Deutsche Presse-Agentur: "Collective action" was necessary to meet the target to cut carbon emissions by 50 per cent by 2050, former British prime minister Tony Blair told a group of international experts from the world’s 20 major greenhouse gas emitters on Saturday in Japan’s Chiba City, near Tokyo. "In theory, each nation, acting unilaterally, could take action that together amounted to the necessary change. But in practice that is unlikely," he said. Blair was speaking at a round of …