I recommend doing a bit of research into how hydrogen is produced (mostly) from fossil fuels. Methane (or "clean-burning Natural Gas") is the primary source, and the process is pretty energy intensive. Electrolysis is possible, but at lower energy efficiency.

Storage of gaseous hydrogen to the typical 5,000 to 10,000 psi used is a very real energy and safety concern. Liquefaction is more energy intensive and much less safe due to the refrigeration required to keep the hydrogen from "boiling off" and producing an extremely combustible cloud. Lose the refrigeration and you are in for a real treat. Hydrogen molecules are so small that they leak through anything.

Storage by adsorption (not absorption) in metal hydrides is much safer, but requires significant energy to store the hydrogen and then release it for use. Add in the cost of building an entirely new infrastructure to produce, store and deliver hydrogen as a fuel and the "clean" benefits are quickly outweighed by the need to build the infrastructure using conventional energy sources, i.e. oil & gas.

And I seem to remember hearing that water vapor is more of a "greenhouse gas" than carbon dioxide.

In short, hydrogen is not the super-simple solution to all of the world's problems, and could, in fact, exacerbate them.