Usefulness of F_ovS as an early‑warning indicator under realistic settings

Determine whether the net meridional freshwater transport by the overturning circulation at 34°S of the Atlantic (F_ovS) remains a useful early‑warning indicator for a future Atlantic Meridional Overturning Circulation (AMOC) collapse when evaluated under realistic climate forcing and modeling assumptions, rather than the implausible assumptions employed in the cited simulation study.

Background

The paper discusses a proposal from van Westen et al. (2024) that the overturning component of the freshwater transport at 34°S (F_ovS) could serve as an early‑warning indicator of an AMOC collapse. However, the simulation supporting this proposal assumes an unrealistically long and intensifying freshwater forcing scenario, raising concerns about the transferability of the result to real‑world conditions.

Because these physical assumptions are not readily correctable in the short term, the present paper focuses on improving statistical methods applicable to short historical series. The broader question of whether F_ovS is actually a useful early‑warning indicator in realistic settings remains unresolved and explicitly noted by the author.