氣候臨界點

氣候臨界點（英語：climate tipping point）是一個關鍵閾值，越過該閾值會導致系統狀態發生巨大且通常不可逆的變化。氣候科學家使用術語「臨界點」來表明氣候系統的脆弱性。^[2]^[3]系統一旦「傾覆」，很可能對人類社會產生嚴重影響。^[4]^[5]

政府間氣候變化專門委員會（IPCC）早在2000年代就開始考慮臨界點的可能性。當時IPCC得出結論，只有在全球相對前工業時代變暖大於或等於4 °C時才會觸發臨界點。但現在認為，在今天的升溫水平（略高於1 °C）下，就有顯著概率已經達到了臨界點，而升溫 2°C的情景下大概率越過了臨界點。^[6]

地球系統中可能觸發臨界點的大尺度要素稱為臨界要素（tipping element）。^[7]氣候系統中至少15個不同要素，例如格陵蘭冰原和南極冰蓋，被認為是可能的臨界要素。^[8]^[9]一個危險是，如果某個系統的臨界點被越過，可能會導致一連串的其他臨界點被相繼越過。^[10]如果發生這種連鎖反應，全球平均溫度可能將會上升至高於過去120萬年任何時期，地球將變成「溫室地球」。^[11]

臨界點未必是突變的。例如，平均溫升在1.5-2 °C之間時，格陵蘭冰原將在數千年內不可逆轉地融化。^[12]^[13]然而，美國地球物理聯盟2021年的一項研究表明，南極洲的思韋茨冰架有可能在2025年之前破碎。^[14]^[15]

參見

溫室和冰室地球（英語：Greenhouse and icehouse Earth）
氣候敏感性（英語：Climate sensitivity）
地球限度理論
地理工程學

參考文獻

^ Otto, I.M. Social tipping elements for stabilizing climate by 2050. PNAS. February 4, 2020, 117 (5): 2354–2365. PMC 7007533 . PMID 31964839. doi:10.1073/pnas.1900577117.
^ IPCC steps up warning on climate tipping points in leaked draft report. The Guardian. 2021-06-23 [2021-07-22]. （原始內容存檔於22 July 2021）（英語）.
^ Lenton, TimothyM.; Rockström, Johan; Gaffney, Owen; Rahmstorf, Stefan; Richardson, Katherine; Steffen, Will; Schellnhuber, Hans Joachim. Climate tipping points — too risky to bet against. Nature. 2019-11-27, 575 (7784): 592–595. Bibcode:2019Natur.575..592L. PMID 31776487. doi:10.1038/d41586-019-03595-0 （英語）.
^ Climate tipping points could topple like dominoes, warn scientists （頁面存檔備份，存於互聯網檔案館）, The Guardian, 3 June 2021
^ Climate change driving entire planet to dangerous 'tipping point『（頁面存檔備份，存於互聯網檔案館）, National Geographic, 28 November 2019
^ Lenton, Timothy M. Tipping points in the climate system. Weather. 2021, 76 (10): 325–326. ISSN 0043-1656. doi:10.1002/wea.4058 （英語）.
^ Lenton, T.M.; Held, H.; Kriegler, E.; Hall, J.W.; Lucht, W.; Rahmstorf, S.; Schellnhuber, H.J. Tipping elements in the Earth's climate system. Proceedings of the National Academy of Sciences. 2008, 105 (6): 1786–1793. Bibcode:2008PNAS..105.1786L. PMC 2538841 . PMID 18258748. doi:10.1073/pnas.0705414105.
^ Climate scientists fear tipping points (maybe you should too) 互聯網檔案館的存檔，存檔日期14 November 2021., PhysOrg, 25 October 2021.
^ Explainer: Nine 『tipping points』 that could be triggered by climate change 互聯網檔案館的存檔，存檔日期11 February 2020., Carbon Brief, 10 February 2020
^ Wunderling, Nico; Donges, Jonathan F.; Kurths, Jürgen; Winkelmann, Ricarda. Interacting tipping elements increase risk of climate domino effects under global warming. Earth System Dynamics. 2021-06-03, 12 (2): 601–619 [4 June 2021]. Bibcode:2021ESD....12..601W. ISSN 2190-4979. doi:10.5194/esd-12-601-2021. （原始內容存檔於4 June 2021）（英語）.
^ Sheridan, Kerry. Earth risks tipping into 'hothouse' state: study. Phys.org. 2018-08-06 [2018-08-08]. （原始內容存檔於3 October 2019）. Hothouse Earth is likely to be uncontrollable and dangerous to many ... global average temperatures would exceed those of any interglacial period—meaning warmer eras that come in between Ice Ages—of the past 1.2 million years.
^ Frank Pattyn; Catherine Ritz; Edward Hanna; Xylar Asay-Davis; Rob DeConto; Gaël Durand; Lionel Favier; Xavier Fettweis; Heiko Goelzer. The Greenland and Antarctic ice sheets under 1.5 °C global warming. Nature Climate Change (Journal Nature). 2018, 8 (12): 1053–1061 [2022-05-09]. Bibcode:2018NatCC...8.1053P. doi:10.1038/s41558-018-0305-8. （原始內容存檔於2022-06-15）.
^ Tipping points in Antarctic and Greenland ice sheets. NESSC. 12 November 2018 [2019-02-25]. （原始內容存檔於26 February 2019）.
^ Douglas, Benn I.; Luck, Adrian; Åström, Jan A.; Crawford, Anna; Cornford, Stephen L.; Bevan, Suzanne L.; Gladstone, Rupert; Zwinger, Thomas; Alley, Karen. Rapid fragmentation of Thwaites Eastern Ice Shelf, West Antarctica. The Cryosphere Discussions. 20 September 2021: 1–25 [2022-01-25]. doi:10.5194/tc-2021-288. （原始內容存檔於2022-02-01）（英國英語）.
^ Pettit, Erin C.; Wild, Christian; Alley, Karen; Muto, Atsuhiro; Truffer, Martin; Bevan, Suzanne Louise; Bassis, Jeremy N.; Crawford, Anna; Scambos, Ted A.; Benn, Doug. Collapse of Thwaites Eastern Ice Shelf by intersecting fractures.. AGU Fall Meeting. New Orleans: American Geophysical Union. 2021-12-15 [2022-05-09]. C34A-07. （原始內容存檔於2022-04-20）.

