I don’t know what made you think that weathering volcanic rock releases CO2. It doesn’t. It is a sink. Many papers and basic chemistry attest to this (see https://www.columbia.edu/~vjd1/carbon.htm). Last year there was a paper by [Beerling et al](https://www.nature.com/articles/s41586-020-2448-9) in Nature exploring the costs and benefits of using enhanced weathering to mitigate climate change.

“Then there is volcanic “ingassing”, take up by weathering of volcanic rocks on land. Dessert et al (2003) estimate this to be about 180 Mt CO2/year, so the net volcanic contribution may be smaller still.”

Errr … weathering of volcanic rocks _releases_ CO2, so adds to the total, How did you figure the opposite? Ingassing indeed!

the geom_line and the size aesthetic are responsible