about the capital of England and the United Kingdom. ... New Orleans is the largest city in the state of Louisiana, United States of America. ...


Future sea level rise, like the recent rise, is not expected to be globally uniform (details below). Some regions show a sea-level rise substantially more than the global average (in many cases of more than twice the average), and others a sea level fall.[14] However, models disagree as to the likely pattern of sea level change.[15]


Intergovernmental Panel on Climate Change results

The results from the IPCC Third Assessment Report (TAR) sea level chapter (convening authors John A. Church and Jonathan M. Gregory) are given below. The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) was issued in 2001. ... Dr John A. Church is an expert on sea level and its changes. ... Jonathan M. Gregory is a climate modeller working on mechanisms of global and large-scale change in climate and sea level on multidecadal and longer timescales. ...

IPCC change factors 1990-2100 IS92a prediction SRES prediction
Thermal expansion 110 to 430 mm
Glaciers 10 to 230 mm[16]
(or 50 to 110 mm)[17]
Greenland ice –20 to 90 mm
Antarctic ice –170 to 20 mm
Terrestrial storage –83 to 30 mm
Ongoing contributions from ice sheets in response to past climate change 0 to 55 mm
Thawing of permafrost 0 to 5 mm
Deposition of sediment not specified
Total global-average sea level rise
(IPCC result, not sum of above)[16]
110 to 770 mm 90 to 880 mm
(central value of 480 mm)

The sum of these components indicates a rate of eustatic sea level rise (corresponding to a change in ocean volume) from 1910 to 1990 ranging from –0.8 to 2.2 mm/yr, with a central value of 0.7 mm/yr. The upper bound is close to the observational upper bound (2.0 mm/yr), but the central value is less than the observational lower bound (1.0 mm/yr), i.e., the sum of components is biased low compared to the observational estimates. The sum of components indicates an acceleration of only 0.2 (mm/yr)/century, with a range from –1.1 to +0.7 (mm/yr)/century, consistent with observational finding of no acceleration in sea level rise during the 20th century. The estimated rate of sea-level rise from anthropogenic climate change from 1910 to 1990 (from modeling studies of thermal expansion, glaciers and ice sheets) ranges from 0.3 to 0.8 mm/yr. It is very likely that 20th century warming has contributed significantly to the observed sea-level rise, through thermal expansion of sea water and widespread loss of land ice.[16] Year 1910 (MCMX) was a common year starting on Saturday (link will display calendar) of the Gregorian calendar (or a common year starting on Friday [1] of the 13-day-slower Julian calendar). ... Year 1990 (MCMXC) was a common year starting on Monday (link displays the 1990 Gregorian calendar). ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901&#8211;2000 in the sense of the Gregorian calendar (1900&#8211;1999... Look up anthropogenic in Wiktionary, the free dictionary. ... Year 1910 (MCMX) was a common year starting on Saturday (link will display calendar) of the Gregorian calendar (or a common year starting on Friday [1] of the 13-day-slower Julian calendar). ... Year 1990 (MCMXC) was a common year starting on Monday (link displays the 1990 Gregorian calendar). ...


A common perception is that the rate of sea-level rise should have accelerated during the latter half of the 20th century, but tide gauge data for the 20th century show no significant acceleration. We have obtained estimates based on AOGCMs for the terms directly related to anthropogenic climate change in the 20th century, i.e., thermal expansion, ice sheets, glaciers and ice caps... The total computed rise indicates an acceleration of only 0.2 (mm/yr)/century, with a range from -1.1 to +0.7 (mm/yr)/century, consistent with observational finding of no acceleration in sea-level rise during the 20th century.[18] The sum of terms not related to recent climate change is -1.1 to +0.9 mm/yr (i.e., excluding thermal expansion, glaciers and ice caps, and changes in the ice sheets due to 20th century climate change). This range is less than the observational lower bound of sea level rise. Hence it is very likely that these terms alone are an insufficient explanation, implying that 20th century climate change has made a contribution to 20th century sea level rise.[5] This tidal gauge is ready to be installed underwater in a marina. ...


