Geomorphology, Год журнала: 2025, Номер unknown, С. 109661 - 109661
Опубликована: Фев. 1, 2025
Язык: Английский
Nature, Год журнала: 2025, Номер 638(8052), С. 987 - 994
Опубликована: Фев. 26, 2025
Abstract The Atlantic Meridional Overturning Circulation (AMOC), vital for northwards heat transport in the Ocean, is projected to weaken owing global warming 1 , with significant climate impacts 2 . However, extent of AMOC weakening uncertain wide variation across models 1,3,4 and some statistical indicators suggesting an imminent collapse 5 Here we show that resilient extreme greenhouse gas North freshwater forcings 34 models. Upwelling Southern driven by persistent Ocean winds, sustains a weakened all cases, preventing its complete collapse. As upwelling must be balanced downwelling or Pacific, can only if compensating Pacific (PMOC) develops. Remarkably, PMOC does emerge almost models, but it too weak balance upwelling, unlikely this century. Our findings reveal AMOC-stabilizing mechanisms implications past future changes, hence ecosystems ocean biogeochemistry. They suggest better understanding estimates Indo-Pacific circulations are urgently needed accurately predict change.
Язык: Английский
Процитировано
4
Scientific Data, Год журнала: 2025, Номер 12(1)
Опубликована: Янв. 27, 2025
Abstract Tipping elements on Earth are components that undergo rapid and irreversible changes when climate change reaches a tipping point. They highly sensitive to variations serve as early warning signs of global change. Human activities, including pledges, significantly influence the state elements. Land external intuitive response change, making it essential identify shifts in land system. We produced 1-km system dataset for terrestrial years 2000, 2010, 2020, 2100 under pledges by integrating GCAM with modified version CLUMondo. Our includes 30 thematic categories, combining three density types ten cover types. The illustrates potential contrasting common SSP RCP scenarios. simulations demonstrate high accuracy, offering valuable insights into assessment impacts Earth.
Язык: Английский
Процитировано
3
Earth s Future, Год журнала: 2025, Номер 13(1)
Опубликована: Янв. 1, 2025
Abstract Marine ecosystems provide essential services to the Earth System and society. These are threatened by anthropogenic activities climate change. Climate change increases risk of passing tipping points; for example, Atlantic Meridional Overturning Circulation (AMOC) might tip under future global warming leading additional changes in system. Here, we look at effect an AMOC weakening on marine forcing Community Model v2 (CESM2) with low (SSP1‐2.6) high (SSP5‐8.5) emission scenarios from 2015 2100. An freshwater flux is added North induce extra AMOC. In CESM2, has a large impact phytoplankton biomass temperature fields through various mechanisms that supply nutrients surface ocean. We drive ecosystem model, EcoOcean, CESM2. see negative impacts Total Biomass (TSB), which larger trophic level organisms. On top change, TSB decreases −3.78 −2.03 SSP1‐2.6 SSP5‐8.5, respectively due weakening. However, regionally individual groups, decrease can be as −30, showing very detrimental local ecosystems. results show will increased threat if weakens put stresses socio‐economic systems dependent biodiversity food income source.
Язык: Английский
Процитировано
1
Earth System Dynamics, Год журнала: 2025, Номер 16(1), С. 115 - 150
Опубликована: Янв. 20, 2025
Abstract. The ocean is forced at the surface by a heat flux and freshwater field from atmosphere. Short-timescale variability in these fluxes, i.e., noise, can influence long-term might even affect Atlantic meridional overturning circulation (AMOC). Often this noise assumed to be Gaussian, but detailed analyses of its statistics appear lacking. Here we study characteristics reanalysis data for two fields that are commonly used force ocean-only models: evaporation minus precipitation 2 m air temperature. We construct several models both fields, pointwise normal inverse Gaussian distribution model gives best performance. An analysis CMIP6 shows do reasonable job representing standard deviation skewness excess kurtosis more difficult capture. performs better than as forcing study, example, noise-induced transitions AMOC.
