What this article doesn't take into account is what I brought up earlier, the atmospheric lifetime of hydrogen. Hydrogen lasts between 4 - 7 years in the atmosphere, while CO2 lasts between 300 - 1000 years. So while hydrogen may short term be worse pound for pound, CO2 is still far more of a threat. Furthermore, C02 is released as a byproduct of combustion as opposed to accidental leaks in the case of hydrogen, so the volume of CO2 being released into the atmosphere is far more than hydrogen even if hydrogen were to become widespread.