Friday, November 14, 2008

Contrails and cattle

click photo to enlarge
The more we study global warming the more we come to appreciate the multiplicity of contributors to the phenomenon.

According to the UN the CO2 equivalent (methane) produced by cattle rearing exceeds the CO2 produced by transportation. Add in all the other sheep, goats, pigs, etc, that produce methane and the contribution made by livestock farming to global warming is massive. And, since methane is, by most measures, a significantly more harmful greenhouse gas than CO2, the case for reducing the scale of animal agriculture is compelling.

Consider too the vapour trails (contrails) that criss-cross our skies. Not only are they a pain for the photographer, they also increase the amount of high level cirrus in the atmosphere. This kind of cloud reflects less heat than it traps, and so raises the temperature of the earth by a measurable amount. Studies in the U.S. suggest that aircraft-generated clouds contribute an increase of somewhere between 0.36 and 0.54 degrees Fahrenheit per decade. That being the case, those calling for a reduction in flying seem to have a point.

This photograph of cows walking along the sea bank at Frampton Marsh, Lincolnshire, caused the disparate subjects of methane and air travel to come to mind. The silhouettes of the group of cows and the lone straggler, along with the vapour trails that had been "distressed" by high level winds, seemed a promising combination of the distinct and the diaphanous. In this flat landscape this ratio of land to sky suggested itself.

photograph & text (c) T. Boughen

Camera: Olympus E510
Mode: Aperture Priority
Focal Length: 76mm (152mm/35mm equiv.)
F No: f7.1
Shutter Speed: 1/500
ISO: 100
Exposure Compensation: 0 EV
Image Stabilisation: On