Human impacts: atmosphere Flashcards
Greenhouse gases
Carbon dioxide,
methane,
water vapour,
nitrous oxides
Role of trees in the carbon cycle
Act as carbon sinks,
sequestering carbon dioxide from the atmosphere by photosynthesis
The main source of CO2 emissions
Burning fossil fuels
Describe the greenhouse effect
- Light energy from the sun reaches the earth and is re-radiated as heat.
- Greenhouse gases in the atmosphere trap the heat, preventing it from escaping into space.
- This regulates the earth’s temperature, preventing it from becoming too cold at night.
Explain the enhanced greenhouse effect
- Deforestation means less CO2 is sequestered.
- Industrialization means more CO2 is released.
- CO2 levels in the atmosphere are increasing.
- This leads to global warming
Sum total of all of an individual’s CO2 emissions
Carbon footprint
Ways to personally reduce CO2 emissions/carbon footprint
- Decrease fuel consumption by walking, cycling, using public transport or using a car-pool.
- Minimise air travel.
- Use less electricity.
- Insulate your home.
- Use alternative energy.
- Buy locally made goods.
- Eat less meat and processed foods.
Main sources of methane emissions
- Decomposition in landfills
- Sewage plants
- Natural gas and crude oil industries
- Rice plantations
- Faeces of livestock
Productive land is transformed into a desert
Desertification
Causes of desertification
- Climate change leads to less rain and warmer weather
- Poor land management
Examples of poor farming practices that lead to desertification.
- Overgrazing or under grazing
- over-cultivation
- irrigation using poor quality groundwater
- deforestation
Effects of desertification
- Loss of vegetation
- Soil erosion
- Loss of biodiversity
- Soil releases more CO2
- The decline in soil quality
- Social unrest
Ways to combat desertification
- Prevent climate change
- Improved farming techniques
- Reduce deforestation
Effects of global warming
- Desertification
- Increase in droughts and floods
- Increase in extreme weather events
- Melting polar ice caps and glaciers
- A rise in sea surface temperatures
- Loss of biodiversity
- Spread of disease
- Social unrest
Deforestation
Permanent destruction of indigenous forest by felling and burning in order to clear land for other purposes
Reasons for deforestation
- Clearing land for urban development or agriculture
- Use of wood for fuel or as a building material
- Mining
- Harvesting for traditional medicines
Effects of deforestation
- Increased global warming due to reduced carbon sequestration
- Soil erosion
- Reduced soil quality
- Flooding
- Loss of biodiversity
- Disruptions to the water cycle
Role of trees in the water cycle
- Return water vapour to the air by transpiration - leads to cloud formation
- Slow run-off and allow water to sink into the soil
Ways to reduce deforestation
- Recycle paper and cardboard
- Legislation to protect forests
- Plant trees
- Select specific trees instead of clear-cutting
- Create awareness
- Promote sustainable practices
- Mosaic forestry
Mosaic forestry
Keeping areas of indigenous plants between trees planted for logging.
Ozone
- O3 gas in the atmosphere
- Highly reactive
- Absorbs UV radiation, preventing it from reaching the lower atmosphere.
The main cause of global warming
Enhanced greenhouse effect caused by the build-up of greenhouse gases in the earth’s atmosphere. (NOT the hole in the ozone layer!).
Ozone-depleting substances
- Gases containing chlorine or bromine.
- When released into the stratosphere they break down releasing Cl or Br, which cause degradation of ozone.
- e.g. CFCs
Responsible for higher levels of UV radiation, especially over the South Pole
Ozone depletion
Ways to combat ozone depletion
- Regulation and banning of ODS use
- Alternatives to ODSs in industry
- Create awareness
- Use “ozone friendly” products
