A report on Sea level rise and Ice sheet

Satellite observations of sea level rise from 1993 to 2021.
A satellite composite image of Antarctica
Historical sea level reconstruction and projections up to 2100 published in 2017 by the U.S. Global Change Research Program for the Fourth National Climate Assessment. RCP2.6 is the scenario where emissions peak before 2020, RCP4.5 the one where they peak around 2040, and RCP8.5 the one where they keep increasing.
Aerial view of the ice sheet on Greenland's east coast
Different sea level rise projections for the 21st century
Map of Greenland
Map of the Earth with a long-term 6 m sea level rise represented in red (uniform distribution, actual sea level rise will vary regionally and local adaptation measures will also have an effect on local sea levels).
Carbon stores and fluxes in present-day ice sheets (2019), and the predicted impact on carbon dioxide (where data exists).
Estimated carbon fluxes are measured in Tg C a−1 (megatonnes of carbon per year) and estimated sizes of carbon stores are measured in Pg C (thousands of megatonnes of carbon). DOC = dissolved organic carbon, POC = particulate organic carbon.
Earth lost 28 trillion tonnes of ice between 1994 and 2017, with melting grounded ice (ice sheets and glaciers) raising the global sea level by 34.6 ±3.1 mm. The rate of ice loss has risen by 57% since the 1990s−from 0.8 to 1.2 trillion tonnes per year.
Ocean heat content (OHC) between 1957 and 2017, NOAA
The Ross Ice Shelf, Antarctica's largest, is about the size of France and up to several hundred metres thick.
grounding zone
Greenland 2007 melt, measured as the difference between the number of days on which melting occurred in 2007 compared to the average annual melting days from 1988 to 2006
Trends in land water storage from GRACE observations in gigatons per year, April 2002 to November 2014 (glaciers and ice sheets are excluded).
A stripe graphic assigns ranges of annual sea level measurements to respective colors, with the baseline white color starting in 1880 and darker blues denoting progressively greater sea level rise.
Jason-1 continued the sea surface measurements started by TOPEX/Poseidon. It was followed by the Ocean Surface Topography Mission on Jason-2, and by Jason-3
Between 1993 and 2018, the mean sea level has risen across most of the world ocean (blue colors).
Tidal flooding in Miami during a king tide (October 17, 2016). The risk of tidal flooding increases with sea level rise.
Major cities threatened by sea level rise. The cities indicated are under threat of even a small sea level rise (of 1.6 foot/49 cm) compared to the level in 2010. Even moderate projections indicate that such a rise will have occurred by 2060.
Bramble Cay melomys Melomys rubicola. In 2016 declared extinct on Bramble Cay, where it had been endemic, and likely also globally extinct, with habitat loss due to sea level rise being the root cause.
Placard "The sea is rising", at the People's Climate March (2017).
Beach nourishment in progress in Barcelona.
Changes in sea level since the end of the last glacial episode

This acceleration is due mostly to climate change, which heats (and therefore expands) the ocean and which melts the land-based ice sheets and glaciers.

- Sea level rise

According to the Intergovernmental Panel on Climate Change (IPCC), loss of Antarctic and Greenland ice sheet mass contributed, respectively, about 0.21 ± 0.35 and 0.21 ± 0.07 mm/year to sea level rise between 1993 and 2003.

- Ice sheet
Satellite observations of sea level rise from 1993 to 2021.

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Overall

Greenland ice sheet

Greenland ice sheet

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Vast body of ice covering 1710000 km², roughly near 80% of the surface of Greenland.

Vast body of ice covering 1710000 km², roughly near 80% of the surface of Greenland.

Greenland ice sheet
Melting ice during July 2012, images created by NASA show the process in the summer
Arctic Temperature Trend 1981–2007
Glaciologist at work
The cold blob visible on NASA's global mean temperatures for 2015, the warmest year on record up to 2015 (since 1880) – Colors indicate temperature evolution (NASA/NOAA; 20 January 2016).
In August 2020 scientists reported that melting of the Greenland ice sheet is shown to have passed the point of no return, based on 40 years of satellite data. The switch to a dynamic state of sustained mass loss resulted from widespread retreat in 2000–2005.
In August 2020 scientists reported that the Greenland ice sheet lost a record amount of ice during 2019.
Meltwater creates rivers caused by cryoconite on July 21, 2012
Meltwater rivers may flow down into moulins
Until 2007, rate of decrease in ice sheet height in cm per year.
Modelling results of the sea-level rise under different warming scenarios.
Satellite image of dark melt ponds.
Albedo change in Greenland

The ice sheet is almost 2900 km long in a north–south direction, and its greatest width is 1100 km at a latitude of 77°N, near its northern margin.

