Land degradation is the persistent reduction of the capacity of the land to support both biodiversity and human needs. It takes many forms, including the loss of soil, or soil health, in croplands; loss of habitat and hydrological function in urban areas; deforestation or over-logging in forests; overgrazing and shrub encroachment in rangelands; and drainage and eutrophication in wetlands.
In March 2018, the Intergovernmental Platform on Biodiversity and Ecosystem Services, or IPBES, released its latest Land Degradation and Restoration Assessment, or LDRA, finding that only a quarter of land on Earth is substantively free of the impacts of human activities. By 2050 this fraction is projected to decline to just a tenth. Wetlands are the most impacted category, having lost 87 percent of their extent in the modern era.
The immediate causes of land degradation are typically local - the inappropriate management of the land resource - but the underlying drivers are often regional or global. The key driver is the growing demand for ecosystem-derived products, beyond the declining capacity of ecosystems to supply them. The consequences of land degradation are also both local and global.
For instance, there is a complex interaction between degradation, poverty, conflict and the migration of people. Degraded land often bleeds sediments and nutrients into rivers, or exports windborne dust to distant locations. Loss of habitat is the key driver of declining terrestrial biodiversity worldwide, and land degradation is a big contributor to global climate change. In the opinion of the LDRA expert authors, most of the UN Sustainable Development Goals cannot be achieved unless land degradation is simultaneously addressed.
Preventing degradation is much cheaper in the long run than permitting it, and then later paying for the impacts and restoration. In many landscapes, we no longer have that choice. Yet, there is hope. In all ecosystems assessed, examples of successful damage rehabilitation can be found. Rehabilitating damaged lands is cost-effective despite the high initial price if the full long-term costs and benefits to society are considered. Many of the necessary actions are at the policy level - locally, nationally and internationally. Coordinated, urgent action is needed to slow and reverse the pervasive undermining of the basis of life on Earth.
Land degradation is a pervasive, systemic phenomenon: it occurs in all parts of the terrestrial world and can take many forms. Combating land degradation and restoring degraded land is an urgent priority to protect the biodiversity and ecosystem services vital to all life on Earth and to ensure human well-being.
