I was just wondering earlier today how long world helium reserves could last. For airships a 90% reduction in carbon emissions won't matter if helium becomes th

I was just wondering earlier today how long world helium reserves could last. For airships a 90% reduction in carbon emissions won't matter if helium becomes the economic bottleneck. Sort of depressing how soon we seem to be reaching a point where depletion of earth resources is inevitable. Hydrogen would be interesting if we could make it safe enough. It could double as a fuel source for the ships, too.