If the entire 2850000 km3 of ice were to melt, it would lead to a global sea level rise of 7.2 m. The Greenland Ice Sheet is sometimes referred to under the term inland ice, or its Danish equivalent, indlandsis.

A map of West Antarctica

West Antarctic Ice Sheet

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Segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere.

Segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere.

A map of West Antarctica
A topographic and bathymetric map of Antarctica without its ice sheets, assuming constant sea levels and no post-glacial rebound
grounding zone

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.

Rapley said, "Parts of the Antarctic ice sheet that rest on bedrock below sea level have begun to discharge ice fast enough to make a significant contribution to sea level rise. Understanding the reason for this change is urgent in order to be able to predict how much ice may ultimately be discharged and over what timescale. Current computer models do not include the effect of liquid water on ice sheet sliding and flow, and so provide only conservative estimates of future behaviour."

A satellite composite image of Antarctica

Antarctic ice sheet

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One of the two polar ice caps of Earth.

One of the two polar ice caps of Earth.

A satellite composite image of Antarctica
Antarctic Skin Temperature Trends between 1981 and 2007, based on thermal infrared observations made by a series of NOAA satellite sensors. Skin temperature trends do not necessarily reflect air temperature trends.
Polar climatic temperature changes throughout the Cenozoic, showing glaciation of Antarctica toward the end of the Eocene, thawing near the end of the Oligocene and subsequent Miocene re-glaciation.
An image of Antarctica differentiating its landmass (dark grey) from its ice shelves (minimum extent, light grey, and maximum extent, white)
Visualization of NASA's mission Operation IceBridge dataset BEDMAP2, obtained with laser and ice-penetrating radar, collecting surface height, bedrock topography and ice thickness.
The bedrock topography of Antarctica, critical to understand dynamic motion of the continental ice sheets.
Ice mass loss since 2002, as measured by NASA's GRACE and GRACE Follow-On satellite projects, was 152 billion metric tons per year.

It holds approximately 61% of all fresh water on Earth, equivalent to about 58 m of sea level rise.

In East Antarctica, the ice sheet rests on a major land mass, while in West Antarctica the bed can extend to more than 2,500 m below sea level.

Average surface air temperatures from 2011 to 2021 compared to the 1956–1976 average

Climate change

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Contemporary climate change includes both global warming and its impacts on Earth's weather patterns.

Contemporary climate change includes both global warming and its impacts on Earth's weather patterns.

