1B - Hot environments - Case Studies Flashcards
THE SAHEL
Background
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The North African Sahel is the most seriously affected region for desertification in the world and has suffered many severe droughts since the 1960s.
It is a semi-arid zone south of the Sahara Desert and rainfall is highly variable and unreliable.
Four main human causes of desertification identified in the Sahel: o Over cultivation o Overgrazing o Deforestation o Mismanagement of irrigation.
The political instability and colonial legacy across the entire region have also not helped matters.
The rainfall has dropped below average almost every year (except for 5 separate years) since 1970.
This lack of precipitation dries the soil and cracks it.
Vegetation is also unable to grow so dies and leaves the soil exposed, causing the soil to lose structure
THE SAHEL - SENEGAL
Causes of desertification
Overgrazing
The use of chemical fertilisers
Global warming and lack of rainfall
THE SAHEL - SENEGAL
Causes of desertification:
Overgrazing
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Increases soil erosion, reduction in soil depth, soil organic matter, and soil fertility. Impairing the land’s future natural and agricultural productivity.
Native plant grass species, both individual bunch grasses and in grasslands, are especially vulnerable.
Occurs when plants are overly exposed to grazing of animals for extended periods of time.
Caused by livestock in poorly managed agricultural systems.
THE SAHEL - SENEGAL
Causes of desertification:
The use of chemical fertilisers
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Soil fertility can sometimes be mitigated by applying the appropriate lime and organic fertilizers.
However, the loss of soil depth and organic matter takes centuries to correct.
Their loss is critical in determining the soil’s water-holding capacity and how well pasture plants do during dry weather.
Causes the soil to have a nutrient imbalance because chemical fertilisers are highly concentrated.
They kill microorganisms living in the soil.
The fertilisers can contaminate water sources.
THE SAHEL - SENEGAL
Impacts of desertification
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Many farmers in Senegal who depend on peanuts and beans have had their livelihoods ruined due to drought and soil erosion
Young people are forced to leave their villages in search of jobs and a better quality of life
Senegal’s agriculture industry occupies roughly 70% of the country’s working population and contributes 15% of the GDP
Senegal has experienced a food deficit and become reliant upon aid and imported food.
THE SAHEL
Solutions to desertification
Acacia tree planting
The Great Green Wall
Government Action
Change in agricultural methods
THE SAHEL - SENEGAL
Causes of desertification:
Global warming and lack of rainfall
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As temperatures rise, land surface warms so moisture from the soil evaporates.
Decreased rainfall in Senegal due to climate change means that vegetation finds it harder and harder to grow so there is less shelter of the soil creating a positive feedback loop.
THE SAHEL
Solutions to desertification
Acacia tree planting
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Acacia trees have been grown to help combat desertification in Senegal as they also provide socio-economic benefits.
From 2004 to 2007, FAO, in partnership with the Senegalese forestry service, provided seeds and seedlings and taught the women in the village how to sow and plant the Acacia trees as well as how to extract and market the gum they produce.
They feed the soil by capturing nitrogen that restores fertility and provides a shelter for crops.
Solutions to desertification
The Great Green Wall
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The goal of the project is to plant a wall of trees, 4,300 miles long and 9 miles wide, across the African continent, from Senegal to Djibouti.
The Great Green Wall has received a total of $1.8 billion from the World Bank
Senegal is currently the furthest along with the Great Green Wall. They’ve planted roughly 50,000 acres of trees in addition to protecting existing trees.
Solutions to desertification:
Have they been successful?
Acacia Tree Planting
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Yes, it has been extremely successful because not only is the environment benefitting from the trees, but also the people are as well
The families can have a sustainable income that doesn’t rely on overgrazing and it is sustainable without damaging the environment
A total of 44 villages have benefited from the Acacia project in Senegal so far
523 people, mainly women and youth, have been trained in sustainable forest management and restoration, as well as forest products and business development.
4 500 hectares of degraded land have been restored and wildlife is being reintroduced in a community-based nature reserve in Koyli-Alpha
Solutions to desertification:
Changing agricultural methods
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Innovative farmers in Burkina Faso had adapted years earlier by necessity.
They built zai, a grid of deep planting pits across rock-hard plots of land that enhanced water infiltration and retention during dry periods. They built stone barriers around fields to contain runoff and increase infiltration from rain.
In Niger, farmers are intercropping edible perennials in their fields, which stabilise the soil against wind and water erosion and also increase fertility
This has also been incredibly successful with tree coverage in Niger increasing greatly between 1975-2003
Solutions to desertification:
Have they been successful?
GGW
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The tree wall is able to protect a lot of the country from the dust carried over from the desert
However, large chunks of the proposed wall were uninhabited so no one would be there to tend to the saplings.
Almost 80% of all trees planted in Africa since 1978 have died
GGW modified - successful?
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Although the GGW itself may not have been successful, it has evolved into something that might
It shifted from a physical wall to a mosaic of land-use practices
Slowly, the idea of a GGW has changed into a program centred around indigenous land use techniques, not planting a forest on the edge of a desert.
Regardless of its realism, the African Great Green Wall has brought together governments and communities in a common commitment to combat desertification and move forward in the fight against poverty.
It has also raised awareness of the lack of access to water and education, and the need for efficient management of the territory to combat desertification
In Niger, the restoration of land has led to the production of 500,000 tonnes of grain every year, enough to feed 2.5 million people.
Solutions to desertification:
Government Action
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In 2000, Niger adopted a National Action Program (NAP) to combat desertification and manage natural resources – relatively successful
However, success of government action in many of the Sahel countries has been hindered by civil unrest.
In Nigeria, Boko Haram militants and criminal gangs are causing havoc close to the Niger border
Jihadi insurgencies in the centre and north of Mali are spreading across the Sahel
There were more than 5,000 deaths in the Sahel (due to this violence) between November and April 2019.
