Light pollution: City of London to ask high-rise buildings to switch off their lights at night

London authorities are mulling over new rules that would see high rise buildings switch off their unnecessary lights at night.
London authorities are mulling over new rules that would see high rise buildings switch off their unnecessary lights at night.   -  Copyright  Canva
By Charlotte Elton

London’s night-time skyline might soon look very different, as city authorities draft rules requiring skyscrapers to dim their lights overnight.

The initiative will “cut light pollution and save energy”, promised the City of London Corporation, the financial district governing body.

If the new plans are adopted, buildings in the Square Mile - the London area where most of its high rise buildings are clustered - will be asked to switch off unnecessary building lights after dark.

New buildings will have to abide by curfews. Existing buildings will be encouraged to adopt the policy, but it won’t be mandatory.

The rules come as a mounting body of evidence shows the devastating impact that light pollution has on biodiversity and human health, not to mention wasted energy.

What will the new policy look like?

The new policy is set out in the 'Lighting Supplementary Planning Document', seen by Britain’s Financial Times.

The plan would instate different curfews on various ‘brightness zones’ throughout the capital.

If the rules are passed, businesses in residential and heritage areas will have to switch off lights at 10pm, whereas businesses in cultural and tourist areas will be able to keep the lights on until 11pm. In commercial areas, unnecessary lights can stay on until midnight.

The document is currently out for consultation, said City of London Corporation planning and transportation committee chairman Shravan Joshi.

Light pollution is a problem for biodiversity.canva

“The City is a unique place in which 24/7 business districts and busy transport hubs rub up against historic buildings and residential neighbourhoods,” he said.

"The strategy laid out in this document is aimed at ensuring an intelligent, sensitive approach to lighting which ensures the City is safe and accessible while protecting its historic character and the amenity of our residents."

How much energy do skyscraper lights use?

In cities around the world, the lights stay on long after the vast majority of workers have clocked off.

But the glittering night skyline comes at a cost.

According to University College London researchers, high rises are far more energy intensive than low rises. Electricity use per square metre of floor area is nearly two and a half times greater in high-rise office buildings of 20 or more storeys, than in low-rises six storeys or less.

According to a 2020 analysis, the energy used overnight by buildings in Canary Wharf - the area taking up most of the square mile - could power over 4,000 homes per year.

This wastage is particularly stark in the context of the current energy crisis.

How bad is light pollution in London?

On a clear dark night, the researchers say the human eye should be able to see thousands of stars. But less than 30 per cent of people around the world are able to get a clear nightly view of the Milky Way.

In most built-up areas, the night sky is blocked out by artificial light.

The ‘skyglow’ has a devastating impact on biodiversity. 60 per cent of wildlife in the UK depends on natural darkness to survive, as natural signals set migration, reproduction, and pollination rhythms.

Light pollution also wreaks havoc with human health by interrupting our circadian sleep rhythms. This can contribute to depression and heart and blood problems.

How are European countries fighting light pollution?

Across Europe, various cities are switching off the lights overnight. Spain has ordered certain shops to turn off their lights after dark, while Berlin has unplugged the spotlights illuminating 200 of its historic buildings overnight.

In Paris, some citizens have taken matters into their own hands. Parkour collective On the Spot have been somersaulting around the city turning off shop lights.

Last year, the French government extended an existing rule requiring shops to turn off their signs between 1am and 6am.