Pub Date : 2024-12-04DOI: 10.1038/s41561-024-01596-x
Chan-Mao Chen, James Hollingsworth, Marin K. Clark, Deepak Chamlagain, Sujata Bista, Dimitrios Zekkos, Anuj Siwakoti, A. Joshua West
In 2021, a catastrophic flood occurred in the Melamchi Valley of Nepal, causing widely distributed erosion in Himalayan headwaters and mobilizing a large sediment volume. As the flood progressed downstream, it induced an erosional cascade, producing 100 m deep incisions into high-elevation valley fills, generating new landslides and burying the lower reaches in alluvium. This event demonstrated the destructive impact of cascading processes and their potential for reshaping the landscape. The 2021 flood in the Melamchi Valley of Nepal triggered a cascade of erosional effects that contributed to the substantial downstream impacts, according to an analysis of satellite imagery and digital surface models.
{"title":"Erosional cascade during the 2021 Melamchi flood","authors":"Chan-Mao Chen, James Hollingsworth, Marin K. Clark, Deepak Chamlagain, Sujata Bista, Dimitrios Zekkos, Anuj Siwakoti, A. Joshua West","doi":"10.1038/s41561-024-01596-x","DOIUrl":"10.1038/s41561-024-01596-x","url":null,"abstract":"In 2021, a catastrophic flood occurred in the Melamchi Valley of Nepal, causing widely distributed erosion in Himalayan headwaters and mobilizing a large sediment volume. As the flood progressed downstream, it induced an erosional cascade, producing 100 m deep incisions into high-elevation valley fills, generating new landslides and burying the lower reaches in alluvium. This event demonstrated the destructive impact of cascading processes and their potential for reshaping the landscape. The 2021 flood in the Melamchi Valley of Nepal triggered a cascade of erosional effects that contributed to the substantial downstream impacts, according to an analysis of satellite imagery and digital surface models.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"18 1","pages":"32-36"},"PeriodicalIF":15.7,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-03DOI: 10.1038/s41561-024-01582-3
Catherine C. Walker, Joanna D. Millstein, Bertie W. J. Miles, Sue Cook, Alexander D. Fraser, Andreas Colliander, Sidharth Misra, Luke D. Trusel, Susheel Adusumilli, Chancelor Roberts, Helen A. Fricker
Antarctica is currently losing net mass to the ocean primarily from West Antarctica and the Antarctic Peninsula, which together hold ~5.5 m of sea level rise potential. Yet, the East Antarctic Ice Sheet stores almost ten times more ice, and its evolution contributes significant uncertainty to sea level rise projections, mainly due to insufficient process-scale observations. Here we report the collapse of the Conger–Glenzer Ice Shelf in East Antarctica that culminated with its March 2022 disintegration. We use a combination of observations to document its evolution over four stages spanning 25 years, starting 1997–2000 when small calving events isolated it from the Shackleton Ice Shelf. In 2011, it retreated from a central pinning point, followed by relative calving quiescence for a decade; the remaining ~1,200 km2 of the ice shelf disintegrated over a few days in mid-March 2022. These observations of the Conger–Glenzer Ice Shelf collapse shed light on the processes involved, in particular, the impacts of ocean and atmospheric warming and extreme weather events. Ice shelf collapses, rare in the satellite record so far, have substantial implications for the stability of the Antarctic ice sheet and its contribution to future sea level rise. Satellite observations reveal that the Conger–Glenzer Ice Shelf collapse in East Antarctica occurred in four stages spanning a period of 25 years, culminating in its rapid disintegration in March 2022.
