Leaders at a U.N. Earth summit in Brazil must take decisive action on population and consumption growth to preserve life as we know it, science academies said. \"For too long, population and consumption have been left off the table due to political and ethical sensitivities,\" said Charles Godfray, a fellow of the Royal Society of London for Improving Natural Knowledge and chairman of the InterAcademy Panel working group, a global network of science academies. \"These are issues that affect developed and developing nations alike, and we must take responsibility for them together,\" said Godfray, who teaches at the University of Oxford. The IAP group said in a statement that world leaders and policymakers meeting at the U.N. Conference on Sustainable Development in Rio de Janeiro Wednesday and Thursday must face the fact that population and consumption determine the rates at which natural resources are used, and affect Earth\'s ability to meet food, water, energy and other demands. \"We are living beyond the planet\'s means. That\'s scientifically proven,\" Gisbet Glaser of the International Council for Science told the British newspaper The Guardian. \"We\'re now at a point in human history where we risk degrading the life-support system for human development,\" Glaser said. By 2050, the world\'s population is projected to rise to between 8 billion and 11 billion from 7 billion. At the same time, consumption of resources is rising rapidly as a result of a growing middle class in developed countries and lavish lifestyles of the very rich across the planet, the scientists said. A draft negotiating text to be discussed at the summit -- also known as Rio+20 or the Rio Earth Summit 2012 -- mentions the need to change \"unsustainable patterns of production and consumption,\" but Washington wants to delete passages that suggest developed countries should take the lead, The Guardian said. U.S. Secretary of State Hillary Clinton is to head the summit\'s U.S. delegation, the State Department said. U.N. Secretary-General Ban Ki-moon had asked U.S. President Barack Obama to participate, along with more than 130 other heads of state and government.