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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.
Since the early 2000s the Sahara has come back strongly into the international political and media arena. The whole region is going through a period of turbulence stemming from its growing economic and strategic importance and a highly confused geopolitical environment. This situation stems from the “Arab spring” events, the fall of Colonel Gaddafi and the installation of Al Qaeda Organization in the Islamic Maghreb (AQIM) in Mali.
A special issue of the journal Hérodote has published review articles on these upheavals by IRD geographers and economists and their and their research partners. Beyond the geopolitical and security aspects, they describe the economic changes, the development of the trans-Saharan migrations and the race for raw materials pursued by the world’s great powers. All these powers seek the underground wealth the region conceals (such as oil, uranium, iron). Simultaneously coveted and feared, the Sahara never ceases to arouse concern in the international community.
One and a half million people per year are poisoned by snake venom in Sub-Saharan Africa. An IRD researcher recently analysed around 100 surveys and medical reports published over the past 40 years. No large-scale study of the situation had hitherto been conducted and public health authorities had underestimated the size of the problem. This means that currently only 10% of victims are treated, owing to a shortage of antivenoms * and lack of awareness among health care practitioners. Yet the clinical complications can be very serious, even fatal. A bite from a cobra or mamba can bring on death by asphyxia –due to respiratory paralysis– within 6h after the incident. Venom injected by the ocellated carpet viper, common in the African savannah, can cause haemorrhages leading to the victim’s death in a few days.
This new study provides authorities with more detailed and reliable figures which should enable them to readjust their health-care services in better tune with needs.
Rice is the world’s most commonly used cereal food, feeding half of humanity. However, rice production will have to double within 20 years from now to meet the needs of a growing population.
Two species are used for cultivation, one Asian and the other African. The Asian species gives much stronger agronomic performances, but the African one is more rustic, more resistant to pathogens, more tolerant to drought and soil salinity.
With the aim of transferring these properties to Asian rice, IRD scientists and their research partners( 1) are seeking to overcome the sterility between the two species( 2). They used genome sequencing to compare the structure of a portion of chromosome, identified as the factor behind the reproductive barrier. These investigations, the first results of which were published recently in the journal PLoS One , have led to the definition of genetic markers allowing more rapid development of fertile lineages of improved Asian rice.
The desert has been nibbling away at the Sahel’s fertile land for several decades. To halt this advancing desertification, 11 African countries( 1) have come together to build a “Great Green Wall”. This immense project, initiated in 2005, aims to replant with trees a 15 km wide strip stretching 7000 km across the Africa, from Dakar to Djibouti.
A community of international specialists, including IRD researchers, has been mobilized to ensure that this wall of greenery will be as effective as possible. Their objectives are to choose the revegetation techniques and the best adapted species. These experts( 2) are focusing on a natural process which functions in most plant species: symbiosis between the plant and a fungus. Favouring this process would improve plant growth in degraded soils and increase their drought resistance. A tree with remarkable properties( 3) is one of the various recommended species that will be used: the filao tree, which can fix nitrogen from the air and hence colonize impoverished land.
It remains to be determined how the project can be integrated into an environment which is already used and how to enable the local communities to benefit from it.