Avant-propos La notion de désertification se définit comme une dégradation des sols en zone aride, semi-aride et subhumide sèche, souvent appelée simplement « zone aride ». On estime qu’elle résulte d’une combinaison de facteurs, parmi lesquels les changements climatiques et l’activité humaine. Plus d’un tiers de la superficie totale de la terre est considéré comme zone aride. En termes démographiques, c’est un cinquième de la population totale du globe qui vit en zone aride déjà dégradée ou menacée de désertification.
Desertification is defined as land degradation in arid, semi-arid and dry sub-humid areas, resulting from various factors, including climatic variations and human activities. More than one third of the surface of the earth consists of drylands. In terms of population, one out of every five people of the world live in already degraded or desertification-prone drylands. These people include many of the world’s poorest, most marginalized, and politically weak citizens. For instance, nearly 325 million people in the African continent live in drylands.
The drylands of Africa, exclusive of hyper-arid zones, occupy about 43 per cent of the continent, and are home to a rapidly growing population that currently stands at about 325 million people. Dry zones, inclusive of hyper-arid lands, cover over 70 per cent of the continent’s terrestrial surface. Outside of the cities many dryland inhabitants are either pastoralists, sedentary or nomadic, or agro-pastoralists, combining livestock-rearing and crop production where conditions allow.
Esto es un Compedio Para Responsables de Politicas "Revertir la degradación de la tierra"
In the not so long history of humankind, our ancestors too often fought for land and water. Those days have returned.
Human activities have resulted in unprecedented phenomena and severe impacts for the 21st century such as land degradation, natural resources scarcity, climate change, and a rapid decline in biodiversity. These alterations engender secondary effects such as political conflicts, disputes over resources, social disruptions and sudden shocks of catastrophic weather events which are becoming more frequent in critical regions of the world, particularly in drylands; and exacerbate threats for human, national and international security.
Often, when people think of drylands, they think of deserts and hostile living conditions, economic hardship and water scarcity. But that is not what drylands are all about. If managed well, drylands are often fertile and capable of supporting the habitats, crops and livestock that sustain the entire global population.
This paper examines the literature on how biodiversity contributes to improved and diversified diets in developing countries. We assess the current state of evidence on how wild and cultivated biodiversity in all forms is related to healthy diets and nutrition, and examine how economic factors, knowledge and social norms interact with availability of biodiversity to influence both production and consumption choices.
La terre — une ressource vitale pour la population mondiale