It would seem that volcanoes provide a temporary cooling effect from the sun-blocking particles they emit, and a longer-term warming effect from the emission of greenhouse gases (this is not unlike recent news about the ironies of fossil fuel burning).

This implies that in addition to conversion to a zero carbon/methane way of life, we need to add some sort of benign geoengineering solutions to offset 1) previous damage and 2) possible non-anthropogenic effects