Cryosphere

The cryosphere (from the Greek κρύος kryos, "cold", "frost" or "ice" and σφαῖρα sphaira, "globe, ball"[2]) is an all-encompassing term for the portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost). Thus, there is a wide overlap with the hydrosphere. The cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation.

Overview of the cryosphere and its larger components[1]

Through these feedback processes, the cryosphere plays a significant role in the global climate and in climate model response to global changes. Approximately 10% of the Earth's surface is covered by ice, but this is rapidly decreasing.[3] The term deglaciation describes the retreat of cryospheric features.

Overall interactions

The cryosphere is one of five components of the climate system. The others are the atmosphere, the hydrosphere, the lithosphere and the biosphere.[4]:1451

Frozen water is found on the Earth’s surface primarily as snow cover, freshwater ice in lakes and rivers, sea ice, glaciers, ice sheets, and frozen ground and permafrost (permanently frozen ground). The residence time of water in each of these cryospheric sub-systems varies widely. Snow cover and freshwater ice are essentially seasonal, and most sea ice, except for ice in the central Arctic, lasts only a few years if it is not seasonal. A given water particle in glaciers, ice sheets, or ground ice, however, may remain frozen for 10–100,000 years or longer, and deep ice in parts of East Antarctica may have an age approaching 1 million years.

Most of the world's ice volume is in Antarctica, principally in the East Antarctic Ice Sheet. In terms of areal extent, however, Northern Hemisphere winter snow and ice extent comprise the largest area, amounting to an average 23% of hemispheric surface area in January. The large areal extent and the important climatic roles of snow and ice, related to their unique physical properties, indicate that the ability to observe and model snow and ice-cover extent, thickness, and physical properties (radiative and thermal properties) is of particular significance for climate research.

There are several fundamental physical properties of snow and ice that modulate energy exchanges between the surface and the atmosphere. The most important properties are the surface reflectance (albedo), the ability to transfer heat (thermal diffusivity), and the ability to change state (latent heat). These physical properties, together with surface roughness, emissivity, and dielectric characteristics, have important implications for observing snow and ice from space. For example, surface roughness is often the dominant factor determining the strength of radar backscatter.[5] Physical properties such as crystal structure, density, length, and liquid water content are important factors affecting the transfers of heat and water and the scattering of microwave energy.

The surface reflectance of incoming solar radiation is important for the surface energy balance (SEB). It is the ratio of reflected to incident solar radiation, commonly referred to as albedo. Climatologists are primarily interested in albedo integrated over the shortwave portion of the electromagnetic spectrum (~300 to 3500 nm), which coincides with the main solar energy input. Typically, albedo values for non-melting snow-covered surfaces are high (~80–90%) except in the case of forests. The higher albedos for snow and ice cause rapid shifts in surface reflectivity in autumn and spring in high latitudes, but the overall climatic significance of this increase is spatially and temporally modulated by cloud cover. (Planetary albedo is determined principally by cloud cover, and by the small amount of total solar radiation received in high latitudes during winter months.) Summer and autumn are times of high-average cloudiness over the Arctic Ocean so the albedo feedback associated with the large seasonal changes in sea-ice extent is greatly reduced. It was found that snow cover exhibited the greatest influence on Earth's radiative balance in the spring (April to May) period when incoming solar radiation was greatest over snow-covered areas.[6]

The thermal properties of cryospheric elements also have important climatic consequences. Snow and ice have much lower thermal diffusivities than air. Thermal diffusivity is a measure of the speed at which temperature waves can penetrate a substance. Snow and ice are many orders of magnitude less efficient at diffusing heat than air. Snow cover insulates the ground surface, and sea ice insulates the underlying ocean, decoupling the surface-atmosphere interface with respect to both heat and moisture fluxes. The flux of moisture from a water surface is eliminated by even a thin skin of ice, whereas the flux of heat through thin ice continues to be substantial until it attains a thickness in excess of 30 to 40 cm. However, even a small amount of snow on top of the ice will dramatically reduce the heat flux and slow down the rate of ice growth. The insulating effect of snow also has major implications for the hydrological cycle. In non-permafrost regions, the insulating effect of snow is such that only near-surface ground freezes and deep-water drainage is uninterrupted.[7]

While snow and ice act to insulate the surface from large energy losses in winter, they also act to retard warming in the spring and summer because of the large amount of energy required to melt ice (the latent heat of fusion, 3.34 x 105 J/kg at 0 °C). However, the strong static stability of the atmosphere over areas of extensive snow or ice tends to confine the immediate cooling effect to a relatively shallow layer, so that associated atmospheric anomalies are usually short-lived and local to regional in scale.[8] In some areas of the world such as Eurasia, however, the cooling associated with a heavy snowpack and moist spring soils is known to play a role in modulating the summer monsoon circulation.[9]

Climate change feedback mechanisms

There are numerous cryosphere-climate feedbacks in the global climate system. These operate over a wide range of spatial and temporal scales from local seasonal cooling of air temperatures to hemispheric-scale variations in ice sheets over time scales of thousands of years. The feedback mechanisms involved are often complex and incompletely understood. For example, Curry et al. (1995) showed that the so-called "simple" sea ice-albedo feedback involved complex interactions with lead fraction, melt ponds, ice thickness, snow cover, and sea-ice extent.

