London’s Dark Sky reserve?

This letter from our chairman Ron Crompton appeared first in the regular Friends' newsletter, which is distributed free to members

I walked away from the fairground-bright street lights outside Richmond Gate and was slowly enveloped by the darkness. The Park was still and mysterious, the silence broken occasionally by an owl calling or a deer mewing nearby.

As I approached the top of Sawyer’s Hill a dull glow started and over the brow the landscape was illuminated by the light of the Roehampton Estate a mile or more away. The stars, which had been sharp in the darkness, were now dimmed and blurred by the light. By Sheen Cross they were invisible.

This is the night sky in much of Richmond Park. There are darker skies in the centre of the Park but there are many brighter ones, tainted by the light from houses and flats just outside the Park and by the yellow glow of the city beyond.

It is a far cry from Van Gogh’s “The Starry Night” – a sky he described in his diary: “In the blue depth, the stars were sparkling, greenish, yellow, white, pink, brilliant, gemlike” – yes, the stars do have different colours when seen in the really dark skies he knew.

Richmond Park is the darkest place in London at night but even it is polluted by light. It is many times lighter than it was 50 or 100 years ago. Over the last 50 years, the amount of light emitted in the UK has increased eight fold. New residential developments have been built all around the Park, many with large picture windows or spotlights outside.

Does this matter? Well, it does to bats, owls and other nocturnal creatures. Most bat species will not emerge from their roosts or feed in light levels above 1 Lux (natural full moon on a clear night). Once they emerge, light, especially bright white light, disrupts their vision and their patterns of movement and foraging.

Artificial light at night also affects owls, preventing them from hunting successfully, especially at dusk when they become active. Little Owls, of which there is a high concentration in the Park, move elsewhere if regularly disturbed by light; with steadily increasing light pollution, their numbers will fall.

And surely it should matter to us. A hundred years ago most Britons had plenty of experience of really dark night skies – of Van Gogh’s Starry Night (painted in 1888); now virtually nobody does. Only 1% of the southeast is now counted as “truly dark”. We live in a world that is permanently light, where we have a “great yellow sky”, as one author has put it, not a dark one.

Starry night skies and natural darkness are one of the “resources” that the US National Parks Service is sworn to protect. The UK National Parks is working to set up Dark Sky Reserves. Maybe Richmond Park, especially its centre, should be designated as London’s Dark Sky Reserve?