According to the World Bank, cities have the potential to play a significant role in combating global warming, as they can act more quickly than governments who are struggling to reach a consensus on a UN climate agreement. Andrew Steer, the World Bank's special envoy for climate change, pointed out that the 10 largest cities in the world emit more greenhouse gases than Japan. He recommended implementing reforms, such as changes to carbon markets, to help cities become more environmentally friendly. A World Bank study highlighted that urban areas, where over half of the world's population resides and contribute to two-thirds of greenhouse gas emissions, could make a difference by adopting greener transportation, utilizing clean energy, and improving waste recycling practices. Steer emphasized that cities are both a major contributor to climate change and a key player in finding solutions to combat it. The report stated that the world's 50 largest cities have significant economic influence, ranking just behind the United States and ahead of China in terms of gross domestic product. Tokyo and New York were highlighted as having economies larger than Canada or Turkey. The UN climate talks, aiming to reach a consensus on measures to combat global warming at the upcoming Cancun conference from Nov. 29 to Dec. 10, face challenges due to the diverse opinions of 194 countries. In 2008, over 1,000 US mayors committed to reducing greenhouse gas emissions in alignment with the UN's Kyoto Protocol, which was not ratified by Washington. Sea levels pose a threat to many major cities around the world that are located near coasts or rivers, such as Tokyo, Shanghai, New York, and Buenos Aires. In order to reduce the risks of floods or sea level rise, these cities have a strong incentive to take action. The World Bank is in favor of revamping a UN market mechanism that currently encourages investments in individual projects in developing nations, like solar panels in Morocco or hydropower in Honduras, to instead allow for a broader, city-wide approach. This proposed reform of the UN's Clean Development Mechanism (CDM) would enable mayors to secure funding for various initiatives, ranging from flood barriers to hydrogen-powered buses, without needing approval for each individual project. The CDM currently allows companies to invest in environmentally friendly projects in developing countries and receive credits for reduced emissions. The World Bank believes that the challenges of measuring emissions for cities are manageable. Steer also mentioned that the opinions of urban residents regarding the ideal living locations were changing. In previous years, due to high levels of industrial air pollution, poorer populations resided in areas like the east side of London. However, in the future, it is predicted that low-lying areas prone to river floods or rising sea levels will be inhabited by the poor.