Uncertainties and criticisms regarding IPCC results

  • Tide records with a rate of 180 mm/century going back to the 19th century show no measurable acceleration throughout the late 19th and first half of the 20th century. The IPCC attributes about 60 mm/century to melting and other eustatic processes, leaving a residual of 120 mm of 20th century rise to be accounted for. Global ocean temperatures by Levitus et al are in accord with coupled ocean/atmosphere modelling of greenhouse warming, with heat-related change of 30 mm. Melting of polar ice sheets at the upper limit of the IPCC estimates could close the gap, but severe limits are imposed by the observed perturbations in Earth rotation. (Munk 2002)
  • By the time of the IPCC TAR, attribution of sea-level changes had a large unexplained gap between direct and indirect estimates of global sea-level rise. Most direct estimates from tide gauges give 1.5–2.0 mm/yr, whereas indirect estimates based on the two processes responsible for global sea-level rise, namely mass and volume change, are significantly below this range. Estimates of the volume increase due to ocean warming give a rate of about 0.5 mm/yr and the rate due to mass increase, primarily from the melting of continental ice, is thought to be even smaller. One study confirmed tide gauge data is correct, and concluded there must be a continental source of 1.4 mm/yr of fresh water. (Miller 2004)
  • From (Douglas 2002): "In the last dozen years, published values of 20th century GSL rise have ranged from 1.0 to 2.4 mm/yr. In its Third Assessment Report, the IPCC discusses this lack of consensus at length and is careful not to present a best estimate of 20th century GSL rise. By design, the panel presents a snapshot of published analysis over the previous decade or so and interprets the broad range of estimates as reflecting the uncertainty of our knowledge of GSL rise. We disagree with the IPCC interpretation. In our view, values much below 2 mm/yr are inconsistent with regional observations of sea-level rise and with the continuing physical response of Earth to the most recent episode of deglaciation."
  • The strong 1997-1998 El Niño caused regional and global sea level variations, including a temporary global increase of perhaps 20 mm. The IPCC TAR's examination of satellite trends says the major 1997/98 El Niño-Southern Oscillation (ENSO) event could bias the above estimates of sea-level rise and also indicate the difficulty of separating long-term trends from climatic variability.[19]

Alternative meaning: Nineteenth Century (periodical) (18th century &#8212; 19th century &#8212; 20th century &#8212; more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Alternative meaning: Nineteenth Century (periodical) (18th century &#8212; 19th century &#8212; 20th century &#8212; more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Wikinews has related news: Scientists warn thawing Siberia may trigger global meltdown A schematic representation of the exchanges of energy between outer space, the Earths atmosphere, and the Earth surface. ... For the band, see 1997 (band). ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... For the band, see 1997 (band). ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ...

Glacier contribution

It is well known that glaciers are subject to surges in their rate of movement with consequent melting when they reach lower altitudes and/or the sea. The contributors to Ann. Glac. 36 (2003) discussed this phenomenon extensively and it appears that slow advance and rapid retreat have persisted throughout the mid to late Holocene in nearly all of Alaska's glaciers. Historical reports of surge occurrences in Iceland's glaciers go back several centuries. Thus rapid retreat can have several other causes than CO2 increase in the atmosphere. This article is about the geological formation. ...


The results from Dyurgerov show a sharp increase in the contribution of mountain and subpolar glaciers to sea level rise since 1996 (0.5 mm/yr) to 1998 (2 mm/yr) with an average of approx. 0.35 mm/yr since 1960.[20] Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... Year 1960 (MCMLX) was a leap year starting on Friday (link will display full calendar) of the Gregorian calendar. ...


Of interest also is Arendt et al,[21] who estimate the contribution of Alaskan glaciers of 0.14±0.04 mm/yr between the mid 1950s to the mid 1990s increasing to 0.27 mm/yr in the middle and late 1990s. the first thing that was invented was the automatic DILDO. Education grew explosively because of a very strong demand for high school and college education. ... For the band, see 1990s (band). ... For the band, see 1990s (band). ...


