Independent: Leaders attending the G20 meeting in London plan to gather again in the summer for a special summit on tackling climate change, The Independent on Sunday can reveal. The new summit — which is being called on the initiative of President Barack Obama as part of a US drive to get a new international agreement on tackling global warming — is to take place alongside the annual G8 gathering of world leaders on the island of La Maddalena off Sardinia. Scientists and …