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416 - Who deforested Central Africa: Man or climate?
November 2012
It is a much debated question: why did Central African forests become partially fragmented between 2,500 and 2,000 years ago, leaving room for more open forest landscapes and savannah? Recently, a publication attempted to explain that it was the farming Bantu peoples who were responsible for this, through the large-scale clearing that they undertook. But several IRD experts and their partners( 1) contest this argument in Science magazine. The fragmentation of the Central African forest was the result of drastic climate change. In fact, during this period a phase of general desiccation spread from the equatorial region right to the edges of the Sahel. Numerous data show that it was only 500 years later, in other words some 2,000 years ago, that Bantu colonisation became widespread. The first Bantu populations therefore merely took advantage of the opening up of the forest to enter these areas and start growing their crops.
392 - Lake Chad: Inhabitants adapt to lower water levels
December 2011
Lake Chad used to be one of the biggest lakes in the world, but its volume has been reduced to a tenth of what it was in the 1960s. The way this lake has dried up has become a symbol of climate change in action. It’s true that the lake’s water level has always changed, but this hasn’t diminished the major changes to the lifestyle of the inhabitants of the lake’s shoreline. Yet, as demonstrated by a French-Nigerian team including the IRD( 1), lake dwellers have made the best of these changes to their environment. Formerly fishermen or herdsmen, they have become farmers, often growing for export. The land that was part of the lake has made it possible for them to develop highly productive crops such as corn, rice and cowpea. In the valley of the Komadugu Yobe River in Niger, they have even commenced the intensive farming of peppers, which is highly lucrative although risky.
Rewatering the lake, as proposed by the Ubangi( 5) international project, would cause upheaval once again to the farming system, particularly if the yearly rise and fall in lake water levels were to cease.
352 - Aids: Cameroon takes up the challenge
June 2010
50 % of Cameroonians in need of treatment against HIV now have access to such health care. In the early 2000s only 1 % had such a possibility yet in less than ten years their numbers have gone from just a few hundred to nearly 80 000.
From the beginning of the decade, a fall in the price of antiretroviral medicines( 1) started the trend. Then decentralization of access to care, set in train by the government in 2002, followed by the availability of tritherapy( 2) free-of-charge, since May 2007, have allowed this incredible progress. Commissioned by the Cameroon Ministry of Public Health, the IRD researchers and their partners in the South and the North( 3) have set up an assessment programme on this bold decentralization reform, with the support of the French Agence Nationale de Recherche sur le Sida et les hépatites virales (ANRS, France). They find that today, the health care provision for patients is achieving performances at least as good in the district services( 4) as in Yaoundé or Douala, the political and economic capitals.
Sub-Saharan Africa : the population emergency
December 2007
