The United Nations is warning that the world is not prepared to deal with the fast growth of cities. The World Economic and Social Survey 2013 calls for new ways to meet the needs of city populations. More than 6.5 billion people are expected to be living in cities by 2050. Most new city dwellers will be in developing countries. The United Nations says the effect on limited resources in many countries will be huge. The World Economic and Social Survey points to the increasing demand for energy, water, sanitation, public services, education and health care. The world population is expected to rise to more than nine billion by 2050, two-thirds of all people are expected to live in cities. The United Nations says about 80 percent of this growing urban population will be found in Africa and Asia. The report says sustainable development of urban areas requires coordination and investments to deal with important issues, these include land-use, food security, job creation and transportation. Willem Van Der Geest is with the United Nations Department of Economic and Social Affairs, he says cities need to work closely with rural communities, so that food supplies can be secured, and the environment can be protected. "We need enough integration(,) with cities... An integration between the rural and urban economies is absolutely vital for issues of nutrition, food security, and environmental sustainability." The report says development in a sustainable way is important to end poverty. The report also examines the problem of food insecurity, which affects hundreds of millions of people around the world. One in eight people still severely lack nutrition. UN officials say some things are clear. The Assistant Secretary-General for Economic Development, Shamshad Akhtar, says world food production will have to increase by 70%, that increase will be needed to feed the additional 2.3 billion people expected on the planet by the middle of the century. She says an important part of meeting that need is to waste less food. "There has to be efforts to reduce food wastage. ." Food and nutrition security are core elements of the sustainable development agenda. From the passage we can infer that   _  .
cities grow so fast that the world can't find out new ways to deal with the growing population. the growing city dwellers who mainly come from the developing countries greatly challenge limited resources in the world. sustainable development of urban areas requires coordination and investments to deal with important issues food wastage is an effective way to feed the additional 2.3 biilion people by the middle of the century.