Climate Change & the Nexus (SL IB Geography)

What impact will climate change have on water supplies?

• There are a number of ways that water supplies are affected by climate change, these include: 
  • Unpredictable rainfall 
  • Floods
  • Droughts
  • Rising sea levels
  • Melting ice sheets/glaciers
• Climate change is impacting on the amount of available freshwater 
• The UN predicts that by 2050, up to 5 billion people worldwide will face freshwater shortages
• The melting of glaciers and ice sheets has led to an estimated 3% reduction in freshwater storage since 1971
• Salinisation of groundwater is increasing annually at a rate of 10% due to salt intrusion caused by sea level rise  
  • This decreases the amount of freshwater available in coastal areas
• Higher water temperatures, droughts and floods decrease water quality 
• More frequent droughts may lead to increased soil degradation and desertification in areas such as the Sahel
  • This will impact on food production due to a lack of water for irrigation
  • Fewer trees and vegetation will mean less biomass for energy production, particularly in areas where people rely on fuelwood for heat and cooking
• High-income countries such as the USA and Australia also face water shortages but this is less likely to impact food and energy security because they can afford to import

What impact will climate change have on food supply?

Crops and livestock

• Increased temperatures and changes in rainfall patterns affect crop yields
• Decreasing freshwater supplies have an impact on:
  • The availability of irrigation
  • Water for livestock
• Increased floods, which destroy crops
• Crop yields are impacted through:
  • Declining water quality
  • Soil degradation and desertification
• Climate change is also affecting the areas affected by pests and diseases, expanding their geographic range
  • Tar spot is a fungal disease affecting maize
    • It was native to Latin America
    • It can lead to a 50% reduction in yields
    • In 2015, it was detected for the first time in the US
• The spread of invasive, non-native species due to higher temperatures can impact food systems

Fish stocks

• Increased sea and river temperatures may affect:
  • Fish breeding patterns
  • Fish populations
  • Increased algae growth, which contaminates seafood
• Decreases in water quality impacts fish and seafood

What impact will climate change have on energy supply?

• Changing weather patterns may impact renewable energy supplies
  • Reduced cloud cover may lead to increased solar power
  • Changing wind patterns may impact the use of wind energy
• Reduced precipitation may lead to challenges in growing biofuels 
  • Increased water scarcity will reduce the amount of water available for irrigation
• As the amount of water stored in glaciers reduces, the spring snowmelt will result in lower discharge
  • This will affect the amount of energy generated by hydropower
  • Tajikistan is reliant on hydropower and is already experiencing changes in river flow
• Sea ice melt in the Arctic may improve access to gas and oil reserves
  • Increasing the availability of fossil fuels
  • Reducing the cost of extraction