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High probability of triggering climate tipping points under current policies modestly amplified by Amazon dieback and permafrost thaw

Identification

Clé publique

radar:r-4402a502416b13290ab28e99c882f7d4

Auteurs

Jakob Deutloff · Hermann Held · Timothy M. Lenton

Année déclarée

2025

Langue déclarée

en

Type source

article

Première détection

2026-11-14T02:00:12.984798+00:00

Dernière observation des métadonnées

2026-11-14T02:00:12.984798+00:00

Dernière vérification HTTP

Non effectuée

Institutions déclarées par la source

Universität Hamburg · University of Exeter · International Max Planck Research School on Earth System Modelling

Pays d’affiliation déclarés

DE · GB

Résumé documentaire — langue originale

We investigate the probabilities of triggering climate tipping points under five Shared Socioeconomic Pathways (SSPs) and how they are altered by including the additional carbon emissions that could arise from tipping points within the Earth's carbon cycle. The crossing of a climate tipping point at a threshold level of global mean surface temperature (threshold temperature) would commit the affected subsystem of the Earth to abrupt and largely irreversible changes with negative impacts on human well-being. However, it remains unclear which tipping points would be triggered under the different SSPs due to uncertainties in the climate sensitivity to anthropogenic greenhouse gas emissions, the threshold temperatures and timescales of climate tipping points, and the response of tipping points within the Earth's carbon cycle to global warming. We include those uncertainties in our analysis to derive probabilities of triggering for 16 previously identified climate tipping points within the Earth system. To conduct our analysis, we use the reduced complexity climate model FaIR (Finite amplitude Impulse Response) which is coupled to a conceptual model of the tipping processes within the Amazon rainforest and permafrost, which are the two major tipping points within the Earth's carbon cycle. Uncertainties are propagated by employing a Monte Carlo approach for the construction of large model ensembles. We find that carbon tipping points increase the risk for high-temperature pathways, but on average their warming effect remains small, with its median staying 1 order of magnitude lower than the median anthropogenic warming for all SSPs. Therefore, they have low potential to increase the probability of triggering other tipping points. The maximum triggering probability increase from carbon tipping points among all SSPs occurs under SSP2-4.5, with a 3 percentage point increase averaged over all tipping points. The warming trajectory expected from current policies compares best to SSP2-4.5, which we find to be unsafe with regard to triggering climate tipping points. Our most conservative estimate of triggering probabilities averaged over all tipping points is 62 % under SSP2-4.5, and nine tipping points have a more than 50 % probability of getting triggered. Under SSP1-2.6 and SSP1-1.9, the risk of triggering climate tipping points is reduced significantly compared to SSP2-4.5; however, it also remains less constrained since the behaviour of climate tipping points in the case of a temperature overshoot is still highly uncertain.

Identifiants

OPENALEX

https://openalex.org/W4409694140

DOI

10.5194/esd-16-565-2025

Repères documentaires

Famille documentaire

article

Types déclarés par les sources

article

Éditeurs

Copernicus Publications

Les mentions d’entités ne constituent pas une preuve de reconnaissance juridique. La juridiction étudiée est distincte du pays d’affiliation des auteurs.

Sources

OpenAlex · Document 1

• Document · https://doi.org/10.5194/esd-16-565-2025

Statut documentaire

Pertinence à examiner

Bibliothèque

Cette identité n’est pas encore intégrée à la Bibliothèque juridique.