The Role of Sustainable Land Management for Climate ... - CAADP

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flooding in sloping lands and prolonged drought periods causing depletion of vegetation and soil
microfauna in cultivated lands and rangelands. In general, increased temperatures and reduced
rainfall will increase aridity. ICRISAT estimates that with a 2 o C increase in temperature coupled
with a 10 percent decline in rainfall, 1.6 million km 2 of sub-humid areas in Africa will become
semi-arid and 1.1 million km 2 of semi-arid areas will become arid (Cooper et al. 2009). The
Millennium Ecosystem Assessment (MEA 2005) notes that both effects are likely to alter
vegetation cover, both in terms of reducing overall levels, but also by altering the diversity of
species (those which can thrive on higher temperatures and increased carbon dioxide levels will
outcompete others).
These effects are quite evident in the rainfall – vegetation cover relationships in the
Sahelian rangelands. Between 1970 and 2000, annual rainfall in 26 of the 30 years was below
the historic long term average (Brooks 2004) creating what many observed as desertification (see
also section 2). Droughts, in combination with human or livestock population pressure, have
induced a conversion from grasslands to more degraded shrublands (MEA 2005).
The flipside of prolonged and frequent droughts are floods. In 2007 and 2008, over 20
African countries have been severely affected by floods causing great crop loss and dozens of
deaths. One of the latest examples was in southern Africa from December 2007-January 2008.
That experience showed that prevailing topography and soil characteristics in the region can lead
quickly to soil saturation and flooding, even with modest increases in rainfall above the norm.
Climate change may also lead to more rapid conversion of natural habitats into agriculture or to
unsustainable use/harvesting of natural resources. As trends over the past 20 years have shown,
expansion of agricultural area remains high in Africa. By contrast, the Green Revolution in Asia
is estimated to have saved as much as 271 million of hectares of land from conversion to
cropland compared to the absence of global cereal productivity increases (UNFCCC 2008). Low
productivity is undoubtedly a contributing factor to high rates of land clearing, and climate
change is expected to put even more downward pressure on yields of major crops in much of
Africa. Studies in Africa have also shown that in times of drought and other hardships,
communities often resort to harvesting of wild resources – fruits, fodders, grasses, and other
marketable products – for survival. Where climate change increases the frequency and scale of
demand for natural resource harvesting, there is greater likelihood of resource degradation.
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