The role of snow cover in modulating the monsoon is just one example of a short-term cryosphere-climate feedback involving the land surface and the atmosphere.[9]

Components

Snow

Snow-covered trees in Kuusamo, Finland
Snow drifts forming around downwind obstructions

Most of the Earth's snow-covered area is located in the Northern Hemisphere, and varies seasonally from 46.5 million km2 in January to 3.8 million km2 in August.[10]

Snow cover is an extremely important storage component in the water balance, especially seasonal snowpacks in mountainous areas of the world. Though limited in extent, seasonal snowpacks in the Earth’s mountain ranges account for the major source of the runoff for stream flow and groundwater recharge over wide areas of the midlatitudes. For example, over 85% of the annual runoff from the Colorado River basin originates as snowmelt. Snowmelt runoff from the Earth's mountains fills the rivers and recharges the aquifers that over a billion people depend on for their water resources.

Furthermore, over 40% of the world's protected areas are in mountains, attesting to their value both as unique ecosystems needing protection and as recreation areas for humans.

Sea ice

Broken pieces of Arctic sea ice with a snow cover
Satellite image of sea ice forming near St. Matthew Island in the Bering Sea

Sea ice covers much of the polar oceans and forms by freezing of sea water. Satellite data since the early 1970s reveal considerable seasonal, regional, and interannual variability in the sea ice covers of both hemispheres. Seasonally, sea-ice extent in the Southern Hemisphere varies by a factor of 5, from a minimum of 3–4 million km2 in February to a maximum of 17–20 million km2 in September.[11][12] The seasonal variation is much less in the Northern Hemisphere where the confined nature and high latitudes of the Arctic Ocean result in a much larger perennial ice cover, and the surrounding land limits the equatorward extent of wintertime ice. Thus, the seasonal variability in Northern Hemisphere ice extent varies by only a factor of 2, from a minimum of 7–9 million km2 in September to a maximum of 14–16 million km2 in March.[12][13]

The ice cover exhibits much greater regional-scale interannual variability than it does hemispherical. For instance, in the region of the Sea of Okhotsk and Japan, maximum ice extent decreased from 1.3 million km2 in 1983 to 0.85 million km2 in 1984, a decrease of 35%, before rebounding the following year to 1.2 million km2.[12] The regional fluctuations in both hemispheres are such that for any several-year period of the satellite record some regions exhibit decreasing ice coverage while others exhibit increasing ice cover.[14]

Lake ice and river ice

Ice forms on rivers and lakes in response to seasonal cooling. The sizes of the ice bodies involved are too small to exert anything other than localized climatic effects. However, the freeze-up/break-up processes respond to large-scale and local weather factors, such that considerable interannual variability exists in the dates of appearance and disappearance of the ice. Long series of lake-ice observations can serve as a proxy climate record, and the monitoring of freeze-up and break-up trends may provide a convenient integrated and seasonally-specific index of climatic perturbations. Information on river-ice conditions is less useful as a climatic proxy because ice formation is strongly dependent on river-flow regime, which is affected by precipitation, snow melt, and watershed runoff as well as being subject to human interference that directly modifies channel flow, or that indirectly affects the runoff via land-use practices.

Lake freeze-up depends on the heat storage in the lake and therefore on its depth, the rate and temperature of any inflow, and water-air energy fluxes. Information on lake depth is often unavailable, although some indication of the depth of shallow lakes in the Arctic can be obtained from airborne radar imagery during late winter (Sellman et al. 1975) and spaceborne optical imagery during summer (Duguay and Lafleur 1997). The timing of breakup is modified by snow depth on the ice as well as by ice thickness and freshwater inflow.

Frozen ground and permafrost

Map showing extent and types of permafrost in the Northern Hemisphere

Permafrost (from perma- 'permanent', and frost) is soil or underwater sediment which continuously remains below 0 °C (32 °F) for two years or more: the oldest permafrost had been continuously frozen for around 700,000 years.[15] While the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than 1,500 m (4,900 ft).[16] Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions.[17] The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which freezes and thaws depending on the season.[18]

Around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost,[19] with the total area of around 18 million km2 (6.9 million sq mi).[20] This includes substantial areas of Alaska, Greenland, Canada, and Siberia. It is also located in high mountain regions, with the Tibetan Plateau a prominent example. Only a minority of permafrost exists in the Southern Hemisphere, where it is consigned to mountain slopes like in the Andes of Patagonia, the Southern Alps of New Zealand, or the highest mountains of Antarctica.[17][15]

Permafrost contains large amounts of dead biomass that have accumulated throughout millennia without having had the chance to fully decompose and release their carbon, making tundra soil a carbon sink.[17] As global warming heats the ecosystem, frozen soil thaws and becomes warm enough for decomposition to start anew, accelerating the permafrost carbon cycle. Depending on conditions at the time of thaw, decomposition can either release carbon dioxide or methane, and these greenhouse gas emissions act as a climate change feedback.[21][22][23] The emissions from thawing permafrost will have a sufficient impact on the climate to impact global carbon budgets. Exact estimates of permafrost emissions are hard to model because of the uncertainty about different thaw processes. There is a widespread agreement they will be smaller than human-caused emissions and not large enough to result in "runaway warming".[24] Instead, projected annual permafrost emissions have been compared to global emissions from deforestation, or to annual emissions of large countries such as Russia, the United States or China.[25]