Greenland contribution

Krabill et al.[22] estimate a net contribution from Greenland to be at least 0.13 mm/yr in the 1990s. Joughin et al.[23] have measured a doubling of the speed of Jakobshavn Isbræ between 1997 and 2003. This is Greenland's largest-outlet glacier; it drains 6.5% of the ice sheet, and is thought to be responsible for increasing the rate of sea level rise by about 0.06 millimeters per year, or roughly 4% of the 20th century rate of sea level increase.[24] In 2004, Rignot et al.[25] estimated a contribution of 0.04±0.01 mm/yr to sea level rise from southeast Greenland. For the band, see 1990s (band). ... Satellite image of Jakobshavn Isbræ. The coloured lines show the retreat of the calving front of the Jakobshavn Isbræ since 1850. ... For the band, see 1997 (band). ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...


Rignot and Kanagaratnam[26] produced a comprehensive study and map of the outlet glaciers and basins of Greenland. They found widespread glacial acceleration below 66 N in 1996 which spread to 70 N by 2005; and that the ice sheet loss rate in that decade increased from 90 to 200 cubic km/yr; this corresponds to an extra 0.25 to 0.55 mm/yr of sea level rise. Aletsch glacier, Switzerland A glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. ...


In July 2005 it was reported[27] that the Kangerdlugssuaq glacier, on Greenland's east coast, was moving towards the sea three times faster than a decade earlier. Kangerdlugssuaq is around 1000 m thick, 7.2 km (4.5 miles) wide, and drains about 4% of the ice from the Greenland ice sheet. Measurements of Kangerdlugssuaq in 1988 and 1996 showed it moving at between 5 and 6 km/yr (3.1 to 3.7 miles/yr) (in 2005 it was moving at 14 km/yr (8.7 miles/yr). “Miles” redirects here. ...


According to the 2004 Arctic Climate Impact Assessment, climate models project that local warming in Greenland will exceed 3° Celsius during this century. Also, ice sheet models project that such a warming would initiate the long-term melting of the ice sheet, leading to a complete melting of the Greenland ice sheet over several millennia, resulting in a global sea level rise of about seven meters.[28] The Arctic Climate Impact Assessment (ACIA) is a study describing the ongoing climate change in the Arctic and its consequences: rising temperatures, loss of sea ice, unprecedented melting of the Greenland ice sheet, and many impacts on ecosystems, animals, and people. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Outline Map of Greenland with ice sheet depths. ...


Effects of snowline and permafrost

The snowline altitude is the altitude of the lowest elevation interval in which minimum annual snow cover exceeds 50%. This ranges from about 5500 metres above sea-level at the equator down to sea-level at about 65° N&S latitude, depending on regional temperature amelioration effects. Permafrost then appears at sea-level and extends deeper below sea-level pole-wards. The depth of permafrost and the height of the ice-fields in both Greenland and Antarctica means that they are largely invulnerable to rapid melting. Greenland Summit is at 3200 metres, where the average annual temperature is minus 32 °C. So even a projected 4 °C rise in temperature leaves it well below the melting point of ice. Frozen Ground 28, December 2004, has a very significant map of permafrost affected areas in the Arctic. The continuous permafrost zone includes all of Greenland, the North of Labrador, NW Territories, Alaska north of Fairbanks, and most of NE Siberia north of Mongolia and Kamchatka. Continental ice above permafrost is very unlikely to melt quickly. As most of the Greenland and Antarctic ice sheets lie above the snowline and/or base of the permafrost zone, they cannot melt in a timeframe much less than several millennia; therefore they are unlikely to contribute significantly to sea-level rise in the coming century. The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...


