In my opinion not even God himself (if he exists) can address the causes of migration unless He changes the natural rules overnight. The idea that you and me or even Elon Musk + Bill Gates can actually do something to address the actual causes of migration sounds very naive, horribly naive, and please don't take it as an offense. Lets say for a moment that there is a miracle and "we" fix the poverty and the climate in the world tomorrow. How long do you think will that last ? 20-30 years until the world population doubles again ? What do you do then when this overpopulation combined with the corresponding consumption and pollution brings us back to the current situation ? Will you invite "us" all again to fix everything back ? How are "we" going to fix this situation ? By working each of us overtime or what ?