There were no consecutive large volcanic eruptions in the 20th century, and none that could have caused the recent slowdown in the rate of global warming. (pnas.org)
The ash and aerosol clouds from large volcanic eruptions spread quickly through the atmosphere. (scientificamerican.com)
Researchers know that large amounts of aerosols can significantly cool the planet; the effect has been observed after large volcanic eruptions. (sciencedaily.com)