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Thermohaline circulation

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A summary of the path of the thermohaline circulation. Blue paths represent deep-water currents, while red paths represent surface currents.
Thermohaline circulation

Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes.[1][2] The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content, factors which together determine the density of sea water. Wind-driven surface currents (such as the Gulf Stream) travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water). This dense water then flows into the ocean basins.[3] While the bulk of it upwells in the Southern Ocean, the oldest waters (with a transit time of about 1000 years) upwell in the North Pacific.[4] Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth's oceans a global system.[3] The water in these circuits transport both energy (in the form of heat) and mass (dissolved solids and gases) around the globe. As such, the state of the circulation has a large impact on the climate of the Earth.

The thermohaline circulation is sometimes called the ocean conveyor belt, the great ocean conveyor, or the global conveyor belt, coined by climate scientist Wallace Smith Broecker.[5][6] It is also referred to as the meridional overturning circulation, or MOC. This name is used because not every circulation pattern caused by temperature and salinity gradients is necessarily part of a single global circulation. Further, it is difficult to separate the parts of the circulation driven by temperature and salinity alone from those driven by other factors, such as the wind and tidal forces.[7]

This global circulation has two major limbs - Atlantic meridional overturning circulation (AMOC), centered in the north Atlantic Ocean, and Southern Ocean overturning circulation or Southern Ocean meridional circulation (SMOC), around Antarctica. Because 90% of the human population lives in the Northern Hemisphere,[8] the AMOC has been far better studied, but both are very important for the global climate. Both of them also appear to be slowing down due to climate change, as the melting of the ice sheets dilutes salty flows such as the Antarctic bottom water.[9][10] Either one could outright collapse to a much weaker state, which would be an example of tipping points in the climate system. The hemisphere which experiences the collapse of its circulation would experience less precipitation and become drier, while the other hemisphere would become wetter. Marine ecosystems are also likely to receive fewer nutrients and experience greater ocean deoxygenation. In the Northern Hemisphere, AMOC's collapse would also substantially lower the temperatures in many European countries, while the east coast of North America would experience accelerated sea level rise. The collapse of either circulation is generally believed to be more than a century away and may only occur under high warming, but there is a lot of uncertainty about these projections.[10][11]

History of research

[edit]
Effect of temperature and salinity upon sea water density maximum and sea water freezing temperature.

It has long been known that wind can drive ocean currents, but only at the surface.[12] In the 19th century, some oceanographers suggested that the convection of heat could drive deeper currents. In 1908, Johan Sandström performed a series of experiments at a Bornö Marine Research Station which proved that the currents driven by thermal energy transfer exist, but require that "heating occurs at a greater depth than cooling".[13][1] Normally, the opposite occurs, because ocean water is heated from above by the Sun and becomes less dense, so the surface layer floats on the surface above the cooler, denser layers, resulting in ocean stratification. However, wind and tides cause mixing between these water layers, with diapycnal mixing caused by tidal currents being one example.[14] This mixing is what enables the convection between ocean layers, and thus, deep water currents.[1]

In the 1920s, Sandström's framework was expanded by accounting for the role of salinity in ocean layer formation.[1] Salinity is important because like temperature, it affects water density. Water becomes less dense as its temperature increases and the distance between its molecules expands, but more dense as the salinity increases, since there is a larger mass of salts dissolved within that water.[15] Further, while fresh water is at its most dense at 4 °C, seawater only gets denser as it cools, up until it reaches the freezing point. That freezing point is also lower than for fresh water due to salinity, and can be below −2 °C, depending on salinity and pressure.[16]

Structure

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The global conveyor belt on a continuous-ocean map (animation)

These density differences caused by temperature and salinity ultimately separate ocean water into distinct water masses, such as the North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW). These two waters are the main drivers of the circulation, which was established in 1960 by Henry Stommel and Arnold B. Arons.[17] They have chemical, temperature and isotopic ratio signatures (such as 231Pa / 230Th ratios) which can be traced, their flow rate calculated, and their age determined. NADW is formed because North Atlantic is a rare place in the ocean where precipitation, which adds fresh water to the ocean and so reduces its salinity, is outweighed by evaporation, in part due to high windiness. When water evaporates, it leaves salt behind, and so the surface waters of the North Atlantic are particularly salty. North Atlantic is also an already cool region, and evaporative cooling reduces water temperature even further. Thus, this water sinks downward in the Norwegian Sea, fills the Arctic Ocean Basin and spills southwards through the Greenland-Scotland-Ridge – crevasses in the submarine sills that connect Greenland, Iceland and Great Britain. It cannot flow towards the Pacific Ocean due to the narrow shallows of the Bering Strait, but it does slowly flow into the deep abyssal plains of the south Atlantic.[18]

