Health & Environmental Change (AQA A Level Geography)
Revision Note
Impacts of Ozone Depletion
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
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%
Examiner Tip
An exam question on this section could ask you for an assessment or evaluation of these illnesses. If so, try and convey how the impact of rates of skin cancer and cataracts vary over space and time. For example, you could explain where in world the rates are highest, and highlight any differences between the two. Also, you could describe how the rates have changed due to strategies dealing with the root causes.
Impacts of a Changing Climate
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
Examiner Tip
Try to make links between the various impacts of climate change. For example, an increase in vector-borne diseases will mean fewer people will be able to work in agriculture if they become ill, which will impact on food supplies and nutritional standards in some areas.
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