The meaning of this word is much debated. It is defined by the UN as the degradition or destruction of land, which results in desert-like conditions. Thomas in J. Holden (2012) defines desertification as ‘an often misunderstood and abused term used to describe land degradation in drylands. Misunderstanding often arises because natural environmental (especially plant system) responses to drought, from which recovery usually occurs, have been confused with longer-term and more persistent negative changes’. The causes and consequences of desertification are complex and little understood. ‘Occasional droughts, due to the seasonal factors or inter-annual variations of rains, and severe droughts of long periods can be caused or aggravated by human influence on the environment, reduction of vegetation covering, change of the effect of albedo, local climate changes, greenhouse effect, etc.’ (UNCCD 2004). However, J. Letera et al. (2006) challenge negative perceptions of pastoralism. ‘Herd mobility is now recognised as a rational strategy in unstable environments, and some countries have taken steps to facilitate movement of herds’ (see Touré (2004) IIED issue paper 126). Rasmussen et al. (2001) Glob. Env. Change 11, 4 conclude that ‘broad generalisations on land degradation processes, based on local-scale studies, are risky. Significant variations exist at the landscape level, and trends in ecosystem dynamics are sometimes totally reversed even within small regions…conclusions concerning “irreversible” degradation, based on few years or decades of observations may be premature’.