Agence France-Presse: World leaders on Sunday insisted that the climate deal clinched in desperation at the UN summit was the best that could be done as they returned home to a lashing from critics. Newspapers widely branded the accord a failure and experts such as the head of a Nobel Peace prize-winning climate panel said “urgent” action was now needed. US President Barack Obama acknowledged that all of the world’s polluters would quickly have to do more, but German Chancellor Angela Merkel said …