Accelerating growth of human coastal populations at the global and continent levels: 2000–2018

TLDR

Human populations along coastlines are expanding at a rate that threatens to collide with increasing natural and anthropogenic hazards, and reliable data on their magnitude, distribution, and change are essential for comprehensive coastal monitoring. The study aims to develop methods to estimate annual continental and global coastal populations from 2000 to 2018 using recently available ambient dasymetric data. The authors use ambient, dasymetric data to estimate annual coastal populations by measuring populations horizontally from the shoreline inward across continents and globally. The analysis reveals that about 2 billion people live within 50 km of coastlines, 1 billion within 10 km, coastal growth outpaces inland growth, distance from coast strongly predicts population distribution, and macro patterns can be modeled as a power function, underscoring rising anthropogenic impacts and risks from sea‑level rise, land subsidence, extreme weather, and public health.

Abstract

Current human population growth along Earth's coasts is on a collision path with anticipated consequences of increasing natural and anthropogenic induced coastal hazards. Using recently-available ambient, dasymetric data, we developed methods to estimate annual continental and global coastal populations from (2000-2018) measured horizontally from the shoreline inward. We found: (1) large concentrations of population in relatively small bands and regions along the coast (~ 2 billion within 50 km and ~ 1 billion within 10 km); (2) higher growth rates of coastal population than inland population (an addition of 463 million within 50 km and 233 million within 10 km); (3) strong influence of distance from the coast to predict population distribution; and (4) that macro population patterns and growth could be expressed and modeled as a power function at continental and global levels. Findings point to emerging macro population patterns along the coast as contributing to increasing anthropogenic effects on Earth systems and increasing human risks associated with sea-level rise, land subsidence, extreme weather, and public health. Reliable data tracking of the magnitude, spatial distribution and change of human populations in the coastal regions is essential for comprehensive coastal monitoring.