Desertification has been defined in the text of the United Nations Convention to Combat Desertification (UNCCD) as "land degradation in arid, semi-arid and dry sub-humid regions resulting from various factors, including climatic variations and human activities."

Desertification is mostly a problem in Southern Europe, but also under cold climatic conditions in Northern Europe, most notably in Iceland. This process is extremely complex because the way it expresses itself is highly site specific, and governed by the complex interplay between bio-physical, socio-economic and political factors. Recent projects such as DESURVEY and DESIRE have increased our understanding of this complexity. DESIRE, for example, developed an approach that selected SLM measures in a participatory process. One of the main challenges that remain however is how to upscale from local scale to a larger scale.