global population futures

Ozone depletion

Caused by halogenated chemicals such as CFCs. Used in refrigeration insulation, aerosols etc. (2O3→3O2). Ozone utilises and filters out much of incoming UV radiation. If ozone is depleted more UV rays reach Earth → impacts human health, fauna and flora. Lead to hold over Antarctica and health problems such as cataracts and skin cancer. Although CFCs were banned in Montreal Protocol 1987 there effects remain for another 50 years due to long lifetime (catalysts).

Skin cancer

1/3 of diagnosed cancers globally. Long-term exposure to sun or short periods of intense exposure causes damage to skin cells. Increased by 5 fold since 1970s. Affects elderly and most affluent and light-skinned populations in area of high UV index e.g. Australia. Cost $500mn in 2010 to Australia’s health system.

cataracts

Form of eye damage which causes loss of transparency in the lens of the eye→ cloudiness and eventual blindness. Caused by smoke (firewood and smoking), diabetes, exposure to UV radiation and poor nutrition. Leading cause of blindness; increased ozone depletion is putting those who spend a lot of time outdoors at risk of cataracts. Risk factors depend on: geographical location, altitude, time of day, rural locations (can increase reflectivity and less shade), wealth (only effective treatment is surgery and lens implants).

climate change and agreements

GHGs emitted, no legally binding agreements. Paris 2015→ 195 countries signed to reduce CO2 emissions and limit warming to 1.5C. May bring some localised benefits of less winter deaths however overall -ve impacts and disproportionately impact LICs. Estimates by WHO of an additional 250,000 deaths due to CC between 2030 and 2050.

thermal stress

Can be extreme hot or cold. E.g. European 2003 heatwave → 20,000 deaths. Heatwaves may become more common and more intense→ respiratory and cardiovascular diseases. However winters may be milder therefore reducing winter deaths. Overall deaths from heatwaves to > reduced winter deaths.

CC and vectors

Changing temperature and precipitation patterns→ emergence of water-borne diseases in newer areas, especially those flooded frequently. Currently more than half of the world’s population at risk. Seasonal changes can affect prevalence of vector borne diseases and forced migration due to water shortages putting previously unaffected populations at risk.

Agricultural productivity

Farming is finely adapted to local climate conditions. CC threatens balances and upsets equilibrium of agricultural systems. Impacts:

• increased pests of diseases as CO2 levels increase.

• increased salinisation due to higher evaporation rates and risk of desertification.

• Reduced growing seasons in dry areas as rainy season is late.

• Rising sea levels → saltwater intrusion.

• Increasing extreme weather events.

Some areas may see more productivity e.g. in colder areas- 45% increase in growing season in Fairbanks, Alaska in last 100 years.

nutritional standards

CC is reducing crop yields most in tropical regions. CC forces food prices to rise therefore consumers may choose to eat cheaper, less healthy food. CC may force a shift in agricultural production in areas and cease crop production in current locations. Obesity rates likely to increase in low earners in HICs as unhealthy food is cheaper. Estimated that changes to diet from CC will cause over 500,000 deaths by 2050.

Outline the different factors in future population-environment relationships (8)

CC: increased sea levels, diminishing water supplies as glaciers dry up → positive feedbacks.

Destruction of natural habitats: expected another 1/4 of remaining forest to be removed in the next 50 years for settlement, golf courses etc.

Loss of biodiversity

Unsafe water supplies: over 1bn in LICs lack access to safe drinking water. Freshwater stores used up faster than replaced therefore aquifers are being depleted.

Soil erosion: 40% currently of soils used for agriculture degraded.

Loss of wild food sources: overfishing impacting sustainable LIC practises.

Fossil Fuels: finite and contributes to pollution and CC

Toxic Chemicals: impacts health e.g. association with birth defects and mental health problems.

How are populations predicted to change globally? What does this depend on?

Populations are continuing to grow and UN predictions put population between 9.6-12.3bn by 2100. Growth rates of population are decreasing and will continue to slow. Other forecasts predict populations will peak at 9.6bn and decrease to 9bn by 2100. Dependent upon reducing fertility rates through improving education to girls particularly in LICs such as Nigeria, who are set to overtake USA as 3rd largest population.

How are populations expected to change spatially?

Populations expected to fall in Europe, however continue to grow in LDCs, especially in Africa who will drive population growth in the future.

What two factors impact population growth?

Fertility rates: halved since 60s and continue to as countries develop.

Life expectancy: more children surviving as living standards have improved globally, especially in LICs due to transfers of medical knowledge through NGOs. Life expectancy has increased, driving future population growth. Life expectancy has reached a limit in some HICs, e.g. fell in 2021 in the UK.

How does pop growth and development pose a threat?

Creating challenges for carbon budget and ecological footprint- energy demand expected to rise by 40% by 2030, pressures on fuelwoods in LICs→ deforestation, fossil fuel use. Increasing pressures for clean drinking water and food.