Mitigation Scenarios to Prevent Unsafe AMOC Overshoot

Abstract

It is known that the Atlantic Meridional Overturning Circulation (AMOC) is a relevant tipping element within the Earth climate system. This research investigates its response to transient overshooting freshwater forcing scenarios, utilizing a fully-implicit global ocean model. The AMOC behavior is explored under conditions where piecewise linear forcing exceeds established thresholds. The study clarifies the physics of the collapse and recovery of the AMOC and uncovers that the potential for recovery from overshoots is tightly linked to the delicate balance of salt fluxes in the North Atlantic. The sign of the time derivative of the integrated salt content in the northern region has been identified as a relevant indicator for the system recovery and has been tested varying forcing rates of change as well as forcing peaks. The insights gained can be relevant to inform climate policy strategies, highlighting the necessity for thoughtful management of overshoots to prevent definitive AMOC collapse.