The world's population is projected to increase by more than one-third over the next 30 years, adding two billion people (United Nations, 2002). This additional growth is set to concentrate in urban areas. By the end of this decade, more than half of the world's population will live in cities. Cities around the world gain roughly millions of new residents a week. Many developing cities lack sanitary sewage disposals, 50% do not have an adequate supply of drinking water. In 1950, New York was the only city in the world with a population above 10 million (called a megacity). By 1975, there were five megacities. By 2001, there were 17 megacities. It is projected that the world will have 21 megacities by 2015.

What we're looking at is the world of urbanization. Urbanization refers to an influx in population within a city, over a period of time. Population growth leads many to assume that a direct correlation exists between economic growth and urbanization. In many cases, this is true. Economic growth must be maintained for optimal sustainability. There are positive aspects of urbanization. For instance, the higher population density makes social goods economically feasible. However, under improper management, economic development can damage the socio-economic and environmental system through resource degradation, over-harvesting and pollution (Islam, S. M. N. and Clarke, M. F., 2005).

Urbanization's ethical dilemma confronts economic growth and sustainable development. Humankind must promote an environmental ethic through governance, population planning, participation, and empowerment (Rogers, et. al, 2006). The Coase Theorem states that everyone should get together and decide on an efficient level of pollution and an efficient level of degradation. Here lies the empirical question; what is best for a community, present and future, urbanization or sustainability?

Sustainable development (SD) provides a theoretical and technical approach favoring long run economic, social, and environmental growth. Each of these aspects relates to institutions on regional and national scales. SD requires specific goals according to legislation and institutions. SD will be defined according to the principle that favors intergenerational progression. Without action or leadership, SD cannot fulfill short run and long run requirements. Short run development produces swift results, sometimes without consideration for the long run. Sustainability can often be achieved in the short run, but not the long run. Short run development requires less planning compared to the long run, because externalities, environmental degradation/justice, social impact, and economic inequalities are not always taken into account. Sustainable development's purpose is to further positive social, economic, and environmental development on a grand scale. Specific regions (developed countries) must not adopt SD as a means to promote its own agenda, but use SD to cross boundaries and implement action where the need is great. The disparity between rich and poor will continue to widen without proper implementation of effective management. Without leadership and community involvement, politicians will decide on SD policy, where persuasion, unfortunately, is taken into account. Here, the general public continues to believe that environmental matters are secondary or optional issues (Weisken and Gray, 1992). Under the correct leadership, SD can provide sustainability to all generations if understanding and commitment is the objective. Botkin and Keller (2005) write, �The scientific education of those in government and business, as well as of all citizens is crucial� (p. 30).

As stated, by the end of this decade, more than half of the world's population will live in cities. A majority will impose a burden on the environment. Fuels burned in cities generate over three-quarters of global carbon emissions stemming from anthropogenic sources. Between 1980 and 2000, the United States has added more than 50 million people to its population, a 24% increase. Historically, the United States development accelerated in the 1990s. An estimated 6.6 billion people currently make up the world's population. Of that 6.6 billion, 1.2 billion people live in developed countries, and 5.3 billion live in developing countries. A developing country is a country with a relatively low standard of living, an undeveloped industrial base, and a moderate to low Human Development Index (HDI). A developed country is a term used to categorize countries with developed economies, ones in which the tertiary and quaternary sectors of industry dominate. This level of economic development usually translates into a high income per capita, and a high Human Development Index (HDI) (Wikipedia, 2006).

Currently, 20% of the world's population lives in developed countries while 80%, the majority, live in less developed countries. Afghanistan, Madagascar, Angola, Malawi, Bangladesh, Maldives, Benin, Mali, Bhutan, and Mauritania make up the top ten least developed countries (United Nations, 2006). The United States, Japan, Germany, China, United Kingdom, France, Italy, Spain, Canada, and Brazil make up the most developed countries, according to total GDP 2005 (World Bank, 2006).

In 2025, the world population is projected to near 7.9 billion people, increasing 18%. For developed countries, the population is set to near 1.3 billion (8% increase) and 6.7 billion for developing countries (26% increase). In 2025, 15% of the world's population will live in developed countries and 85% will live in developing countries.

One might begin to question how this will affect social, economic, and environmental aspects on a global scale. Seemingly, it appears that all countries are experiencing growth, whether exponentially or at a decreasing marginal rate; however, there are countries that predict a decline in population. Estonia, Latvia and Italy are predicted to decline in population growth. For example, Italy's current population is 59 million.

In 2025, the population is set to near 58.7 million and 55.9 million by 2050 (6% decrease). Moreover, as a result of its below-replacement fertility, the Italian population is projected to stop growing in size and start decreasing, with the highest pace and intensity within the European context (Department of Economic and Social Affairs, 2006). On the opposite side of the spectrum, India is set to increase its population of 1 billion to 1.6 billion by 2050.

Overall, the world's population is projected to increase in actual size/population. Here, a moral value cannot be given on trends and projected figures; we should, however, consider our effect on the environment. As indicated, cities are continually growing in size. Conceptual ideology will require an environmental ethic if we and nature are to survive.