The agglomeration and dispersion dichotomy of human settlements on Earth

TL;DR

This paper classifies global human settlement patterns into agglomeration and dispersion, linking these spatial arrangements to environmental and socio-economic impacts, and proposes a model to simulate their growth.

Contribution

It provides the first global classification of human settlement spatial patterns and introduces a model that accurately simulates their growth and distribution.

Findings

Two main settlement classes: agglomeration and dispersion.

Model achieves an F1 score of 0.73 in matching observed patterns.

Settlement patterns correlate with CO2 emissions and land use impacts.

Abstract

Human settlements on Earth are scattered in a multitude of shapes, sizes and spatial arrangements. These patterns are often not random but a result of complex geographical, cultural, economic and historical processes that have profound human and ecological impacts. However, little is known about the global distribution of these patterns and the spatial forces that creates them. This study analyses human settlements from high-resolution satellite imagery and provides a global classification of spatial patterns. We find two emerging classes, namely agglomeration and dispersion. In the former, settlements are fewer than expected based on the predictions of scaling theory, while an unexpectedly high number of settlements characterizes the latter. Our global classification of spatial patterns correlates with some urban outcomes, such as the amount of CO2 emitted for transportation, providing insights into the relationship between land use patterns and socio-economic and environmental indicators. To explain the observed spatial patterns, we also propose a model that combines two agglomeration forces and simulates human settlements' historical growth. Our results show that our model accurately matches the observed global classification (F1: 0.73), helps to understand and estimate the growth of human settlements and, in turn, the distribution and physical dynamics of all human settlements on Earth, from small villages to cities.