Volcanism and glaciation during the past 40 millennia

CLOSE relationships between the timing of volcanic eruption and of glaciation in the past millennia have been noted1–3together with the possibility that the three main Neoglacial ice advances were contemporaneous with the three well dated volcanic activity periods in the Southern Andes3. Here, I show that glacial advance phases in the Western Northern, Eastern Northern and Southern Hemispheres are mainly synchronous with volcanic activity periods in New Zealand, Japan and southern South America over the past 40,000 yr (the period of reasonably accurate 14C measurements).