外部連結

[1] Otto, I.M. Social tipping elements for stabilizing climate by 2050. PNAS. February 4, 2020, 117 (5): 2354–2365. PMC 7007533 . PMID 31964839. doi:10.1073/pnas.1900577117.

[2] IPCC steps up warning on climate tipping points in leaked draft report. The Guardian. 2021-06-23 [2021-07-22]. （原始內容存檔於22 July 2021）（英語）.

[:1-3] Lenton, TimothyM.; Rockström, Johan; Gaffney, Owen; Rahmstorf, Stefan; Richardson, Katherine; Steffen, Will; Schellnhuber, Hans Joachim. Climate tipping points — too risky to bet against. Nature. 2019-11-27, 575 (7784): 592–595. Bibcode:2019Natur.575..592L. PMID 31776487. doi:10.1038/d41586-019-03595-0 （英語）.

[4] Climate tipping points could topple like dominoes, warn scientists （頁面存檔備份，存於互聯網檔案館）, The Guardian, 3 June 2021

[5] Climate change driving entire planet to dangerous 'tipping point『（頁面存檔備份，存於互聯網檔案館）, National Geographic, 28 November 2019

[6] Lenton, Timothy M. Tipping points in the climate system. Weather. 2021, 76 (10): 325–326. ISSN 0043-1656. doi:10.1002/wea.4058 （英語）.

[Lenton_2008-7] Lenton, T.M.; Held, H.; Kriegler, E.; Hall, J.W.; Lucht, W.; Rahmstorf, S.; Schellnhuber, H.J. Tipping elements in the Earth's climate system. Proceedings of the National Academy of Sciences. 2008, 105 (6): 1786–1793. Bibcode:2008PNAS..105.1786L. PMC 2538841 . PMID 18258748. doi:10.1073/pnas.0705414105.

[8] Climate scientists fear tipping points (maybe you should too) 互聯網檔案館的存檔，存檔日期14 November 2021., PhysOrg, 25 October 2021.

[carbonbrief.org-9] Explainer: Nine 『tipping points』 that could be triggered by climate change 互聯網檔案館的存檔，存檔日期11 February 2020., Carbon Brief, 10 February 2020

[esd.copernicus.org-10] Wunderling, Nico; Donges, Jonathan F.; Kurths, Jürgen; Winkelmann, Ricarda. Interacting tipping elements increase risk of climate domino effects under global warming. Earth System Dynamics. 2021-06-03, 12 (2): 601–619 [4 June 2021]. Bibcode:2021ESD....12..601W. ISSN 2190-4979. doi:10.5194/esd-12-601-2021. （原始內容存檔於4 June 2021）（英語）.

[Phys2018-11] Sheridan, Kerry. Earth risks tipping into 'hothouse' state: study. Phys.org. 2018-08-06 [2018-08-08]. （原始內容存檔於3 October 2019）. Hothouse Earth is likely to be uncontrollable and dangerous to many ... global average temperatures would exceed those of any interglacial period—meaning warmer eras that come in between Ice Ages—of the past 1.2 million years.

[12] Frank Pattyn; Catherine Ritz; Edward Hanna; Xylar Asay-Davis; Rob DeConto; Gaël Durand; Lionel Favier; Xavier Fettweis; Heiko Goelzer. The Greenland and Antarctic ice sheets under 1.5 °C global warming. Nature Climate Change (Journal Nature). 2018, 8 (12): 1053–1061 [2022-05-09]. Bibcode:2018NatCC...8.1053P. doi:10.1038/s41558-018-0305-8. （原始內容存檔於2022-06-15）.

[NESSC2018-13] Tipping points in Antarctic and Greenland ice sheets. NESSC. 12 November 2018 [2019-02-25]. （原始內容存檔於26 February 2019）.

[:0-14] Douglas, Benn I.; Luck, Adrian; Åström, Jan A.; Crawford, Anna; Cornford, Stephen L.; Bevan, Suzanne L.; Gladstone, Rupert; Zwinger, Thomas; Alley, Karen. Rapid fragmentation of Thwaites Eastern Ice Shelf, West Antarctica. The Cryosphere Discussions. 20 September 2021: 1–25 [2022-01-25]. doi:10.5194/tc-2021-288. （原始內容存檔於2022-02-01）（英國英語）.

[15] Pettit, Erin C.; Wild, Christian; Alley, Karen; Muto, Atsuhiro; Truffer, Martin; Bevan, Suzanne Louise; Bassis, Jeremy N.; Crawford, Anna; Scambos, Ted A.; Benn, Doug. Collapse of Thwaites Eastern Ice Shelf by intersecting fractures.. AGU Fall Meeting. New Orleans: American Geophysical Union. 2021-12-15 [2022-05-09]. C34A-07. （原始內容存檔於2022-04-20）.

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