**Assessing Volcanic-Induced Climate Forcing**

**Reference**

Hyde, W.T. and Crowley, T.J. 2000. Probability of future climatically significant volcanic eruptions.

*Journal of Climate*

**13**: 1445-1450.

**What was done**

Statistical properties of climatically significant volcanic eruptions over the last 600 years were analyzed in an effort to estimate the probability of future eruptions over the next decade.

**What was learned**

The authors determined that there is a 35% to 40% probability of a volcanic eruption with the capability of producing a radiative perturbation of -1 Wm^{-2} or larger in the next 10 years. Such an eruption is estimated to produce a 0.1°C to 0.15°C cooling over a 2-3 year period. The probability of a larger, Mt. Pinatubo-scale, eruption with a radiative perturbation of -3 Wm^{-2} is 15% to 25%.

**What it means**

The authors are concerned with the idea that were a major volcanic eruption to occur in the next decade -- which seems a fairly good possibility -- it could "mask the CO2 effect and complicate discussions on a greenhouse gas protocol." They are correct; but that's how the real world operates.

Reviewed 15 May 2000