  We determine the volcano climate sensitivity and response time for the Mount
Pinatubo eruption. This is achieved using observational measurements of the
temperature anomalies of the lower troposphere and the aerosol optical density
(AOD) in combination with a radiative forcing proxy for AOD. Using standard
linear response theory we find sensitivity = 0.18 +- 0.04 K/(W/m2), which
implies a negative feedback of -1.0 +- 0.4. The intrinsic response time is
5.8+-1.0 months. Both results are contrary to the conventional paradigm that
includes long response times and positive feedback. In addition, we analyze the
outgoing longwave radiation during the Pinatubo eruption and find that its time
dependence follows the forcing much more closely than the temperature, and even
has an amplitude equal to that of the AOD proxy. This finding is independent of
the response time and feedback results.
