Caesar, Levke and Rahmstorf, S and Feulner, G (2021) Reply to Comment on ‘On the relationship between Atlantic meridional overturning circulation slowdown and global surface warming’. Environmental Research Letters, 16 (3). 038002. ISSN 1748-9326

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Abstract

In their comment on our paper (Caesar et al 2020 Environ. Res. Lett. 15 024003), Chen and Tung (hereafter C&T) argue that our analysis, showing that over the last decades Atlantic meridional overturning circulation (AMOC) strength and global mean surface temperature (GMST) were positively correlated, is incorrect. Their claim is mainly based on two arguments, neither of which is justified: first, C&T claim that our analysis is based on ‘established evidence’ that was only true for preindustrial conditions—this is not the case. Using data from the modern period (1947–2012), we show that the established understanding (i.e. deep-water formation in the North Atlantic cools the deep ocean and warms the surface) is correct, but our analysis is not based on this fact. Secondly, C&T claim that our results are based on a statistical analysis of only one cycle of data which was furthermore incorrectly detrended. This, too, is not true. Our conclusion that a weaker AMOC delays the current surface warming rather than enhances it, is based on several independent lines of evidence. The data we show to support this covers more than one cycle and the detrending (which was performed to avoid spurious correlations due to a common trend) does not affect our conclusion: the correlation between AMOC strength and GMST is positive. We do not claim that this is strong evidence that the two time series are in phase, but rather that this means that the two time series are not anti-correlated.

Item Type:	Article
Additional Information:	REPLY • OPEN ACCESS Reply to Comment on ‘On the relationship between Atlantic meridional overturning circulation slowdown and global surface warming’ Cite as: L Caesar et al 2021 Environ. Res. Lett. 16 038002
Keywords:	Atlantic meridional overturning circulation; global surface warming; ocean heat uptake;
Academic Unit:	Faculty of Social Sciences > Geography Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	15745
Identification Number:	https://doi.org/10.1088/1748-9326/abc776
Depositing User:	Levke Caesar
Date Deposited:	29 Mar 2022 11:42
Journal or Publication Title:	Environmental Research Letters
Publisher:	IOP Publishing
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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