Delayed winter warming: A robust decadal response to strong tropical volcanic eruptions?

Climate simulations suggest that strong tropical volcanic eruptions (SVEs) induce decadal dynamical responses in the coupled ocean‐atmosphere system, which protract the climate recovery beyond the short‐lived radiative forcing. Here, for the first time, we diagnose the signature of such responses in European seasonal climate reconstructions over the past 500 years. The signature consists of a decadal‐scale positive phase of the winter North Atlantic Oscillation accompanied by winter warming over Europe peaking approximately one decade after a major eruption. The reconstructed delayed winter warming is compatible with formerly suggested mechanisms behind simulated SVE‐driven climate responses, thus corroborating the existence of SVE‐driven decadal climate variability. Historical climate‐state uncertainty may, however, hamper unambiguous statistical and dynamical assessments both for multiple and for individual SVEs. Key Points Volcanic forcing has long‐lasting repercussions on European winter climate The decadal climate response to volcanic forcing entails European warm winters This delayed winter warming is tractable only in a statistical sense