• Climate scenarios for semi-arid and sub-humid regions. A comparison of climate scenarios for the dryland regions, in West Africa from 1990 to 2050

      van den Born GJ; Schaeffer M; Leemans R; NOP (Rijksinstituut voor Volksgezondheid en Milieu RIVMICCDWageningen, 2001-02-23)
      The identification of climate scenarios for dryland areas in Sub-Saharan West Africa is part of a project to assess the impact of climate change on water availability, agriculture and food security in drylands (ICCD-project). The project is financed by Netherlands Research Programme on Global Air Pollution and Climate Change (NRP) and part of theme 'Vulnerability of Natural and Social Systems for Climate'. The report describes the development and description of climate scenarios by using results from both integrated assessement models (IAMs) and global atmospheric circulation models (GCMs) for climate change. The resulting scenarios will be appropriate for Sub-Saharan West Africa. The report describes a common definiton of drylands, their general characteristics and geographical distribution, and gives an introduction to climate change and its potential impacts on ecosystems, agro-systems and society. To improve the understanding of the existing methods, special attention is given to the various approaches commonly used to simulate the impact. The focus of the report is mainly the climate-change scenario development and the application of IAMs and GCMs, especially the use of comprehensive IMAGE scenarios to dynamically calculate transient impacts at global, regional and sub-regional scale. For most indicators the situation in 1990, the projection for 2050 and the absolute change are presented, both in table and map format. The last part of the report summarises the results for a set of climate indicators for Sub-Saharan West Africa.<br>
    • Impact of climate change on water availability, agriculture and food security in semi-arid regions, with special focus on West Africa

      Verhagen A; Dietz AJ; Ruben R; NOP (ICCDWageningen, 2001-11-23)
      The research effort started with a geographical inventory of all tropical and sub-tropical drylands to map the diversity in aridity, land degradation, population densities and urbanisation of the world's drylands and to put the drylands of West Africa in perspective. It also guided a choice of in-depth study regions within West Africa. The scenario analysis shows a wide variety of outcomes, but with rather strong suggestions that most of dryland West Africa is expected to become a lot dryer. The consequences of these projections are an increase in high-risk environments for agriculture, including a southward shift of the arid and semi-arid zones. Changes in rainfall distribution could mean an additional stress on agricultural production in these areas. Simulation studies clearly reveal a shift of the onset of the growing season and lower yield levels. To understand farmers' behaviour in West African drylands in preparing ('insuring') for dryer conditions and for agro-climatological droughts, in coping with droughts and adverse production conditions, and in adapting to changed conditions afterwards, we looked at their performance before, during and after drought years in the past identifying several adaptation strategies and policy recommendations. The conclusions don't look very grim, contrary to the much-painted 'picture of doom' for Africa. West Africa's shock experience in the 1970s and 1980s did have the result that it became much better prepared for possible new drought shocks, and that its agricultural production performance in the 1990s (when rainfall became considerably better) improved. The future for the Sahel is not necessarily gloomy. However, system breakdown can occur during droughts. One may fear that in those situations religion will be used as a major catalyst for political support to exclusionist claims (Islam versus Christianity and religious sub-groups versus sub-groups) and may result in massive violence and rapid deterioration of all local livelihood options, resulting in a large death toll and mass migration southward and overseas.