Glaciers and ice sheets

Representation of glaciers on a topographic map
The Taschachferner glacier in the Ötztal Alps in Austria. The mountain to the left is the Wildspitze (3.768 m), second highest in Austria. To the right is an area with open crevasses where the glacier flows over a kind of large cliff.[26]

Ice sheets and glaciers are flowing ice masses that rest on solid land. They are controlled by snow accumulation, surface and basal melt, calving into surrounding oceans or lakes and internal dynamics. The latter results from gravity-driven creep flow ("glacial flow") within the ice body and sliding on the underlying land, which leads to thinning and horizontal spreading.[27] Any imbalance of this dynamic equilibrium between mass gain, loss and transport due to flow results in either growing or shrinking ice bodies.

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

Relationships between global climate and changes in ice extent are complex. The mass balance of land-based glaciers and ice sheets is determined by the accumulation of snow, mostly in winter, and warm-season ablation due primarily to net radiation and turbulent heat fluxes to melting ice and snow from warm-air advection[28][29] Where ice masses terminate in the ocean, iceberg calving is the major contributor to mass loss. In this situation, the ice margin may extend out into deep water as a floating ice shelf, such as that in the Ross Sea.

A glacier (US: /ˈɡlʃər/; UK: /ˈɡlæsiər, ˈɡlsiər/) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.

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. Between latitudes 35°N and 35°S, glaciers occur only in the Himalayas, Andes, and a few high mountains in East Africa, Mexico, New Guinea and on Zard-Kuh in Iran.[30] With more than 7,000 known glaciers, Pakistan has more glacial ice than any other country outside the polar regions.[31][32] Glaciers cover about 10% of Earth's land surface. Continental glaciers cover nearly 13 million km2 (5 million sq mi) or about 98% of Antarctica's 13.2 million km2 (5.1 million sq mi), with an average thickness of ice 2,100 m (7,000 ft). Greenland and Patagonia also have huge expanses of continental glaciers.[33] The volume of glaciers, not including the ice sheets of Antarctica and Greenland, has been estimated at 170,000 km3.[34]

In glaciology, an ice sheet, also known as a continental glacier,[35] is a mass of glacial ice that covers surrounding terrain and is greater than 50,000 km2 (19,000 sq mi).[36] The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, 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 sheets are bigger than ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery.

Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams.

The present-day polar ice sheets are relatively young in geological terms. The Antarctic Ice Sheet first formed as a small ice cap (maybe several) in the early Oligocene, 33.9-23.0 Ma, but retreated and advanced many times until the Pliocene, 5.33-2.58Ma, when it came to occupy almost all of Antarctica. The Greenland ice sheet did not develop at all until the late Pliocene, but apparently developed very rapidly with the first continental glaciation. This had the unusual effect of allowing fossils of plants that once grew on present-day Greenland to be much better preserved than with the slowly forming Antarctic ice sheet.

Changes due to climate change

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.[37] The rate of ice loss has risen by 57% since the 1990s−from 0.8 to 1.2 trillion tonnes per year.[37]
Melting of glacial mass is approximately linearly related to temperature rise.[38]
Shrinkage of snow cover duration in the Alps, starting ca. end of the 19th century, highlighting climate change adaptation needs[39]
The cryosphere, the area of the Earth covered by snow or ice, is extremely sensitive to changes in global climate.[40] There has been an extensive loss of snow on land since 1981. Some of the largest declines have been observed in the spring.[41] During the 21st century, snow cover is projected to continue its retreat in almost all regions.[42]:39–69

Snow cover decrease

Studies in 2021 found that Northern Hemisphere snow cover has been decreasing since 1978, along with snow depth.[43] Paleoclimate observations show that such changes are unprecedented over the last millennia in Western North America.[44][45][43]

North American winter snow cover increased during the 20th century,[46][47] largely in response to an increase in precipitation.[48]

Because of its close relationship with hemispheric air temperature, snow cover is an important indicator of climate change.

Global warming is expected to result in major changes to the partitioning of snow and rainfall, and to the timing of snowmelt, which will have important implications for water use and management. These changes also involve potentially important decadal and longer time-scale feedbacks to the climate system through temporal and spatial changes in soil moisture and runoff to the oceans.(Walsh 1995). Freshwater fluxes from the snow cover into the marine environment may be important, as the total flux is probably of the same magnitude as desalinated ridging and rubble areas of sea ice.[49] In addition, there is an associated pulse of precipitated pollutants which accumulate over the Arctic winter in snowfall and are released into the ocean upon ablation of the sea ice.

