Reassessing the cooling that followed the 1991 volcanic eruption of Mt. Pinatubo

Abstract

A cooling of up to 0.5 °C which lasted 18–36 months is attributed to the 1991 Mt. Pinatubo eruption. A simple mathematical approach is here applied to the 43-year-long satellite global temperature time series. This time series is fitted with a parabolic function representing global warming, multiple sinusoidal functions representing natural variability, and a rectangular function representing the cooling of Mt. Pinatubo. The cooling is estimated at up to 0.28 °C, 0.2 °C on average. Similarly shorter is the duration of the cooling, about 13 months. This result impacts the risk-to-benefit ratio of SAI which may be worse than thought.