Fig. 3.

Volcano-induced regime shifts in STREC. Comparison (A) between STREC, a reconstruction of global stratospheric volcanic sulfate aerosol injections (9), and a reconstruction of ice-cap expansion dates from Arctic Canada (22). Detected regime shifts in STREC based on a four-component Bayesian hidden Markov model with normal probability distributions (SI Methods) are also shown (B), as well as the posterior probability density functions of the mean temperature of each regime (C). In B, each reconstructed value is assigned to the most likely regime (color dots) and the mean temperature of the last decade is shown (horizontal dashed lines), as well as the dates of the A.D. 1257 Samalas and A.D. 1815 Tambora eruptions (vertical dashed lines).