Glaciers and ice sheets decline

Since the beginning of the twentieth century, there has been a widespread retreat of glaciers.[50]:1215 Those glaciers that are not associated with the polar ice sheets lost around 8% of their mass between 1971 and 2019.[50]:1275 In the Andes in South America and in the Himalayas in Asia, the retreat of glaciers could impact water supply.[51][52] The melting of those glaciers could also cause landslides or glacial lake outburst floods.[53]

The melting of the Greenland and West Antarctic ice sheets will continue to contribute to sea level rise over long time-scales. The Greenland ice sheet loss is mainly driven by melt from the top. Antarctic ice loss is driven by warm ocean water melting the outlet glaciers.[50]:1215

Future melt of the West Antarctic ice sheet is potentially abrupt under a high emission scenario, as a consequence of a partial collapse.[54]:595–596 Part of the ice sheet is grounded on bedrock below sea level. This makes it possibly vulnerable to the self-enhancing process of marine ice sheet instability. Marine ice cliff instability could also contribute to a partial collapse. But there is limited evidence for its importance.[50]:1269–1270 A partial collapse of the ice sheet would lead to rapid sea level rise and a local decrease in ocean salinity. It would be irreversible for decades and possibly even millennia.[54]:595–596 The complete loss of the West Antarctic ice sheet would cause over 5 metres (16 ft) of sea level rise.[55]

In contrast to the West Antarctic ice sheet, melt of the Greenland ice sheet is projected to take place more gradually over millennia.[54]:595–596 Sustained warming between 1 °C (1.8 °F) (low confidence) and 4 °C (7.2 °F) (medium confidence) would lead to a complete loss of the ice sheet. This would contribute 7 m (23 ft) to sea levels globally.[56]:363 The ice loss could become irreversible due to a further self-enhancing feedback. This is called the elevation-surface mass balance feedback. When ice melts on top of the ice sheet, the elevation drops. Air temperature is higher at lower altitudes, so this promotes further melting.[56]:362

Sea ice decline

The overall trend indicated in the passive microwave record from 1978 through mid-1995 shows that the extent of Arctic sea ice is decreasing 2.7% per decade.[57] Subsequent work with the satellite passive-microwave data indicates that from late October 1978 through the end of 1996 the extent of Arctic sea ice decreased by 2.9% per decade while the extent of Antarctic sea ice increased by 1.3% per decade.[58] Sea ice extent for the Northern Hemisphere showed a decrease of 3.8% ± 0.3% per decade from November 1978 to December 2012.[59]

Reporting the reduction in Antarctic sea ice extent in mid 2023, researchers concluded that a "regime shift" may be taking place "in which previously important relationships no longer dominate sea ice variability".[60]

Sea ice reflects 50% to 70% of the incoming solar radiation back into space. Only 6% of incoming solar energy is reflected by the ocean.[61] As the climate warms, the area covered by snow or sea ice decreases. After sea ice melts, more energy is absorbed by the ocean, so it warms up. This ice-albedo feedback is a self-reinforcing feedback of climate change.[62] Large-scale measurements of sea ice have only been possible since we have been using satellites.[63]

Sea ice in the Arctic has declined in recent decades in area and volume due to climate change. It has been melting more in summer than it refreezes in winter. The decline of sea ice in the Arctic has been accelerating during the early twenty-first century. It has a rate of decline of 4.7% per decade. It has declined over 50% since the first satellite records.[64][65][66] Ice-free summers are expected to be rare at 1.5 °C (2.7 °F) degrees of warming. They are set to occur at least once every decade with a warming level of 2 °C (3.6 °F).[67]:8 The Arctic will likely become ice-free at the end of some summers before 2050.[50]:9

Sea ice extent in Antarctica varies a lot year by year. This makes it difficult to determine a trend, and record highs and record lows have been observed between 2013 and 2023. The general trend since 1979, the start of the satellite measurements, has been roughly flat. Between 2015 and 2023, there has been a decline in sea ice, but due to the high variability, this does not correspond to a significant trend.[68]

Permafrost thaw

Recently thawed Arctic permafrost and coastal erosion on the Beaufort Sea, Arctic Ocean, near Point Lonely, Alaska in 2013.

Globally, permafrost warmed by about 0.3 °C (0.54 °F) between 2007 and 2016, with stronger warming observed in the continuous permafrost zone relative to the discontinuous zone. Observed warming was up to 3 °C (5.4 °F) in parts of Northern Alaska (early 1980s to mid-2000s) and up to 2 °C (3.6 °F) in parts of the Russian European North (1970–2020). This warming inevitably causes permafrost to thaw: active layer thickness has increased in the European and Russian Arctic across the 21st century and at high elevation areas in Europe and Asia since the 1990s.[69]:1237 Between 2000 and 2018, the average active layer thickness had increased from ~127 centimetres (4.17 ft) to ~145 centimetres (4.76 ft), at an average annual rate of ~0.65 centimetres (0.26 in).[70] In Yukon, the zone of continuous permafrost might have moved 100 kilometres (62 mi) poleward since 1899, but accurate records only go back 30 years. The extent of subsea permafrost is decreasing as well; as of 2019, ~97% of permafrost under Arctic ice shelves is becoming warmer and thinner.[71][24]:1281 Based on high agreement across model projections, fundamental process understanding, and paleoclimate evidence, it is virtually certain that permafrost extent and volume will continue to shrink as the global climate warms, with the extent of the losses determined by the magnitude of warming.[69]:1283

Permafrost thaw is associated with a wide range of issues, and International Permafrost Association (IPA) exists to help address them. It convenes International Permafrost Conferences and maintains Global Terrestrial Network for Permafrost, which undertakes special projects such as preparing databases, maps, bibliographies, and glossaries, and coordinates international field programmes and networks.[72]

"Cryospheric sciences" is an umbrella term for the study of the cryosphere. As an interdisciplinary Earth science, many disciplines contribute to it, most notably geology, hydrology, and meteorology and climatology; in this sense, it is comparable to glaciology.

