Edit: just did some research on electric vs. gas vehicles and their total environmental impact. Nothing specifically on motorcycles, but some of the data would apply.
"Based on where EVs have been sold, driving the average EV produces global warming pollution equal to a gasoline vehicle that gets 88 miles per gallon (mpg) fuel economy." https://blog.ucsusa.org/dave-reichmuth/are-electric-vehicles...
"In a 2015 study, the Union of Concerned Scientists found that gas-powered cars emitted almost double the emissions that contribute to global warming as electric vehicles, which can make up the difference from the manufacturing stage in six to 18 months of driving, depending on the size of the battery." https://www.businessinsider.com/building-electric-cars-how-m...
Most vehicles are not electric yet.