Warren, A. and Batterbury, S.P.J. 2004. Desertification. In Forsyth T.J. (ed.) The Routledge Encyclopedia of International Development. London: Routledge   (in revised form)




1200 words


Andrew Warren, Simon Batterbury


The term itself dates from the 1940s, but it took the African droughts of the late 1960s and 1970s in the western Sahel (see Sahel entry), and attendant widespread famine, to stir up a major international response.  This included the foundation of the UN Sahelian Office (now called the Drylands Development Centre) in 1973 and its efforts to relieve suffering from drought, and the United Nations Desertification Conference in 1977. By 1994 the UN-ratified Convention to Combat Desertification had been established, with a focus on desertification as “land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities”. This includes reduction in quality of resources in and around arid lands, of both anthropogenic and natural provenance.


The history of desertification ‘narratives’ is more complex than this, and includes many accounts, based on dubious science and sweeping warnings of the imminent demise of dryland environments and societies affected by moving sands, or extreme land degradation. Science influenced the thinking of colonial governments under both capitalist and socialist regimes, and the early UN initiatives tended to blame dryland people for overgrazing, over cultivation, and salinization (Thomas and Middleton 1994). In the 1970s meagre funding was allocated to projects that focused on the physical remediation of erosion (many involving massive earthworks or shelter-belts).  Most were top-down, state-led, and unsuccessful.  Twenty years later the addition of “climatic variations” in the CCD definition is more accurate and welcome, but the term is still coloured by “scientism” and vagueness (Warren and Ollsen 2004).  The CCD itself may have raised the profile of drylands problems worldwide, but despite its ratification into “soft law”, it still has too little funding, and risks being caught up in bureaucratic procedures.


A rapidly growing body of scientific research now shows that deserts have expanded and contracted over geological, even recent geological time, without any significant interference from people.  The Sahara did grow in the 20th century, but only temporarily.  Much more alarming is the evidence that it grew substantially in the late Neolithic, about 5,000 years ago (and stayed enlarged), and that there have been many shorter periods of expansion since. The research shows that changes to desert margins has often been sudden (within a decade), as in the North American Midwest and the Western Sahel in the Holocene, and in western India at the end of the last glacial period. These were all unforced by human agency. But anthropogenic causation cannot be wholly dismissed: the Aral Sea, and the former Lake Owens in northern California were both deprived of water by diversion, and both are now the origins of unpleasant, even dangerous clouds wind-blown of dust. The vast Diyala plains to the east of Baghdad and smaller but significant parts of central Asia and the Indian subcontinent have been salinized since large-scale irrigation was discovered four millennia ago.


With land degradation such a central part of the present definition of the problem, it is worrying that techniques to assess it all suffer problems of interpretation and their scale-dependency is seldom acknowledged. The scientific and socio-economic task of assessment is huge and is not made easier by repeated changes in scientific thinking.  Following Ellis and Swift’s lead (1988), few range scientists now believe earlier damning biophysical assessments of indigenous grazing methods. In agricultural regions, too little effort has gone into the assessment of physical land use changes, particularly soil fertility, on crop and pasture yield.  The scientific community is still uncertain as to whether changes in land use affect regional climate.  Despite the new ideas and data (some of it now well substantiated), it is difficult to escape the conclusion that policy is still founded on a belief in the misbehaviour of indigenous farmers and pastoralists, particularly in the Ministries of dryland nations. Hasty judgments are still common, and cloud thinking about the management of environments that are more resilient that once believed, though maybe not as resilient as some now maintain.


Despite this lack of clarity, dryland problems are real. The arid west of the United States and the dry parts of South America suffer water shortages, and some salinization. The dry heart of Australia suffers from periodic droughts, a greater extent of “dry-land salinization” than any other part of the world (perhaps because its ancient land surface has collected salt for many millennia), and some wet-land salinization in the Murray-Darling system. The Chinese drylands suffer wind erosion, dune encroachment and salinization (though the battle against these may be being won). The Central Asian deserts, apart from the Aral Sea, and the salinity legacy of ill-designed Soviet irrigation schemes, may also be seeing a revival of vegetation cover in many areas as state-controlled agriculture and pastoralism contract.  The dry parts of India suffer endemic water shortages, despite major investments in canals and dams, and some wind erosion and dune encroachment.  The huge irrigation schemes of the Indo-Gangetic plains have suffered a continuous build-up of salinization since they were built nearly two centuries ago. 


In the African drylands which lack such irrigation schemes, droughts are a way of life.  Plants and animals only survive if they can withstand them.  The same is true of most rain-fed agricultural and pastoral (and even hunting and gathering) communities, at least until recently.  It is true that droughts of the severity of the Sahelian ones of the 1970s and 80s initiate drastic changes. People diversify away from agriculture and pastoralism, as far as they are able. Some migrate to the wetter zones, or to the towns, and some never return. Herd size is diminished. But, though some changes are permanent, it is surprising how few years it takes for systems to become re-established even after severe droughts, because dryland society is well adapted to quotidian vulnerability. Most indigenous land use systems have developed strategies to cope, painful though they often are. The successful dryland development policies, many now enacted by NGOs and bilateral agencies, are built around increasing local resilience – helping to diversify livelihood options, providing credit for the purchase of livestock, or financing locally appropriate conservation efforts. The science that assists these efforts is becoming more adaptive, and is more focused on understand coupled human-environmental systems and responses at multiple scales (Reynolds and Stafford-Smith, 2002). Understanding vulnerability and resilience, however, necessarily involves addressing the effects of international trade and subsidy on the livelihoods of dryland peoples, remedying inequity and uncertainty of access to land and resources, and managing complex socio-political emergencies - all of these concerns lie beyond the remit of the CCD (Toulmin 2001). 


The next chapter in the desertification story has yet to be written, but may be much more sombre. People will continue to live in drylands, although a greater percentage of them will be in urban environments. They will be vulnerable now not only to the decadal droughts, but to the repercussions of global warming, brought about by the artificial release of greenhouse gasses. But due to current inadequacies in climate modelling, its impacts on dryland temperature, rainfall, and the soil water balance are not at all clear.  The extreme and unprecedented hot summer of 2003 in Europe and elsewhere in the world brought a very worrying message, although, ironically the Sahel and other parts of the tropical dry world may not suffer widespread desiccation. In fact, the northern Sahel has seen a revival of vegetation since 1984. 


Ellis J.E. and D.M. Swift. 1988 Stability of African pastoral systems: alternate paradigms and implications for development. Journal of Range Management. 41 (6) :450-459.


Reynolds, J.F., and D.M. Stafford-Smith (eds.) 2002 Global desertification: do humans cause deserts? Berlin: Dahlem University Press


Toulmin C 2001 Lessons from the Theatre: should this be the final curtain call for the Convention to Combat Desertification? London: International Institute for Environment and Development. (available at http://www.iied.org/docs/wssd)


Thomas, D.S.G. and Middleton, N. 1994. Desertification: exploding the myth. Chichester: Wiley.


Warren A. and  L. Olsson 2004. Desertification: loss of credibility despite the evidence. Annals of Arid Zone (India).  Forthcoming.