Polar ice

The sea level could rise above its current level if more polar ice melts. However, compared to the heights of the ice ages, today there are very few continental ice sheets remaining to be melted. It is estimated that Antarctica, if fully melted, would contribute more than 60 metres of sea level rise, and Greenland would contribute more than 7 metres. Small glaciers and ice caps on the margins of Greenland and the Antarctic Peninsula might contribute about 0.5 metres. While the latter figure is much smaller than for Antarctica or Greenland it could occur relatively quickly (within the coming century) whereas melting of Greenland would be slow (perhaps 1500 years to fully deglaciate at the fastest likely rate) and Antarctica even slower.[3] However, this calculation does not account for the possibility that as meltwater flows under and lubricates the larger ice sheets, they could begin to move much more rapidly towards the sea. [4] [5]


In 2002, Rignot and Thomas[29] found that the West Antarctic and Greenland ice sheets were losing mass, while the East Antarctic ice sheet was probably in balance (although they could not determine the sign of the mass balance for The East Antarctic ice sheet). Kwok and Comiso (J. Climate, v15, 487-501, 2002) also discovered that temperature and pressure anomalies around West Antarctica and on the other side of the Antarctic Peninsula correlate with recent Southern Oscillation events. Also see: 2002 (number). ... Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ...


In 2004 Rignot et al.[25] estimated a contribution of 0.04±0.01 mm/yr to sea level rise from South East Greenland. In the same year, Thomas et al.[30] found evidence of an accelerated contribution to sea level rise from West Antarctica. The data showed that the Amundsen Sea sector of the West Antarctic Ice sheet was discharging 250 cubic kilometres of ice every year, which was 60% more than precipitation accumulation in the catchment areas. This alone was sufficient to raise sea level at 0.24 mm/yr. Further, thinning rates for the glaciers studied in 2002-2003 had increased over the values measured in the early 1990s. The bedrock underlying the glaciers was found to be hundreds of meters deeper than previously known, indicating exit routes for ice from further inland in the Byrd Subpolar Basin. Thus the West Antarctic ice sheet may not be as stable as has been supposed. A catchment is any device or structure that captures water. ... Bedrock is the native consolidated rock underlying the Earths surface. ...


In 2005 it was reported that during 1992-2003, East Antarctica thickened at an average rate of about 18 mm/yr while West Antarctica showed an overall thinning of 9 mm/yr. associated with increased precipitation. A gain of this magnitude is enough to slow sea-level rise by 0.12±0.02 mm/yr.[31]


Effects of sea level rise

Based on the projected increases stated above, the IPCC TAR WG II report notes that current and future climate change would be expected to have a number of impacts, particularly on coastal systems.[32] Such impacts may include increased coastal erosion, higher storm-surge flooding, inhibition of primary production processes, more extensive coastal inundation, changes in surface water quality and groundwater characteristics, increased loss of property and coastal habitats, increased flood risk and potential loss of life, loss of nonmonetary cultural resources and values, impacts on agriculture and aquaculture through decline in soil and water quality, and loss of tourism, recreation, and transportation functions. Many stretches of the coastline of East Anglia, England, are prone to high rates of erosion, as illustrated by this collapsed section of the cliffs at Hunstanton, Norfolk. ... Global oceanic and terrestrial photoautotroph abundance, from September 1997 to August 2000. ... Water quality is the physical, chemical and biological characteristics of water, characterized through the methods of hydrometry. ... Look up habitat in Wiktionary, the free dictionary. ... For other uses, see Culture (disambiguation). ... Workers harvest catfish from the Delta Pride Catfish farms in Mississippi Aquaculture is the cultivation of aquatic organisms. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Technically, soil forms the pedosphere: the interface between the lithosphere (rocky part of the planet) and the biosphere, atmosphere, and hydrosphere. ... Tourist redirects here. ... “Fun” redirects here. ...


There is an implication that many of these impacts will be detrimental. The report does, however, note that owing to the great diversity of coastal environments; regional and local differences in projected relative sea level and climate changes; and differences in the resilience and adaptive capacity of ecosystems, sectors, and countries, the impacts will be highly variable in time and space and will not necessarily be negative in all situations. A coral reef near the Hawaiian islands is an example of a complex marine ecosystem. ...


Statistical data on the human impact of sea level rise is scarce. A study in the April, 2007 issue of Environment and Urbanization reports that 634 million people live in coastal areas within 30 feet of sea level. The study also reported that about two thirds of the world's cities with over five million people are located in these low-lying coastal areas. A city is an urban area, differentiated from a town, village, or hamlet by size, population density, importance, or legal status. ...


Are islands "sinking"?

