Artificial light at night (ALAN) is increasingly recognised as a widespread anthropogenic pressure on coastal ecosystems. This study develops and applies a scalable satellite-based ecological indicator of ALAN exposure along European coasts from 2016 to 2023 using Visible Infrared Imaging Radiometer Suite Day/Night Band (VIIRS-DNB) data. We quantified spatial and temporal patterns of ALAN across three contiguous domains (land 0–1 km inland, sea 0–1 km, and sea 1 km–1 nm) and compared exposure inside and outside marine Natura 2000 protected areas. Mean radiance increased in all domains over the study period, with consistently higher levels and faster growth rates outside protected sites. Built-up coastal areas were the dominant driver of ALAN intensity, even though they occupied less than 2% of the coastal fringe. Protected waters remained significantly less exposed than adjacent non-protected waters, yet still showed notable light intrusion, particularly in lagoon-rich and urban-adjacent sectors. These results demonstrate that ALAN, derived from VIIRS-DNB, can serve as a robust, large-scale ecological indicator for monitoring anthropogenic pressure in coastal zones and for evaluating the effectiveness of marine protected area networks. The indicator is directly relevant to the Marine Strategy Framework Directive and Natura 2000 management, offering a practical tool for evidence-based mitigation at the land–sea interface.
Maccarrone et al. (Tue,) studied this question.