Earth observations by satellite now provide a means of collecting data for large areas relatively cheaply and uniformly. While this technology will certainly reduce the need for ground measurements, it does not make all direct observations or ground-truthing redundant. More importantly, many of the data categories that are needed to draw up policy-relevant assessments—on resource efficiency, impacts on human well-being and suchlike—cannot be detected from space.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities. Agenda 21 encourages coordination of satellite missions and of the networks, systems and procedures for processing and disseminating their data; and development of the interface with research users of Earth observation data and with the UN EARTHWATCH system.
The importance of information and decision support tools for sustainable management in agriculture, forest and fisheries has long been recognized by FAO, which introduced remote sensing in renewable natural resources management in the early 1970s. In response to UNCED decisions, the Environment and Natural Resources Service (SDRN) was created within the Sustainable Development Department through the merging of several environmentally related programmes, including the FAO Remote Sensing Centre. The Service supports a wide range of normative and field programmes concerned with the development of environmental databases and decision-support tools, environmental analysis and natural resources management. Remote sensing and GIS have also become important tools for addressing issues relating to environmental agreements, such as Conventions on biological diversity, desertification and climate change.