U.S. State-level Projections of the Spatial Distribution of Population Consistent with Shared Socioeconomic Pathways

Hamidreza Zoraghein,Brian C O’Neill

doi:10.3390/su12083374

Hamidreza Zoraghein, Brian C O’Neill

Open Access

https://doi.org/10.3390/su12083374

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Journal: Sustainability	Publication Date: Apr 21, 2020
Citations: 18	License type: CC BY 4.0

Affiliation: Population Council, University of Denver

Abstract

Spatial population distribution is an important determinant of both drivers of regional environmental change and exposure and vulnerability to it. Spatial projections of population must account for changes in aggregate population, urbanization, and spatial patterns of development, while accounting for uncertainty in each. While an increasing number of projections exist, those carried out at relatively high resolution that account for subnational heterogeneity and can be tailored to represent alternative scenarios of future development are rare. We draw on state-level population projections for the US and a gravity-style spatial downscaling model to design and produce new spatial projections for the U.S. at 1 km resolution consistent with a subset of the Shared Socioeconomic Pathways (SSPs), scenarios of societal change widely used in integrated analyses of global and regional change. We find that the projections successfully capture intended alternative development patterns described in the SSPs, from sprawl to concentrated development and mixed outcomes. Our projected spatial patterns differ more strongly across scenarios than in existing projections, capturing a wider range of the relevant uncertainty introduced by the distinct scenarios. These projections provide an improved basis for integrated environmental analysis that considers uncertainty in demographic outcomes.

Highlights

Projections of the spatial distribution of population are consequential for integrated human-environment analysis
We present spatial population projection results based on SSP2, SSP3, and SSP5 that are consistent with state-level population totals for those scenarios [31]
The discrepancy in results stems from the inherent uncertainty about population aggregates in states, their urbanization levels and spatial development patterns mandated by each scenario

Summary

Introduction

Projections of the spatial distribution of population are consequential for integrated human-environment analysis. Projections of the spatial distribution of population help identify those that are likely to be most affected by climate change and other environmental stress, which can inform resource allocation, adaptation, and mitigation policies in relation to environmental hazards. Such projections have been used to find that the increasing likelihood of storm surge and coastal flooding ensuing from sea level rise [5] may impact the considerable proportion of the world population that is already living close to coastal areas [6,7].

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