The term deglaciation describes the retreat of cryospheric features.

See also

References

  1. "Cryosphere - Maps and Graphics at UNEP/GRID-Arendal". 2007-08-26. Archived from the original on 2007-08-26. Retrieved 2023-09-25.
  2. σφαῖρα Archived 2017-05-10 at the Wayback Machine, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
  3. "Global Ice Viewer – Climate Change: Vital Signs of the Planet". climate.nasa.gov. Retrieved 27 November 2021.
  4. Planton, S. (2013). "Annex III: Glossary" (PDF). In Stocker, T.F.; Qin, D.; Plattner, G.-K.; Tignor, M.; Allen, S.K.; Boschung, J.; Nauels, A.; Xia, Y.; Bex, V.; Midgley, P.M. (eds.). Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
  5. Hall, Dorothy K. (1985). Remote Sensing of Ice and Snow. Dordrecht: Springer Netherlands. ISBN 978-94-009-4842-6.
  6. Groisman, Pavel Ya.; Karl, Thomas R.; Knight, Richard W. (14 January 1994). "Observed Impact of Snow Cover on the Heat Balance and the Rise of Continental Spring Temperatures". Science. 263 (5144): 198–200. Bibcode:1994Sci...263..198G. doi:10.1126/science.263.5144.198. PMID 17839175. S2CID 9932394. Retrieved 25 February 2022.
  7. Lynch-Stieglitz, M., 1994: The development and validation of a simple snow model for the GISS GCM. J. Climate, 7, 1842–1855.
  8. Cohen, J., and D. Rind, 1991: The effect of snow cover on the climate. J. Climate, 4, 689–706.
  9. Vernekar, A. D., J. Zhou, and J. Shukla, 1995: The effect of Eurasian snow cover on the Indian monsoon. J. Climate, 8, 248–266.
  10. Robinson, D. A., K. F. Dewey, and R. R. Heim, 1993: Global snow cover monitoring: an update. Bull. Amer. Meteorol. Soc., 74, 1689–1696.
  11. Zwally, H. J., J. C. Comiso, C. L. Parkinson, W. J. Campbell, F. D. Carsey, and P. Gloersen, 1983: Antarctic Sea Ice, 1973–1976: Satellite Passive-Microwave Observations. NASA SP-459, National Aeronautics and Space Administration, Washington, D.C., 206 pp.
  12. Gloersen, P., W. J. Campbell, D. J. Cavalieri, J. C. Comiso, C. L. Parkinson, and H. J. Zwally, 1992: Arctic and Antarctic Sea Ice, 1978–1987: Satellite Passive-Microwave Observations and Analysis. NASA SP-511, National Aeronautics and Space Administration, Washington, D.C., 290 pp.
  13. Parkinson, C. L., J. C. Comiso, H. J. Zwally, D. J. Cavalieri, P. Gloersen, and W. J. Campbell, 1987: Arctic Sea Ice, 1973–1976: Satellite Passive-Microwave Observations, NASA SP-489, National Aeronautics and Space Administration, Washington, D.C., 296 pp.
  14. Parkinson, C. L., 1995: Recent sea-ice advances in Baffin Bay/Davis Strait and retreats in the Bellinshausen Sea. Annals of Glaciology, 21, 348–352.
  15. McGee, David; Gribkoff, Elizabeth (4 August 2022). "Permafrost". MIT Climate Portal. Retrieved 27 September 2023.
  16. "What is Permafrost?". International Permafrost Association. Retrieved 27 September 2023.
  17. Denchak, Melissa (26 June 2018). "Permafrost: Everything You Need to Know". Natural Resources Defense Council. Retrieved 27 September 2023.
  18. Cooper, M. G.; Zhou, T.; Bennett, K. E.; Bolton, W. R.; Coon, E. T.; Fleming, S. W.; Rowland, J. C.; Schwenk, J. (4 January 2023). "Detecting Permafrost Active Layer Thickness Change From Nonlinear Baseflow Recession". Water Resources Research. 57 (1): e2022WR033154. Bibcode:2023WRR....5933154C. doi:10.1029/2022WR033154. S2CID 255639677.
  19. Obu, J. (2021). "How Much of the Earth's Surface is Underlain by Permafrost?". Journal of Geophysical Research: Earth Surface. 126 (5): e2021JF006123. Bibcode:2021JGRF..12606123O. doi:10.1029/2021JF006123.
  20. Sayedi, Sayedeh Sara; Abbott, Benjamin W; Thornton, Brett F; Frederick, Jennifer M; Vonk, Jorien E; Overduin, Paul; Schädel, Christina; Schuur, Edward A G; Bourbonnais, Annie; Demidov, Nikita; Gavrilov, Anatoly (22 December 2020). "Subsea permafrost carbon stocks and climate change sensitivity estimated by expert assessment". Environmental Research Letters. 15 (12): B027-08. Bibcode:2020AGUFMB027...08S. doi:10.1088/1748-9326/abcc29. S2CID 234515282.
  21. Schuur, T. (November 22, 2019). "Permafrost and the Global Carbon Cycle". Natural Resources Defense Council via NOAA.