{"title":"Multi-decadal collapse of East Antarctica’s Conger–Glenzer Ice Shelf","authors":"Catherine C. Walker, Joanna D. Millstein, Bertie W. J. Miles, Sue Cook, Alexander D. Fraser, Andreas Colliander, Sidharth Misra, Luke D. Trusel, Susheel Adusumilli, Chancelor Roberts, Helen A. Fricker","doi":"10.1038/s41561-024-01582-3","DOIUrl":"10.1038/s41561-024-01582-3","url":null,"abstract":"Antarctica is currently losing net mass to the ocean primarily from West Antarctica and the Antarctic Peninsula, which together hold ~5.5 m of sea level rise potential. Yet, the East Antarctic Ice Sheet stores almost ten times more ice, and its evolution contributes significant uncertainty to sea level rise projections, mainly due to insufficient process-scale observations. Here we report the collapse of the Conger–Glenzer Ice Shelf in East Antarctica that culminated with its March 2022 disintegration. We use a combination of observations to document its evolution over four stages spanning 25 years, starting 1997–2000 when small calving events isolated it from the Shackleton Ice Shelf. In 2011, it retreated from a central pinning point, followed by relative calving quiescence for a decade; the remaining ~1,200 km2 of the ice shelf disintegrated over a few days in mid-March 2022. These observations of the Conger–Glenzer Ice Shelf collapse shed light on the processes involved, in particular, the impacts of ocean and atmospheric warming and extreme weather events. Ice shelf collapses, rare in the satellite record so far, have substantial implications for the stability of the Antarctic ice sheet and its contribution to future sea level rise. Satellite observations reveal that the Conger–Glenzer Ice Shelf collapse in East Antarctica occurred in four stages spanning a period of 25 years, culminating in its rapid disintegration in March 2022.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1240-1248"},"PeriodicalIF":15.7,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-03DOI: 10.1038/s41561-024-01607-x
Karen E. Alley
The loss of the Conger–Glenzer ice shelf in 2022 was the culmination of a multidecadal process of disintegration, signalling East Antarctica may not be as stable as we once thought.
{"title":"Ice-shelf disintegration in East Antarctica","authors":"Karen E. Alley","doi":"10.1038/s41561-024-01607-x","DOIUrl":"10.1038/s41561-024-01607-x","url":null,"abstract":"The loss of the Conger–Glenzer ice shelf in 2022 was the culmination of a multidecadal process of disintegration, signalling East Antarctica may not be as stable as we once thought.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1193-1194"},"PeriodicalIF":15.7,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.1038/s41561-024-01595-y
Suzanne E. Smrekar, Colby Ostberg, Joseph G. O’Rourke
{"title":"Author Correction: Earth-like lithospheric thickness and heat flow on Venus consistent with active rifting","authors":"Suzanne E. Smrekar, Colby Ostberg, Joseph G. O’Rourke","doi":"10.1038/s41561-024-01595-y","DOIUrl":"10.1038/s41561-024-01595-y","url":null,"abstract":"","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"18 1","pages":"105-105"},"PeriodicalIF":15.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01595-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142735685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.1038/s41561-024-01602-2
J. R. Williams, S. L. C. Giering, C. A. Baker, K. Pabortsava, N. Briggs, H. East, B. Espinola, S. Blackbird, F. A. C. Le Moigne, M. Villa-Alfageme, A. J. Poulton, F. Carvalho, C. Pebody, K. Saw, C. M. Moore, S. A. Henson, R. Sanders, A. P. Martin
The Southern Ocean, a region highly vulnerable to climate change, plays a vital role in regulating global nutrient cycles and atmospheric CO2 via the biological carbon pump. Diatoms, photosynthetically active plankton with dense opal skeletons, are key to this process as their exoskeletons are thought to enhance the transfer of particulate organic carbon to depth, positioning them as major vectors of carbon storage. Yet conflicting observations obscure the mechanistic link between diatoms, opal and particulate organic carbon fluxes, especially in the twilight zone where greatest flux losses occur. Here we present direct springtime flux measurements from different sectors of the subpolar Southern Ocean, demonstrating that across large areas of the subpolar twilight zone, carbon is efficiently transferred to depth, albeit not by diatoms. Rather, opal is retained near the surface ocean, indicating that processes such as diatom buoyancy regulation and grazer repackaging can negate ballast effects of diatoms’ skeletons. Our results highlight that the presence of diatoms in surface waters of the Southern Ocean’s largest biome does not guarantee their importance as vectors for efficient carbon transfer through the subpolar twilight zone. Climate change-driven shifts in phytoplankton community composition may affect biologically sequestered carbon pools less than currently predicted. Diatom skeletons largely remain near the surface of the subpolar Southern Ocean following diatom bloom events, suggesting that they do not play as big a role in the downward flux of organic matter as previously thought, according to data from two expeditions focused on the marine twilight zone.
