transition demographic model population stage human affluence developed has technology environment world description mark question society evidence trend later below
malthusian population growth catastrophe model technology human affluence curve food carrying capacity environment periodic predicts striking unchecked similarity note figure
hunger world map population quotes food undernourished percentage security hungry nation fast men global know things rid numbers undernourishment wikipedia
gdp affluence density world map technology population domestic gross europe production america china north figure psu education edu
development sustainable modernization figure environment psu education edu
world population density biodiversity hotspots map figure society psu
exponential growth reindeer matthew science feedback island st population graph equations mechanisms figure assumed herd curve decay math 1966 visionlearning
affluence interaction societies simplest
environment diagram human systems system feedback humanity example education between mechanisms affects revisiting figure simple two psu edu
vulnerability global climate world adaptation distribution change psu education edu