  22. Koven, Charles D.; Ringeval, Bruno; Friedlingstein, Pierre; Ciais, Philippe; Cadule, Patricia; Khvorostyanov, Dmitry; Krinner, Gerhard; Tarnocai, Charles (6 September 2011). "Permafrost carbon-climate feedbacks accelerate global warming". Proceedings of the National Academy of Sciences. 108 (36): 14769–14774. Bibcode:2011PNAS..10814769K. doi:10.1073/pnas.1103910108. PMC 3169129. PMID 21852573.
  23. Galera, L. A.; Eckhardt, T.; Beer C., Pfeiffer E.-M.; Knoblauch, C. (22 March 2023). "Ratio of in situ CO2 to CH4 production and its environmental controls in polygonal tundra soils of Samoylov Island, Northeastern Siberia". Journal of Geophysical Research: Biogeosciences. 128 (4): e2022JG006956. Bibcode:2023JGRG..12806956G. doi:10.1029/2022JG006956. S2CID 257700504.
  24. Fox-Kemper, B., H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L. Edwards, N.R. Golledge, M. Hemer, R.E. Kopp, G. Krinner, A. Mix, D. Notz, S. Nowicki, I.S. Nurhati, L. Ruiz, J.-B. Sallée, A.B.A. Slangen, and Y. Yu, 2021: Chapter 9: Ocean, Cryosphere and Sea Level Change. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1211–1362.
  25. Schuur, Edward A.G.; Abbott, Benjamin W.; Commane, Roisin; Ernakovich, Jessica; Euskirchen, Eugenie; Hugelius, Gustaf; Grosse, Guido; Jones, Miriam; Koven, Charlie; Leshyk, Victor; Lawrence, David; Loranty, Michael M.; Mauritz, Marguerite; Olefeldt, David; Natali, Susan; Rodenhizer, Heidi; Salmon, Verity; Schädel, Christina; Strauss, Jens; Treat, Claire; Turetsky, Merritt (2022). "Permafrost and Climate Change: Carbon Cycle Feedbacks From the Warming Arctic". Annual Review of Environment and Resources. 47: 343–371. doi:10.1146/annurev-environ-012220-011847. S2CID 252986002.
  26. Google Maps: Distance between Wildspitze and Hinterer Brochkogel, cf. image scale at lower edge of screen
  27. Greve, R.; Blatter, H. (2009). Dynamics of Ice Sheets and Glaciers. Springer. doi:10.1007/978-3-642-03415-2. ISBN 978-3-642-03414-5.
  28. Paterson, W. S. B., 1993: World sea level and the present mass balance of the Antarctic ice sheet. In: W.R. Peltier (ed.), Ice in the Climate System, NATO ASI Series, I12, Springer-Verlag, Berlin, 131–140.
  29. Van den Broeke, M. R., 1996: The atmospheric boundary layer over ice sheets and glaciers. Utrecht, Universitiet Utrecht, 178 pp.
  30. Post, Austin; LaChapelle, Edward R (2000). Glacier ice. Seattle: University of Washington Press. ISBN 978-0-295-97910-6.
  31. Staff (June 9, 2020). "Millions at risk as melting Pakistan glaciers raise flood fears". Al Jazeera. Retrieved 2020-06-09.
  32. Craig, Tim (2016-08-12). "Pakistan has more glaciers than almost anywhere on Earth. But they are at risk". The Washington Post. ISSN 0190-8286. Retrieved 2020-09-04. With 7,253 known glaciers, including 543 in the Chitral Valley, there is more glacial ice in Pakistan than anywhere on Earth outside the polar regions, according to various studies.
  33. National Geographic Almanac of Geography, 2005, ISBN 0-7922-3877-X, p. 149.
  34. "170'000 km cube d'eau dans les glaciers du monde". ArcInfo. Aug 6, 2015. Archived from the original on August 17, 2017.
  35. American Meteorological Society, Glossary of Meteorology Archived 2012-06-23 at the Wayback Machine
  36. "Glossary of Important Terms in Glacial Geology". Archived from the original on 2006-08-29. Retrieved 2006-08-22.
  37. Slater, Thomas; Lawrence, Isobel R.; Otosaka, Inès N.; Shepherd, Andrew; Gourmelen, Noel; Jakob, Livia; Tepes, Paul; Gilbert, Lin; Nienow, Peter (25 January 2021). "Review article: Earth's ice imbalance". The Cryosphere. 15 (1): 233–246. Bibcode:2021TCry...15..233S. doi:10.5194/tc-15-233-2021. Fig. 4.
  38. Rounce, David R.; Hock, Regine; Maussion, Fabien; Hugonnet, Romain; et al. (5 January 2023). "Global glacier change in the 21st century: Every increase in temperature matters". Science. 379 (6627): 78–83. Bibcode:2023Sci...379...78R. doi:10.1126/science.abo1324. PMID 36603094. S2CID 255441012.
  39. Carrer, Marco; Dibona, Raffaella; Prendin, Angela Luisa; Brunetti, Michele (February 2023). "Recent waning snowpack in the Alps is unprecedented in the last six centuries". Nature Climate Change. 13 (2): 155–160. Bibcode:2023NatCC..13..155C. doi:10.1038/s41558-022-01575-3. ISSN 1758-6798.
  40. Getting to Know the Cryosphere Archived 15 December 2019 at the Wayback Machine, Earth Labs