{"title":"Inefficient transfer of diatoms through the subpolar Southern Ocean twilight zone","authors":"J. R. Williams, S. L. C. Giering, C. A. Baker, K. Pabortsava, N. Briggs, H. East, B. Espinola, S. Blackbird, F. A. C. Le Moigne, M. Villa-Alfageme, A. J. Poulton, F. Carvalho, C. Pebody, K. Saw, C. M. Moore, S. A. Henson, R. Sanders, A. P. Martin","doi":"10.1038/s41561-024-01602-2","DOIUrl":"10.1038/s41561-024-01602-2","url":null,"abstract":"The Southern Ocean, a region highly vulnerable to climate change, plays a vital role in regulating global nutrient cycles and atmospheric CO2 via the biological carbon pump. Diatoms, photosynthetically active plankton with dense opal skeletons, are key to this process as their exoskeletons are thought to enhance the transfer of particulate organic carbon to depth, positioning them as major vectors of carbon storage. Yet conflicting observations obscure the mechanistic link between diatoms, opal and particulate organic carbon fluxes, especially in the twilight zone where greatest flux losses occur. Here we present direct springtime flux measurements from different sectors of the subpolar Southern Ocean, demonstrating that across large areas of the subpolar twilight zone, carbon is efficiently transferred to depth, albeit not by diatoms. Rather, opal is retained near the surface ocean, indicating that processes such as diatom buoyancy regulation and grazer repackaging can negate ballast effects of diatoms’ skeletons. Our results highlight that the presence of diatoms in surface waters of the Southern Ocean’s largest biome does not guarantee their importance as vectors for efficient carbon transfer through the subpolar twilight zone. Climate change-driven shifts in phytoplankton community composition may affect biologically sequestered carbon pools less than currently predicted. Diatom skeletons largely remain near the surface of the subpolar Southern Ocean following diatom bloom events, suggesting that they do not play as big a role in the downward flux of organic matter as previously thought, according to data from two expeditions focused on the marine twilight zone.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"18 1","pages":"72-77"},"PeriodicalIF":15.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01602-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142735698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1038/s41561-024-01611-1
Genevieve L. Noyce, Alexander J. Smith, Matthew L. Kirwan, Roy L. Rich, J. Patrick Megonigal
{"title":"Author Correction: Oxygen priming induced by elevated CO2 reduces carbon accumulation and methane emissions in coastal wetlands","authors":"Genevieve L. Noyce, Alexander J. Smith, Matthew L. Kirwan, Roy L. Rich, J. Patrick Megonigal","doi":"10.1038/s41561-024-01611-1","DOIUrl":"10.1038/s41561-024-01611-1","url":null,"abstract":"","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1316-1316"},"PeriodicalIF":15.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01611-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1038/s41561-024-01593-0
Samuel C. Mogen, Nicole S. Lovenduski, Stephen G. Yeager, Antonietta Capotondi, Michael G. Jacox, Stephen Bograd, Emanuele Di Lorenzo, Elliot L. Hazen, Mercedes Pozo Buil, Who Kim, Nan Rosenbloom
Marine heatwaves and ocean acidification extreme events are periods during which temperature and acidification reach statistically extreme levels (90th percentile), relative to normal variability, potentially endangering ecosystems. As the threats from marine heatwaves and ocean acidification extreme events grow with climate change, there is need for skilful predictions of events months to years in advance. Previous work has demonstrated that climate models can predict marine heatwaves up to 12 months in advance in key regions, but forecasting of ocean acidification extreme events has been difficult due to the complexity of the processes leading to extremes and sparse observations. Here we use the Community Earth System Model Seasonal-to-Multiyear Large Ensemble to make predictions of marine heatwaves and two forms of ocean acidification extreme events, as defined by anomalies in hydrogen ion concentration and aragonite saturation state. We show that the ensemble skilfully predicts marine heatwaves and ocean acidification extreme events as defined by aragonite saturation state up to 1 year in advance. Predictive skill for ocean acidification extremes as defined by hydrogen ion concentration is lower, probably reflecting mismatch between model and observed state. Skill is highest in the eastern Pacific, reflecting the predictable contribution of El Niño/Southern Oscillation to regional variability. A forecast generated in late 2023 during the 2023–2024 El Niño event finds high likelihood for widespread marine heatwaves and ocean acidification extreme events in 2024. One type of ocean acidification extreme event, as well as marine heatwaves, can be confidently predicted up to 1 year in advance, according to forecasts stemming from an Earth system model ensemble.
