Week 16-17 Climate Change

• Climate


  The average daily weather for an extended period of time at a certain location
• Weather


  Reflects short term conditions of atmosphere, can change from minute-to-minute, hour-to-hour, day-to-day and season-to-season
• Climate is the average of weather over time and space
• Climate consists of many kinds of weather events, their periodicities, intensities, and nature of dynamism
• Climate change


  Refers to major changes in temperature, rainfall, snow, or wind patterns lasting for decades or longer
• Climate change includes changes in ocean current, melting of ice, and loss of biodiversity
• Climate change refers to any change in the climate over time, whether due to natural variability or as a result of human activity
• Causes of climate change

  • Natural events
  • Human (anthropogenic) activities
• Greenhouse gases


  • Carbon Dioxide (CO2)
  • Methane (CH4)
  • Nitrous Oxides
  • CFCs, HFCs, PFCs, SF6

  
• Natural sources of greenhouse gases

  • Soils (biological processes)
  • Ocean
  • Wetlands
  • Termites
  • Tropical soils (wet forests)
• Human-induced sources of greenhouse gases

  • Burning of fossil fuels for power/energy generation, manufacturing, industrial processes, fuel for transportation
  • Land-use changes, deforestation
  • Flooded rice agriculture
  • Livestock production
  • Waste management system
  • Nitrogen-based fertilizers and chemicals
  • Acid production processes, other industrial processes
  • Coolants, sealants, insulations
• Since the industrial revolution began in 1750 human activities have contributed substantially to climate change by adding CO2 and other heat trapping gases to the atmosphere
• Greenhouse gas concentrations are increasing
• Factors that cause Earth's climate to change many times

  • Variations in the sun's energy reaching earth
  • Changes in the reflectivity of earth's atmosphere and surface
  • Changes in the greenhouse effect, which affects the amount of heat retained by earth's atmosphere

  
• Greenhouse effect


  Refers to rise in global temperature due to the process by which the gases in the atmosphere trap the heat coming from the sun that is re-radiated by the earth's surface

  
• Without the greenhouse effect, the Earth's average surface temperature would be some 30°C colder or approximately -15°C and possibly not warm enough to sustain life
• Humans are affecting atmospheric greenhouse gas concentrations by introducing new sources or by interfering with natural processes that destroy or remove GHGs

  
• Earth's temperature depends on the balance between energy entering and leaving the planet's system
• When incoming energy from the sun is absorbed by the Earth system, earth warms
• When the sun's energy is reflected back into space, earth avoids warming

  
• When absorbed energy is released back into space, earth cools

  
• Many factors both natural and human can cause changes in earth's energy balance
• It is very likely that most of the climate change in the current era is the result of human activities
• Humans are increasingly influencing the climate and the earth's temperature by burning fossil fuels, cutting down rainforests and farming livestock
• Human activities have increased concentrations of greenhouse gases in the atmosphere

  
• These gases trap heat and cause the Earth to warm
• Since CO2 is already in the atmosphere naturally, emissions from human activity are significant because human activities have significantly disturbed the natural carbon cycle by extracting long-buried fossil fuels and burning them for energy thus releasing CO2 to the atmosphere
• By burning fossil fuels due to industrialization and to sustain our modern lifestyle, the level of GHGs increase rapidly. The higher the concentration of greenhouse gases in the atmosphere, the stronger the greenhouse effect making it into enhanced greenhouse effect
• Consequences of climate change

  • Expansion of greenhouse effect
  • Changing precipitation patterns
  • Increase in sea level which results in flooding and erosion of coastal and low lying areas
  • Extreme weather
  • Risk to human health
  • Risk for wildlife extinction
  • Imposes heavy cost on society and economy
• The two major causes of global sea-level rise are thermal expansion caused by warming of the oceans and the loss of land-based ice, such as glaciers and ice sheets, due to increased melting
• Higher temperatures caused by global warming have led to greater-than-average summer melting as well as diminished snowfall due to later winters and earlier springs
• Scientists also believe meltwater from above and seawater from below is seeping beneath Greenland's and West Antarctica's ice sheets, causing them to move more quickly into the sea
• Climate change impacts


  • Coastal/Marine Ecosystem
  • Agriculture
  • Human Health
  • Water Resources
  • Forest/Biodiversity
  • Industry and Energy
• Relationship between mitigation and adaptation

  • Mitigation (locate/invent alternative fuels, increase efficiency, sequester carbon)
  • Adaptation (move inland, construct dikes and levees, adapt to shifting agricultural zones)
• Climate change is a core development issue
• Reduction of carbon emissions

  • Burn less fossil fuel
  • Plant trees for shade and CO2 uptake
  • Insulate your house
  • Replace old appliances
  • Use compact fluorescence light bulbs
  • Use renewable energy
• Climate change solutions will be achieved through low-carbon and climate-resilient development