Carbon neutrality has never been more highly prized. Half of New Zealand's greenhouse gas emissions come from the guts of sheep and cows; Norway spews ever more gases from its North Sea oil platforms; Iceland has soaring emissions thanks to its aluminium smelters. But all have promised to cut their emissions to zero by becoming founding members of the Climate Neutral Network, set up by the UN Environment Programme at a meeting in Monaco last week. Feb 27, 2008