1. Population
             Now the population of the world has reached 6 billion in 2000. And it is estimated to have 10.5~11 billion of population until the population of the world will stabilize. This means that the world will need to provide food, shelter, cloth for the addition of 5 billion people. But this is not the only problem. This additional population will worsen the condition of the land, and will shorten the natural resource rapidly. Also the health of the population will be a big issue. Due to the decline of the population growth , sustainable development of children started. Recently AID is one of the most popular disease in the world. It reduces the life expectency about 15 to 47 years. And thinking about the year when there will be 5 billion more people in this world, we won't know which disease will kill how many people.
             Increase of the population does not only have the negative effects to the world. It also give us new opportunity. First increase in the population will provide the world more intelligent people, and these people will help to solve the problems of the over populated world. And when people get crowded they will search for a better condition to live in and this might help the people to find a new land to live in or a new resource to use. Also they will try to prevent so many people from dying by the same disease which will yeild to a development in medicine which will improve the life of the people.
            
             2. Poverty and Inequality
             Poverty is not a good phenomenon for the citizens of the world, especially when the standard of life is improving. Majority of the low income people locate in Asia, and Africa. There incomes are less than a dollar per day. There is another problem, inequality among the people. This inequality is a obstacle to a sustainable development. Most of the reason of this inequality is because of the economic gap between the countries rather than the within the countries. Because of the poverty and th...