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Dryland degradation: a people problem


Science and people must work together to slow degradation of the drylands

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Women in Keita, Niger, working on degraded land being rehabilitated as part of an FAO project. Fertile pasture used to cover the area, but deforestation and soil erosion slashed food production. (FAO/18875/F.Paladini/R.Carucci)

New technology can help us hold back the desert. But land degradation is also a people problem, and people must be part of the solution.

That was the message from a recent meeting at FAO headquarters that brought together participants in Land Degradation Assessment in Dry Areas (LADA), a global project to assess just how much of the world's dry areas are degraded and how they got that way. It will also assess how people cope with desertification.

LADA, begun in December 2001, has many partners. United Nations bodies include the Global Mechanism that implements the United Nations Convention to Combat Desertification (UNCCD) and the United Nations Environment Programme (UNEP). Other partners are the international agricultural research centres, farmers' organizations, universities and other civil society institutions, and the 170 countries that are signatories to the UNCCD. The first year will see pilot projects in four countries -- Argentina, China, Senegal and Tunisia.

Land degradation is usually defined as a temporary or permanent lowering of the land's productivity. It can be the result of climate change or natural phenomena, but it's more likely to arise from human activity.

Assessment of degradation is possible at least partly through new technology, such as satellite imaging and greater computing power. But that is not enough, according to Louise Fresco, FAO Assistant Director-General for Agriculture. "It is very tempting to sit behind a computer, but it is important to find out exactly what happens in the field," Dr Fresco told the 50 participants at the LADA meeting, who came from national governments, UN agencies and agricultural research institutions.

The experts recommended that researchers work closely with national institutions and local communities to correlate data with a host of human factors such as people's use of land, water and livestock and the natural forces that drive degradation worldwide.

FAO is the co-funding and executing agency of LADA, which will pool together all the knowledge and the efforts of experts worldwide. Major funding is also coming from the Global Environment Facility (GEF), a funding body for environmental projects. Other funding partners include the Global Mechanism and UNEP, which is one of the implementing agencies of GEF projects. The organizations comprising LADA will together establish a consistent assessment methodology.

Sheep grazing in the ancient city of Palmyra in the Syrian steppe. An FAO programme is working to rehabilitate local grazing lands, helped by the traditional knowledge of the region's nomadic livestock farmers. (FAO/20553/M.Acunzo)

Fragile land
Dr Fresco stressed the humanitarian urgency of dealing with dryland degradation -- it affects 2 billion people and up to 70 percent of arid and semi-arid areas worldwide.

Indeed, there is now a new class of displaced person -- the environmental refugee. A conference in Geneva in 1996 estimated that more than 135 million people risked displacement because of severe desertification. But even in less-affected areas, crop yields are declining.

"When we speak of 'desertification', the threat is obviously not to land which is already desert," says FAO expert Freddy Nachtergaele. "We are talking about degradation of the productive but fragile lands that receive 100 to 1 000 mm annual rainfall. Unwise use can damage or wreck them."

Some of this land may be under crops. Some, such as rangelands or steppe, lies at the low end of the rainfall range and provides grazing for sheep or camels while sheltering much plant biodiversity. If there is overgrazing or excessive fuelwood gathering, desertification will occur and the true desert may take over.

But the farmland itself, with higher but still moderate rainfall, is also vulnerable in dry countries. Unwise or badly managed irrigation can lead to soil salinity, which reduces yields and may force the land right out of production. In arid and semi-arid regions, up to 25 percent of irrigated land is affected by some degree of salinization. This could threaten up to 10 percent of the global grain harvest -- and over 800 million people already have too little to eat.

How much land is being degraded or turned into desert? Where is it?

Remote sensing through satellite images has helped us find out. For example, we now know that the "vegetation border" -- the point at which vegetation stops growing -- south of the Sahara can extend up to 200 km in a dry year. But it can move back just as quickly when normal rainfall resumes.

"Satellite imagery can show us the process as it happens," says Dr Nachtergaele. "One of the first indicators of desertification might be a change from forest to pasture use." This could mean that dry spells, compounded by tree-cutting by local people, can leave the land far more vulnerable to degradation, although temporarily productive.

Over time, remote sensing, combined with computer modelling and checking of data on the ground, can even warn of declining crop yields, because satellite images can reveal the quantity as well as the quality of vegetation. Meanwhile geographic information systems allow researchers to overlay different types of information about a given area, including data gathered on the ground, and then retrieve it in the form or detail they want.

Degradation is a people problem
Much of LADA's work will be centred around people, their practices and the socio-economic forces driving desertification, says Dr Parviz Koohafkan, Chief of FAO's Land and Plant Nutrition Management Service.

If vegetation is declining on the desert margin, it's important to find out why. Is someone grazing too many sheep on a fragile steppe? If so, why -- have traditional clan grazing agreements broken down?

If crop yields are falling, is land becoming salinized? Why? Are government subsidies inducing farmers to grow an irrigated crop where the land or water are unsuitable? Or is it a question of poor irrigation management? In the latter case, irrigation might be perfectly sustainable provided the farmer gets technical assistance, for example, with water application frequency and adequate drainage.

"What this workshop has done is to emphasize the need to marry technology with the human factor," says Dr Koohafkan. "That will make LADA a better project. If we are to have sustainable food production in dry areas, that need cannot be restated often enough."

27 February 2002

FAO Desertification Site

 

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