Hello! I would say that the lines from that poem are an example of a hyperbole. This is because when it says, “I’ll love you dear, I’ll love you, Till China and Africa meet”, he doesn’t actually mean it. It’s a comparison of two things, one that will never happen, to solidify that fact that this person will love the other forever, because China and Africa will probably never meet until the world ends. So yeah, the official definition of hyperbole, “exaggerated statements or claims not meant to be taken literally” definitely describes this line in the poem.