Defined as a long-term decline in ecosystem function and productivity, land degradation is increasing in severity and extent in many parts of the world, with more than 20 percent of all cultivated areas, 30 percent of forests and 10 percent of grasslands undergoing degradation.
An estimated 1.5 billion people, or a quarter of the world’s population, depend directly on land that is being degraded.
The consequences of land degradation include reduced productivity, migration, food insecurity, damage to basic resources and ecosystems, and loss of biodiversity through changes to habitats at both species and genetic levels.
“Land degradation also has important implications for climate change mitigation and adaptation, as the loss of biomass and soil organic matter releases carbon into the atmosphere and affects the quality of soil and its ability to hold water and nutrients,” notes Parviz Koohafkan, Director of FAO’s Land and Water Division.
The data indicate that despite the stated determination of 193 countries that ratified the United Nations Conference to Combat Desertification in 1994, land degradation is worsening rather than improving.
Some 22 percent of degrading land is in very arid to dry-subhumid areas, while 78 percent of it is in humid regions. The study found that degradation is being driven mainly by poor land management.
Comparing with previous assessments, the present study shows that land degradation since 1991 has affected new areas; meanwhile some historically degraded areas were so severely affected that they are now stable having been abandoned or managed at low levels of productivity.
The data on global land degradation are part of a study released by FAO, the United Nations Environment Programme and the World Soil Information (ISRIC) on global land degradation entitled Land Degradation Assessment in Drylands. Funding for the study was provided by the Global Environment Facility.
But the news is not all bad. Bright spots were also identified in the study in cases where land is being used sustainably (19% of cropland) or is showing improved quality and productivity (10% of forests and 19% of grassland).
Many gains in cropland are associated with irrigation, but there are also swaths of improvement in rain-fed cropland and pastures in the prairies and plains of North America and western India. Some gains are a result of increasing tree cover, either through forest plantations, especially in Europe and North America, and some significant land reclamation projects, for instance in northern China. However, some of the positive trends represent woodland and bush encroachment into rangeland and farmland - which is not generally regarded as land improvement.
The study shows that land degradation remains a priority issue requiring renewed attention by individuals, communities and governments.