Nowadays, to measure the wealth of a country it is no longer taken into consideration only its economy, but it is used what is known as Global Capital of wealth produced, covering not only the GDP but also the natural, human, social and institutional resources. So, the measurement of variations in the wealth allows quantifying the sustainability of the development, offering an instruction to the national, state and local governments to evaluate if the policy broadly conceived can produce an increase of the current or future social welfare.

The concept of natural capital is an extension of the term economic capital to goods and services. It refers to the reserve of natural resources that produce a flow not only of goods but also of services and it is particularly important for the non-industrialized economies. A recent study of the World Bank calculates that the natural capital represents 26% of the total wealth of the low-income countries compared to 13% of the middle-income countries and 2% of the high-income countries of the OECD (World Bank 2006).

In numerous cases, we see that the goals of environmental sustainability are considered as being distinct from- and sometimes even as being in conflict with- development goals. The demand of the limited public funds to deal with the urgent needs of economic growth and reduction of poverty, implicates that the environment tends to maintain a limited priority on the public investment and preparation of policies.

However, environment must be considered, as regards statistical, policy, and budgetary terms, in an equitable way concerning other capital reserves and productive sources of wealth in the economy. Because the poor tend to depend much more on the environmental goods and services than the other sectors of the population , and because these poor people have less capacity to face the effects of degradation and loss of the environment, it is essential to keep the environment healthy in order to satisfy the basic needs and lighten poverty in the medium and short term.

It must be established which are the environmental assets the city have at a local level.The environmental asset is a valuable reserve of natural capital and it is composed of ecosystems and productive natural resources which generate goods and services of economic importance. Sustainable environmental management and natural resource extraction ensure the avoidance of economic costs and losses in the long-term. In most cases, the costs of environmental degradation are immense when calculated at the national level, and the long-term losses of unsustainable land use and resource exploitation are equally vast.

Working on this direction, it is pursued that the economic investments that are carried out at different levels are aimed at the promotion of social welfare. This includes the following: ensuring that sufficient public funds are allocated to the agencies responsible for environmental manage and conservation; giving priority to the objectives of environment and incorporating these objectives to the macroeconomic and sectoral policies and to the instruments used to accomplish them, and finally, that development and economic projects include calculations of environmental costs and benefits. Environmental investment refers to the effort, attention and material support given to the environmental sustainability in the public budgeting, policies and planning. To this effect, it it is essential that the policy-makers do not consider environmental sustainability as a luxury that governments cannot allow, but recognize it as a necessity they cannot took the liberty of not investing.