A report on Ice sheet and Greenland ice sheet

A satellite composite image of Antarctica

Aerial view of the ice sheet on Greenland's east coast

Melting ice during July 2012, images created by NASA show the process in the summer

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.

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.

The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum (LGM) the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South America.

- Ice sheet

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.

- Greenland ice sheet

4 related topics with Alpha

Sea level rise

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Tide gauge measurements show that the current global sea level rise began at the start of the 20th century.

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.

Different sea level rise projections for the 21st century

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).

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.

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.

Melting of the Greenland ice sheet would contribute 4-7.5 m of sea level rise.

Greenland

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Island country that is part of the Kingdom of Denmark.

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.

An English map of 1747, based on Hans Egede's descriptions and misconceptions, by Emanuel Bowen

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.

Greenland bedrock, at current elevation above sea level

Aurora Borealis, the northern lights at the sky 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.

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.

A bilingual sign in Nuuk, displaying the Danish and Kalaallisut for "Parking forbidden for all vehicles"

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

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

Three-quarters of Greenland is covered by the only permanent ice sheet outside of Antarctica.

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.

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.

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>

Additional warming will increase these impacts and may trigger tipping points, such as the melting of the Greenland ice sheet.

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

Ice-sheet model

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A diagram of some of the aspects of an ice-sheet model

In climate modelling, Ice-sheet models use numerical methods to simulate the evolution, dynamics and thermodynamics of ice sheets, such as the Greenland ice sheet, the Antarctic ice sheet or the large ice sheets on the northern hemisphere during the last glacial period.