In the Southern Ocean, strong katabatic winds blowing from the Antarctic continent onto the ice shelves will blow the newly formed sea ice away, opening polynyas in locations such as Weddell and Ross Seas, off the Adélie Coast and by Cape Darnley. The ocean, no longer protected by sea ice, suffers a brutal and strong cooling (see polynya). Meanwhile, sea ice starts reforming, so the surface waters also get saltier, hence very dense. In fact, the formation of sea ice contributes to an increase in surface seawater salinity; saltier brine is left behind as the sea ice forms around it (pure water preferentially being frozen). Increasing salinity lowers the freezing point of seawater, so cold liquid brine is formed in inclusions within a honeycomb of ice. The brine progressively melts the ice just beneath it, eventually dripping out of the ice matrix and sinking. This process is known as brine rejection. The resulting Antarctic bottom water sinks and flows north and east. It is denser than the NADW, and so flows beneath it. AABW formed in the Weddell Sea will mainly fill the Atlantic and Indian Basins, whereas the AABW formed in the Ross Sea will flow towards the Pacific Ocean. At the Indian Ocean, a vertical exchange of a lower layer of cold and salty water from the Atlantic and the warmer and fresher upper ocean water from the tropical Pacific occurs, in what is known as overturning. In the Pacific Ocean, the rest of the cold and salty water from the Atlantic undergoes haline forcing, and becomes warmer and fresher more quickly.[19][20][21][22][23]

Surface water flows north and sinks in the dense ocean near Iceland and Greenland. It joins the global thermohaline circulation into the Indian Ocean, and the Antarctic Circumpolar Current.[24]

The out-flowing undersea of cold and salty water makes the sea level of the Atlantic slightly lower than the Pacific and salinity or halinity of water at the Atlantic higher than the Pacific. This generates a large but slow flow of warmer and fresher upper ocean water from the tropical Pacific to the Indian Ocean through the Indonesian Archipelago to replace the cold and salty Antarctic Bottom Water. This is also known as 'haline forcing' (net high latitude freshwater gain and low latitude evaporation). This warmer, fresher water from the Pacific flows up through the South Atlantic to Greenland, where it cools off and undergoes evaporative cooling and sinks to the ocean floor, providing a continuous thermohaline circulation.[25][26]

Upwelling

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As the deep waters sink into the ocean basins, they displace the older deep-water masses, which gradually become less dense due to continued ocean mixing. Thus, some water is rising, in what is known as upwelling. Its speeds are very slow even compared to the movement of the bottom water masses. It is therefore difficult to measure where upwelling occurs using current speeds, given all the other wind-driven processes going on in the surface ocean. Deep waters have their own chemical signature, formed from the breakdown of particulate matter falling into them over the course of their long journey at depth. A number of scientists have tried to use these tracers to infer where the upwelling occurs. Wallace Broecker, using box models, has asserted that the bulk of deep upwelling occurs in the North Pacific, using as evidence the high values of silicon found in these waters. Other investigators have not found such clear evidence.[27]

Computer models of ocean circulation increasingly place most of the deep upwelling in the Southern Ocean, associated with the strong winds in the open latitudes between South America and Antarctica.[28] Direct estimates of the strength of the thermohaline circulation have also been made at 26.5°N in the North Atlantic, by the UK-US RAPID programme. It combines direct estimates of ocean transport using current meters and subsea cable measurements with estimates of the geostrophic current from temperature and salinity measurements to provide continuous, full-depth, basin-wide estimates of the meridional overturning circulation. However, it has only been operating since 2004, which is too short when the timescale of the circulation is measured in centuries.[29]

Effects on global climate

[edit]

The thermohaline circulation plays an important role in supplying heat to the polar regions, and thus in regulating the amount of sea ice in these regions, although poleward heat transport outside the tropics is considerably larger in the atmosphere than in the ocean.[30] Changes in the thermohaline circulation are thought to have significant impacts on the Earth's radiation budget.

