Independent: The UN’s Rio Plus 20 summit on sustainable development ended yesterday amid a torrent of criticism from environment and development campaigners, who said the colossal, three-day international meeting had achieved nothing. More than 50,000 policymakers, environmentalists and business leaders from around the world gathered in Rio de Janeiro for a conference to mark the 20th anniversary of the celebrated “Earth Summit”. But in contrast to the 1992 meeting, which saw the signature of the important UN…