Does hydrogen as a fuel contribute to the greenhouse effect?
If hydrogen is made industrially from methane, then carbon dioxide is a by-product of the process. If not all this CO2 is used for other purposes, then there is a contribution to the greenhouse effect. Hydrogen itself also contributes to the greenhouse effect in an indirect way as it reacts in the atmosphere to increase methane and ozone, both of which are greenhouse gases. However, this contribution should be compared with the greater impact presented by fossil fuels, which release CO2.
