African leaders at a development summit with Japan pledged Friday to take action to reduce greenhouse gas emissions as part of the fight against global warming. Global negotiations to draft a new climate treaty covering after 2012, when the Kyoto Protocol? obligations to slash emissions expire, have been bogged down by disputes between wealthy and poor countries. Developing countries insist the primary burden should be on major industrial countries historically responsible for global warming, which scientists say could threaten species and exacerbate natural disasters if unchecked. A joint declaration signed by leaders of 51 African nations and Japan said that climate change was an ?rgent challenge?for Africa, considering its vulnerability to droughts and floods. ?t is necessary for all countries, including those in Africa, to collaborate and develop an effective framework beyond 2012 on climate change and take action toward the goal of reducing global greenhouse gas emissions,?it said. The declaration, which did not mention any more specific reduction target, was reached at a three-day summit in Yokohama at which Japan pledged to double aid an investment to Africa. Japanese prime minister Yasuo Fukuda said African leaders he met voiced support for Tokyo? ?ool Earth Partnership?unveiled earlier this year to help developing countries tackle climate change. The initiative promises to provide 10 billion dollars, largely in low-interest loans, over the next five years to help developing countries address global warming. Japan is the home of the Kyoto Protocol but is far behind in meeting its own commitments by 2012 as its economy recovers from slumber in the 1990s. With the support of the United States, the only major industrial country to reject Kyoto, Japan has insisted that commitments after 2012 must be global and include fast-growing polluters such as China.