Issues of Energy Sustainability (AQA A Level Geography)

Enhanced greenhouse effect

• The world’s increasing need for energy security has led to an increase in the number of greenhouse gases in the atmosphere
• It is estimated that energy accounts for more than two-thirds of total greenhouse gas emissions globally
  • Carbon dioxide (CO2) levels in the atmosphere have increased by more than 100 parts per million (ppm) to 420 ppm in 2020

• Sources of greenhouse gases from energy production and consumption include:
• CO2
• Burning of fossil fuels  for power stations and vehicles
• Burning of wood for heating and cooking in LICs
• Methane
• Emitted during the production and transport of coal, natural gas, and oil
• Of the 135 million tonnes (Mt) of annual global energy-related emissions
• 42 Mt are from coal mines
• 41 Mt from oil
• 39 Mt are from extracting, processing and transporting natural gas
• Nitrous Oxide
• Emitted during combustion of fossil fuels
• Increased amounts of greenhouse gases have led to the enhanced greenhouse effect:
• Less long-wave radiation (heat) can escape the atmosphere
• Average global temperatures have increased 1°C above pre-industrial times

The enhanced greenhouse effect

• The enhanced greenhouse effect is leading to climate change with significant impacts on people and places

Impacts of climate change

Acid rain

• Sources of acid rain arise from the search for energy security
• Burning of fossil fuels to generate electricity
• Vehicles and heavy equipment.
• Manufacturing, oil refineries and other industries

• Acid rain results when sulphur dioxide and nitrogen oxides are emitted into the atmosphere 
• They react with atmospheric water, oxygen and other chemicals to form sulfuric and nitric acids
• These then mix with water and other materials and are transported by wind and air currents
• Deposits can be also be dry, as gas and minute particles
• They can fall as acidic deposits far from the source
  • An example of transboundary pollution

• The impacts of acid deposits can be damaging to ecosystems and soils
  • Reduces the pH of bodies of water
    • Kills fish and affects spawning, e.g. of rainbow trout
  • Soil acidification reduces the availability of mineral ions
    • Plant nutrients leached out of the soil by percolation of acidic water
    • Toxic metals such as aluminium ions released 
      • Poisons plant roots
      • Kills microorganisms so soil is no longer broken down
    • Phosphates become fixed so dissolved aluminium increases
      • Phosphate becomes less accessible to plants

• Impacts can be all-year round, or ‘chronic’
• Or they can be ‘episodic’
  • After periods of heavy rain or snowmelt, large amounts of acid can be flushed out of soils into waterways
  • Known as an acid shock
• Sulphur emissions have fallen across Europe and North America in the last 20 years
• • Only 10% of lakes in northeast USA are now affected by long-term chronic acidification 
  • But episodic acidification is still an issue
    • 31% of northeast US lakes still affected by acid shock
• Emissions in China and other EMEs remain high so transboundary pollution still an issue in some parts of the world

Energy conservation

• Combined heat and power (CHP) is one strategy to conserve energy in industrial settings
• Heat generated during electricity generation is transferred to other settings, e.g. to heat homes
• Overall energy consumption is reduced 
• Heating and electricity supplies remain cheap and stable
• Denmark uses CHP networks to provide 60% of it’s space and water heating
• Other measures to conserve energy in homes and small businesses include:
• Improving thermal efficiency of walls, windows and roof-spaces with insulation
• Installing double-glazing to windows
• Replacing tungsten light bulbs with LED bulbs
• Sensors to turn lights off when not in use
• Information to consumers about the energy efficiency of the appliances they buy
• New buildings in the UK have to be developed with strict codes to ensure energy efficiency
• Requirements include:
• Thermal insulation
• Air permeability (airtightness)
• Energy-efficient heating systems
• Lighting efficiency
• Controls for heating, ventilation, and hot water systems
• The regulations set a limit on the carbon emissions from buildings
• Energy performance certificates to provide evidence of compliance