Over recent decades, light pollution has emerged as a growing concern, affecting areas from astronomy to human health, with the most significant impacts on the environment and biodiversity. Numerous studies confirm the severe effects of artificial light at night (ALAN) on various species, prompting regulatory developments at local, national, and international levels.
A global overview of regulatory efforts (IAU CPS, 2024) shows that over 30 countries have adopted measures to mitigate light pollution. Despite this progress, regulations remain limited, fragmented, and inconsistent, resulting in a continued rise in light pollution that harms ecosystems. Light pollution increases by over 10% annually, with over 99% of populations and wildlife in Europe and the US living under artificially lit skies. This rapid escalation demands broader international discussion to develop coherent global regulations, as further neglect will exacerbate biodiversity loss and hinder the achievement of biodiversity targets.
At the international level, the CMS was among the first to highlight the loss of natural nocturnal environments and the transboundary nature of light pollution. CMS has adopted various documents on this topic, with the latest, the International Light Pollution Guidelines for Migratory Species (CMS, 2024), offering tools to assess ALAN’s impact and recommend management practices. These guidelines have gained recognition in countries like Australia and New Zealand, but wider adoption is needed.
The Convention on Biological Diversity (CBD) also recognises the environmental impact of light pollution. Its Kunming-Montreal Global Biodiversity Framework (GBF) sets a target to reduce pollution from all sources by 2050, identifying pollution as a key driver of biodiversity loss. While ALAN is not explicitly mentioned, guidance clarifies that “all pollution sources” include artificial light. Countries such as Austria, Belgium, France, Germany, and Spain have reflected this in their National Biodiversity Strategies and Action Plans. Additionally, International organisations like the IUCN have joined the effort, recently adopting Motion 46: Global Strategy for Natural Darkness Restoration, calling for the protection of natural night environments.
This proposed side event at CMS COP15 aims to raise awareness of light pollution as a neglected pollutant, promote its inclusion in CMS and UNEP agendas, and advocate an eco-centric approach recognising the importance of natural darkness for biodiversity and human well-being. It will discuss practical solutions from the CMS Guidelines and PLAN-B European Policy Brief and share country experiences.
A similar event at UNFCCC COP30 (in the House of Biodiversity) engaged Brazilian officials interested in tackling light pollution. This event will unite nocturnal conservation efforts, elevate light pollution on the international agenda, and potentially catalyse UNEP action. Further events are planned at CBD COP and other UNEP meetings to deliver a unified call to protect the world’s night skies.