How the model works
Each region gets an attractiveness score: 0.45·economy + 0.30·political + 0.25·environment. A gravity model sends people from the less attractive region to the more attractive one: bigger populations move more, and the stream shrinks with distance (÷ (1 + km/1000)^1.2), restricted borders, and low urban pull. When the origin's political or environmental score drops below 30, a second, forced stream is added that depends on the crisis, not on the destination. Every stream returns a counter-stream of 12–37%. Numbers are for reasoning, not forecasting.
Map and country lookup use ArcGIS Online basemaps and the World Countries (Generalized) feature service.