{"title":"Multi-month forecasts of marine heatwaves and ocean acidification extremes","authors":"Samuel C. Mogen, Nicole S. Lovenduski, Stephen G. Yeager, Antonietta Capotondi, Michael G. Jacox, Stephen Bograd, Emanuele Di Lorenzo, Elliot L. Hazen, Mercedes Pozo Buil, Who Kim, Nan Rosenbloom","doi":"10.1038/s41561-024-01593-0","DOIUrl":"10.1038/s41561-024-01593-0","url":null,"abstract":"Marine heatwaves and ocean acidification extreme events are periods during which temperature and acidification reach statistically extreme levels (90th percentile), relative to normal variability, potentially endangering ecosystems. As the threats from marine heatwaves and ocean acidification extreme events grow with climate change, there is need for skilful predictions of events months to years in advance. Previous work has demonstrated that climate models can predict marine heatwaves up to 12 months in advance in key regions, but forecasting of ocean acidification extreme events has been difficult due to the complexity of the processes leading to extremes and sparse observations. Here we use the Community Earth System Model Seasonal-to-Multiyear Large Ensemble to make predictions of marine heatwaves and two forms of ocean acidification extreme events, as defined by anomalies in hydrogen ion concentration and aragonite saturation state. We show that the ensemble skilfully predicts marine heatwaves and ocean acidification extreme events as defined by aragonite saturation state up to 1 year in advance. Predictive skill for ocean acidification extremes as defined by hydrogen ion concentration is lower, probably reflecting mismatch between model and observed state. Skill is highest in the eastern Pacific, reflecting the predictable contribution of El Niño/Southern Oscillation to regional variability. A forecast generated in late 2023 during the 2023–2024 El Niño event finds high likelihood for widespread marine heatwaves and ocean acidification extreme events in 2024. One type of ocean acidification extreme event, as well as marine heatwaves, can be confidently predicted up to 1 year in advance, according to forecasts stemming from an Earth system model ensemble.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1261-1267"},"PeriodicalIF":15.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1038/s41561-024-01592-1
Qiang Wang, Sergey Danilov, Thomas Jung
A two-decade-long accumulation of freshwater in the Arctic Ocean’s Beaufort Gyre has recently started to be released. Here we use satellite observations and model simulations to show that changes in wind regimes and sea ice declines are causing freshwater to accumulate close to the export gateways to the North Atlantic. This emerging buffer zone plays an important role in modulating the propagation of freshwater into the subpolar North Atlantic. Freshwater being released from the Beaufort Gyre is accumulating in an Arctic Ocean buffer zone before it can reach the North Atlantic, according to an analysis of satellite observation and modelling.
{"title":"Arctic freshwater anomaly transiting to the North Atlantic delayed within a buffer zone","authors":"Qiang Wang, Sergey Danilov, Thomas Jung","doi":"10.1038/s41561-024-01592-1","DOIUrl":"10.1038/s41561-024-01592-1","url":null,"abstract":"A two-decade-long accumulation of freshwater in the Arctic Ocean’s Beaufort Gyre has recently started to be released. Here we use satellite observations and model simulations to show that changes in wind regimes and sea ice declines are causing freshwater to accumulate close to the export gateways to the North Atlantic. This emerging buffer zone plays an important role in modulating the propagation of freshwater into the subpolar North Atlantic. Freshwater being released from the Beaufort Gyre is accumulating in an Arctic Ocean buffer zone before it can reach the North Atlantic, according to an analysis of satellite observation and modelling.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1218-1221"},"PeriodicalIF":15.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01592-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1038/s41561-024-01577-0
Zachary A. Holden, Solomon Z. Dobrowski, Alan Swanson, Zachary Hoylman, Drew Lyons, Allen Warren, Marco Maneta
Climate change and disturbance threaten forested ecosystems across the globe. Our ability to predict the future distribution of forests requires understanding the limiting factors for regeneration. Forest canopies buffer against near-surface air temperature and vapour pressure deficit extremes, and ongoing losses of forest canopy from disturbances such as wildfire can exacerbate climate constraints on natural regeneration. Here we combine experimental, empirical and simulation-based evidence to show that soil surface temperatures constrain the low-elevation extent of forests in the western United States. Simulated potential soil surface temperatures predict the position of the low-elevation forest treeline, exhibiting temperature thresholds consistent with field and laboratory studies. High-resolution historical and future surface temperature maps show that 107,000–238,000 km2 (13–20%) of currently forested area exceeds the critical thermal threshold for forest regeneration and this area is projected to more than double by 2050. Soil surface temperature is an important physical control on seedling survival at low elevations that will likely be an increasing constraint on the extent of western United States forests as the climate warms. Soil surface temperatures constrain the low-elevation extent of forests in the western United States through their direct effects on seedling mortality, according to analyses of the relationship between post-fire tree recruitment and soil surface temperature across this region.
