the great green wall

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  • The Great Green Wall

  • The Concept The Great Green Wall is a major climate change mitigation initiative aimed at

    addressing the social, economic and environmental impacts of land degradation and

    desertification in northern Africa, specifically the Saharan and Sahel regions.

    It involves the eleven nations that cross African from the Atlantic coast to the Red


    Burkina Faso, Chad, Djibouti, Eritrea, Ethiopia, Mali, Mauritania, Niger, Nigeria,

    Senegal and Sudan

  • The Concept The initial idea of a line of trees crossing Africa

    originated in the 1980s and reemerged in the early 2000s

    It was finally approved in 2007 with the first trees being planted in 2008.

    Subsequently the vision of a Great Green Wall has evolved into that of a mosaic of interventions addressing the challenges facing the people of this region

  • The Sahel Region: Geography and Climate The Sahel is the ecoclimatic and

    biogeographic zone of transition in Africa, between the Sahara desert in the north and the Sudanian Savanna in the south.

    The Sahel covers parts of (from west to east), The Gambia, Senegal, southern Mauritania, central Mali, Burkina Faso, southern Algeria and Niger northern Nigeria and Cameroon, central Chad southern Sudan, northern South Sudan and Eritrea.

    The Sahelian climate is a tropical semi-arid climate with the dry season mainly (but not exclusively) during the cooler months.

  • The Sahel Region: Geography and Climate The mean monthly temperature of these

    months is around 18C. The Sahel is mostly covered in grassland

    and savanna, with areas of woodland and shrubland.

    Grass cover is fairly continuous across the region and is the source of grazing for both livestock and native wildlife

    Over grazing of livestock is an important contributor to the problem of desertification of the region.

  • Desertification and Climate Change

    Desertification is a form of land degradation whereby land in dry regions becomes increasingly

    arid, meaning that it can no longer be used for agriculture.

    This can come about from a variety of factors including deforestation, overgrazing and other

    human activities as well as climate change.

  • Desertification: Feedback Loops

    There are feedback loops between desertification and climate change.

    Vegetation that is removed by human activity means that there are fewer plants in the

    region to hold moisture.

    This moisture would normally evaporate in the warm climate and subsequently condense

    to form rain clouds which typically produce rain the afternoons.

    Decreased rainfall dries the soil which can then be easily blown away creating desert.

    As land turns to desert, carbon stored in the drying land vegetation and soil is released to

    the atmosphere.

    Because of its geography, many regions in Africa can expect to have decreased rainfall as

    a result of climate change.

  • Desertification: Rainfall

    Since 1970 countries in this region have experience significant variation in expected rainfall.

    Burkina Faso there has been around 50 mm less rainfall on average

    In Nigeria there has been an increase of around 250 mm on average. In addition temperatures in the region have risen by 2C on average over the same time period [9].

    In Senegal the rainy season typically started in July or august but now starts in September and the capital city of Dakar, which is over a thousand miles from the Sahara desert, is more frequently subjected to sand storms [10].

    In Chad, Lake Chad which is a principal source of water and also the source of this land locked nations fishing industry had been drying significantly in this time period as can be seen in the photo below [11].

  • Objectives of the Great Green Wall

    The planting of trees is expected to provide a barrier against desert winds and will help to hold moisture in the air and soil.

    This will allow agriculture to be sustained which will enhance regional food security and provide job opportunities in local communities.

    It is also expected that the Wall will reduce erosion, enhance biodiversity and improve countries resilience to climate change.

    Additional the project should provide local communities with knowledge to change current practices which lead to land degradation

  • Objectives of the Great Green Wall

    The project also has major symbolic significance given that it represents a multinational initiative to mitigate the consequences of climate change.

    For instance the Global Economic Facility (GEF), which is a major funder of the project, sees it as "a visual concept symbolizing the collective work we all have to do in order to combat environmental degradation".

  • Early Progress - Senegal

    Senegal seems to be the nation most enthusiastically embracing the project and bearing the early successes. Trees have to be planted during the short rainy season and so far 50,000 acres of trees have been planted.

    One example of success is a tree planting project in the village of Widou which has resulted in the creation of market gardens which provide an additional food and income source for the villagers.

  • Early Progress - Senegal

    Villagers are taught how to plant vegetable crops and use drip irrigation by connecting a small elevated water tank to perforated pipes that deliver small amounts of water to each plant .

    When the trees are more fully developed it is expected that they will also provide nutrients for the goats that the villagers tend as well as help stabilize the water plane.

    The choice of trees matches those in the local area and the communities have been involved in the decision making process.

  • Skepticism - Timberwatch

    Timberwatch points to the failure of a similar project which was undertaken in China which resulted in worsening the environmental situation

    Whilst they acknowledge that the Widou project has utilized trees that fit local environments, Timberwatch has a concern that this will not be the case across the region and that too often consultation will actually take the form of misleading local communities.

  • Skepticism - United States Geological Survey

    The United States Geological Survey believes that natural regeneration is much more likely to succeed than planting trees.

    They point to Niger where historically farmers habitually removed any trees or bushes as they sprouted their fields.

    This practice changed after the devastating drought in the 1980s.

    Farmers decided to allow the natural vegetation to grow and planted food crops around it.

    The result was a surplus of food and 12 million acres of trees.

  • References Slide 1:

    Slide 2-3: Great Green Wall, Don Leiber. The Great Green Wall

    of Africa - A 4,000 Mile Defense Against Climate. Planet Save. 21 April 2013 http://planetsave.

    com/2013/04/21/the-great-green-wall-of-africa-a-4000-mile-defense-against-climate-change/ The African Wall http:


    Slide 4-5: Sahel

    Slide 6: The African Wall Desertification Deserticiation in the Saheel

    Slide 7: Desertification and Climate Change. Learning Zone. BBC. Desertification. World Preservation Foundation. Climate Change and Desertification. World Meteorological Organization.

  • References Slide 8 Tierney Smith. Climate change, desertification and migration: Connecting the dots. Responding to

    Climate Change. 14 August 2012. Bobby Bascombe. Senegal begins planting the Great Green Wall against Climate Change. The Guardian. 13 July 2012. Shrinking Lake Chad.

    Slide 9: African nations strive to stem desertification with a Great Green Wall. UN News Centre.

    Slide 10: Daniel Ajegbo. The Great Green Wall? Think Africa Press. 5 September 2011.

    Slide 11: Bobby Bascombe. Senegal begins planting the Great Green Wall against Climate Change. The Guardian. 13 July 2012.

    Slide 12: SENEGAL: Prospects and pitfalls along a Great Green Wall. IRIN. Africas Great Green Wall Bears Fruit For Families In Senegal. World Food Programme. 11 April 2013.

    Slide 13 - 14 AFRICA: Opposition building to Great Green Wall. IRIN. Daniel Ajegbo. The Great Green Wall? Think Africa Press. 5 September 2011. Bobby Bascombe. Senegal begins planting the Great Green Wall against Climate Change. The Guardian. 13 July 2012.