The UN climate agency has called for a special summit to address climate change, but stated that high-level ministerial talks could also be effective if world leaders are not willing to participate. Yvo de Boer, the head of the UN Climate Change Secretariat, noted that UN Secretary-General Ban Ki-moon had agreed to send envoys to assess government willingness for a high-level meeting on global warming during talks in New York. De Boer stated that Ban's envoys would investigate the possibility of a high-level meeting, potentially during the UN General Assembly in New York in September, and clarified that it did not necessarily have to involve heads of state. "It could be a different level, like foreign affairs or energy ministers." Ban stated on March 1 that global warming was as big a threat as war and called on the United States to take a leading role in addressing climate change. However, Ban's spokeswoman confirmed that despite requests from UN environment agencies, there were no current plans to organize a summit. "I don't see it as a change of heart. What is being considered is a high-level meeting to involve a wider range of participants - including foreign affairs, energy, trade, economy, and transportation," de Boer explained. He stated that there is a need for a more extensive effort and broader support, regardless of whether or not leaders convene. Discussions on a global effort to combat climate change, largely attributed to the burning of fossil fuels, have come to a halt. Reports from the UN this year suggest that human activities are likely contributing to global warming, which could result in increased hunger, droughts, floods, heatwaves, melting glaciers, and rising sea levels. De Boer stressed the importance of accelerating discussions on expanding the UN Kyoto Protocol, which mandates emissions reductions for 35 industrialized nations until 2012. The United States and Australia withdrew from the agreement in 2001, citing concerns over the high costs associated with Kyoto. The Kyoto nations represent just one third of global carbon dioxide emissions, with only Russia committed to a Kyoto target among the top four emitters - the United States, China, Russia, and India. De Boer suggested that a new meeting could expand upon the Group of Eight summit in June, where German Chancellor Angela Merkel plans to address climate change. The G8 summit will also include leaders from China, India, Brazil, Mexico, and South Africa, who together account for the majority of worldwide carbon dioxide emissions. De Boer mentioned that the G8 summit does not include certain groups like small island states, the poorest nations in sub-Saharan Africa, and Australia, which are all affected by issues like rising seas. The next round of formal UN climate negotiations will take place in Bali, Indonesia, in December, where environment ministers will meet.