Politics.co.uk: There are 50 days to go until vital climate change negotiations begin in Copenhagen, with 17 of the world’s biggest economies meeting in London this weekend. The latest meeting of the Major Economies Forum (MEF) follows previous summits in L’Aquila and Washington DC. Barack Obama established the MEF earlier this year in a bid to provide “a more informal discussion space” on a range of issues, including climate change. With crucial talks to replace the Kyoto treaty due in …