First Estimation of Global Trends in Nocturnal Power Emissions Reveals Acceleration of Light Pollution

Alejandro Sánchez De Miguel,Jonathan Bennie,Emma Rosenfeld,Simon Dzurjak,Kevin J Gaston

doi:10.3390/rs13163311

Alejandro Sánchez De Miguel, Jonathan Bennie + Show 3 more

Open Access

https://doi.org/10.3390/rs13163311

Copy DOI

Abstract

The global spread of artificial light is eroding the natural night-time environment. The estimation of the pattern and rate of growth of light pollution on multi-decadal scales has nonetheless proven challenging. Here we show that the power of global satellite observable light emissions increased from 1992 to 2017 by at least 49%. We estimate the hidden impact of the transition to solid-state light-emitting diode (LED) technology, which increases emissions at visible wavelengths undetectable to existing satellite sensors, suggesting that the true increase in radiance in the visible spectrum may be as high as globally 270% and 400% on specific regions. These dynamics vary by region, but there is limited evidence that advances in lighting technology have led to decreased emissions.

Highlights

Satellite images of the Earth at night strikingly illustrate the extent of the distribution of artificial light sources associated with human settlement, industry and transport links, across its surface [1]
We estimated the effect that changes in light technology towards blue-rich solid-state (LED) lighting may had on detected light emissions since 2012, given the poor detection of blue light by the satellites, and produce high and low estimates of the actual radiance given the detected radiance under three different scenarios of technological change
Utilising data of typical conversion and replacement rates to estimate the possible fraction of undetected light assuming different scenarios of uptake and replacement of gas-discharge lighting with lightemitting diode (LED), suggests that there has been a marked recent acceleration to global emitted power (Figure 2)

Summary

Introduction

Satellite images of the Earth at night strikingly illustrate the extent of the distribution of artificial light sources associated with human settlement, industry and transport links, across its surface [1]. The quantity of artificial light detected from satellites includes a mixed signal of direct emissions from outdoor lighting that is not vertically shielded, as well as reflected light from the ground, buildings and vegetation, and light scattered within the atmosphere This signal has increasingly been used as an important indicator of urbanisation, industrial activity [2,3] and economic development [4,5]. To determine how the global magnitude of the impacts of light pollution is changing on multi-decadal scales, as has been performed for many other anthropogenic environmental pressures, time series data on artificial light emissions are required This proved challenging for a combination of reasons, including technical difficulties in distinguishing faint artificial light sources from natural ones, limitations of the available satellite sensors, and a paucity of ground-truthed sources. Studies to date [18,19] have been severely limited in their spatial and temporal coverage, and in the inferences that could be drawn

Methods

Results

Conclusion