Secretary-General Ban Ki-moon attended yesterday the Climate Leaders' Summit in Washington, D.C., recalling the importance of keeping global warming as a top concern in the development agenda, and urging Governments to reach a universal legal climate deal by the end of the year. "Climate change is the defining issue of our times. It has sweeping implications for the entire security and development agenda," said the United Nations chief to a group of world leaders, including the President of the World Bank Group, Jim Yong Kim. He urged global leaders to reach an ambitious and achievable agreement to limit global temperature rise within 2 degrees Celsius above pre-industrial levels, which is "what the international community has agreed is the upper limit of safety," and beyond which "the consequences will be unpredictable, highly dangerous and perhaps irreversible." "Climate impacts are already affecting agriculture and food security, human health, water supplies, and ecosystems on land and sea," warned Mr. Ban, adding that "the world is not prepared yet." The UN chief is convening this upcoming 23 September a Climate Change Summit, with leaders from Governments, businesses and civil society, to "raise the level of ambition, catalyse action on the ground and increase political momentum." While global warming is a threat, said the Secretary-General, it presents also "a golden opportunity to promote prosperity, security and a brighter future for all." The UN chief called on all leaders to make the necessary political investments for a sustainable future. "We need to address market distortions, such as fossil fuel subsidies, that promote more energy use and greater emissions and inhibit the adoption of cleaner technologies," he stressed, adding that we need to be clear about the risks of investing in fossil fuels." "None of these areas are politically easy," he noted. "Addressing them will demand vision and leadership -- in the climate negotiations and at home." In addition to political investments, Mr. Ban also called for financial investments in climate action. "Financing is the key to achieving a universal legal climate agreement in 2015. We have to provide $100 billion by 2020 and thereafter $100 billion. We have developed a Green Climate Fund but that is not yet capitalized," he said. "I am counting on you to provide funds for it," he told the world leaders, stressing that developing countries, in particular, are in need of investments as they build their own low-carbon futures. The Secretary-General explained that "public policy must pave the way -- with a financial framework that is conducive for private money to flow at scale into the green space," noting that "all business leaders say they are ready to finance a green economy but they need clear direction and predictable policies from governments."