Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting

Bakker, Pepijn; Schmittner, Andreas; Lenaerts, Jan T. M.; Abe‐Ouchi, Ayako; Bi, Daohua; Broeke, M. R. van den; Chan, Wing‐Le; Hu, Aixue; Beadling, R. L.; Marsland, Simon J.; Mernild, Sebastian H.; Saenko, Oleg A.; Swingedouw, Didier; Sullivan, Arnold; Yin, Jingxue

doi:10.1002/2016gl070457

Cited by 174 publications

(142 citation statements)

References 41 publications

(64 reference statements)

Supporting

Mentioning

138

Contrasting

Unclassified

Order By: Relevance

“…org/10.1029/2018GL080083 1961 and 1995 (~0.02 Sv on average; Curry, 2005). This is especially true if we are to identify the forcing(s) responsible for the ongoing AMOC weakening (Bakker et al, 2016;Thornalley et al, 2018). It is therefore increasingly critical that we understand the impacts of climate change and freshwater release on convection in the Labrador Sea and its corresponding impact on AMOC intensity (Gregory et al, 2005).…”

Section: Citationmentioning

confidence: 99%

Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation

Thibodeau

Not

Zhu

et al. 2018

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

The Atlantic meridional overturning circulation (AMOC) is a key component of the global climate system. Recent studies suggested a twentieth‐century weakening of the AMOC of unprecedented amplitude (~15%) over the last millennium. Here we present a record of δ18O in benthic foraminifera from sediment cores retrieved from the Laurentian Channel and demonstrate that the δ18O trend is linked to the strength of the AMOC. In this 100‐year record, the AMOC signal decreased steadily to reach its minimum value in the late 1970s, where the weakest AMOC signal then remains constant until 2000. We also present a longer δ18O record of 1,500 years and highlight the uniqueness of the last century δ18O trend. Moreover, the Little Ice Age period is characterized by statistically heavier δ18O, suggesting a relatively weak AMOC. Implications for understanding the mechanisms driving the intensity of AMOC under global warming and high‐latitude freshwater input are discussed.

show abstract

Section: Citationmentioning

confidence: 99%

Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation

Thibodeau

Not

Zhu

et al. 2018

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…Future model studies may include sensitivity simulations with prescribed changes in the wind stress over the ocean (e.g., Tschumi et al, 2008) and prescribed meltwater fluxes or apply Earth system models with interactive atmospheric dynamics and ice sheets. Our study, as is the case for most climate change simulations, does not include melting of continental ice sheets, which would tend to further (transiently) reduce circulation (Bakker et al, 2016) and increase the equilibrium climate sensitivity.…”

Section: Uncertainties In O 2 Projectionsmentioning

confidence: 99%

Hazards of decreasing marine oxygen: the near-term and millennial-scale benefits of meeting the Paris climate targets

Battaglia

Joos

2018

Earth Syst. Dynam.

View full text Add to dashboard Cite

Abstract. Ocean deoxygenation is recognized as key ecosystem stressor of the future ocean and associated climate-related ocean risks are relevant for current policy decisions. In particular, benefits of reaching the ambitious 1.5 • C warming target mentioned by the Paris Agreement compared to higher temperature targets are of high interest. Here, we model oceanic oxygen, warming and their compound hazard in terms of metabolic conditions on multi-millennial timescales for a range of equilibrium temperature targets. Scenarios where radiative forcing is stabilized by 2300 are used in ensemble simulations with the Bern3D Earth System Model of Intermediate Complexity. Transiently, the global mean ocean oxygen concentration decreases by a few percent under low forcing and by 40 % under high forcing. Deoxygenation peaks about a thousand years after stabilization of radiative forcing and new steady-state conditions are established after AD 8000 in our model. Hypoxic waters expand over the next millennium and recovery is slow and remains incomplete under high forcing. Largest transient decreases in oxygen are projected for the deep sea. Distinct and near-linear relationships between the equilibrium temperature response and marine O 2 loss emerge. These point to the effectiveness of the Paris climate target in reducing marine hazards and risks. Mitigation measures are projected to reduce peak decreases in oceanic oxygen inventory by 4.4 % • C −1 of avoided equilibrium warming. In the upper ocean, the decline of a metabolic index, quantified by the ratio of O 2 supply to an organism's O 2 demand, is reduced by 6.2 % • C −1 of avoided equilibrium warming. Definitions of peak hypoxia demonstrate strong sensitivity to additional warming. Volumes of water with less than 50 mmol O 2 m −3 , for instance, increase between 36 % and 76 % • C −1 of equilibrium temperature response. Our results show that millennial-scale responses should be considered in assessments of ocean deoxygenation and associated climate-related ocean risks. Peak hazards occur long after stabilization of radiative forcing and new steady-state conditions establish after AD 8000.

show abstract

“…4a). The other continental regions warm up by around 2 K, while the sea surface temperature increases by 1-1.5 K. Recent studies (Bakker et al, 2016;IPCC, 2013) suggest that the Atlantic Meridional Overturning Circulation (AMOC) could weaken in the 21st century, resulting in a temperature reduction in the North Atlantic. Our simulations reproduce this characteristic cooling of 1 K in the northern Atlantic that could be caused by a weakening of the AMOC in the 21st century.…”

Section: Temperature Responsementioning

confidence: 99%

Implications of potential future grand solar minimum for ozone layer and climate

Arsenović¹,

Rozanov

Anet

et al. 2018

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Continued anthropogenic greenhouse gas (GHG) emissions are expected to cause further global warming throughout the 21st century. Understanding the role of natural forcings and their influence on global warming is thus of great interest. Here we investigate the impact of a recently proposed 21st century grand solar minimum on atmospheric chemistry and climate using the SOCOL3-MPIOM chemistry-climate model with an interactive ocean element. We examine five model simulations for the period 2000-2199, following the greenhouse gas concentration scenario RCP4.5 and a range of different solar forcings. The reference simulation is forced by perpetual repetition of solar cycle 23 until the year 2199. This reference is compared with grand solar minimum simulations, assuming a strong decline in solar activity of 3.5 and 6.5 W m −2 , respectively, that last either until 2199 or recover in the 22nd century. Decreased solar activity by 6.5 W m −2 is found to yield up to a doubling of the GHG-induced stratospheric and mesospheric cooling. Under the grand solar minimum scenario, tropospheric temperatures are also projected to decrease compared to the reference. On the global scale a reduced solar forcing compensates for at most 15 % of the expected greenhouse warming at the end of the 21st and around 25 % at the end of the 22nd century. The regional effects are predicted to be significant, in particular in northern high-latitude winter. In the stratosphere, the reduction of around 15 % of incoming ultraviolet radiation leads to a decrease in ozone production by up to 8 %, which overcompensates for the anticipated ozone increase due to reduced stratospheric temperatures and an acceleration of the Brewer-Dobson circulation. This, in turn, leads to a delay in total ozone column recovery from anthropogenic halogen-induced depletion, with a global ozone recovery to the pre-ozone hole values happening only upon completion of the grand solar minimum.

show abstract

Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting

Cited by 174 publications

References 41 publications

Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation

Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation

Hazards of decreasing marine oxygen: the near-term and millennial-scale benefits of meeting the Paris climate targets

Implications of potential future grand solar minimum for ozone layer and climate

Contact Info

Product

Resources

About