When we dig axes into the sides of cliffs, race boats across the oceans and disturb coral when we dive, we harm the natural world through sports. Even more damage is done by the space sports take up as more and more people watch and play them.

The spread of golf courses, for example, has spawned the Global Anti-Golf Movement, which calls for a moratorium on new development. Forests, mangroves and other natural habitats are destroyed to build the courses. The huge amounts of water needed to keep them verdant leave other areas dry: an 18-hole golf course uses an average of 2.4 million litres of water a day, yet there are many bright green ones in countries where water is scarce. The fertilizers and pesticides used on them do further damage.

Ski resorts also take their toll, as mountainsides are cleared and forests cut down to build runs. Skiers damage the flora on the slopes, and the noise and activity disturb animal life.

Building new stadiums, courses and tracks uses enormous amounts of energy and resources, and more are taken up in maintaining, heating, cooling and lighting them. Even transporting players and fans to sporting events causes pollution. Motor racing may be a particularly easy target, but the management of even seemingly harmless sports like football also needs to be concerned.

Yet many sports resorts and centres have been built with nature in mind, improving the land on which they stand. The Phuket Golf Club in Thailand was built on the site of a former tin mine, the Old Works Golf Course in Anaconda, United States, over a disused copper smelter. Both now attract wildlife. 'Heck, we've got herons in the water and deer eating the apples,' says Derf Soller, superintendent of the Old Works Golf Course. 'You didn't see that before.'

The Seven Bridges Ice Arena in Chicago, one of the largest in the United States, uses the waste heat and energy from refrigerating the ice rinks to heat and air-condition the huge building, cutting its energy bill in half. In Australia, the Sydney SuperDome sports centre is powered by a rooftop solar energy system, saving 85 tonnes of greenhouse gases per year.