Desertification

The United Nations Convention to Combat Desertification (UNCCD) defines desertification as land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors. It applies only to drylands (arid, semi-arid, and dry sub-humid areas) and not to hyper-arid deserts. In turn, land degradation is a manifestation of a reduction or loss of the biological or economic productivity of croplands, pastures, or forests. It does not refer to the expansion of deserts.

Desertification is a gradual process of soil productivity loss and the reduction in the vegetative cover because of human activities and climatic variations such as prolonged droughts and floods. Among human causal factors are overcultivation, overgrazing, deforestation, and poor irrigation practices. Such overexploitation is generally caused by economic and social pressure, ignorance, war, and drought.

At its thirteenth session in 2017, the Conference of the Parties (COP) adopted the UNCCD 2018−2030 Strategic Framework with five objectives that are meant to guide the actions of all UNCCD stakeholders and partners in the period 2018-2030. Strategic Objective (SO) 1 is to improve the condition of affected ecosystems, combat desertification/land degradation, promote sustainable land management and contribute to land degradation neutrality.

Degraded land is defined through the above approach as negative changes in land productivity, land cover and soil organic carbon stocks.

• SO1-1 Land cover change is deemed to be a powerful indicator for land degradation as it denotes detrimental change in land cover, loss of habitat and eco-system services.
• SO1-2 Land productivity refers to the ability of a given ecosystem or agricultural land to produce biomass or yield per unit area in a specific period. It is a measure of the efficiency with which the land is used for agricultural production or ecological sustainability.

Land productivity trends are assessed by three metrics:

• Trajectory (the rate of change in primary production over time)
• State (the detection of changes in primary productivity compared to a baseline period)
• Performance (the local productivity relative to other areas that share a similar land cover type for the dedicated region).
  
  Increases in land productivity dynamics are considered as improving while a decrease is seen as degrading.

• SO1-3 Trends in carbon stocks are deemed to be a key indicator of land degradation as it is linked to a range of ecosystem services. Reversing carbon emissions is key to achieve Sustainable Development Goal (SDG) 15.3.1.
  Currently, only the stock of soil organic carbon (SOC) is considered by this indicator.
   
• SO1-4 Proportion of land degraded over the total land area is derived by combining the three indicators using a one-out, all-out (1AOA) approach.
  This means that land is defined as degraded if any single metric shows a negative change.

EUROPEAN COURT OF AUDITORS (ECA) SPECIAL REPORT 33/201

Among the conclusions of the European Court of Auditors (ECA) Special Report 33/2018 was the need to establish a methodology and relevant indicators to assess the extent of land degradation and desertification in the EU. To achieve this goal, the ECA report recommended that the Commission should collate and analyse relevant data on land degradation while building on the existing UNCCD indicator framework for SDG 15.3.1 “proportion of land that is degraded over total land area” (this is also referred  as the Strategic Objective 1 in the UNCCD Strategic Framework 2018-2030).

The methodology to assess land degradation uses a:

• better characterisation of land cover change, through a more relevant nomenclature for the EU, increased spatial resolution and a revised transition matrix that assess the impact of change based on biophysical changes in vegetation cover;
• an optimised characterisation of land productivity for the EU;
• replacement of the changes in soil organic carbon stock indicator with a more comprehensive and representative soil degradation indicator that can be updated through periodic data collection and derived assessments through the Soil Monitoring and Resilience Directive.
• application of an aridity threshold to define desertification;
• identification of areas vulnerable to desertification based on future scenarios of the Aridity Index.

Links to reports

JRC Report on a methodology to characterise land degradation and desertification in the European Union

JRC Report on the application of the methodology based on currently available pan-European data

Please click here to visit the EUSO Desertification and Land Degradation Dashboard.

Updated framework to assess the reporting of desertification

WORLD ATLAS OF DESERTIFICATION

On 21 June 2018, the JRC published a new edition of the World Atlas of Desertification, offering a tool for decision makers to improve local responses to soil loss and land degradation.The Atlas provides the first comprehensive, evidence-based assessment of land degradation at a global level and highlights the urgency to adopt corrective measures.The Atlas provides examples of how human activity drives species to extinction, threatens food security, intensifies climate change and leads to people being displaced from their homes. The Atlas gives a clear overview of the underlying causes of degradation worldwide. It also contains a large number of facts, forecasts and global datasets that can be used to identify important biophysical and socio-economic processes that, on their own or combined, can lead to unsustainable land use and land degradation.

You can download the World Atlas of Desertification