Uncertainties too large to predict tipping times of major Earth system components from historical data

TL;DR

Predicting the exact timing of critical Earth system transitions from historical data is unreliable due to high uncertainties in modeling, data representativeness, and observational preprocessing.

Contribution

This paper critically examines the limitations and uncertainties involved in extrapolating Earth system tipping points from historical observational data.

Findings

Uncertainties hinder reliable prediction of tipping times.

Model assumptions and data issues significantly impact extrapolation accuracy.

Even with approaching tipping points, timing estimates remain highly uncertain.

Abstract

One way to warn of forthcoming critical transitions in Earth system components is using observations to detect declining system stability. It has also been suggested to extrapolate such stability changes into the future and predict tipping times. Here, we argue that the involved uncertainties are too high to robustly predict tipping times. We raise concerns regarding (i) the modeling assumptions underlying any extrapolation of historical results into the future, (ii) the representativeness of individual Earth system component time series, and (iii) the impact of uncertainties and preprocessing of used observational datasets, with focus on nonstationary observational coverage and gap filling. We explore these uncertainties in general and specifically for the example of the Atlantic Meridional Overturning Circulation. We argue that even under the assumption that a given Earth system component has an approaching tipping point, the uncertainties are too large to reliably estimate tipping times by extrapolating historical information.