Desertification

Desertification

1. human causes

   • population growth
     • more people means that more food and more land is required
       • rate of deforestation increases so there is more wood for cooking
         • the protective barrier the vegetation had on the soil has been removed
           • soil erosion is now more likely to happen due to the strong trade winds
             • nutrients have also been removed from the soil so the vegetation is unlikely to re-establish itself in the soil
     • countries in the Sahel region of Africa- population increasing by a rate of 2.5% per year
     • between 19968 and 1997 population in the Sahel region increased from 274 million to 628 million

2. natural causes

   • climate change
     • temperature increases
       • more evapotranspiration
         • this causes vegetation to die as a result
           • the soil becomes depleted of nutrients so vegetation doesn't grow back
       • water evaporates from the surface of the desert
         • saltintation
           • salt is left on the surface causing desert like conditions
         • rivers and water stores dry up causing vegetation to die
     • decreased volume of precipitation
       • in the Sahel rainfall decreased between 1968 and 1997 at around 45%
         • vegetation dies so soil erosion is more likely to occur

3. Impacts

   • reduction in the amount of vegetation
     • biodiversity decreases
   • soil erosion means that the top layer of soil is removed
     • the land becomes less usable as there is also no nutrients in the soil
   • increases soil salinity
     • soil crusts develop
   • causes famine
     • drought and poor land means that crops are more likely to fail and so there is less food
       • Somalia- majority of youthful population are malnourished
         • extremist Islamic group Al-Shabab disrupted aid reaching people that needed it
   • movement of population away from the affected areas
     • more pressure on resources
   • Las Vegas (Mojave desert)
     • water issues
       • there is a 50% chance that the Lake Mead (gets its water from the Colorado River) could run dry by 2021
         • in 1922 each state was allocated a percentage of the the Colorado river water. Southern Nevada receives 2% of the Coloardo River
       • Population increase- 1979: 40,000 2016: 2 million
         • 2 million people depend on the 2% from the Colorado river
       • economic growth- more business and homes requiring water
       • 70% of the water in Southen Nevada is used on outdoor landscaping
       • the Las Vegas strip only uses 3% of the 2% water allocation
       • water is running out: white line on the cliffs behind the Hoover dam (reservoir) 120ft drop from 1999-2009
     • Solutions
       • Southern Nevada Water Authority patrol the neighbourhoods in Las Vegas looking for water waste
         • sprinklers/sprays
           • fines are given
       • Xeriscaping
         • landscaping in a way that requires a minimal volume of water
           • using gravel, stones and drought resistant plants
             • people get paid $1.50 for every square foot they convert- acts as an incentive so they do it and are ultimately using less water
       • drip irrigation
         • water is dropped slowly at the roots
           • less water will be evapourated as temperatures are high and so spraying the water would mean that it would evpaourate before it reached the groud
         • 300 mile pipeline from Baker to Las Vegas
         • 300 mile pipe line from Baker to Las Vegas
       • economically sustainable
         • Las Vegas strip
   • The Sahel
     • population increase was 2.5% each year

4. solutions

   • Jatopha Curas
     • traditional planting method
       • Jatopha Curas is able to grow in poor quality soils and is not eaten by animals
         • its roots help bind the soil together
           • protects the soil from wind and water erosion
     • happening in Niger and Burkina Fuso
     • drought resistant plant
       • the seeds from the plant contain up to 38% oil
         • people can sell this or use it
           • source of income
         • used for medical treatments and local soap production
     • the wood from the plant can also be used for burning
       • reduces deforestation
   • Contour stone bunding
     • stones are placed on the ground and the rainfall is collected as it slowly trickles through the small holes
       • this can increase the yield of crops by 50% which results in a larger income
         • advantages- low cost, bits of dead plants and manure is filtered so this results in a build up of rich sediments which makes the soil more fertile
     • Arg-Forestry project in Burkina Faso
   • External aid- NGOs
     • NGO- Non-governmental organisations
       • They provide free seeds of plants that are suitable for growing in arid conditions
         • there is now more vegetation
           • the Africa desertification control initiative (ADCI) has distributed 50,000 Neem seedlings to farmers in Niger
             • source of employment
               • produces cosmic oils which can be sold
   • New stoves
     • Eritrea- cooking techniques are changed
       • 50% less wood is needed so theres less deforestation which stops soil erosion
         • less smoke is also produced from the method and so it reduces respiratory diseases
     • Chad- 'cookit' solar powered method
       • dependant on weather
         • uses no firewood
   • Afforestation
     • more vegetation
       • there is a protective layer and so there is less soil erosion as less soil is exposed

5. definition- the destruction of the biological potential of the land which can lead to desert like conditions