. I'd also have told him that the CC pushers completely ignore the fact that our planet's volcano's spew more CO2 into the atmosphere in one day than all the airliners, cars, ships and trains do in one month.
Sorry, this "fact" is actually a myth. Volcanos generate about 1% of the CO2 produced by us.
According to the U.S. Geological Survey (USGS), the world’s volcanoes, both on land and undersea, generate about 200 million tons of carbon dioxide (CO2) annually, while our automotive and industrial activities cause some 24 billion tons of CO2 emissions every year worldwide. Despite the arguments to the contrary, the facts speak for themselves: Greenhouse gas emissions from volcanoes comprise less than one percent of those generated by today’s human endeavors.
Another indication that human emissions dwarf those of volcanoes is the fact that atmospheric CO2 levels, as measured by sampling stations around the world set up by the federally funded Carbon Dioxide Information Analysis Center, have gone up consistently year after year regardless of whether or not there have been major volcanic eruptions in specific years. “If it were true that individual volcanic eruptions dominated human emissions and were causing the rise in carbon dioxide concentrations, then these carbon dioxide records would be full of spikes—one for each eruption,” says Coby Beck, a journalist writing for online environmental news portal Grist.org. “Instead, such records show a smooth and regular trend.”
https://www.scientificamerican.com/article/earthtalks-volcanoes-or-humans/
The burning of fossil fuels and changes in land use results in the emission into the atmosphere of approximately 34 billion tonnes of carbon dioxide per year worldwide, according to the U.S. Energy Information Administration (EIA). The fossil fuels emissions numbers are about 100 times bigger than even the maximum estimated volcanic CO2 fluxes. Our understanding of volcanic discharges would have to be shown to be very mistaken before volcanic CO2 discharges could be considered anything but a bit player in contributing to the recent changes observed in the concentration of CO2 in the Earth's atmosphere.
https://www.skepticalscience.com/volcanoes-and-global-warming.htm
Human activities emit 60 or more times the amount of carbon dioxide released by volcanoes each year. Large, violent eruptions may match the rate of human emissions for the few hours that they last, but they are too rare and fleeting to rival humanity’s annual emissions. In fact, several individual U.S. states emit more carbon dioxide in a year than all the volcanoes on the planet combined do.
https://www.climate.gov/news-featur...-carbon-dioxide-volcanoes-or-human-activities
Add all of these up, and you get an estimate of around 645 million tons of CO2 per year. Yes, there are uncertainties; yes, there's annual variation; yes, it's easy to get led astray if you think that Mt. Etna is typical, rather than the unusually large emitter of CO2 that it is. When you realize that volcanism contributes 645 million tons of CO2 per year – and it becomes clearer if you write it as 0.645 billion tons of CO2 per year – compared to humanity's 29 billion tons per year, it's overwhelmingly clear what's caused the carbon dioxide increase in Earth's atmosphere since 1750.
https://www.forbes.com/sites/starts...-co2-does-a-single-volcano-emit/#130c639d5cbf