I drove 1800 miles in a Hydrogen Car

https://www.nytimes.com/2021/08/12/climate/hydrogen-fuel-natural-gas-pollution.html
"In all, they found that the greenhouse gas footprint of blue hydrogen was more than 20 percent greater than burning natural gas or coal for heat. "
summary of this peer-reviewed paper : https://onlinelibrary.wiley.com/doi/full/10.1002/ese3.956