The initial UN special session on climate change was centered around the wealthier nations, with policymakers emphasizing the need for long-standing polluters to take on a significant portion of the responsibility for reducing greenhouse gas emissions. Economist Nicholas Stern stressed the importance of both wealthy and developing countries coming together to address the issue, advocating for a global agreement to limit human-made emissions. Stern proposed a global target of a 50 percent reduction in greenhouse gases by 2050, but suggested that richer nations should aim for even larger cuts, around 75 percent, due to their historical responsibility and greater access to resources. Stern, a former head of the British government's economic service and current professor at the London School of Economics, suggested that it may be necessary to provide financial support for emissions cuts in other countries. British Prime Minister Gordon Brown also emphasized the need for industrialized countries to take responsibility for climate change, as the impacts will disproportionately affect the poorest nations. Sunita Narain, director of India's Center for Science and Environment, criticized the lack of real action by political leaders in addressing climate change, calling for more substantial emissions reductions from the developed world. At a gathering, environmental scientist John Holdren from Harvard University attributed droughts, floods, rising sea levels, and more intense storms to global climate change, stating that these events could not be explained by natural climate fluctuations. The United States, a major emitter of greenhouse gases, did not make a statement during Tuesday's sessions and has resisted setting strict targets for reducing emissions, arguing that it would harm the US economy. Instead, Washington has advocated for voluntary rather than mandatory cuts in emissions. In June, President George W. Bush joined other leaders of the Group of Eight industrialized nations in agreeing to make significant reductions in emissions and to negotiate a new global climate agreement that would build upon the Kyoto Protocol. The two-day climate meeting at the United Nations, which ends on Wednesday, is unique in its substance and approach. The event is environmentally friendly, as any carbon emissions produced by air travel and the UN Headquarters building in New York are counteracted through investment in a biomass fuel project in Kenya.