How do volcanoes affect the envrionment?

Answer 1

Volcanoes are a natural source of CO2 and SO2 and other gasses, you can argue that they do in fact cause global warming however their emissions are what brought the earth out of a snowball and should not be hated by global warming enthusiast.

However although they cause long(ish) term 100s to 10,000s years warming, on a shorter scales 10s years the SO2 forms S aresols clouds which actually cause cooling as the reflect the suns warmth.