Environmental Issues (AQA GCSE Physics: Combined Science)

• The current evidence for climate change is overwhelming – in order to limit global warming, carbon emissions must be limited globally
• Doing so, however, requires a balanced approach – carbon-neutral energy resources either lack public support, reliability or cannot produce sufficient energy to meet the demand
• Nevertheless, over the past 20 years, there has been a gradual shift towards cleaner technologies
  • Government grants have encouraged the development of wind and solar farms
  • Coal has gradually been replaced with cleaner natural gas
  • A new generation of nuclear power stations are currently in development – although with old power stations being shut down, nuclear power is becoming a smaller option

• Further reduction of carbon emissions will require some further measures:
  • More nuclear power stations will be needed to replace existing fossil fuel stations
  • A means of storing energy from unreliable sources (such as solar and wind) will need to be developed

• Although science can identify environmental issues arising from the use of energy sources, political, social, ethical and economic considerations must be taken to deal with these issues

• In the past 30 years in the UK:
  • Fossil fuel use has dropped from 75% to 38%
  • Renewable energy use has increased from 2% to 35%

• Coal used to be the main provider of energy in the UK, but now it is natural gas
  • This is because, out of the 3 main fossil fuels, coal produces the most carbon dioxide, while natural gas produces the least
  • Switching to gas is not the solution to reducing carbon emissions, but as the use of carbon-neutral energy resources increases, it is a step in the right direction

The Greenhouse Effect

• Global warming is a problem caused by the Greenhouse Effect
• The Greenhouse Effect is caused by the increased concentration and effect of greenhouse gases, mainly methane and carbon dioxide

• The process of global warming is as follows:
  • The Sun emits rays that enter the Earth’s atmosphere
  • The infrared radiation is emitted back from the Earth’s surface
  • Some infrared radiation is reflected back out into Space
  • Some infrared radiation is absorbed by Greenhouse gases and becomes trapped within the Earth’s atmosphere, causing the Earth’s average temperature to rise as a result
  • The higher the concentration of greenhouse gases, the higher the Earth's average temperature will rise

• Once the temperature increases too much, this will lead to devastating consequences:
  • Climate change due to the increase in Earth’s temperature
  • Sea levels will rise as glaciers melt because of high temperatures, causing flooding in low-lying countries
  • Extinction of species due to the destruction of natural habitats
  • Migration of species (including humans) as they will move to areas that are more habitable (with no droughts or recurring wildfires)
  • Spread of diseases caused by warmer climate
  • Loss of habitat due to climate change (animals that live on glaciers)

• Many of these consequences have already begun to take effect
  • It is predicted many of these will have taken full effect by 2050 if carbon emissions are not drastically reduced