The concept of sustainability arises as a result of the analysis of the situation in the world, which can be described as a "planetary emergency", as an untenable situation that seriously threatens the future of humanity. There are two types of sustainability weak sustainability and strong sustainability (also called deep or radical) (Costanza, 1995, 193). The first is that natural capital can be substituted for human capital, the result of techno-scientific development, provided that the total level remains constant, the strong sustainability criterion, however, take into consideration the existence of a critical natural capital that can be replaced by humans. This critical natural capital can then be defined as natural capital that is responsible for essential environmental functions that can not be replaced by human capital. Naturally, it is sometimes difficult to determine to what extent the ability to give rise to flows of goods and / or services specified natural capital can be substituted for human capital (Hak, 2007, 63). But that it undertakes to apply the precautionary principle and to preserve and protect this critical natural capital until he has full confidence in its eventual replacement by human capital. It is, therefore, opt for strong sustainability.
Numerous debates are going on the issue that who is more sustainable or Sustainability is more relevant to wealthy countries while the poor are too busy surviving to worry about the future. The much hated answer is that it depends. Sustainable development is to maintain economic development while respecting environmental and social balance. But the concept is increasingly challenged: the term is vague, even contradictory, and it would be used by polluters to give a green image. (Marshall, 2005, 673) It is true that suitability is much relevant to wealth countries while poor, we can analyse it from the gap between rich and poor which is widening at the top. between 2005 and 2007, inequalities in living standards changed little for 90% of the population but widen with the easiest. Average incomes of very high incomes have risen faster than the general population. A person is among the richest 1% from 84 500 Euros of revenue. Half the income of the wealthiest are not earned income (Blewitt, 2008, 445). "The number of persons crossing the symbolic threshold of annual income has also increased, resulting in a significant increase in inequality from above"
Rich countries are getting richer because income inequality in countries has reached the highest level of the last half century. "To the extent that it earns 10% of the population is nine times." Rich countries are having sustainability because the countries deliberately make themselves richer. Their goal is to improve well-being. They think about wealth and how to achieve them. They take full responsibility for their own lives for themselves. They are conscious of their purpose and often they do it. While poor subconsciously and sometimes consciously make them poorer (Ratner, 2004, 50). They are content with what they ...