Global Changes in Urban Vegetation Cover

Daniel R Richards,Richard N Belcher

doi:10.3390/rs12010023

Daniel R Richards, Richard N Belcher

Open Access

https://doi.org/10.3390/rs12010023

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Abstract

Urban vegetation provides many ecosystem services that make cities more liveable for people. As the world continues to urbanise, the vegetation cover in urban areas is changing rapidly. Here we use Google Earth Engine to map vegetation cover in all urban areas larger than 15 km2 in 2000 and 2015, which covered 390,000 km2 and 490,000 km2 respectively. In 2015, urban vegetation covered a substantial area, equivalent to the size of Belarus. Proportional vegetation cover was highly variable, and declined in most urban areas between 2000 and 2015. Declines in proportional vegetated cover were particularly common in the Global South. Conversely, proportional vegetation cover increased in some urban areas in eastern North America and parts of Europe. Most urban areas that increased in vegetation cover also increased in size, suggesting that the observed net increases were driven by the capture of rural ecosystems through low-density suburban sprawl. Far fewer urban areas achieved increases in vegetation cover while remaining similar in size, although this trend occurred in some regions with shrinking populations or economies. Maintaining and expanding urban vegetation cover alongside future urbanisation will be critical for the well-being of the five billion people expected to live in urban areas by 2030.

Highlights

The majority of the world’s population live in urban areas [1], making urban vegetation the type of ecosystem that most people interact with most frequently
The total area of urban vegetation has increased rapidly, at a rate of more than 1% of the 2000 extent every year. This corresponds to the widespread expansion of urban areas, as more than 100,000 km2 of additional urban area was analysed in 2015 than in 2000
Of the 4256 urban areas analysed in both years, 2,307 urban areas declined significantly in vegetation cover

Summary

Introduction

The majority of the world’s population live in urban areas [1], making urban vegetation the type of ecosystem that most people interact with most frequently. In addition to providing opportunities for recreation [2,3], urban greenery can help to regulate urban microclimates, reduce flood risk, and support biodiversity [2,4]. These benefits are known collectively as “urban ecosystem services” [5]. The diverse ecosystem services provided by urban vegetation can make cities more comfortable places for people to live [6], improve public health [7,8], and have substantial economic values [2]. At the scale of the whole city, the proportional cover of vegetation is a key high-level indicator for understanding the likely ecological quality of an urban area [12,13,14,15]

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