IPCC assessments have suggested that deltas and small island states may be particularly vulnerable to sea level rise. Relative sea level rise (mostly caused by subsidence) is causing substantial loss of lands in some deltas.[33] However, sea level changes have not yet been implicated in any substantial environmental, humanitarian, or economic losses to small island states. Previous claims have been made that parts of the island nations of Tuvalu were "sinking" as a result of sea level rise [citation needed]. However, subsequent reviews have suggested that the loss of land area was the result of erosion during and following the actions of 1997 cyclones Gavin, Hina, and Keli.[34][35] According to climate skeptic Patrick J. Michaels, "In fact, areas...such as [the island of] Tuvalu show substantial declines in sea level over that period."[36] A road destroyed by subsidence and shear. ... For morphological image processing operations, see Erosion (morphology). ... For the band, see 1997 (band). ... Patrick J. Michaels (born c. ...


Reuters has reported other Pacific islands are facing a severe risk including Tegua island in Vanuatu. Claims that Vanuatu data shows no net sea level rise, are not substantiated by tide gauge data. Vanuatu tide gauge data[37] show a net rise of ~50 mm from 1994-2004. Linear regression of this short time series suggests a rate of rise of ~7 mm/y, though there is considerable variability and the exact threat to the islands is difficult to assess using such a short time series. In statistics, linear regression is a regression method that models the relationship between a dependent variable Y, independent variables Xi, i = 1, ..., p, and a random term ε. The model can be written as Example of linear regression with one dependent and one independent variable. ...


Numerous options have been proposed that would assist island nations to adapt to rising sea level.[38] Adaptation to global warming covers all actions aimed at reducing the negative effects of global warming. ...


Satellite sea level measurement

Satellite Measurement of Sea Level
Satellite Measurement of Sea Level

Sea level rise estimates from satellite altimetry are 3.1 +/- 0.4 mm/yr for 1993-2003 (Leuliette et al. (2004)). This exceeds those from tide gauges. It is unclear whether this represents an increase over the last decades; variability; true differences between satellites and tide gauges; or problems with satellite calibration.[19] Image File history File links Size of this preview: 800 × 522 pixelsFull resolution (1150 × 750 pixels, file size: 122 KB, MIME type: image/jpeg) Sea Level Rise as measured by the TOPEX/Poseidon and Jason-1 satellites File historyClick on a date/time to view the file as it appeared... Image File history File links Size of this preview: 800 × 522 pixelsFull resolution (1150 × 750 pixels, file size: 122 KB, MIME type: image/jpeg) Sea Level Rise as measured by the TOPEX/Poseidon and Jason-1 satellites File historyClick on a date/time to view the file as it appeared... For other uses, see Satellite (disambiguation). ... calibration refers to the process of determining the relation between the output (or response) of a measuring instrument and the value of the input quantity or attribute, a measurement standard. ...


Since 1992 the NASA/CNES TOPEX/Poseidon (T/P) and Jason-1 satellite programs have provided measurements of sea level change. The current data are available at http://sealevel.colorado.edu/ and http://sealevel.jpl.nasa.gov/. The data show a mean sea level increase of 2.8±0.4 mm/yr. This includes an apparent increase to 3.7±0.2 mm/yr during the period 1999 through 2004.[39] Satellites ERS-1 (July 17, 1991-March 10, 2000),[40] ERS-2 (April 21, 1995-),[41] and Envisat (March 1, 2002-) also have sea surface altimeter components but are of limited use for measuring global mean sea level due to less detailed coverage. Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ... The TOPEX/Poseidon satellite altimeter is a science project to measure the ocean surface topography. ... This article contains material and/or images that originally came from a NASA website. ... is the 198th day of the year (199th in leap years) in the Gregorian calendar. ... Year 1991 (MCMXCI) was a common year starting on Tuesday (link will display the 1991 Gregorian calendar). ... March 10 is the 69th day of the year (70th in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ... is the 111th day of the year (112th in leap years) in the Gregorian calendar. ... Year 1995 (MCMXCV) was a common year starting on Sunday (link will display full 1995 Gregorian calendar). ... is the 60th day of the year (61st in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ...

