Dramatic reduction in light pollution during lockdown, nationwide Star Count reveals

  • Light pollution levels were much lower at the start of 2021 compared to previous year, finds CPRE, the countryside charity  
  • Launched to mark International Dark Skies Week, CPRE’s annual Star Count shows a 10% drop in severe light pollution compared to 2020, and the largest percentage of truly dark skies since 2013 

A nationwide Star Count conducted in February has revealed a significant drop in light pollution levels across the UK. The annual citizen science project asks people to count the number of stars they see in the Orion constellation.  

Nearly 8,000 counts were submitted between 6 and 14 February 2021, with 51% of people noting ten or fewer stars, indicating severe light pollution. This compares to 61% during the same period last year. 30 or more stars indicates truly dark skies and were seen by 5% of participants - the highest figure since 2013. 

Lockdown is the most likely reason for this change, with reduced human activity resulting in quieter than usual urban areas. Similar patterns have been found with air pollution, which has also dropped across the country. Results have varied across the UK with counties such as Cumbria experiencing an even more dramatic drop in light pollution.

‘Dark Skies Cumbria’1 Project Officer, Jack Ellerby, said:

“We compared results in Cumbria from 2019 with this year’s 2021 (2020 was a weather wash out, so only 18 unrepresentative recordings) which highlights a major change in light pollution across the county.

       2019        2021 % Change
10 stars or less 51.9% 32% Almost -20% (-10% nationally)
30 stars or more 1.9% 8.1% +6.2% (+5% nationally)
No. of readings 54 269

“It’s good news that we can all enjoy better views of our night sky but we cannot be complacent. Lockdown is likely to have played a major part in the reduction in light pollution so we have to continue with our efforts to enhance and protect the long term visibility of our glorious night skies.  

Image: Camp on Harter Fell looking NW with the glow of Keswick and the West Coast apparent by Rob Fraser

“To identify the worst light pollution ‘hot-spots’ in Cumbria, we’ve compared satellite data taken in 2013 and 2019, and Lighting Consultants are currently carrying out an audit of lighting in three pilot areas. What’s coming through is that the growth in poor lighting, which shines up into the sky instead of down where it’s needed, is commercial and industrial ‘security’ lighting. 

“Penrith is showing one of the worst local increases in light pollution.  The good news is Eden District Council through their climate change and greening plans are now keen to tackle the problem. 

“The satellite images also show that Cumbria County Council’s LED road lighting replacement programme since 2013, by stopping upward light projection and glare, has helped to reduce light pollution across most of our towns. Carlisle City Council is now in the process of changing its road and footway lights to more energy efficient and Dark Sky friendly ones to. We hope that other local authorities will follow this great work. 

“The message is simple – use sensible lighting, make it friendly to our Dark Skies and dim it down or switch them off when not needed.”

National results have been launched to mark International Dark Skies Week, run by the International Dark-Sky Association (IDSA), which raises awareness on the impacts of light pollution.   

Light pollution can negatively affect human health and wildlife by disturbing animals’ natural cycles and behaviours. Badly designed, wasteful light also contributes to climate change and obscures our connection to the Universe.  

Therefore, CPRE and IDSA want to combat light pollution through strong local and national policies, while also protecting and enhancing existing dark skies. This involves putting the right light in the right places, such as LED lights that only illuminate where we walk, and turning off lights in places like office buildings when they’re unoccupied.  

CPRE and IDSA hope this fall in people experiencing the most severe light pollution - an unintended but positive consequence of lockdown - continues long after coronavirus restrictions are lifted so more people can experience the wonder of a truly dark sky. 

(1). The Dark Skies Cumbria Project, working with the Parish and Town Councils for Kendal-Oxenholme, Patterdale and the Melbreak parishes – Buttermere, Lorton and Loweswater. Manchester-based lighting consultants Cundall Light4 are producing Lighting Audit and Action Plans (LAAPs) for the 3 pilot areas, and their reports are due at the end of May.