Health & Environmental Change (AQA A Level Geography)

• Depletion of the layer of ozone (O3) in the upper atmosphere, from 15-30 km high, has the potential to cause ill health and change population 
• Ozone is a gas that protects the earth from the Sun’s shortwave ultraviolet radiation (UVR)
• In the 1980s scientists discovered thinning of the ozone layer and holes above Antarctica and the Arctic
• Depletion caused by damage from chlorofluorocarbons such as chlorine, and halocarbons such as bromine
• Heavy industry, fridges and aerosol sprays were the main sources of these gases
• Increased exposure to UVR in humans is a health risk and can lead to increased rates of skin cancer
• Higher rates of melanoma skin cancer at higher latitudes
• In 2020 Australia had 37 incidences of skin cancer for every 100,000 population, compared to a global average rate of 3.4 per 100,000
• Skin cancer is the 17th most common cancer worldwide
• Globally, cases of melanoma skin cancer are predicted to rise by 18% between 2018-2025
• CFC emissions have been reduced by 99% since 196 countries signed the Montreal Protocol in 1987
• A later ammendment at a summit in Copenhagen in 1992 tightened restrictions further
• The layer is recovering but will take another 50 years to fully thicken to original levels
• CFCs are also powerful greenhouse gases, so the reduction in their emissions helps to mitigate climate change

The Effects of CFC Reduction on Predicted Skin Cancer Rates in Northwest Europe

• Another health risk from increased UVR exposure is cataracts
  • Cataracts lead to blurred vision caused by the lens of the eye becoming cloudy
  • Causes blindness in approximately 20 million people worldwide each year
• The risk of both skin cancer and cataracts can be increased by:
  • Geographic location
    • Tropical areas have higher levels of UVR, although high latitudes can also be high risk due to less ozone protection
    • More exposure in open spaces with reflective surfaces such as sand and snow
    • Less exposure in urban areas as there is more shade
  • Time of day
    • Higher risk of exposure between 10am-2pm when the sun is most directly overhead
  • Altitude
    • At higher altitudes less atmosphere is available to absorb UVR
    • With every 1000m in altitude, UVR levels increase by approximately 10%

Impacts of a Changing Climate

• Climate change is having negative impacts on human health in three ways:
• Direct impacts of more extreme weather, such as flooding and tropical storms
• Indirect impacts of reduced environmental quality, such as air and water pollution and infectious diseases
• Indirect impacts of reduced levels of mental health, such as increased trauma from climate-induced natural disasters
• The World Health Organisation (WHO) predicts that by 2050 climate change will be responsible for an extra 250,000 deaths worldwide each year
• There are some positive health impacts too, such as increased food supply in some parts of the world

Health Impacts of Climate Change