  41. Thackeray, Chad W.; Derksen, Chris; Fletcher, Christopher G.; Hall, Alex (2019-12-01). "Snow and Climate: Feedbacks, Drivers, and Indices of Change". Current Climate Change Reports. 5 (4): 322–333. doi:10.1007/s40641-019-00143-w. ISSN 2198-6061. S2CID 201675060.
  42. IPCC, 2019: Technical Summary [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, E. Poloczanska, K. Mintenbeck, M. Tignor, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.- O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 39–69. https://doi.org/10.1017/9781009157964.002
  43. Fox-Kemper, B.; Hewitt, H.T.; Xiao, C.; Aðalgeirsdóttir, G.; Drijfhout, S.S.; Edwards, T.L.; Golledge, N.R.; Hemer, M.; Kopp, R.E.; Krinner, G.; Mix, A. (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S.L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.). "Ocean, Cryosphere and Sea Level Change" (PDF). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA. 2021: 1283–1285. doi:10.1017/9781009157896.011. ISBN 9781009157896.
  44. Pederson, Gregory T.; Gray, Stephen T.; Woodhouse, Connie A.; Betancourt, Julio L.; Fagre, Daniel B.; Littell, Jeremy S.; Watson, Emma; Luckman, Brian H.; Graumlich, Lisa J. (2011-07-15). "The Unusual Nature of Recent Snowpack Declines in the North American Cordillera". Science. 333 (6040): 332–335. Bibcode:2011Sci...333..332P. doi:10.1126/science.1201570. ISSN 0036-8075. PMID 21659569. S2CID 29486298.
  45. Belmecheri, Soumaya; Babst, Flurin; Wahl, Eugene R.; Stahle, David W.; Trouet, Valerie (2016). "Multi-century evaluation of Sierra Nevada snowpack". Nature Climate Change. 6 (1): 2–3. Bibcode:2016NatCC...6....2B. doi:10.1038/nclimate2809. ISSN 1758-6798.
  46. Brown, Ross D.; Goodison, Barry E.; Brown, Ross D.; Goodison, Barry E. (1996-06-01). "Interannual Variability in Reconstructed Canadian Snow Cover, 1915–1992". Journal of Climate. 9 (6): 1299–1318. Bibcode:1996JCli....9.1299B. doi:10.1175/1520-0442(1996)009<1299:ivircs>2.0.co;2.
  47. Hughes, M. G.; Frei, A.; Robinson, D.A. (1996). "Historical analysis of North American snow cover extent: merging satellite and station-derived snow cover observations". Proceedings of the Annual Meeting - Eastern Snow Conference. Williamsburg, Virginia: Eastern Snow Conference. pp. 21–31. ISBN 9780920081181.
  48. Groisman, P. Ya, and D. R. Easterling, 1994: Variability and trends of total precipitation and snowfall over the United States and Canada. J. Climate, 7, 184–205.
  49. Prinsenberg, S. J. 1988: Ice-cover and ice-ridge contributions to the freshwater contents of Hudson Bay and Foxe Basin. Arctic, 41, 6–11.
  50. Fox-Kemper, B., H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L. Edwards, N.R. Golledge, M. Hemer, R.E. Kopp, G.  Krinner, A. Mix, D. Notz, S. Nowicki, I.S. Nurhati, L. Ruiz, J.-B. Sallée, A.B.A. Slangen, and Y. Yu, 2021: Chapter 9: Ocean, Cryosphere and Sea Level Change. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L.  Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US doi:10.1017/9781009157896.011.
  51. Lee, Ethan; Carrivick, Jonathan L.; Quincey, Duncan J.; Cook, Simon J.; James, William H. M.; Brown, Lee E. (2021-12-20). "Accelerated mass loss of Himalayan glaciers since the Little Ice Age". Scientific Reports. 11 (1): 24284. Bibcode:2021NatSR..1124284L. doi:10.1038/s41598-021-03805-8. ISSN 2045-2322. PMC 8688493. PMID 34931039.
  52. The Andean glacier and water atlas : the impact of glacier retreat on water resources. Tina Schoolmeester, Koen Verbist, Kari Synnøve Johansen. Paris, France. 2018. p. 9. ISBN 978-92-3-100286-1. OCLC 1085575303.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  53. "As Himalayan Glaciers Melt, a Water Crisis Looms in South Asia". Yale E360. Retrieved 2023-05-01.
  54. Collins M., M. Sutherland, L. Bouwer, S.-M. Cheong, T. Frölicher, H. Jacot Des Combes, M. Koll Roxy, I. Losada, K. McInnes, B. Ratter, E. Rivera-Arriaga, R.D. Susanto, D. Swingedouw, and L. Tibig, 2019: Chapter 6: Extremes, Abrupt Changes and Managing Risk. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C.  Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 589–655. https://doi.org/10.1017/9781009157964.008.
