5.4B Human activity and drought

• • The activities enhance the climate conditions increasing the risk of drought
  • Human activity increases the risk of drought in a number of ways, the main way is over-abstraction of: -> Surface water resources -> Ground water aquifers
• Australian droughts:

  • In Australia droughts are a regular occurrence 
  • In 2006 the country experienced a 1 in 1000 year drought event - also known as the Millennium drought
• Causes of Australias drought:

  • low rainfall through 1996/7 followed by dry years in 2001, 2002 and 2003 
  • Between 2001 and 2003 El Niño exacerbated the drought conditions
• Human activity in Australia causing drought:

  • Climate change as a result of increased greenhouse gas emissions
  • Widespread deforestation 
  • Overgrazing of sheep and cattle has led to vegetation loss
  • Over-abstraction by farmers - until recently farmers could take as much water as they wanted
  • High water consumption - 340 litres per person per day
• Effects of Australias drought:

  • The Murray-darling river system was 54% below the record minimum 
  • Drinking water shortages were experienced in cities such as Adelaide
  • It was ended by the occurrence of a La Niña phase in 2010 which led to floods 
  • Crop yield was reduced to 10 million tonnes from the 25 million tonnes average due to less irrigation
  • Reservoirs were at 40% of their capacity