The UN climate agency has suggested a special summit to address climate change, but may consider high-level ministerial talks if world leaders are not on board. Yvo de Boer, head of the UN Climate Change Secretariat, stated that UN Secretary-General Ban Ki-moon is looking into the possibility of a high-level meeting to address global warming, with envoys set to gauge government interest. The meeting could take place on the sidelines of the UN General Assembly in September, and would not necessarily involve heads of state. "It might involve a different level, like foreign affairs or energy ministers." Ban stated on March 1 that global warming was as serious a threat as war and called on the United States to take the lead in addressing climate change. Despite requests from UN environmental agencies, Ban's spokeswoman mentioned that there were no immediate plans for a summit. De Boer explained, "I don't believe it's a change in attitude. What we are considering is a high-level meeting to involve a wider range of stakeholders, including foreign affairs, energy, trade, economy, and transportation." "It requires a more extensive effort and broader backing," he stated, regardless of whether leaders come together. Global discussions on expanding efforts to combat global warming, largely attributed to the burning of fossil fuels, have come to a standstill. UN scientific reports released this year indicate that human emissions of greenhouse gases are very likely the cause of global warming, which could lead to increased hunger, droughts, floods, heatwaves, glacier melting, and rising sea levels. De Boer emphasizes the need for accelerated negotiations to expand the UN Kyoto Protocol, which mandates emissions cuts for 35 industrialized nations until 2012. The United States and Australia withdrew from the agreement in 2001, citing the high cost of compliance. The Kyoto nations account for just one-third of global carbon dioxide emissions, with Russia being the only one bound by a Kyoto target among the top four emitters - the United States, China, Russia, and India. De Boer suggested that a new meeting could complement, rather than repeat, the Group of Eight summit in June, where German Chancellor Angela Merkel plans to address climate change. The G8 summit will include leaders from China, India, Brazil, Mexico, and South Africa, who, along with the G8, account for the majority of worldwide carbon dioxide emissions. De Boer stated that the G8 summit does not include important groups such as small island states facing the threat of rising sea levels, the poorest nations in sub-Saharan Africa, and Australia. Environment ministers will convene for the next round of formal UN climate discussions in Bali, Indonesia, in December.