Large influxes of low-density meltwater from Lake Agassiz and deglaciation in North America are thought to have led to a shifting of deep water formation and subsidence in the extreme North Atlantic and caused the climate period in Europe known as the Younger Dryas.[31]

Slowdown or collapse of AMOC

[edit]
Modelled 21st century warming under the "intermediate" global warming scenario (top). The potential collapse of the subpolar gyre in this scenario (middle). The collapse of the entire Atlantic Meriditional Overturning Circulation (bottom).
This section is an excerpt from Atlantic meridional overturning circulation § Major review studies.[edit]

In 2021, the IPCC Sixth Assessment Report again said the AMOC is "very likely" to decline within the 21st century and that there was a "high confidence" changes to it would be reversible within centuries if warming was reversed.[32]: 19  Unlike the Fifth Assessment Report, it had only "medium confidence" rather than "high confidence" in the AMOC avoiding a collapse before the end of the 21st century. This reduction in confidence was likely influenced by several review studies that draw attention to the circulation stability bias within general circulation models,[33][34] and simplified ocean-modelling studies suggesting the AMOC may be more vulnerable to abrupt change than larger-scale models suggest.[35]

In 2022, an extensive assessment of all potential climate tipping points identified 16 plausible climate tipping points, including a collapse of the AMOC. It said a collapse would most likely be triggered by 4 °C (7.2 °F) of global warming but that there is enough uncertainty to suggest it could be triggered at warming levels of between 1.4 °C (2.5 °F) and 8 °C (14 °F). The assessment estimates once AMOC collapse is triggered, it would occur between 15 and 300 years, and most likely at around 50 years.[36][37] The assessment also treated the collapse of the Northern Subpolar Gyre as a separate tipping point that could tip at between 1.1 °C (2.0 °F) degrees and 3.8 °C (6.8 °F), although this is only simulated by a fraction of climate models. The most likely tipping point for the collapse of Northern Subpolar Gyre is 1.8 °C (3.2 °F) and once triggered, the collapse of the gyre would occur between 5 and 50 years, and most likely at 10 years. The loss of this convection is estimated to lower the global temperature by 0.5 °C (0.90 °F) while the average temperature in Europe would decrease by around 3 °C (5.4 °F). There would also be substantial effects on regional precipitation levels.[36][37]
This section is an excerpt from Atlantic meridional overturning circulation § Effects of AMOC slowdown.[edit]

As of 2024, there is no consensus on whether a consistent slowing of the AMOC circulation has occurred but there is little doubt it will occur in the event of continued climate change.[38] According to the IPCC, the most-likely effects of future AMOC decline are reduced precipitation in mid-latitudes, changing patterns of strong precipitation in the tropics and Europe, and strengthening storms that follow the North Atlantic track.[38] In 2020, research found a weakened AMOC would slow the decline in Arctic sea ice.[39] and result in atmospheric trends similar to those that likely occurred during the Younger Dryas,[40] such as a southward displacement of Intertropical Convergence Zone. Changes in precipitation under high-emissions scenarios would be far larger.[39]

A decline in the AMOC would be accompanied by an acceleration of sea level rise along the U.S. East Coast;[38] at least one such event has been connected to a temporary slowing of the AMOC.[41] This effect would be caused by increased warming and thermal expansion of coastal waters, which would transfer less of their heat toward Europe; it is one of the reasons sea level rise along the U.S. East Coast is estimated to be three-to-four times higher than the global average.[42][43][44]

Slowdown or collapse of SMOC

[edit]
This section is an excerpt from Southern Ocean overturning circulation § Climate change impacts.[edit]

Additionally, the main controlling pattern of the extratropical Southern Hemisphere's climate is the Southern Annular Mode (SAM), which has been spending more and more years in its positive phase due to climate change (as well as the aftermath of ozone depletion), which means more warming and more precipitation over the ocean due to stronger westerlies, freshening the Southern Ocean further.[45][46]: 1240  Climate models currently disagree on whether the Southern Ocean circulation would continue to respond to changes in SAM the way it does now, or if it will eventually adjust to them. As of early 2020s, their best, limited-confidence estimate is that the lower cell would continue to weaken, while the upper cell may strengthen by around 20% over the 21st century.[46] A key reason for the uncertainty is the poor and inconsistent representation of ocean stratification in even the CMIP6 models – the most advanced generation available as of early 2020s.[47] Furthermore, the largest long-term role in the state of the circulation is played by Antarctic meltwater,[48] and Antarctic ice loss had been the least-certain aspect of future sea level rise projections for a long time.[49]

