The relatively muted warming of the surface and lower troposphere since 1998 has attracted considerable attention. One contributory factor to this “warming hiatus” is an increase in volcanic cooling over the early 21st century. Our recent research has identified the signals of late 20th and early 21st century volcanic activity in multiple observed climate variables. Volcanic signals are statistically discernible in spatial averages of tropical and near-global sea-surface temperature, tropospheric temperature, net clear-sky short-wave radiation, and atmospheric water vapor.