Achieving food security for all is at the heart of FAO's efforts—to make sure people have regular access to enough high-quality food to lead active, healthy lives. FAO's three main goals are: (i) the eradication of hunger, food insecurity and malnutrition; (ii) the elimination of poverty and the driving forward of economic and social progress for all; and (iii) the sustainable management and utilization of natural resources, including land, water, air, climate and genetic resources for the benefit of present and future generations. To support these goals, Article 1 of its constitution requires FAO to "collect, analyse, interpret and disseminate information related to nutrition, food and agriculture". Information on natural resources, especially land and water, is central to this respect.
By 1980, FAO had developed a geo-referenced information system on land resources based on the FAO/UNESCO world map of soils, but a global geographically-based water resources database did not exist.
In 1992, FAO's Land and Water Division proposed to establish a global water information system to provide high-quality information on water resources and uses, mainly for agriculture, as a basis for analysis and planning at national and international levels. At national level, such data would help the country devise appropriate policies and strategies for the development and management of its water resources. It would also allow the country to compare its situation and achievements with other countries. At the international level, the data provides the basis for studying the evolution of water resources development, relative levels of water scarcity, potentials and trends. The system was also expected to provide the necessary data for forecasts, and the study of phenomena such as the impact of global warming on water and agriculture.
In 1993, the Global Water Information System (GWIS) was initiated. Country statistics and specific country studies were collected and processed to extract the required information and to develop regional and continental data, in addition to national data. The approach had two implications. First, there was a need to develop very detailed standards to compute different indicators which best represented the state of water resources and use in agriculture. Definitions of terms related to water resources, irrigation, water withdrawal, etc. are anything but trivial and can be interpreted in very different ways in different countries. A set of well-described variables and indicators was thus developed at the beginning of the programme and is being continuously improved, based on experience gained in progressively collecting country information. Second, water is frequently a transboundary resource. In fact, not only can water resources be computed in different ways by different countries, but also the computation of transboundary flows is often performed in different ways on both sides of the border. A consistent physical approach, based on a hydrological division of the land, needed to be superimposed on the division in countries and administrative units to ensure the integrity of water resources data and analysis at the global level.
GWIS thus developed as two complementary programmes:
In 1994, the first of these two programmes became known as AQUASTAT, FAO's global information system on water and agriculture, comprising the most reliable national information on water resources and uses and making it available, in a standard format, to users interested in global or regional prospects. While the basis of AQUASTAT was—and remains—the collection and publishing of statistical information, the programme has evolved tremendously over the last 20 years and has also addressed and incorporated the second programme, i.e. the transboundary, hydrological perspective.
While agriculture is by far the largest water withdrawal sector, in times of increasing water scarcity it is the first one to suffer, long before the municipal and industrial sectors. Although the mandate of AQUASTAT was primarily linked to water and agriculture, it soon became evident that it could not limit itself to agricultural water only in view of the absence of sufficient country-level information on the other sectors elsewhere. Information on the other water withdrawal sectors as well as on water resources is indispensible in order to be able to provide a more complete picture of the water situation in the world, in view of increasing competition between different sectors, and to estimate the pressure on water resources. Since then, AQUASTAT has been the global leader in reporting national-level data on renewable water resources and water withdrawals.