Similar processes are taking place with Atlantic meridional overturning circulation (AMOC), which is also affected by the ocean warming and by meltwater flows from the declining Greenland ice sheet.[50] It is possible that both circulations may not simply continue to weaken in response to increased warming and freshening, but eventually collapse to a much weaker state outright, in a way which would be difficult to reverse and constitute an example of tipping points in the climate system.[51] There is paleoclimate evidence for the overturning circulation being substantially weaker than now during past periods that were both warmer and colder than now.[52] However, Southern Hemisphere is only inhabited by 10% of the world's population, and the Southern Ocean overturning circulation has historically received much less attention than the AMOC. Consequently, while multiple studies have set out to estimate the exact level of global warming which could result in AMOC collapsing, the timeframe over which such collapse may occur, and the regional impacts it would cause, much less equivalent research exists for the Southern Ocean overturning circulation as of the early 2020s. There has been a suggestion that its collapse may occur between 1.7 °C (3.1 °F) and 3 °C (5.4 °F), but this estimate is much less certain than for many other tipping points.[51]

See also

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References

[edit]
  1. ^ a b c d Rahmstorf, S (2003). "The concept of the thermohaline circulation" (PDF). Nature. 421 (6924): 699. Bibcode:2003Natur.421..699R. doi:10.1038/421699a. PMID 12610602. S2CID 4414604.
  2. ^ Lappo, SS (1984). "On reason of the northward heat advection across the Equator in the South Pacific and Atlantic ocean". Study of Ocean and Atmosphere Interaction Processes. Moscow Department of Gidrometeoizdat (in Mandarin): 125–9.
  3. ^ a b "What is the global ocean conveyor belt?". NOAA. Archived from the original on 31 December 2017.
  4. ^ Primeau, F (2005). "Characterizing transport between the surface mixed layer and the ocean interior with a forward and adjoint global ocean transport model" (PDF). Journal of Physical Oceanography. 35 (4): 545–64. Bibcode:2005JPO....35..545P. doi:10.1175/JPO2699.1. S2CID 130736022.
  5. ^ Schwartz, John (20 February 2019). "Wallace Broecker, 87, Dies; Sounded Early Warning on Climate Change". The New York Times. ISSN 0362-4331. Retrieved 5 June 2022.
  6. ^ de Menocal, Peter (26 March 2019). "Wallace Smith Broecker (1931–2019)". Nature. 568 (7750): 34. Bibcode:2019Natur.568...34D. doi:10.1038/d41586-019-00993-2. S2CID 186242350.
  7. ^ Wunsch, C (2002). "What is the thermohaline circulation?". Science. 298 (5596): 1179–81. doi:10.1126/science.1079329. PMID 12424356. S2CID 129518576.
  8. ^ Collins, Kevin (3 November 2023). "El Niño may be drying out the southern hemisphere – here's how that affects the whole planet". The Conversation.
  9. ^ "NOAA Scientists Detect a Reshaping of the Meridional Overturning Circulation in the Southern Ocean". NOAA. 29 March 2023.
  10. ^ a b Lenton, T. M.; Armstrong McKay, D.I.; Loriani, S.; Abrams, J.F.; Lade, S.J.; Donges, J.F.; Milkoreit, M.; Powell, T.; Smith, S.R.; Zimm, C.; Buxton, J.E.; Daube, Bruce C.; Krummel, Paul B.; Loh, Zoë; Luijkx, Ingrid T. (2023). The Global Tipping Points Report 2023 (Report). University of Exeter.
  11. ^ Logan, Tyne (29 March 2023). "Landmark study projects 'dramatic' changes to Southern Ocean by 2050". ABC News.