{"title":"Low-elevation forest extent in the western United States constrained by soil surface temperatures","authors":"Zachary A. Holden, Solomon Z. Dobrowski, Alan Swanson, Zachary Hoylman, Drew Lyons, Allen Warren, Marco Maneta","doi":"10.1038/s41561-024-01577-0","DOIUrl":"10.1038/s41561-024-01577-0","url":null,"abstract":"Climate change and disturbance threaten forested ecosystems across the globe. Our ability to predict the future distribution of forests requires understanding the limiting factors for regeneration. Forest canopies buffer against near-surface air temperature and vapour pressure deficit extremes, and ongoing losses of forest canopy from disturbances such as wildfire can exacerbate climate constraints on natural regeneration. Here we combine experimental, empirical and simulation-based evidence to show that soil surface temperatures constrain the low-elevation extent of forests in the western United States. Simulated potential soil surface temperatures predict the position of the low-elevation forest treeline, exhibiting temperature thresholds consistent with field and laboratory studies. High-resolution historical and future surface temperature maps show that 107,000–238,000 km2 (13–20%) of currently forested area exceeds the critical thermal threshold for forest regeneration and this area is projected to more than double by 2050. Soil surface temperature is an important physical control on seedling survival at low elevations that will likely be an increasing constraint on the extent of western United States forests as the climate warms. Soil surface temperatures constrain the low-elevation extent of forests in the western United States through their direct effects on seedling mortality, according to analyses of the relationship between post-fire tree recruitment and soil surface temperature across this region.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1249-1253"},"PeriodicalIF":15.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1038/s41561-024-01568-1
Gabriel M. Pontes, Laurie Menviel
The Atlantic Meridional Overturning Circulation is the main driver of northward heat transport in the Atlantic Ocean today, setting global climate patterns. Whether global warming has affected the strength of this overturning circulation over the past century is still debated: observational studies suggest that there has been persistent weakening since the mid-twentieth century, whereas climate models systematically simulate a stable circulation. Here, using Earth system and eddy-permitting coupled ocean–sea-ice models, we show that a freshening of the subarctic Atlantic Ocean and weakening of the overturning circulation increase the temperature and salinity of the South Atlantic on a decadal timescale through the propagation of Kelvin and Rossby waves. We also show that accounting for upper-end meltwater input in historical simulations significantly improves the data–model agreement on past changes in the Atlantic Meridional Overturning Circulation, yielding a slowdown of 0.46 sverdrups per decade since 1950. Including estimates of subarctic meltwater input for the coming century suggests that this circulation could be 33% weaker than its anthropogenically unperturbed state under 2 °C of global warming, which could be reached over the coming decade. Such a weakening of the overturning circulation would substantially affect the climate and ecosystems. Fresh meltwater entering the Labrador and Irminger seas has resulted in a slowing of the Atlantic Meridional Overturning Circulation since the 1950s, according to a combination of modelling approaches.
{"title":"Weakening of the Atlantic Meridional Overturning Circulation driven by subarctic freshening since the mid-twentieth century","authors":"Gabriel M. Pontes, Laurie Menviel","doi":"10.1038/s41561-024-01568-1","DOIUrl":"10.1038/s41561-024-01568-1","url":null,"abstract":"The Atlantic Meridional Overturning Circulation is the main driver of northward heat transport in the Atlantic Ocean today, setting global climate patterns. Whether global warming has affected the strength of this overturning circulation over the past century is still debated: observational studies suggest that there has been persistent weakening since the mid-twentieth century, whereas climate models systematically simulate a stable circulation. Here, using Earth system and eddy-permitting coupled ocean–sea-ice models, we show that a freshening of the subarctic Atlantic Ocean and weakening of the overturning circulation increase the temperature and salinity of the South Atlantic on a decadal timescale through the propagation of Kelvin and Rossby waves. We also show that accounting for upper-end meltwater input in historical simulations significantly improves the data–model agreement on past changes in the Atlantic Meridional Overturning Circulation, yielding a slowdown of 0.46 sverdrups per decade since 1950. Including estimates of subarctic meltwater input for the coming century suggests that this circulation could be 33% weaker than its anthropogenically unperturbed state under 2 °C of global warming, which could be reached over the coming decade. Such a weakening of the overturning circulation would substantially affect the climate and ecosystems. Fresh meltwater entering the Labrador and Irminger seas has resulted in a slowing of the Atlantic Meridional Overturning Circulation since the 1950s, according to a combination of modelling approaches.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 12","pages":"1291-1298"},"PeriodicalIF":15.7,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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