Risk of tipping the overturning circulation due to increasing rates of ice melt

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Risk of tipping the overturning circulation due to increasing rates of ice melt. / Lohmann, Johannes; Ditlevsen, Peter D.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 118, No. 9, e2017989118, 02.03.2021.

Research output: Contribution to journalJournal articlepeer-review

Harvard

Lohmann, J & Ditlevsen, PD 2021, 'Risk of tipping the overturning circulation due to increasing rates of ice melt', Proceedings of the National Academy of Sciences of the United States of America, vol. 118, no. 9, e2017989118. https://doi.org/10.1073/pnas.2017989118

APA

Lohmann, J., & Ditlevsen, P. D. (2021). Risk of tipping the overturning circulation due to increasing rates of ice melt. Proceedings of the National Academy of Sciences of the United States of America, 118(9), [e2017989118]. https://doi.org/10.1073/pnas.2017989118

Vancouver

Lohmann J, Ditlevsen PD. Risk of tipping the overturning circulation due to increasing rates of ice melt. Proceedings of the National Academy of Sciences of the United States of America. 2021 Mar 2;118(9). e2017989118. https://doi.org/10.1073/pnas.2017989118

Author

Lohmann, Johannes ; Ditlevsen, Peter D. / Risk of tipping the overturning circulation due to increasing rates of ice melt. In: Proceedings of the National Academy of Sciences of the United States of America. 2021 ; Vol. 118, No. 9.

Bibtex

@article{23d1b0098ae249a48431747772e0f0d2,
title = "Risk of tipping the overturning circulation due to increasing rates of ice melt",
abstract = "Central elements of the climate system are at risk for crossing critical thresholds (so-called tipping points) due to future greenhouse gas emissions, leading to an abrupt transition to a qualitatively different climate with potentially catastrophic consequences. Tipping points are often associated with bifurcations, where a previously stable system state loses stability when a system parameter is increased above a well-defined critical value. However, in some cases such transitions can occur even before a parameter threshold is crossed, given that the parameter change is fast enough. It is not known whether this is the case in high-dimensional, complex systems like a state-of-the-art climate model or the real climate system. Using a global ocean model subject to freshwater forcing, we show that a collapse of the Atlantic Meridional Overturning Circulation can indeed be induced even by small-amplitude changes in the forcing, if the rate of change is fast enough. Identifying the location of critical thresholds in climate subsystems by slowly changing system parameters has been a core focus in assessing risks of abrupt climate change. This study suggests that such thresholds might not be relevant in practice, if parameter changes are not slow. Furthermore, we show that due to the chaotic dynamics of complex systems there is no well-defined critical rate of parameter change, which severely limits the predictability of the qualitative long-term behavior. The results show that the safe operating space of elements of the Earth system with respect to future emissions might be smaller than previously thought.",
keywords = "tipping points, rate-induced tipping, abrupt climate change, overturning circulation, GLOBAL OCEAN CIRCULATION, THERMOHALINE CIRCULATION, CLIMATE, STABILITY, MODEL, BIFURCATION, SYSTEMS, POINTS",
author = "Johannes Lohmann and Ditlevsen, {Peter D.}",
year = "2021",
month = mar,
day = "2",
doi = "10.1073/pnas.2017989118",
language = "English",
volume = "118",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "The National Academy of Sciences of the United States of America",
number = "9",

}

RIS

TY - JOUR

T1 - Risk of tipping the overturning circulation due to increasing rates of ice melt

AU - Lohmann, Johannes

AU - Ditlevsen, Peter D.

PY - 2021/3/2

Y1 - 2021/3/2

N2 - Central elements of the climate system are at risk for crossing critical thresholds (so-called tipping points) due to future greenhouse gas emissions, leading to an abrupt transition to a qualitatively different climate with potentially catastrophic consequences. Tipping points are often associated with bifurcations, where a previously stable system state loses stability when a system parameter is increased above a well-defined critical value. However, in some cases such transitions can occur even before a parameter threshold is crossed, given that the parameter change is fast enough. It is not known whether this is the case in high-dimensional, complex systems like a state-of-the-art climate model or the real climate system. Using a global ocean model subject to freshwater forcing, we show that a collapse of the Atlantic Meridional Overturning Circulation can indeed be induced even by small-amplitude changes in the forcing, if the rate of change is fast enough. Identifying the location of critical thresholds in climate subsystems by slowly changing system parameters has been a core focus in assessing risks of abrupt climate change. This study suggests that such thresholds might not be relevant in practice, if parameter changes are not slow. Furthermore, we show that due to the chaotic dynamics of complex systems there is no well-defined critical rate of parameter change, which severely limits the predictability of the qualitative long-term behavior. The results show that the safe operating space of elements of the Earth system with respect to future emissions might be smaller than previously thought.

AB - Central elements of the climate system are at risk for crossing critical thresholds (so-called tipping points) due to future greenhouse gas emissions, leading to an abrupt transition to a qualitatively different climate with potentially catastrophic consequences. Tipping points are often associated with bifurcations, where a previously stable system state loses stability when a system parameter is increased above a well-defined critical value. However, in some cases such transitions can occur even before a parameter threshold is crossed, given that the parameter change is fast enough. It is not known whether this is the case in high-dimensional, complex systems like a state-of-the-art climate model or the real climate system. Using a global ocean model subject to freshwater forcing, we show that a collapse of the Atlantic Meridional Overturning Circulation can indeed be induced even by small-amplitude changes in the forcing, if the rate of change is fast enough. Identifying the location of critical thresholds in climate subsystems by slowly changing system parameters has been a core focus in assessing risks of abrupt climate change. This study suggests that such thresholds might not be relevant in practice, if parameter changes are not slow. Furthermore, we show that due to the chaotic dynamics of complex systems there is no well-defined critical rate of parameter change, which severely limits the predictability of the qualitative long-term behavior. The results show that the safe operating space of elements of the Earth system with respect to future emissions might be smaller than previously thought.

KW - tipping points

KW - rate-induced tipping

KW - abrupt climate change

KW - overturning circulation

KW - GLOBAL OCEAN CIRCULATION

KW - THERMOHALINE CIRCULATION

KW - CLIMATE

KW - STABILITY

KW - MODEL

KW - BIFURCATION

KW - SYSTEMS

KW - POINTS

U2 - 10.1073/pnas.2017989118

DO - 10.1073/pnas.2017989118

M3 - Journal article

C2 - 33619095

VL - 118

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 9

M1 - e2017989118

ER -

ID: 259045879