  12. ^ Schmidt, Gavin (26 May 2005). "Gulf Stream slowdown?". RealClimate. Archived from the original on 20 February 2006.
  13. ^ Rahmstorf, S (2006). "Thermohaline Ocean Circulation" (PDF). In Elias, S. A. (ed.). Encyclopedia of Quaternary Sciences. Elsevier Science. ISBN 0-444-52747-8.
  14. ^ Eden, Carsten (2012). Ocean Dynamics. Springer. pp. 177. ISBN 978-3-642-23449-1.
  15. ^ Wyrtki, K (1961). "The thermohaline circulation in relation to the general circulation in the oceans". Deep-Sea Research. 8 (1): 39–64. Bibcode:1961DSR.....8...39W. doi:10.1016/0146-6313(61)90014-4.
  16. ^ Pawlowicz, Rich (2013). "Key Physical Variables in the Ocean: Temperature, Salinity, and Density". Nature Magazine. Retrieved 11 March 2024.
  17. ^ Stommel, H., & Arons, A. B. (1960). On the abyssal circulation of the world ocean. – I. Stationary planetary flow patterns on a sphere. Deep Sea Research (1953), 6, 140–154.
  18. ^ Reagan, James; Seidov, Dan; Boyer, Tim (11 June 2018). "Water Vapor Transfer and Near-Surface Salinity Contrasts in the North Atlantic Ocean". Scientific Reports. 8: 8830. Bibcode:2018NatSR...8.8830R. doi:10.1038/s41598-018-27052-6. PMC 5995860. PMID 29891855.
  19. ^ Massom, R.; Michael, K.; Harris, P.T.; Potter, M.J. (1998). "The distribution and formative processes of latent heat polynyas in East Antarctica". Annals of Glaciology. 27: 420–426. Bibcode:1998AnGla..27..420M. doi:10.3189/1998aog27-1-420-426.
  20. ^ Tamura, Takeshi; Ohshima, Kay I.; Nihashi, Sohey (April 2008). "Mapping of sea ice production for Antarctic coastal polynyas". Geophysical Research Letters. 35 (7). Bibcode:2008GeoRL..35.7606T. doi:10.1029/2007GL032903. ISSN 0094-8276.
  21. ^ Morrison, A. K.; Hogg, A. McC.; England, M. H.; Spence, P. (May 2020). "Warm Circumpolar Deep Water transport toward Antarctica driven by local dense water export in canyons". Science Advances. 6 (18): eaav2516. Bibcode:2020SciA....6.2516M. doi:10.1126/sciadv.aav2516. ISSN 2375-2548. PMC 7195130. PMID 32494658.
  22. ^ Williams, G. D.; Herraiz-Borreguero, L.; Roquet, F.; Tamura, T.; Ohshima, K. I.; Fukamachi, Y.; Fraser, A. D.; Gao, L.; Chen, H.; McMahon, C. R.; Harcourt, R.; Hindell, M. (23 August 2016). "The suppression of Antarctic bottom water formation by melting ice shelves in Prydz Bay". Nature Communications. 7 (1): 12577. Bibcode:2016NatCo...712577W. doi:10.1038/ncomms12577. ISSN 2041-1723. PMC 4996980. PMID 27552365.
  23. ^ Narayanan, Aditya; Gille, Sarah T.; Mazloff, Matthew R.; du Plessis, Marcel D.; Murali, K.; Roquet, Fabien (June 2023). "Zonal Distribution of Circumpolar Deep Water Transformation Rates and Its Relation to Heat Content on Antarctic Shelves". Journal of Geophysical Research: Oceans. 128 (6). Bibcode:2023JGRC..12819310N. doi:10.1029/2022JC019310. ISSN 2169-9275.
  24. ^ The Thermohaline Circulation – The Great Ocean Conveyor Belt Archived 19 December 2022 at the Wayback Machine NASA Scientific Visualization Studio, visualizations by Greg Shirah, 8 October 2009. Public Domain This article incorporates text from this source, which is in the public domain.
  25. ^ United Nations Environment Programme / GRID-Arendal, 2006, [1] Archived 28 January 2017 at the Wayback Machine. Potential Impact of Climate Change
  26. ^ Talley, Lynne (1999). "Some aspects of ocean heat transport by the shallow, intermediate and deep overturning circulations". Mechanisms of Global Climate Change at Millennial Time Scales. Geophysical Monograph Series. Vol. 112. pp. 1–22. Bibcode:1999GMS...112....1T. doi:10.1029/GM112p0001. ISBN 0-87590-095-X.
