In the past 20 years, several methods have been developed which allow quantifying the use of materials by modern societies. Material Flow Accounting and Analysis (MFA) is one of the key methods and internationally recognised as an important tool for measuring the material use of countries and economic sectors and thus for providing an empirical basis for evaluating resource use policies. The principle concept underlying MFA is a simple model of the interrelation between the economy and the environment, in which the economy is an embedded subsystem of the environment. Similar to living beings, this subsystem is dependent on a constant throughput of materials and energy. Raw materials, water and air are extracted from the natural system as inputs, transformed into products and finally re-transferred to the natural system as outputs (waste and emissions). In order to highlight the similarity to natural metabolic processes, the terms "industrial" or "societal" metabolism have been introduced.
According to the laws of thermodynamics, total inputs from natural systems into the economy must by definition equal total outputs plus net accumulation of materials in the socio-economic system. This material balance principle holds true for the economy as a whole as well as for any sub-system (an economic sector, a company, a household). It thus follows that increasing problems associated with waste generation and emissions are directly related to the scale of material input. From this point of view, a reduction in the use of materials (i.e. dematerialisation) for instance by means of increasing resource efficiency could provide a successful strategy to combat global environmental problems such as climate change, the loss of biodiversity or desertification.
In the past 15 years, a number of academic and statistical institutions have been working towards the standardisation of an accounting method for material flows. These efforts resulted in the publication of methodological guidebooks for economy-wide MFA by the European Statistical Office (EUROSTAT); the first published in 2001 (see 2013 version here). The methodological framework was also adopted by the OECD in 2007 (see here). Depending on question to be answered, one can assess material inputs, in order to illustrate what amount of natural resources a city or a country consumes and where these resources originate. The focus can also be placed on waste and emissions which are returned to the natural system. The latter is particularly important, if, for example, a new waste management plan is to be implemented in a village or a city. A complete MFA comprises both material inputs extracted from nature, the assessment of the stocks of materials in society, and disposal of materials back to nature.