Now I understand. The argument for a physical wall is all about doomsday prepping. In the medium term all I'm predicting is an economic downturn on the scale of the Great Depression. I am not predicting nuclear war and hundreds of millions dead or indeed thousands of millions dying across the globe.
This is the economics page so I'll try to stick to it. Perhaps we need to consider the impact of climate change on the inhabitability of tropical zones over the next 50 years. Should this happen, mass migrations will follow but the impact on each tropical zone will likely differ due to ocean currents, proximity to the ocean e.t.c.