Average surface air temperatures from 2011 to 2021 compared to the 1956–1976 average
Change in average surface air temperature since the industrial revolution, plus drivers for that change. Human activity has caused increased temperatures, with natural forces adding some variability.
Global surface temperature reconstruction over the last 2000 years using proxy data from tree rings, corals, and ice cores in blue. Directly observed data is in red.
Drivers of climate change from 1850–1900 to 2010–2019. There was no significant contribution from internal variability or solar and volcanic drivers.
concentrations over the last 800,000 years as measured from ice cores (blue/green) and directly (black)
The Global Carbon Project shows how additions to since 1880 have been caused by different sources ramping up one after another.
The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy.
Sea ice reflects 50% to 70% of incoming solar radiation while the dark ocean surface only reflects 6%, so melting sea ice is a self-reinforcing feedback.
Projected global surface temperature changes relative to 1850–1900, based on CMIP6 multi-model mean changes.
The sixth IPCC Assessment Report projects changes in average soil moisture that can disrupt agriculture and ecosystems. A reduction in soil moisture by one standard deviation means that average soil moisture will approximately match the ninth driest year between 1850 and 1900 at that location.
Historical sea level reconstruction and projections up to 2100 published in 2017 by the U.S. Global Change Research Program
The IPCC Sixth Assessment Report (2021) projects that extreme weather will be progressively more common as the Earth warms.
Scenarios of global greenhouse gas emissions. If all countries achieve their current Paris Agreement pledges, average warming by 2100 would still significantly exceed the maximum 2 °C target set by the Agreement.
Coal, oil, and natural gas remain the primary global energy sources even as renewables have begun rapidly increasing.
Economic sectors with more greenhouse gas contributions have a greater stake in climate change policies.
Most emissions have been absorbed by carbon sinks, including plant growth, soil uptake, and ocean uptake (2020 Global Carbon Budget).
Since 2000, rising emissions in China and the rest of world have surpassed the output of the United States and Europe.
Per person, the United States generates at a far faster rate than other primary regions.
Academic studies of scientific consensus reflect that the level of consensus correlates with expertise in climate science.
Data has been cherry picked from short periods to falsely assert that global temperatures are not rising. Blue trendlines show short periods that mask longer-term warming trends (red trendlines). Blue dots show the so-called global warming hiatus.
The 2017 People's Climate March took place in hundreds of locations. Shown: the Washington, D.C. march, protesting policies of then-U.S. President Trump.
Tyndall's ratio spectrophotometer (drawing from 1861) measured how much infrared radiation was absorbed and emitted by various gases filling its central tube.
alt=Underwater photograph of branching coral that is bleached white|Ecological collapse. Bleaching has damaged the Great Barrier Reef and threatens reefs worldwide.<ref>{{Cite web|url=https://sos.noaa.gov/datasets/coral-reef-risk-outlook/|title=Coral Reef Risk Outlook|access-date=4 April 2020|publisher=National Oceanic and Atmospheric Administration|quote=At present, local human activities, coupled with past thermal stress, threaten an estimated 75 percent of the world's reefs. By 2030, estimates predict more than 90% of the world's reefs will be threatened by local human activities, warming, and acidification, with nearly 60% facing high, very high, or critical threat levels.}}</ref>
alt=Photograph of evening in a valley settlement. The skyline in the hills beyond is lit up red from the fires.|Extreme weather. Drought and high temperatures worsened the 2020 bushfires in Australia.<ref>{{harvnb|Carbon Brief, 7 January|2020}}.</ref>
alt=The green landscape is interrupted by a huge muddy scar where the ground has subsided.|Arctic warming. Permafrost thaws undermine infrastructure and release methane, a greenhouse gas.
alt=An emaciated polar bear stands atop the remains of a melting ice floe.|Habitat destruction. Many arctic animals rely on sea ice, which has been disappearing in a warming Arctic.<ref>{{harvnb|IPCC AR5 WG2 Ch28|2014|p=1596|ps=: "Within 50 to 70 years, loss of hunting habitats may lead to elimination of polar bears from seasonally ice-covered areas, where two-thirds of their world population currently live."}}</ref>
alt=Photograph of a large area of forest. The green trees are interspersed with large patches of damaged or dead trees turning purple-brown and light red.|Pest propagation. Mild winters allow more pine beetles to survive to kill large swaths of forest.<ref>{{Cite web|url=https://www.nps.gov/romo/learn/nature/climatechange.htm|title=What a changing climate means for Rocky Mountain National Park|publisher=National Park Service|access-date=9 April 2020}}</ref>
Environmental migration. Sparser rainfall leads to desertification that harms agriculture and can displace populations. Shown: Telly, Mali (2008).<ref>{{harvnb|Serdeczny|Adams|Baarsch|Coumou|2016}}.</ref>
Agricultural changes. Droughts, rising temperatures, and extreme weather negatively impact agriculture. Shown: Texas, US (2013).<ref>{{harvnb|IPCC SRCCL Ch5|2019|pp=439, 464}}.</ref>
Tidal flooding. Sea-level rise increases flooding in low-lying coastal regions. Shown: Venice, Italy (2004).<ref name="NOAAnuisance">{{cite web|url=http://oceanservice.noaa.gov/facts/nuisance-flooding.html |title=What is nuisance flooding? |author=National Oceanic and Atmospheric Administration |access-date=April 8, 2020}}</ref>
Storm intensification. Bangladesh after Cyclone Sidr (2007) is an example of catastrophic flooding from increased rainfall.<ref>{{harvnb|Kabir|Khan|Ball|Caldwell|2016}}.</ref>
Heat wave intensification. Events like the June 2019 European heat wave are becoming more common.<ref>{{harvnb|Van Oldenborgh|Philip|Kew|Vautard|2019}}.</ref>

These include sea level rise, and warmer, more acidic oceans.

Global sea level is rising as a consequence of glacial melt, melt of the ice sheets in Greenland and Antarctica, and thermal expansion.

