A Theory of Abrupt Climate Changes: Their Genesis and Anatomy
We combine our ice-sheet and climate models to formulate a deductive theory of abrupt climate changes pertaining to Heinrich/Dansgaard–Oeschger (H/DO) cycles and the last deglaciation punctuated by the Younger Dryas (YD). Since they are all accompanied by ice-rafted debris, we posit their common ori...
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| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Geosciences |
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| Online Access: | https://www.mdpi.com/2076-3263/12/11/391 |
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| author | Hsien-Wang Ou |
| author_facet | Hsien-Wang Ou |
| author_sort | Hsien-Wang Ou |
| collection | DOAJ |
| description | We combine our ice-sheet and climate models to formulate a deductive theory of abrupt climate changes pertaining to Heinrich/Dansgaard–Oeschger (H/DO) cycles and the last deglaciation punctuated by the Younger Dryas (YD). Since they are all accompanied by ice-rafted debris, we posit their common origin in the calving of the ice sheet due to a thermal switch at its bed, which naturally endows abruptness to these climate signals of the millennial timescale characteristics of the ice-mass balance. To distinguish the H/DO cycles, we differentiate the thermal triggers by geothermal-heat/surface-melt in the calving of inland/coastal ice, which provide their respective freshwater sources. Since surface-melt requires post-H warmth during the glacial, but is already operative in the Holocene, the DO cycles are encased within the H cycle during the glacial, but self-sustaining in the Holocene. They otherwise share the same time signature, thus resolving this seeming puzzle of commonality without invoking unknown climate forcing. The DO cycles transcend deglaciation to produce the observed sequence, but the calving-induced freshwater flux needs to be boosted by the rerouting of continental meltwater to cause YD. We discern a key process of an eddying ocean in its millennial adjustment toward maximum entropy production (MEP), which would melt the H-induced sea ice to cause an abrupt post-H warming followed by a gradual cooling that anchors the DO cycles to form the hierarchical Bond cycle. Since the modelled anatomies resemble the observed ones, our theory may provide a robust and unified account of abrupt climate changes. |
| first_indexed | 2024-03-09T19:04:01Z |
| format | Article |
| id | doaj.art-f25f0c221cda471182b1f9f8bbf572ca |
| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-03-09T19:04:01Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
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| series | Geosciences |
| spelling | doaj.art-f25f0c221cda471182b1f9f8bbf572ca2023-11-24T04:49:40ZengMDPI AGGeosciences2076-32632022-10-01121139110.3390/geosciences12110391A Theory of Abrupt Climate Changes: Their Genesis and AnatomyHsien-Wang Ou0Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USAWe combine our ice-sheet and climate models to formulate a deductive theory of abrupt climate changes pertaining to Heinrich/Dansgaard–Oeschger (H/DO) cycles and the last deglaciation punctuated by the Younger Dryas (YD). Since they are all accompanied by ice-rafted debris, we posit their common origin in the calving of the ice sheet due to a thermal switch at its bed, which naturally endows abruptness to these climate signals of the millennial timescale characteristics of the ice-mass balance. To distinguish the H/DO cycles, we differentiate the thermal triggers by geothermal-heat/surface-melt in the calving of inland/coastal ice, which provide their respective freshwater sources. Since surface-melt requires post-H warmth during the glacial, but is already operative in the Holocene, the DO cycles are encased within the H cycle during the glacial, but self-sustaining in the Holocene. They otherwise share the same time signature, thus resolving this seeming puzzle of commonality without invoking unknown climate forcing. The DO cycles transcend deglaciation to produce the observed sequence, but the calving-induced freshwater flux needs to be boosted by the rerouting of continental meltwater to cause YD. We discern a key process of an eddying ocean in its millennial adjustment toward maximum entropy production (MEP), which would melt the H-induced sea ice to cause an abrupt post-H warming followed by a gradual cooling that anchors the DO cycles to form the hierarchical Bond cycle. Since the modelled anatomies resemble the observed ones, our theory may provide a robust and unified account of abrupt climate changes.https://www.mdpi.com/2076-3263/12/11/391abrupt climate changeHeinrich eventsDansgaard–Oeschger cyclesbond cyclesyounger dryasice-sheet instability |
| spellingShingle | Hsien-Wang Ou A Theory of Abrupt Climate Changes: Their Genesis and Anatomy Geosciences abrupt climate change Heinrich events Dansgaard–Oeschger cycles bond cycles younger dryas ice-sheet instability |
| title | A Theory of Abrupt Climate Changes: Their Genesis and Anatomy |
| title_full | A Theory of Abrupt Climate Changes: Their Genesis and Anatomy |
| title_fullStr | A Theory of Abrupt Climate Changes: Their Genesis and Anatomy |
| title_full_unstemmed | A Theory of Abrupt Climate Changes: Their Genesis and Anatomy |
| title_short | A Theory of Abrupt Climate Changes: Their Genesis and Anatomy |
| title_sort | theory of abrupt climate changes their genesis and anatomy |
| topic | abrupt climate change Heinrich events Dansgaard–Oeschger cycles bond cycles younger dryas ice-sheet instability |
| url | https://www.mdpi.com/2076-3263/12/11/391 |
| work_keys_str_mv | AT hsienwangou atheoryofabruptclimatechangestheirgenesisandanatomy AT hsienwangou theoryofabruptclimatechangestheirgenesisandanatomy |