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 SVEdriven climate responses, thus corroborating the existence of SVE-driven decadal climate variability. Historical climatestate uncertainty may, however, hamper unambiguous statistical and dynamical assessments both for multiple and for individual SVEs. © 2013. American Geophysical Union. All Rights Reserved.