[Uncle George]

Those little volcanos couldn't help could they? They have been spewing trillions of tons of soot for 10000000 years.

[explodingspleen]

We must shut down the geothermal power plants!

[fellowpatriot]

It couldn't be the volcanoes, don't they tend to cool the atmosphere when they erupt?

[Looking for Diogenes]

Those little volcanos couldn't help could they?

The major discharge from volcanoes that I've seen is ash, which is light colored. Cinders are dark, but I don't think they account for the same degree of surface covering as ash does.