Greenland

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Island country that is part of the Kingdom of Denmark.

Island country that is part of the Kingdom of Denmark.

Greenland visible from space
Areas of Independence I and Independence II cultures around Independence Fjord
The Kingittorsuaq Runestone from Kingittorsuaq Island (Middle Ages)
One of the last contemporary written mentions of the Norse Greenlanders records a marriage which took place in 1408 in the church of Hvalsey – today the best-preserved Nordic ruins in Greenland. The married couple then travelled to Iceland, which is why the account has been preserved.
Ingibjørg Tombstone.
Pictures of Greenland, c. 1863
An English map of 1747, based on Hans Egede's descriptions and misconceptions, by Emanuel Bowen
Godthåb in Greenland, c. 1878
1869 photograph of Greenlandic Inuit.
Map of Eirik Raudes Land
The orthography and vocabulary of the Greenlandic language is governed by Oqaasileriffik, the Greenlandic language secretariat, located in the Ilimmarfik University of Greenland, Nuuk.
The United States has operated Thule Air Base since the 1950s.
Sermiligaaq. Greenland has more than 60 settlements.
Map of Greenland
Greenland bedrock, at current elevation above sea level
Aurora Borealis, the northern lights at the sky in Greenland
Muskoxen in Greenland
The Greenland Dog was brought from Siberia 1,000 years ago.
Humpback whale, Megaptera novaeangliae, in Disko Bay near Ilulissat
The special territories of the European Union (pre 31 January 2020)
Nuuk is Greenland's capital and the seat of the government.
Municipalities of Greenland
A proportional representation of Greenland exports, 2019
Greenland electricity production by source
Air Greenland operates passenger and cargo freight services by air from, to and across Greenland.
Arctic Umiaq Line operates passenger and freight services by sea across Greenland.
Buses service in Ilulissat
Tunumiit Inuit couple from Kulusuk
A bilingual sign in Nuuk, displaying the Danish and Kalaallisut for "Parking forbidden for all vehicles"
Ilimmarfik university Campus in Nuuk
Most Greenlandic villages, including Nanortalik, have their own church.
Nive Nielsen, Greenlandic singer and songwriter
Panel discussion with Greenlandic movie maker Inuk Silis Høegh at the launch of his movie about groundbreaking Greenlandic band Sumé
Teletaarnet Headquarters in Nuuk Greenland
Arctic television in Ilulissat
Estimated extent of Arctic cultures in Greenland from 900 AD to 1500 AD. Colored areas on each map indicate the extent and migration patterns over time of the Dorset, Thule, and Norse cultures.
Pilersuisoq Supermarket in Kangerlussuaq

The weight of the ice sheet has depressed the central land area to form a basin lying more than 300 m below sea level, while elevations rise suddenly and steeply near the coast.

The glaciers of Greenland are also contributing to a rise in the global sea level faster than was previously believed.

The Amundsen Sea area of Antarctica

Amundsen Sea

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Arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lies between Cape Flying Fish to the east and Cape Dart on Siple Island to the west.

Arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lies between Cape Flying Fish to the east and Cape Dart on Siple Island to the west.

The Amundsen Sea area of Antarctica
Antarctic iceberg floating in the Amundsen Sea water, October 2009.
Large B-22 iceberg breaking off from Thwaites Glacier and remnants of the B-21 iceberg from Pine Island Glacier in Pine Island Bay to the right of the image
Amundsen Sea as part of the Southern Ocean

The ice sheet which drains into the Amundsen Sea averages about 3 km in thickness; roughly the size of the state of Texas, this area is known as the Amundsen Sea Embayment (ASE); it forms one of the three major ice-drainage basins of the West Antarctic Ice Sheet.

Scientists have found that the flow of these glaciers has increased starting in the mid-2000s decade; if they were to melt completely global sea levels would rise by about 0.9–1.9 m (1–2 yards).

The glacier of the Geikie Plateau in Greenland.

Glacier

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Persistent body of dense ice that is constantly moving under its own weight.

Persistent body of dense ice that is constantly moving under its own weight.

