Almost nothing, yes. Only active GH gas sequestration from atmosphere can be clean, and even then it's not guaranteed. We, as humanity, need to somehow quantify

Almost nothing, yes. Only active GH gas sequestration from atmosphere can be clean, and even then it's not guaranteed. We, as humanity, need to somehow quantify total emissions produced from any given activity, and then grade it somehow. Currently we have super primitive grading - 1) green and 2) not green. Which is completely insufficient and often misleading in third decade of 21 century. I don't have hard numbers, but I'm pretty sure that hydrogen is much much less green than some other alternatives like solar in total footprint. But we lump them together as if they are equally good. Same as with corporations going carbon neutral - one company is doing actual carbon sequestration and is really neutral, another company is cheating and just buying carbon credits from some undeveloped country and pretends to be neutral too (especially if they are just using existing forests as a claim). They are not the same but the names are.