Greenhouse Gases & Global Warming

GREENHOUSE GASES Why Is Our Climate Changing GREENHOUSE GASES Why Is Our Climate Changing? The Earth's climate changes through natural processes, but also as a result of our society's greenhouse gas (GHG) emissions. GHGs, such as carbon dioxide and methane, have an insulating effect on our atmosphere.

Anthropogenic Greenhouse Gases Anthropogenic: resulting from human activity ½ of carbon dioxide released due to human influence ends up in the atmosphere.

Greenhouse Gases (GHGs) Atmospheric composition: Nitrogen: 78.09% Oxygen: 20.9% Argon: 0.93% Carbon dioxide: 0.035% All other gases: 0.05% Common GHGs: water vapour (H2O) carbon dioxide (CO2) methane (CH4) nitrous oxide (N2O) ozone (O3) halocarbons (CFCs, HFCs, etc.)

Carbon Dioxide in the Atmosphere Largely created by burning fossil fuels (coal, oil, natural gas) Fossil fuels are used in transportation, heating, electricity, industry.

Carbon Dioxide Removal Much of this carbon dioxide is captured by forests during photosynthesis: 6CO2 + 6H2O  C6H12O6+ 6O2 Carbon dioxide + water  glucose + oxygen Trees therefore act as CARBON SINKs, as they remove carbon from the atmosphere. 10% of carbon dioxide emissions are due to deforestation – stored CO2 is released and carbon sink is removed.

Methane (CH4) Methane is 25 times more effective as a greenhouse gas than CO2. This means that although methane is less abundant than CO2, its presence has a major impact on heat absorption in the atmosphere.

Methane (CH4) Agricultural Activities- rice farming, cattle ranching Bacterial decay in landfills and sewage treatment plants Coal mining Natural Gas Extraction “Slash and Burn” clearcutting of forests.

Nitrous Oxide (N2O) livestock feed and waste Nitrogen fertilizers Industrial processes

Chlorofluorocarbons (CFC’s) No natural sources Refrigerants and Air conditioners Industrial processes

The Greenhouse Effect GHGs in our atmosphere keep the sun's heat in and help make our planet livable. Without this natural insulation, the average temperature on Earth would be -18˚C, rather than 15˚C! What’s the Problem?

Climate Explained (sort of…) © Environment Canada

How does it affect us? Average temperatures in Ontario could rise by as much as 8°C. 

How does it affect us? Less snow but more freezing rain a threat to transmission lines, road and airline safety.

How does it affect us? More extremely hot days (above 35°C) increasing the risk of heat stress-related illness among the old, the young and those with chronic lung diseases such as asthma.

How does it affect us? Changes in wildlife habitats and crop yields, requiring more irrigation and increasing the risk of warm climate diseases such as Lyme and West Nile diseases and malaria.

How does it affect us? A drop in Great Lakes water levels by as much as one metre by 2050, affecting shipping, fisheries, water quality, water intake systems in our cities and shoreline property.

What Can We Expect? © CIDA © NFB © NFB © IISD

What Can We Do? © Environment Canada

Consolidate List 6 major greenhouse gases. Describe 2 natural and 2 anthropogenic sources of GHGs. Using a labeled diagram, explain the greenhouse effect. Describe in detail 2 ways in which an increase in GHGs will affect life on Earth. Provide 2 examples of changes you can make in your everyday life that will decrease GHG emissions.

Natural vs. Anthropogenic Natural Sources: Volcanic eruptions Water vapour Forest fires Decomposition of carbonate rocks Methane emissions from swamps and marshes. Anthropogenic Sources: Energy from burning of fossil fuels (transportation, heating & cooling, manufacturing) Deforestation Methane from agriculture, mining, landfills, etc.