Global Choke Points May Link Sea Level and Human Settlement at the Last Glacial Maximum
Global choke points are preeminent nodes in geographic networks and geopolitical touchpoints subject to control by nations. They appear today as recurring theaters of conflict worldwide and also in archaeological investigations delving thousands of years back in time. How different were today?s global choke points at the Last Glacial Maximum (LGM) ~ 20,000 years ago? For the first time, we map nine of them to visualize their conditions at LGM. The global feature aquaterra?all lands inundated and exposed repeatedly during the Late Pleistocene ice ages?initially was mapped as first approximations of sea level. Here we refine its boundaries using Glacial Isostatic Adjustment (GIA) models to account for the Earth?s deformation and horizontal migrations of shorelines in response to glacial melting. We found three choke points sufficiently open to navigation, but six others presented substantially greater barriers than today. Implications include strategic insights on where to search for submerged evidence of human settlement.