Hmm, it does not make sense. 200 years ago the industry produced gases were a tiny fraction of what is today and even smaller fraction of what volcanoes spit out. Also in the past few thousands of years there were warmer periods than today.
I will worry about global warming when Greenland is a green land again.
" . . . it does not make sense. 200 years ago the industry produced gases were a tiny fraction of what is today . . "
You are almost certainly correct, but I wouldn't be surprised if the terribly inefficient wood/coal/peat burning back then produced similarly amounts of greenhouse gas for comparably little usable energy.
Lots of studies show both Europe and North America actually have MORE trees and forests now than existed when Columbus sailed the ocean blue.
And all the descriptions of old London were basically of a soot-filled nightmare.
That said, I would think you are correct. But I am not sure.
Volcanoes produce (on average) about 150 times less CO2 than human industrial (energy-related) processes. They produce a lot more S02, but due to its short lifetime in the atmosphere, cooling effects from volcanic S02 only last a few years after major eruptions.
Right now, industry produces 10 times more atmosphereic Carbon Dioxide per year than volcanoes do, so pollution has been producing more CO2 than volcanoes for quite some time.
And, of course, volcanoes produce huge amounts of Sulfur Dioxide, which blocks sunlight and cools the earth, so overall volcanic eruptions tend to cool the earth.
200 years ago we had no weather data. Hell, even 50 years ago our weather data globally was suspect.