  55. Stokes, Chris R.; Abram, Nerilie J.; Bentley, Michael J.; et al. (August 2022). "Response of the East Antarctic Ice Sheet to past and future climate change". Nature. 608 (7922): 275–286. Bibcode:2022Natur.608..275S. doi:10.1038/s41586-022-04946-0. ISSN 1476-4687. PMID 35948707. S2CID 251494636.
  56. Oppenheimer, M., B.C. Glavovic , J. Hinkel, R. van de Wal, A.K. Magnan, A. Abd-Elgawad, R. Cai, M. Cifuentes-Jara, R.M. DeConto, T. Ghosh, J. Hay, F. Isla, B. Marzeion, B. Meyssignac, and Z. Sebesvari, 2019: Chapter 4: Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 321–445. https://doi.org/10.1017/9781009157964.006.
  57. Johannessen, O. M., M. Miles, and E. Bjørgo, 1995: The Arctic’s shrinking sea ice. Nature, 376, 126–127.
  58. Cavalieri, D. J., P. Gloersen, C. L. Parkinson, J. C. Comiso, and H. J. Zwally, 1997: Observed hemispheric asymmetry in global sea ice changes. Science, 278, 1104–1106.
  59. "Climate Change 2013: The Physical Science Basis" (PDF). ipcc. Intergovernmental Panel on Climate Change. p. 324. Archived (PDF) from the original on 2014-11-11. Retrieved 16 June 2015.
  60. Purich, Ariaan; Doddridge, Edward W. (13 September 2023). "Record low Antarctic sea ice coverage indicates a new sea ice state". Communications Earth & Environment. 4: 314. doi:10.1038/s43247-023-00961-9. S2CID 261855193.
  61. "Thermodynamics: Albedo | National Snow and Ice Data Center". nsidc.org. Archived from the original on 11 October 2017. Retrieved 14 October 2020.
  62. "How does sea ice affect global climate?". NOAA. Retrieved 21 April 2023.
  63. "Arctic Report Card 2012". NOAA. Archived from the original on 17 February 2013. Retrieved 8 May 2013.
  64. Huang, Yiyi; Dong, Xiquan; Bailey, David A.; Holland, Marika M.; Xi, Baike; DuVivier, Alice K.; Kay, Jennifer E.; Landrum, Laura L.; Deng, Yi (2019-06-19). "Thicker Clouds and Accelerated Arctic Sea Ice Decline: The Atmosphere-Sea Ice Interactions in Spring". Geophysical Research Letters. 46 (12): 6980–6989. Bibcode:2019GeoRL..46.6980H. doi:10.1029/2019gl082791. hdl:10150/634665. ISSN 0094-8276. S2CID 189968828.
  65. Senftleben, Daniel; Lauer, Axel; Karpechko, Alexey (2020-02-15). "Constraining Uncertainties in CMIP5 Projections of September Arctic Sea Ice Extent with Observations". Journal of Climate. 33 (4): 1487–1503. Bibcode:2020JCli...33.1487S. doi:10.1175/jcli-d-19-0075.1. ISSN 0894-8755. S2CID 210273007.
  66. Yadav, Juhi; Kumar, Avinash; Mohan, Rahul (2020-05-21). "Dramatic decline of Arctic sea ice linked to global warming". Natural Hazards. 103 (2): 2617–2621. doi:10.1007/s11069-020-04064-y. ISSN 0921-030X. S2CID 218762126.
  67. IPCC, 2018: Summary for Policymakers. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 3-24. https://doi.org/10.1017/9781009157940.001.
  68. "Understanding climate: Antarctic sea ice extent". NOAA Climate.gov. 14 March 2023. Retrieved 2023-03-26.
  69. Fox-Kemper, B., H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L. Edwards, N.R. Golledge, M. Hemer, R.E. Kopp, G.  Krinner, A. Mix, D. Notz, S. Nowicki, I.S. Nurhati, L. Ruiz, J.-B. Sallée, A.B.A. Slangen, and Y. Yu, 2021: Chapter 9: Ocean, Cryosphere and Sea Level Change. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L.  Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1211–1362, doi:10.1017/9781009157896.011.
  70. Li, Chuanhua; Wei, Yufei; Liu, Yunfan; Li, Liangliang; Peng, Lixiao; Chen, Jiahao; Liu, Lihui; Dou, Tianbao; Wu, Xiaodong (14 June 2022). "Active Layer Thickness in the Northern Hemisphere: Changes From 2000 to 2018 and Future Simulations". JGR Atmospheres. 127 (12): e2022JD036785. Bibcode:2022JGRD..12736785L. doi:10.1029/2022JD036785. S2CID 249696017.
  71. Overduin, P. P.; Schneider von Deimling, T.; Miesner, F.; Grigoriev, M. N.; Ruppel, C.; Vasiliev, A.; Lantuit, H.; Juhls, B.; Westermann, S. (17 April 2019). "Submarine Permafrost Map in the Arctic Modeled Using 1-D Transient Heat Flux (SuPerMAP)" (PDF). Journal of Geophysical Research: Oceans. 124 (6): 3490–3507. Bibcode:2019JGRC..124.3490O. doi:10.1029/2018JC014675. hdl:1912/24566. S2CID 146331663.
  72. "Frozen Ground, the News Bulletin of the IPA". International Permafrost Association. 2014-02-10. Retrieved 2016-04-28.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.