The degradation of land in arid areas by which fertile land becomes desert like

  • 75 billion tonnes of soil eroded annually


Human Causes:

  • Overgrazing
    • Reduces vegetation > soil erosion (due to lack of plant roots)
    • Trampling by animals > compressed & breaks down structure of soil > erosion more likely
  • Overcultivation:
    • Reduces soil productivity > without plants > soil is easily eroded
  • Irrigation:
    • Depletes surface water and may involve unsustainable pumping of aquifers. As water levels are lowered, water availability for plants decreases, leading to soil erosion.
    • Surface irrigation= large amounts of water added to soil quickly, washing topsoil away
    • Too much water to irrigate crops = excess sink into soil and raise groundwater levels.
      • If aquifer saline, may bring high conc. of salt close to the surface, increasing salinity


Impacts of Desertification

  • Landscapes: The ground surface becomes more prone to erosion because:
    • Vegetation slows wind speed, so reducing vegetation cover increases wind speed.
    • Moisture evaporates from soil more quickly when it isn’t sheltered by plants, so it dries out.
    • Plant roots that help to bind the sediment together are lost.
    • Higher wind speeds = more mobile sediment can also = more sand to be blown into an area
  • Ecosystems:
    • Land less fertile, less plant life > reduces amount of organic matter that is put into the soil > further reducing vegetation growth. Less vegetation > less animal supported > – biodiversity
    • Distribution of species. Plant & animal may die out or migrate to less degraded areas.
    • Releases carbon stored in soil into atmosphere > climate change > widespread impact
  • Populations:
    • Reduction in the fertility of land > decline in agricultural productivity= migrate from the area >
      • Often people migrate from rural to urban areas > may lead to overcrowding.
    • Human health in other ways, e.g. dust from soil erosion can = respiratory diseases


Future Climate Change Impact:

  • Semi-arid areas to become hotter and drier- More extreme weather events, such as heat waves
  • Global temperatures are expected to rise up to 6 degrees between 2015 and 2100.

Future for Locals: uncertainty surround the potential strategies

  • Depends mitigation of impacts of and prevent more land from being degraded.

Futures for Desertification:

  • Desertification may continue:
    • If action isn’t taken to reduce desertification, or if strategies aren’t funded or managed
    • Decrease in agricultural yields > increase malnutrition and famine = hinder development
    • May be conflict within and between countries as food and water becomes more scarce
  • Humans may stop or reverse desertification:
    • LOCAL: People plant vegetation to bind the soil and act as windbreaks. Farmers can carry out crop rotation to allow the soil to recover, and improve irrigation systems.
    • GLOBAL: responses to climate change could have a major effect. However, this would require major commitment and cooperation around the globe.
  • Humans may reduce the impacts of desertification:
    • Local populations may change their lifestyles in order to adapt and reduce its impacts.
    • g. local farmers could change their farming methods E.g. keeping small livestock such as goats and chickens, which would be less affected by desertification than crops
    • Improvements in agricultural technology = increase food they produce per hectare