Skyglow: the phantom menace?

LA21 Public Meeting on Light Pollution

Light pollution increased dramatically in the south east of England between 1993 and 2000. David Gilburt from the Campaign to Protect Rural England (CPRE), gave a talk on this topical environmental issue which has received publicity following the CPRE 'Night Blight' campaign for dark skies. Les Brown from the Institute of Light Engineers (ILE) talked about the practical steps being taken to reduce light pollution.

What do people see when looking up to the night sky in Surrey? Certainly not the Milky Way as it is no longer visible from this County. Most likely it is a few of the brightest stars in the pink or orange glow that can be seen for miles around our towns and cities. Satellite pictures demonstrated marked deterioration of dark skies between 1993 and 2000. It is thought that 21% of Surrey is now saturated with light where stars cannot be seen.

Light pollution has three forms:

Sky Glow - the scattering of artificial light by airborne dust and water droplets.

Glare - the uncomfortable brightness of a light source when viewed against a darker background.

Light Trespass - light spilling beyond the boundaries of the property on which a light is located.

As a keen amateur astronomer, Mr Gilburt explained how light pollution was destroying the dark night sky, rendering stars, planets, galaxies and the Milky Way invisible. One hundred years ago there was no light pollution and only 35-40 years ago very little. In 2004 light pollution in the UK is a major environmental concern and it is set to get worse unless action is taken. Ten years from now, on present trends, there will be no stars visible in Surrey and the present dark sites will have become polluted.

There are other detrimental effects from excessive lighting - the waste of energy which contributes to global warming, the nuisance caused to others by bright security lights and wildlife is affected by lights being on at night. Exterior lights are required for safety but these can be designed to prevent excess energy use and to shine downwards only.

So what can be done?

Currently there are Government controls and practical advice on lighting but no legislation. DEFRA are to produce a report which the CPRE hope will declare excess lighting to be a statutory nuisance.

One thing that the public can do is to ensure that exterior lighting only illuminates the area required and that 150 watt bulbs are used for security lights. Porch lights which are sensitive to motion could be considered.

Les Brown explained a number of steps that were being taken by the industry to overcome some of the issues. Exterior lighting has benefits - it can save up to 30% of night accidents and decreases crime by 20%. Town centres can function for longer if they are well lit.

It is possible to control all this lighting by using the appropriate size of bulb, mounting lights to minimise scatter, glare and trespass and setting detectors to minimise switching on and off. Mr Brown gave an interesting demonstration of how environmentally friendly lights and bulbs had been developed.

Councillor Howard, who chaired the meeting, announced that Woking Borough Council had agreed to take steps to address the problem and would aim to introduce lighting to comply with the ILE guidelines. Planning guidance would in future include directions regarding light pollution. A copy of the report by the Light Pollution Task Group, which was adopted by Woking Borough Council can be downloaded here.