Язык: Английский
Процитировано
1
SSRN Electronic Journal, Год журнала: 2025, Номер unknown
Опубликована: Янв. 1, 2025
Язык: Английский
Процитировано
1
Geophysical Research Letters, Год журнала: 2023, Номер 50(22)
Опубликована: Ноя. 17, 2023
Abstract We study hysteresis properties of the Atlantic Meridional Overturning Circulation (AMOC) under a slowly‐varying North (20°N–50°N) freshwater flux forcing in state‐of‐the‐art global climate model (GCM), Community Earth System Model. Results are presented full simulation (4,400 years) and show that there is width about 0.4 Sv. This demonstrates an AMOC collapse recovery do not only occur conceptual idealized models, but also GCM. The factor six faster than this asymmetry due to major effect sea‐ice distribution on recovery. results have implications for projections possible future behavior explaining relatively rapid transitions geological past.
Язык: Английский
Процитировано
19
Earth System Dynamics, Год журнала: 2024, Номер 15(3), С. 635 - 652
Опубликована: Май 27, 2024
Abstract. The Greenland Ice Sheet (GIS) and Atlantic Meridional Overturning Circulation (AMOC) are considered tipping elements in the climate system, where global warming exceeding critical threshold levels forcing can lead to large-scale nonlinear reductions ice volume overturning strength, respectively. positive–negative feedback loop governing their interaction with a destabilizing effect on AMOC due loss subsequent freshwater flux into North as well stabilizing of net cooling around an weakening may determine long-term stability both elements. Here we explore potential dynamic regimes arising from this physically motivated conceptual model. Under idealized scenarios identify conditions under which different kinds cascades occur: herein, distinguish between overshoot/bifurcation cascades, leading GIS AMOC, rate-induced despite not having crossed its own intrinsic point, tips nonetheless fast rate Greenland. occurrence these is affected by sheet disintegration time thus eventually imposed timescales. Our results suggest that it necessary only avoid surpassing respective environmental drivers for Circulation, but also respect safe rates change mitigate domino effects.
Язык: Английский
Процитировано
8
Journal of Geophysical Research Oceans, Год журнала: 2024, Номер 129(6)
Опубликована: Июнь 1, 2024
Abstract The freshwater transport ( M ov ) by the Atlantic Meridional Overturning Circulation (AMOC) across 34.5°S is computed using observations from 49 eXpendable BathyThermograph (XBT) transects between 2002 and 2019. at serves as a possible indicator of AMOC stability, with negative (southward) indicating bistable regime positive (northward) monostable regime. A mean −0.15 ± 0.09 Sv estimated repeated XBT transects, suggesting Results are complemented two data sets derived Argo float observations, numerical ocean models, coupled climate models. More than half models examined, 20 out 32, present values. To investigate causes differing signs we examine salinity vertical structure in , fresher upper saltier deep waters . South meridional fluxes show linear relationships, slope (positively correlated magnitude) /MOC /MHT, correlated) MHT/MOC. Seasonally, most considered here, more MOC MHT austral fall winter April to August 34.5°S.
Язык: Английский
Процитировано
6
Chaos An Interdisciplinary Journal of Nonlinear Science, Год журнала: 2024, Номер 34(5)
Опубликована: Май 1, 2024
The basin entropy is a measure that quantifies, in system has two or more attractors, the predictability of final state, as function initial conditions. While been demonstrated on variety multistable dynamical systems, to best our knowledge, it not yet tested systems with time delay, whose phase space infinite dimensional because conditions are functions defined interval [−τ,0], where τ delay time. Here, we consider simple time-delayed consisting bistable linear delayed feedback term. We show captures relevant properties basins attraction coexisting attractors. Moreover, can give an indication proximity Hopf bifurcation, but fails capture pitchfork bifurcation. bifurcation detected before fixed points become unstable, oscillatory, limit-cycle behavior appears coexists points. new limit cycle modifies structure attraction, and this change captured by reaches maximum In contrast, do approached. Our results suggest yield useful insights into long-term which often have
Язык: Английский
Процитировано
5
Science Advances, Год журнала: 2024, Номер 10(31)
Опубликована: Авг. 2, 2024
One way to warn of forthcoming critical transitions in Earth system components is using observations detect declining stability. It has also been suggested extrapolate such stability changes into the future and predict tipping times. Here, we argue that involved uncertainties are too high robustly We raise concerns regarding (i) modeling assumptions underlying any extrapolation historical results future, (ii) representativeness individual component time series, (iii) impact preprocessing used observational datasets, with focus on nonstationary coverage gap filling. explore these general specifically for example Atlantic Meridional Overturning Circulation. even under assumption a given an approaching point, large reliably estimate times by extrapolating information.
Язык: Английский
Процитировано
5