  • TOPEX/Poseidon began their series of measurements in 1992, and the scientific mission was ended in October 2005.
  • Jason-1, launched December 7, 2001, has now taken over the mission, and is flying the same groundtrack.

Because significant short-term variability in sea level can occur, extracting the global mean sea level information is complex. Also, the satellite data has a much shorter record than tidal gauges, which have been found to require years of operation to extract trends. is the 341st day of the year (342nd in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ...


There is a range of distances involved.

  • 140 to 320 mm: Increased height of sea level within 1997-1998 El Niño Pacific region.[42]
  • 140 mm: Range of typical regional sea level variations (±70 mm).[43]
  • 100 mm: Accuracy of ERS-1 radar altimeter.[44]
  • 43 mm: Accuracy of ocean surface height calculations with T/P.[45]
  • 30 to 40 mm: Accuracy of TOPEX and POSEIDON-1 radar altimeters, which measure distance to ocean surface.
  • 20 to 30 mm: Accuracy of determination of T/P satellite orbital height (laser ranging, doppler shifts, GPS).
  • 20 mm: Accuracy of Jason-1 POSEIDON-2 radar altimeter.[46]
  • 7-14 mm: Global mean sea level surge during 1997-1998 El Niño period.[47]
  • Several mm: Precision of global mean sea level measurement after averaging 10-day coverage.[48]
  • 10 mm: Stability of T/P orbit heights over 4 years.[49]
  • 2.8 ±0.4 mm: Average annual global sea level rise since 1992 according to T/P.

There apparently is a problem with the ERS-2 altimeter. Mean sea level changes were compared between satellites for 60°N and 60°S from May 1995 to June 1996:[50] For the band, see 1997 (band). ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ... Year 1995 (MCMXCV) was a common year starting on Sunday (link will display full 1995 Gregorian calendar). ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ...

  • -4.7 ±1.5 mm/yr for ERS-1
  • -5.6 ±1.3 mm/yr for TOPEX
  • +9.0 ±2.1 mm/yr for ERS-2

Ongoing altimeter comparisons are available at: http://www7300.nrlssc.navy.mil/altimetry/intercomp.html
The various readings there are of current sea level variations, not global sea level, so the comparison is only in differences between the values. That data is of variations in centimeters; further processing is done to reach the millimeter-level resolution needed for mean sea level studies.


Comparisons of T/P with Pacific island tide gauge data show that the monthly mean deviations are accurate at the level of 20 mm.[51]


Also, it should be noted that since satellite results are partially calibrated against tide gauge readings, they are not an entirely independent source.[52]


The strong 1997-1998 El Niño event "has imprinted a strong signature on the sea surface height field in the mid-latitude eastern Pacific. This signal will be tracked over the next decade as the eastern boundary manifestation of this El Niño event propagates westward toward the Kuroshio Extension."[53]


Other satellites:

  • Geosat Follow-On is a U.S. Navy altimeter mission that was launched on February 10, 1998. On November 29, 2000, the Navy accepted the satellite as operational. During its mission life, the satellite will be retained in the GEOSAT Exact Repeat Mission (ERM) orbit (800 km altitude, 108 deg inclination, 0.001 eccentricity, and, 100 min period). This 17-day Exact Repeat Orbit (ERO) retraces the ERM ground track to +/-1 km. As with the original GEOSAT ERM, the data will be available for ocean science through NOAA/NOS and NOAA/NESDIS. Radar Altimeter - single frequency (13.5 GHz) with 35 mm height precision. Note that the GPS receiver is not functional.
    • Geosat Follow-On @ NOAA/LSA[54]
    • NAVY GEOSAT FOLLOW-ON (GFO) ALTIMETRY MISSION[55]
    • NASA WFF Geosat Follow-On[56]

Other sea level analysis: is the 41st day of the year in the Gregorian calendar. ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... is the 333rd day of the year (334th in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ...

  • Sea Level Analysis from ERS Altimetry[57]
  • Ssalto/Duacs multimission altimeter products:[58] Combined current data from Topex/Poseidon, Geosat Follow On, Jason-1 and Envisat.

