Understanding, monitoring and forecasting the processes of desertification

Assessment and monitoring of desertification processes
Strengthening basic knowledge of desertification processes

The first programme area mentioned in Chapter 12 of Agenda 21 on desertification aims at:

"strengthening the knowledge base and developing information and monitoring systems for regions prone to desertification and drought, including the economic and social aspects of these ecosystems."

In fact, evaluations carried out on the state and development of desertification, whether on a world or regional scale, have revealed gaps in the knowledge about the geographical extent and evolution of the processes. Since very few countries have the means to observe and analyse the phenomena of the desertification processes FAO considers that positive action is required to reinforce national capabilities in this sphere.

Assessment and monitoring of desertification processes

Despite modern observation techniques using satellite imagery and software to analyse recorded data, there is still a great deal of uncertainty at the local, national and world level as to the origin, extent and gravity of the desertification processes. This uncertainty handicaps natural resource managers in planning and decisionmaking. It also restricts warning and emergency plans for agricultural production and other risks (e.g. locust invasions). FAO believes that improvements should address acquisition systems as much as communication and analytical methods and end products in order to strengthen the efficiency of national and regional centres so as to deal better with the actual needs of users and decision-makers.

Problems to be resolved include:

• acquisition of data and production of basic data: information suited to needs;
• storage and analysis: where, what format, on what scale and at which frequency, which system and for what end product? and
• dissemination and communication of products to users.

These problems are the same for all basic geographical, meteorological, hydrological, ecological, land and socio-economic data, whether from remote sensing satellites or from the various survey, observation and census networks and stations.

These problems involve improving and harmonizing data from meteorological satellites such as NOAA and METEOSAT in order to:

• have standard, compatible outputs for the exchange of information and for analysing various data of common interest to different end-users; and to
• provide products to aid decision-making in agricultural warning and forecasting (in particular by estimating rainfall and plant activity).

Knowledge is also needed about the exploitable aquifer reserves of large catchment areas; methods of estimation vary, and yield very different and non-comparable results. Concerted scientific activity would enable managers and decision-makers to obtain reliable information on groundwater reserves as well as the necessary management tools in the form of maps or information adapted to their needs.

Another problem is the need to improve soil degradation assessments at the world and regional levels, as well as at national and local levels. This could be accomplished by combining remote-sensing information from satellites, such as I.ANDSAT or SPOT, with data from ground observation sites. At the national level, despite substantial progress, results are still a long way from satisfying demands for information. FAO supports the establishment and strengthening of national centres to study and observe natural resources. National remote-sensing and ecological monitoring centres could continuously monitor climatic change and land degradation, and map information with remote-sensing techniques and geographic information systems (GISs).

FAO believes that information is most important and most needed at the local and national levels. The results of analysing high-resolution spatial and spectral satellite pictures, such as LANDSAT or SPOT, combined with those from satellites with higher temporal frequency and low spatial resolution, such as METEOSAT or NOAA, could be integrated into GISs and spatial models and complemented by new methods of gathering ground data through navigation satellites. FAO supports the development of these methods, which enable both biophysical and socio-economic data to be observed, evaluated and monitored.

Strengthening basic knowledge of desertification processes

It is fairly simple to understand drought. In contrast, desertification is a complex, evolutionary process resulting from several factors with implications in all fields, including human behaviour, and having a continuous effect on all elements of the ecosystem. Efforts must be made to clarify this complex issue and understand its mechanisms. A whole spectrum of research needs to be carried out, particularly in the nerds of:

• climatic monitoring and forecasting - improving and validating techniques for analysing satellite data in order to estimate and correlate reliable and significant indicators (vegetation indices, surface temperature, evaporation, insolation, albedo, dust, etc.); and understanding and quantifying climatic variables, in order to be able to monitor the situation and climatic impact;
• study of genetic diversity and its erosion;
• land occupation and use;
• drainage, salinization and alkalinization of soils;
• vegetation development;
• relationships between animal and plant resources;
• population dynamics;
• ways of managing natural resources (e.g. agropastoral, agroforestry and pastoral systems); and
• the impact of natural resource management policies on these resources.

Action must be taken to integrate information resulting from such research. It would seem desirable, at subregional and national levels, to set up some form of GIS to provide the main physical and socioeconomic data of interest to natural resource managers and decision-makers in charge of rural development in areas subject to desertification.