  27. ^ S., Broecker, Wallace (2010). The great ocean conveyor : discovering the trigger for abrupt climate change. Princeton University Press. ISBN 978-0-691-14354-5. OCLC 695704119.{{cite book}}: CS1 maint: multiple names: authors list (link)
  28. ^ Marshall, John; Speer, Kevin (26 February 2012). "Closure of the meridional overturning circulation through Southern Ocean upwelling". Nature Geoscience. 5 (3): 171–80. Bibcode:2012NatGe...5..171M. doi:10.1038/ngeo1391.
  29. ^ "RAPID: monitoring the Atlantic Meridional Overturning Circulation at 26.5N since 2004". www.rapid.ac.uk.
  30. ^ Trenberth, K; Caron, J (2001). "Estimates of Meridional Atmosphere and Ocean Heat Transports". Journal of Climate. 14 (16): 3433–43. Bibcode:2001JCli...14.3433T. doi:10.1175/1520-0442(2001)014<3433:EOMAAO>2.0.CO;2.
  31. ^ Broecker, WS (2006). "Was the Younger Dryas Triggered by a Flood?". Science. 312 (5777): 1146–8. doi:10.1126/science.1123253. PMID 16728622. S2CID 39544213.
  32. ^ IPCC, 2019: Summary for Policymakers. 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. doi:10.1017/9781009157964.001.
  33. ^ Mecking, J.V.; Drijfhout, S.S.; Jackson, L.C.; Andrews, M.B. (1 January 2017). "The effect of model bias on Atlantic freshwater transport and implications for AMOC bi-stability". Tellus A: Dynamic Meteorology and Oceanography. 69 (1): 1299910. Bibcode:2017TellA..6999910M. doi:10.1080/16000870.2017.1299910. S2CID 133294706.
  34. ^ Weijer, W.; Cheng, W.; Drijfhout, S. S.; Fedorov, A. V.; Hu, A.; Jackson, L. C.; Liu, W.; McDonagh, E. L.; Mecking, J. V.; Zhang, J. (2019). "Stability of the Atlantic Meridional Overturning Circulation: A Review and Synthesis". Journal of Geophysical Research: Oceans. 124 (8): 5336–5375. Bibcode:2019JGRC..124.5336W. doi:10.1029/2019JC015083. ISSN 2169-9275. S2CID 199807871.
  35. ^ Lohmann, Johannes; Ditlevsen, Peter D. (2 March 2021). "Risk of tipping the overturning circulation due to increasing rates of ice melt". Proceedings of the National Academy of Sciences. 118 (9): e2017989118. Bibcode:2021PNAS..11817989L. doi:10.1073/pnas.2017989118. ISSN 0027-8424. PMC 7936283. PMID 33619095.
  36. ^ a b Armstrong McKay, David; Abrams, Jesse; Winkelmann, Ricarda; Sakschewski, Boris; Loriani, Sina; Fetzer, Ingo; Cornell, Sarah; Rockström, Johan; Staal, Arie; Lenton, Timothy (9 September 2022). "Exceeding 1.5°C global warming could trigger multiple climate tipping points". Science. 377 (6611): eabn7950. doi:10.1126/science.abn7950. hdl:10871/131584. ISSN 0036-8075. PMID 36074831. S2CID 252161375.
  37. ^ a b Armstrong McKay, David (9 September 2022). "Exceeding 1.5°C global warming could trigger multiple climate tipping points – paper explainer". climatetippingpoints.info. Retrieved 2 October 2022.
  38. ^ a b c 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
  39. ^ a b Liu, Wei; Fedorov, Alexey V.; Xie, Shang-Ping; Hu, Shineng (26 June 2020). "Climate impacts of a weakened Atlantic Meridional Overturning Circulation in a warming climate". Science Advances. 6 (26): eaaz4876. Bibcode:2020SciA....6.4876L. doi:10.1126/sciadv.aaz4876. PMC 7319730. PMID 32637596.
  40. ^ Douville, H.; Raghavan, K.; Renwick, J.; Allan, R. P.; Arias, P. A.; Barlow, M.; Cerezo-Mota, R.; Cherchi, A.; Gan, T.Y.; Gergis, J.; Jiang, D.; Khan, A.; Pokam Mba, W.; Rosenfeld, D.; Tierney, J.; Zolina, O. (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S. L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.). "Chapter 8: Water Cycle Changes" (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, US: 1055–1210. doi:10.1017/9781009157896.010.
