The world's 20 major greenhouse gas emitters ended two days of discussions in Japan Sunday without reaching consensus on a concrete plan to tackle climate change, reported dpa. Senior officials and experts from the Group of 20 nations (G-20), which are responsible for 80 per cent of the world's CO2 emissions, however, agreed with former British Prime Minister Tony Blair's conviction. Former British Prime Minister Tony Blair on Saturday urged the G-20 members to take collective action to reduce carbon emissions by 50 per cent by 2050 because the world has come to "the critical moment of decision." The former British leader joined the dialogue on a climate treaty to succeed the Kyoto Protocol, which expires in 2012. While industrialized nations supported Japan's proposal to introduce a sector-based system, the developing nations expressed concern that they would be subjected to unfair obligations to reduce carbon emissions. Some G-20 nations including the two largest carbon emitters - the United States and China - have no emission caps required by the Kyoto Protocol. The meeting involved China, India, South Korea, Mexico, Australia, Indonesia, Spain, Poland, South Africa, Iran, Brazil, Nigeria and the G-8 industrialized nations. The fourth round of talks under the G-8 Gleneagles Dialogue on Climate Change, Clean Energy and Sustainable Development was held to find ways to provide financial aid and environmental technologies to developing nations in the global fight against climate change. The dialogue is leading up to the G-8 summit that Japan is to host at Lake Toya in the northern island of Hokkaido on July 7-9.