The glacier of the Geikie Plateau in Greenland.
With 7,253 known glaciers, Pakistan contains more glacial ice than any other country on earth outside the polar regions. At 62 km in length, its Baltoro Glacier is one of the world's longest alpine glaciers.
Aerial view of a glacier in Chugach State Park, Alaska, United States
Webber Glacier on Grant Land (northern Ellesmere Island) is an advancing polar glacier and frozen to the glacier bed. Debris rich layers of the ground moraine are sheared and folded into the ice. The steep icefront shows waterfalls. The glacier front is 6 km broad and up to 40 m high (July 20, 1978)
Shear or herring-bone crevasses on Emmons Glacier (Mount Rainier); such crevasses often form near the edge of a glacier where interactions with underlying or marginal rock impede flow. In this case, the impediment appears to be some distance from the near margin of the glacier.
Forbes bands on the Mer de Glace glacier in France
Black ice glacier near Aconcagua, Argentina
Fox Glacier in New Zealand finishes near a rainforest.
Diagram of glacial plucking and abrasion
Glacially plucked granitic bedrock near Mariehamn, Åland
Glacial moraines above Lake Louise, Alberta, Canada
A drumlin field forms after a glacier has modified the landscape. The teardrop-shaped formations denote the direction of the ice flow.
Features of a glacial landscape
Landscape produced by a receding glacier
South Cascade Glacier in Washington documented from 1928 to 2003 showing the recent rapid glacier retreating. By looking at this photo it's clear to see how quickly the glaciers are retreating in the modern world. This kind of retreating is the result of climate change which has significantly increased due to human impacts. This photo was taken from USGS U.S. Department of Interior research looking at the last 50 years of glacier change.
Isostatic pressure by a glacier on the Earth's crust
Northern polar ice cap on Mars.
Ice calving from the terminus of the Perito Moreno Glacier in western Patagonia, Argentina.
The Aletsch Glacier, the largest glacier of the Alps, in Switzerland.
The Quelccaya Ice Cap is the second-largest glaciated area in the tropics, in Peru.
Mouth of the Schlatenkees Glacier near Innergschlöß, Austria.
The Grotta del Gelo is a cave of Etna volcano, the southernmost glacier in Europe.
Sightseeing boat in front of a tidewater glacier, Kenai Fjords National Park, Alaska.
Gorner Glacier in Switzerland.
An aerial photograph of the Gorner Glacier (left side of image) together with the Grenzgletscher (r.) flowing into it, both framing the Monte Rosa massif in the middle
A packrafter passes a wall of freshly exposed blue ice on Spencer Glacier, in Alaska. Glacial ice acts like a filter on light, and the more time light spends traveling through the ice, the bluer it becomes.
A glacier cave located on the Perito Moreno Glacier in Argentina.
Ice cracks in the Titlis Glacier.
Crossing a crevasse on the Easton Glacier, Mount Baker, in the North Cascades, United States.
An exposed glacier tube that once transported water down the interior of the glacier.
Romer Lake's Elephant Foot Glacier in the Earth's Arctic, as seen by Landsat 8. This picture shows several glaciers that have the same shape as many features on Mars that are believed to also be glaciers.  The next three images from Mars show shapes similar to the Elephant Foot Glacier.
Mesa in Ismenius Lacus quadrangle, as seen by CTX. Mesa has several glaciers eroding it. One of the glaciers is seen in greater detail in the next two images from HiRISE. Image from Ismenius Lacus quadrangle.
Glacier as seen by HiRISE under the HiWish program. Area in the rectangle is enlarged in the next photo. Zone of accumulation of snow at the top. Glacier is moving down valley, then spreading out on plain. Evidence for flow comes from the many lines on surface. Location is in Protonilus Mensae in Ismenius Lacus quadrangle.
Enlargement of area in rectangle of the previous image. On Earth, the ridge would be called the terminal moraine of an alpine glacier. Picture taken with HiRISE under the HiWish program. Image from Ismenius Lacus quadrangle.

On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand.

Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level.

This marker indicating sea level is situated between Jerusalem and the Dead Sea.

Sea level

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Average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured.

Average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured.

This marker indicating sea level is situated between Jerusalem and the Dead Sea.
Sea level measurements from 23 long tide gauge records in geologically stable environments show a rise of around 200 mm during the 20th century (2 mm/year).
Sea level sign seen on cliff (circled in red) at Badwater Basin, Death Valley National Park
Water cycles between ocean, atmosphere and glaciers
Global sea level during the Last Glacial Period
Melting glaciers are causing a change in sea level

However, 20th century and current millennium sea level rise is presumed to be caused by climate change, and careful measurement of variations in MSL can offer insights into ongoing climate change.

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.