Climate change

• Sahel:

  • Rainfall varies from 100mm - 600mm /year
• Sahel:

  • Up to 90% of rainfall is in July - September
• Sahel:

  • 1970s + 1980s rain failed, with it declining by 40% between 1950 - 1980
• Sahel:

  • Since 1996, region is regreening. Dry landscapes change to productive farmland. However increased competition for water
• Sahel:

  • Periods of constant drought declined with increased wet years such as in 2009 + 2011
• Sahel:

  • Re greening advantages: natural regeneration of water retaining shrubs. Low cost reforesting.
• California:

  • In 2014, Sierra Nevada region faced 3x the normal number of wildfires due to dry ground
• California:

  • Cornell University forecasts intense mega droughts lasting 30 years + decade long dry periods
• California:

  • 2012 - 2015 continuous drought. The worst in 1200 years. Water rationing imposed on cities
• California:

  • 50% chance of mega drought in SW Califronia and 90% decade long drought
• California:

  • Increased evaporation rates + fall in percipitation rates has caused these droughts
• California:

  • Problems with future water demand: surface runoff and soil moisture decreasing, forested areas > grassland. Ground water levels fallen by 30m from 2011 - 2015
• California:

  • Lake Cachuma fell to 9% capacity (Sept 2016)
• California:

  • Snowpack (permanent snow) in 2015 falls to lowest level in 500 years. Its meltwater provides 1/3 of water for California's cities and farms.