Human Impact on the Environment

Human Impact on the Environment

1. Increased concentration of carbon dioxide in the environment

   • Burning of fossil fuels
     • For electricity, powering vehicles and industrial processes
     • Combustion of carbon-rich fuels releases carbon stored within them
   • Deforestation
     • Cutting down trees and removing vegetation
     • Decreases amount of carbon dioxide taken up by plants. Increases carbon dioxide in atmosphere
   • Greenhouse gas, absorbs long wave radiation emitted from Earth, preventing it from escaping back into the atmosphere, increased concentrations leads to increase in greenhouse effect, may result in global warming

2. Increased concentration of methane in atmosphere

   • Increased number of landfills
     • Decaying organic matter in waterlogged soils releases methane
   • Increased number of livestock
     • Ruminants like cows release methane gas through their digestive tracts
   • Mining of coal

3. Increased temperatures may lead to:

   • More evaporation of water
     • Lead to increased precipitation - increasing potential for flooding
   • Rising sea-levels
     • Caused by melting ice in glaciers
     • Eventually increase risk of flooding
   • Increased wildfires
     • Increases chances of soil erosion and desertification
   • Increased loss of biodiversity
     • Species are unable to cope with rising temperatures
   • Increased droughts
     • Leading to desertification and food insecurity

4. Carbon footprint

   • Measure of total amount of carbon dioxide emissions of individual, business etc
   • Strategies to reduce carbon footprint
     • Reuse and recycle
       • Less fossil fuels burn in production of some material
     • Drive less
       • Use public transport, walking, bicycles
     • Reduce need for heating
       • Insulating walls and building energy-efficient homes
     • Carbon off-setting
       • Using alternative energy (solar, wind) and reforestation to act as carbon reservoir
     • Technological developments
       • Decreases amount of energy needed for production and decrease dependency on carbon emitting fuels

5. Destruction of the ozone layer

   • Greenhouse gas absorbing ultraviolet rays from the sun. Rays can damage DNA
   • Caused by: chemicals called CFCs, released by refrigerators, aerosol sprays and fast-food packaging
   • Significant increase in number of skin cancer cases
   • Ultraviolet rays reaching Earth's surface may cause permanent damage to our eyes

6. Water quality and availability

   • Availability of Water
     • Construction of dams
       • Plays major role in increasing quantity of water stored
     • Destruction of Wetlands
       • Should not be destroyed as they influence availability and quality of water
     • Water wastage
       • Poor Farming practices such as open drain irrigation leads to loss of water by evaporation
       • Leaking taps, toilets, faulty pipelines
       • Can be reduced by reducing pressure in pipes, educating people on using water wisely, maintaning plumbing
     • Cost of water
       • Influenced by availability and quality of water
       • Cost per kilolitre (kl) increase with increased use of water, meant to discourage over-use of water
       • Certain amount available free to everyone to make sure even poorest have access
     • Poor farming practices
       • Contamination of water sources such as fertilizers and pesticides decreases amount of clean water available, increased costs of purification
       • Over-grazing leads to soil erosion, water runs off rapidly not soaking the ground, thus wasted
     • Droughts and floods
       • Drought - water availability decreases. Water from dams cannot be easily replaced
       • Natural vegetation can hold back water from floods. If removed, flood waters are lost
     • Boreholes and aquifers
       • Boreholes increase water availability in some areas that don't have direct access
       • Constant use leads to drying up of aquifers decreasing water availability
     • Water recycling
       • Water availability can be increased if existing water used more than once. Sewerage water can be treated and reused
     • Exotic plantations and depletion of water table
       • Some exotic plants use large quantities of water from ground. This decreases level of water table making water less available
   • Quality of Water
     • Eutrophication and algal bloom
       • Agricultural water may contain pesticides, herbicides and fertilizers, polluting the water
       • Added nutrients lead to increase in algal growth, depleting oxygen in water reducing potential for life
     • Thermal Pollution
       • Refers to heating of water caused by using water for cooling in industries
       • Quality of water is affected because heated water has lower oxygen content, difficult to sustain life
     • Domestic, agricultural and industrial use
       • Domestic purposes: may contain detergents and pathogenic bacteria. Water has to be treated before using again
       • Industrial purposes: may contain heavy metals, oil, heat and fertilizers. Negatively affects quality of water and all life
       • May run off into rivers, ponds and dams polluting water
     • Mining
       • Water returned generally acidic and toxic, water is hot and contributes to thermal pollution
     • Alien Plants
       • Block waterways, reducing light to other plants. Plants eventually die and decompose, these bacteria eventually deplete oxygen in water
     • Water Purification
       • Quality of water is improved. Undrinkable water can be made drinkable