geogrpahy

• This is possibly the most talked about environmental issue of the past two decades. Although there may still be some debate about the exact causes and consequences, there is strong agreement from a majority of atmospheric scientists that Global Warming exists, and that it is an issue which is of critical importance to the future of the earth.
• The Greenhouse Effect is often confused with another significant environmental issue relating to industrial development and energy use; the depletion of the ozone layer. However, the cause of global warming has little to do with the thinning of the ozone layer. They are essentially two separate environmental issues.
• Greenhouse Effect


  A totally natural phenomenon where certain gases (e.g. water vapour) act as a 'blanket' to trap some of the sun's energy in the atmosphere. Without it the earth would be about 33 degrees Celsius cooler and life on earth could not be sustained.
• The Enhanced Greenhouse Effect is how humans are exaggerating the effects of the natural greenhouse effect, leading to unnatural warming.
• Climate has changed before, as the ice ages of the past demonstrate.
• What causes the Enhanced Greenhouse Effect?

  • Human-caused greenhouse gas (GHG) emissions
  • Energy (electricity, heat generation, transportation, manufacturing)
  • Agriculture
  • Land-use, land-use change and forestry
• Carbon Dioxide


  The big one - the level of CO2 in the atmosphere has been rising over the past century. Burning fossil fuels and deforestation release CO2 back into the atmosphere, contributing to human-induced global warming.
• Methane


  Also has a big effect - produced by decomposition of organic matter and internal fermentation by cattle. Pound for pound, methane is 25 times more potent as a greenhouse gas than CO2.
• Nitrous Oxide


  Released into the atmosphere mainly from fertilizers used in agriculture.
• Chlorofluorocarbons (CFCs)


  Act as greenhouse gases when present in the lower atmosphere, and also damage the ozone layer in the upper atmosphere.
• Ozone


  Desirable in the stratosphere where it helps filter UV rays, but can also form in the lower atmosphere as a greenhouse gas.
• Satellite images, ice core samples, and temperature records provide evidence of global warming and climate change.
• Many of the predicted consequences of climate change are dire and could even make parts of the planet uninhabitable, resulting in poverty, deaths, and mass migrations.
• Carbon Dioxide Fertilizer Effect


  Higher CO2 levels can stimulate plant growth, potentially increasing some agricultural crop yields by 10-15%.
• Some areas may become more productive

  Warmer climate in frozen areas like northern Russia and Canada may make them more suitable for agriculture. Drier areas may become wetter due to changes in weather patterns.
• Negative Impacts


  • Reduction in crop lands and forest industries
  • Loss of tourism potential
  • Increased risk of climatic hazards and disasters
  • Endangered species
• What can be done to globally manage climate change?

  • Reduce greenhouse gas emissions
  • Remove greenhouse gases that have already accumulated in the atmosphere by planting trees
• Pumping cold water to the tropics and warm water to the poles

  Could dramatically accelerate the process of climate change
• Acidification of the oceans
• Coral bleaching caused by water temperature increase and acidification

  Is putting the world's coral reefs at risk
• Causes of global warming

  • Volcanic eruptions
  • Wildfires
  • Burning of fossil fuels
  • Deforestation
  • Reduction in wetlands
• Effects of global warming

  • Rising sea level
  • More storms
  • Desertification
  • Decreases ice and snow cover
• The overwhelming scientific opinion is that Global Warming is a reality and that the overall consequences will be negative
• Ways of combating climate change

  1. Reducing greenhouse gas emissions

  2. Removing greenhouse gases that have already accumulated in the atmosphere
• Removing greenhouse gases that have already accumulated in the atmosphere

  1. Stop deforestation

  2. Replant billions of trees to replace the ones lost over past generations
• Young growing plants actually remove and 'lock-away' more CO2 from the atmosphere than mature ones
• Harvesting a tree for its timber

  Is not necessarily a bad thing, provided a new one is planted in its place
• Reducing carbon dioxide emissions

  1. New ways of producing food - Growing vertically

  2. Switching to green/clean energy
• Vertical farming


  • Sustainably growing fresh vegetables in repurposed steel mill warehouses
  • Uses 95% less water than field farming
  • Reduces food waste
• Almost 30% of the food production inside the U.S. is wasted
• Technology could change the food waste problem
• Big changes are happening with food choices, driven by health, animal welfare, and environmental concerns
• Green/clean energy


  • Thermal solar power plant in the Nevada desert
  • 10,000 mirrors track the sun and focus rays onto a molten salt storage tank to generate electricity
• Reducing carbon dioxide emissions from fossil fuels

  1. More fuel-efficient cars

  2. Alternative fuels with less or no CO2 emissions

  3. Increased use of public transport
• In Australia, coal is burned to generate nearly all electricity, releasing significant levels of greenhouse gases
• Reducing greenhouse gas emissions from electricity generation

  1. Use the most energy efficient appliances

  2. Use renewable energy sources like hydroelectric, solar, wind, and tidal
• There are environmental concerns with some renewable energy sources, like the visual impact of wind farms and power transmission lines
• Nuclear power


  Can supply large base-load capacity without emitting greenhouse gases, but has risks of nuclear accidents and radioactive waste
• Some advanced countries like France produce significantly less CO2 per capita than Australia, in part because they use nuclear energy for much of their power needs
• For an electric car to be a zero emissions vehicle

  The electricity used to charge the car must come from renewable or nuclear sources