so EU's oil imports from russia have significantly increased after the end of cold war. germany gets about a third of its oil from russia. oil will become pretty expensive if we don't get russian oil anymore. we'd need other sources. EU may release some of its reserves but that doesnt solve the problem, only delay it. importing from other countries isn't so good either because of the lack of pipelines. because of expensive oil and no exports to russia, EU economy will go down. because of globalization us economy will go down too. russian economy will of course go down too because of western sanctions and no energy export.
if invade ww3 starts. my guess is no one would use nuclear weapons though. because of annihilation. at least not at the start. cant guarantee what will happen if one side is about to lose. they might start one last strike. a final one.
so what do?