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Study shows that melting Greenland ice-sheets could affect agriculture and induce migration in the Sahel.

Increased ice sheet melting in the Artic could lead to further drying in the African Sahel, and significantly disrupt future agriculture and livelihoods. This is according to a study led by scientists from the Institute Pierre Simon Laplace in France and involving several researchers taking part in FCFA’s AMMA-2050 consortium. The scientists used models (climate, ice-sheet, and agro-ecological) to test how melting ice sheets’ disturbance of major ocean currents can in turn affect agriculture and, by extension, migration in the Sahel.

The West African Sahelian region is a well-known climate change hot-spot due to persistent high temperatures and occurrence of extreme events. A recent study indicated that extreme events tripled over the past three decades. The region is also highly dependent on agriculture, which remains the most important sector in terms of employment and an important contributor to GDP. Given that farming in the region is largely rain-fed, the region is highly vulnerable to climate induced food insecurity; any projections of negative future changes in rainfall in the African Sahel region would be worrying. Yet, it is projected by the recent modeling study that partial melt of Greenland ice sheets can induce a drastic decrease of West African monsoon rainfall.

Scientists have shown that the relationship between the influx of fresh water from melting ice sheets into the North Atlantic has significant global climatic impacts. This includes a strong cooling of the Northern Hemisphere down to the Sahara, which is related to a strong slow down in north Atlantic deep water. A series of chain reactions are set up, one of which leads to a weakening of the west African Monsoon, drying of the region and an increase in surface temperatures i.e. the region becomes hotter and drier.

The study demonstrated that past relationships between melting ice sheets and North Atlantic climates will likely carry into the future and, more importantly, that under extreme scenarios this will lead to more extreme environmental impacts. Monsoon rainfall was projected to decrease by up to 60% under extreme scenarios. These changes have significant implications for agriculture and livelihoods in the region. Commenting in a Washington Post article, Prof. Chris Taylor, Principal Investigator of AMMA-2050 stated, “the implications, when expressed in terms of vulnerability of the population in the region are really dramatic and bring home just how sensitive livelihoods are in this region to climatic change”.

That perennial staple crops such as millet and sorghum in the region are vulnerable to decreasing rainfall and rising temperature, is an established fact. Model projections show that ice-sheet melt will likely lead to losses in large tracts of cultivable land for the staple crops, with more than 1 million square kilometers of arable land lost as a result of a 1 meter rise in sea-level.

The human implications of these effects on agriculture in a region where so many rely on subsistence farming cannot be gainsaid. Migration for many farming families would be the only option, if the costs of improving agricultural techniques and investing in adaptive technologies became unsustainable in the context of subsistence. Furthermore farmers have historically migrated to coastal areas in search of better livelihoods in times of famine or drought. This may no longer be an option when the coastal areas are de-stabilised by rising sea levels. The urban areas in the Sahel will thus become the most obvious, or only viable option for migration, bringing with it a unique set of challenges. Cross-border migration is also likely to increase, with the attendant migration-related destabilization and conflict likely to increase.