It is widely believed that an atmospheric increase in the greenhouse gases CO2 has played a significant role in global warming. Even now, CO2 accounts for less than 1/3 of greenhouse gases. Water vapor, on the other hand, accounts for approximately 70% of all greenhouse gases.
The byproduct of hydrogen fuel cells is water vapor. Let’s pretend that every vehicle in America is powered by hydrogen say 10 years from now. That’s a lot of water vapor! What effect would it have?