Is globalism required to solve it?

That's almost funny, since it's exactly how cosmopolitan humanist types would frame it: 'Give us the global government that we want, yes, give up your cultures, ethnicities, nationalities, and so forth, and become consumerist, individualized humanists like us, and then we will "solve" this problem that we are constantly fearmongering about'.

No realistic 'solution' outside of something like carbon capture technology becoming vastly more effective. There are only hypothetical ones that will never actually happen, such as the first-world forcibly preventing the third-world from 'developing' or everyone simply accepting a big hit to their living standards. The Left would become the biggest climate change deniers almost overnight if any of those solutions were seriously entering policy agendas. 'The climate situation is not so bad that it justifies racial discrimination!' It is not the case that for every problem there are one or more solutions that are conveniently there just waiting to be implemented: that would be to make the metaphysical claim that the cosmos is structured in such a way that there can be no such things as insoluble problems, rather like how we already believe that there are no such things as causeless effects.