See also

energy Portal

Image File history File links Portal. ... The 8. ... The Antarctic Cold Reversal (ACR) was an important episode of cooling in the climate history of the Earth, during the deglaciation at the close of the last ice age. ... Surface temperature of Antarctica in winter and summer The climate of Antarctica is the coldest on earth, with the lowest temperature ever recorded on earth being -89. ... Marine regression is a geological process ocurring when areas of submerged seafloor are exposed above the sea level. ... The Older Peron transgression was a period of unusually warm climate during the Holocene Epoch. ... A view down the Whitechuck Glacier in North Cascades National Park in 1973 The same view as seen in 2006, where this branch of glacier retreated 1. ...

External links

The Permanent Service for Mean Sea Level (PSMSL), established in 1933, is a repository for tide gauge data used in the measurement of long-term sea level change. ... For the band, see 1997 (band). ...

References

  1. ^ Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  2. ^ a b c Church, John & White, Neil (January 6, 2006), "A 20th century acceleration in global sea-level rise", Geophysical Research Letters 33, L01602, DOI:10.1029/2005GL024826, <http://www.pol.ac.uk/psmsl/author_archive/church_white/GRL_Church_White_2006_024826.pdf>. Retrieved on 2007-10-13 PDF format
  3. ^ a b Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  4. ^ http://www.ldeo.columbia.edu/~mstuding/wais.html
  5. ^ a b Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  6. ^ http://sealevel.colorado.edu
  7. ^ IPCC TAR, figure 11.4. Retrieved on 2005-12-19.
  8. ^ Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  9. ^ U. S. Enviromental Protection Agency "Sea Level Changes"
  10. ^ LANDMARK STUDY CONFIRMS RISING AUSTRALIAN SEA LEVEL
  11. ^ Australian Mean Sea Level Survey 2003
  12. ^ http://www.grida.no/climate/ipcc_tar/wg1/013.htm
  13. ^ Church, J.A. and J.M. Gregory (Co-ordinating Lead Authors), 2001 Climate Change 2001: The Scientific Basis, Ch. 11. Changes in Sea Level, Integovernmental Panel on Climate Change, http://www.grida.no/climate/ipcc_tar/wg1/408.htm Accessed on Dec. 19, 2005
  14. ^ Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  15. ^ Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  16. ^ a b c Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  17. ^ Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  18. ^ Climate Change 2001: The Scientific Basis. Retrieved on 2005-12-19.
  19. ^ Cite error 8; No text given.
  20. ^ Dyurgerov, Mark. 2002. Glacier Mass Balance and Regime: Data of Measurements and Analysis. INSTAAR Occasional Paper No. 55, ed. M. Meier and R. Armstrong. Boulder, CO: Institute of Arctic and Alpine Research, University of Colorado. Distributed by National Snow and Ice Data Center, Boulder, CO. A shorter discussion is at [1]
  21. ^ Arendt; et al (July 2002). "{{{title}}}". Science 297: 382. 
  22. ^ Krabill; et al (21 July 2000). "{{{title}}}". Science 289 (5478): 428-430. 
  23. ^ Joughin; et al (December 2004). "{{{title}}}". Nature 432: 608. 
  24. ^ http://www.spaceref.com/news/viewpr.html?pid=15611
  25. ^ a b Rignot; et al (2004). "{{{title}}}". Geophysical Research Letters 31: L10401. 
  26. ^ Rignot; Kanagaratnam (2006). "{{{title}}}". Science 311: 986 et seq.. 
  27. ^ http://news.independent.co.uk/world/environment/article301493.ece
  28. ^ http://www.metoffice.gov.uk/corporate/pressoffice/adcc/BookCh4Jan2006.pdf
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  33. ^ http://www.wbgu.de/wbgu_sn2006_en.pdf
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  35. ^ Levine, Mark. "Tuvalu Toodle-oo", Outside Magazine, December 2002. Retrieved on 2005-12-19. 
  36. ^ http://www.cnsnews.com/ViewCulture.asp?Page=%5CCulture%5Carchive%5C200512%5CCUL20051207a.html
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