  41. ^ Yin, Jianjun & Griffies, Stephen (25 March 2015). "Extreme sea level rise event linked to AMOC downturn". CLIVAR. Archived from the original on 18 May 2015.
  42. ^ Mooney, Chris (1 February 2016). "Why the U.S. East Coast could be a major 'hotspot' for rising seas". The Washington Post.
  43. ^ Karmalkar, Ambarish V.; Horton, Radley M. (23 September 2021). "Drivers of exceptional coastal warming in the northeastern United States". Nature Climate Change. 11 (10): 854–860. Bibcode:2021NatCC..11..854K. doi:10.1038/s41558-021-01159-7. S2CID 237611075.
  44. ^ Krajick, Kevin (23 September 2021). "Why the U.S. Northeast Coast Is a Global Warming Hot Spot". Columbia Climate School. Retrieved 23 March 2023.
  45. ^ Stewart, K. D.; Hogg, A. McC.; England, M. H.; Waugh, D. W. (2 November 2020). "Response of the Southern Ocean Overturning Circulation to Extreme Southern Annular Mode Conditions". Geophysical Research Letters. 47 (22): e2020GL091103. Bibcode:2020GeoRL..4791103S. doi:10.1029/2020GL091103. hdl:1885/274441. S2CID 229063736.
  46. ^ a b 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). "Ocean, Cryosphere and Sea Level Change". In Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S.L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I. Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Vol. 2021. Cambridge University Press. pp. 1239–1241. doi:10.1017/9781009157896.011. ISBN 9781009157896.
  47. ^ Bourgeois, Timothée; Goris, Nadine; Schwinger, Jörg; Tjiputra, Jerry F. (17 January 2022). "Stratification constrains future heat and carbon uptake in the Southern Ocean between 30°S and 55°S". Nature Communications. 13 (1): 340. Bibcode:2022NatCo..13..340B. doi:10.1038/s41467-022-27979-5. PMC 8764023. PMID 35039511.
  48. ^ Li, Qian; England, Matthew H.; Hogg, Andrew McC.; Rintoul, Stephen R.; Morrison, Adele K. (29 March 2023). "Abyssal ocean overturning slowdown and warming driven by Antarctic meltwater". Nature. 615 (7954): 841–847. Bibcode:2023Natur.615..841L. doi:10.1038/s41586-023-05762-w. PMID 36991191. S2CID 257807573.
  49. ^ Robel, Alexander A.; Seroussi, Hélène; Roe, Gerard H. (23 July 2019). "Marine ice sheet instability amplifies and skews uncertainty in projections of future sea-level rise". Proceedings of the National Academy of Sciences. 116 (30): 14887–14892. Bibcode:2019PNAS..11614887R. doi:10.1073/pnas.1904822116. PMC 6660720. PMID 31285345.
  50. ^ Bakker, P; Schmittner, A; Lenaerts, JT; Abe-Ouchi, A; Bi, D; van den Broeke, MR; Chan, WL; Hu, A; Beadling, RL; Marsland, SJ; Mernild, SH; Saenko, OA; Swingedouw, D; Sullivan, A; Yin, J (11 November 2016). "Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting". Geophysical Research Letters. 43 (23): 12, 252–12, 260. Bibcode:2016GeoRL..4312252B. doi:10.1002/2016GL070457. hdl:10150/622754. S2CID 133069692.
  51. ^ a b Lenton, T. M.; Armstrong McKay, D.I.; Loriani, S.; Abrams, J.F.; Lade, S.J.; Donges, J.F.; Milkoreit, M.; Powell, T.; Smith, S.R.; Zimm, C.; Buxton, J.E.; Daube, Bruce C.; Krummel, Paul B.; Loh, Zoë; Luijkx, Ingrid T. (2023). The Global Tipping Points Report 2023 (Report). University of Exeter.
  52. ^ Huang, Huang; Gutjahr, Marcus; Eisenhauer, Anton; Kuhn, Gerhard (22 January 2020). "No detectable Weddell Sea Antarctic Bottom Water export during the Last and Penultimate Glacial Maximum". Nature Communications. 11 (1): 424. Bibcode:2020NatCo..11..424H. doi:10.1038/s41467-020-14302-3. PMC 6976697. PMID 31969564.

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