Attribution of CMIP6 AMOC collapses to a salt‑advection tipping mechanism

Determine whether AMOC collapses simulated in CMIP6 models under freshwater and global warming forcing are caused by a single bifurcation‑induced tipping point driven by the salt‑advection feedback, or whether they result from multiple feedbacks and mechanisms acting in concert.

Background

Multiple positive feedbacks and alternative pathways (e.g., convective feedbacks, subpolar gyre transitions, migration of deep‑water formation) may contribute to AMOC collapse in comprehensive models. The paper underscores that these mechanisms can yield partial or full collapses and complicate the attribution to a single salt‑advection feedback.

Clarifying the dominant mechanism(s) behind modelled AMOC collapses is essential to interpret early‑warning signals and to assess the relevance of the saddle‑node bifurcation picture across CMIP6‑class models.