env- climate change

• Mount Everest


  • Highest elevation on Earth
• Conditions at summit of Mount Everest

  • Wind blows ~250km/h due to jet stream
  • Only 1/3 the concentration of oxygen per unit air compared to sea level
  • Temperature below freezing; can go to -75⁰C
• Troposphere

  
  

  11km thick

  • rain occurs here
  • Temperature gets colder the higher you go
  • Lots of mixing of the air
• Stratosphere

  • 11-50km above the surface
  • Air is thin, does not move around much
  • Contains ozone (O3 ) which absorbs some radiation, causing the stratosphere to warm
• Sources of Nitrous Oxide (NOx)

  • Natural
  • Anthropogenic (major sources)
• Energy balance


  • Energy passing through the atmosphere drives ecological systems
  • The amount of energy arriving at the Earth from solar radiation is balanced by a similar amount of radiation leaving the Earth's atmosphere
• Climate change

  • Climate = long-term atmospheric conditions
  • Weather = conditions at localized sites over hours or days
  • Global climate change = trends and variations in Earth's climate
  • Global warming = an increase in Earth's average temperature
• Positive feedback cycle

  Warming increases evaporation = water vapour absorbs energy = warming and more evaporation (positive radiative forcing)
• Negative feedback cycle

  Warming leads to evaporation = water vapour creates clouds = reflects incoming energy (negative radiative forcing)
• Radiative forcing


  • Amount of change in energy balance caused by one or more factors
  • Positive forcing warms & negative cools
  • Earth experiencing positive forcing overall (2.29 watts/m2)
• Atmospheric pressure


  • Measures the weight per unit area produced by a column of air
  • Decreases with altitude
• Relative Humidity


  Amount of water vapour a given volume of air holds relative to the maximum amount it could hold for a given temperature
• Temperature

  • Varies with location and time
  • Temperature differences affect air circulation
• Jet stream

  -The Earth rotates from west to east

  -At high altitudes, combination of Earth's rotation and pressure cells creates fast-moving currents of air
• Oceans

  • Cover 75% of Earth's surface
  • Major source of water to hydrologic cycle
  • Major source of heat to atmosphere
  • Stores and conveys heat
  • Linked to major weather events
  • Thermohaline circulation
  • El Niño and La Niña (oscillations)
• Greenhouse effect

  • Is a naturally-occurring process that moderates the Earth's surface temperature
  • Creates a range of surface temperatures suitable to living creatures
• Greenhouse gases

  • Certain gases in the atmosphere
  • Allow short-wave radiation to pass through unhindered
  • Absorb & re-radiate longer-wave radiation
  • These gases cause the "greenhouse effect" & are popularly called "greenhouse gases" (GHGs)
  • Are known in climate science as "forcing agents"
• Known atmospheric forcing agents (and their concentrations)

  • Water vapour: H2O (about 1% of total atmospheric volume but varies
  • Carbon dioxide: CO2 (423 ppm)
  • Methane: CH4 (1,800 ppb)
  • Nitrous oxide: N2O (334 ppb)
  • CFCs: (4 ppb)
• Anthropogenic climate change


  We are increasing the levels of greenhouse gases in the atmosphere, thus increasing the greenhouse effect
• Carbon dioxide has long been known to have a forcing effect on climate and atmospheric concentrations have increased rapidly in past 200 years, with no known source except human activity
• Key forces/processes that affect climate

  • Incoming solar radiation
  • Circulation of air
  • Circulation of ocean water
  • Long-term oscillations (e.g. ENSO)
  • Presence of greenhouse gases (forcing agents)
• Additional Climate Influences

  • Albedo
  • Volcanic Activity
  • Sunspots
• Impacts on human populations

  • Economy: costs expected to outweigh benefits, widen gap between rich and poor, cost roughly 5-20% of world GDP
  • Agriculture: Overall global production may increase, some regions will see significant declines, increased risk of droughts/floods other extreme weather events
  • Forestry: Increased fire activity, disease outbreaks, invasive species
• Impacts on human populations: Health

  • Death and injury related to extreme weather events
  • Malnutrition
  • Respiratory health impacts – air pollution; aeroallergens
  • Infectious disease: Foodborne, water-borne, vector-borne
  • Mental health
  • Migration
• Vulnerability

  Vulnerability (V) = potential for harm or loss

  V = f (E,S,A)

  Where: E = physical changes to which a population is exposed

  S = sensitivity of that population to climatic variability and change

  A = adaptive capacity of that population
• Intergovernmental Panel on Climate Change is established by the UN to provide an objective, scientific view of climate change + its political and economic impacts. They do not conduct original research but rely on thousands of researchers from around the world, volunteering their time.
• Who is most vocal in opposing action to reduce GHGs?

  • Fossil fuel industry and industries that rely on cheap fossil fuels (e.g. auto sector)
  • Investors, banks, etc. that profit off the fossil fuel industry
  • Governments that receive large revenues from fossil fuels
  • Politicians beholden to fossil fuel industry
• Responding to climate change

  • Mitigation – reduce GHG emissions
  • Intervention – large scale (technological) modifications
  • Adaptation – adjust and reduce vulnerability
• Mitigation: Policy Options

  • Carbon pricing (aka carbon 'tax')
  • Cap and trade/ tradeable credits
  • Remove subsidies to fossil fuels
  • Subsidize renewable energy
  • Invest in renewable energy/divest from fossil fuels
  • Invest in nuclear
  • Invest in energy efficiency
  • Store CO2 (ocean, underground) - sequestration
  • Invest in forests – terrestrial sequestration
  • Limit population growth
  • Discourage consumption
  • Promote more sustainable urban design
• Mitigation: International Commitments


  • United Nations Framework Convention on Climate Change (UNFCCC)
  • Kyoto Protocol (1997; COP-3)
  • Paris agreement (2015; COP-21)
• Canada has been very successful at missing our climate targets, with 4 PMs committing to 9 targets since the 1980s, all of which were missed by serious margins.
• Adaptation: some strategies

  • Construction: green roofs, higher foundations, seawalls, higher ground
  • Agriculture: improve irrigation, drought resistant crops, erosion prevention
  • Reforestation, forestation
  • Share resources: reduce poverty, improve information/education, institutional capacity, funding for most affected countries
  • Managed retreat, migration
• Climate change adaptation is a major issue in urban planning and climate change adaptation services are becoming a flourishing business.
• What can we do?

  • Green your commute
  • Consume less, waste less, enjoy life more
  • Eat for a climate-stable planet
  • Use energy wisely — and save money
  • Invest in renewables and divest from fossil fuels
  • Vote for climate action