1Case Study: Heating Up the Arctic
What are the impacts?
• Temperature is increasing significantly.
• Sea ice thinner and less extensive
• Opens up Northwest Passage to shipping
• Impact on wildlife (polar bears, caribou)
• Warming in the Arctic can affect whole world
o Release of CH4 and CO2 from permafrost
o Increasing meltwater
2How Have the Earth’s Temperature and Cimate Changed in the Past?
• Past global temperatures
- Prolonged periods of global cooling and warming
• Recent trends in global temperatures
- Stable(ish) over past 12 000 years
- Regional climate changes
- In past 1000 years, temperatures dropped
slightly, then started to rise 200 years ago
with the Industrial Revolution
3What Are the Major Greenhouse Gases?
• Carbon dioxide
• Methane
• Nitrous oxide
• Chlorofluorocarbons
• Hydrochlorofluorocarbons
• Hydrofluorocarbons
• Halons
• Carbon tetrachloride
4Activities Contributing to Increased Greenhouse Gases
• Increased use of fossil fuels
• Deforestation and clearing
• Raising large number of cattle
- unnatural feed (corn, etc.) leads to inc. methane from digestion
• Planting rice
• Using inorganic fertilizers
5Factors Affecting the Earth’s Temperature:
Can the Oceans Store More CO2 and Heat?
• Oceans remove ~29% of excess CO2 from atmosphere
• Absorb heat and transfer to deep ocean for storage
• We don’t fully understand the impacts of ocean currents.
• How quickly can they transfer heat?
• How long will that heat be stored?
• Ocean acidification
• Absorption of CO2 forms carbonic acid – pH dropping
up to 0.5 units
• Many effects on marine life – dissolve many shelled
organisms
• long will that heat be stored?
6Factors Affecting the Earth’s Temperature
Cloud Cover and Outdoor Air Pollution
Increased Photosynthesis
7How Might a Warmer Troposphere Affect Canada?
• Longer growing season
• Warmer in both summer and winter
• Higher seas in British Columbia and Eastern Canada
• More droughts in Prairies
• Arctic and Subarctic subject to widespread changes
• Great Lakes—more heat waves and lower lake levels
8Dealing With the Threat of Global Warming: What Are Our Options?
Wait and see
• Do more research before we act.
Act now
• Follow the precautionary principles.
• We pay to insure our homes and lives against far less certain events.
Act now with no regrets
• Strategies have benefit regardless of the extent of global warming.
9Solutions to Global Warming: Prevention (list some)
Cut fossil fuel use
(especially coal).
Shift from coal to natural
gas.
Improve energy efficiency.
Shift to renewable energy
resources.
Transfer energy efficiency
and renewable energy
technologies to developing
countries.
Reduce deforestation.
Use more sustainable
agriculture.
Limit urban sprawl.
Reduce poverty.
Slow population growth.
10Solutions to Global Warming: Cleanup (list some)
Remove CO2 from
smokestack and vehicle
emissions.
Store (sequester) CO2 by
planting trees.
Sequester CO2 deep
underground.
Sequester CO2 in soil by
using no-till cultivation
and taking crop land out
of production.
Sequester CO2 in the deep ocean.
Repair leaky natural gas pipelines
and facilities.
Use feeds that reduce CH4
emissions by belching cows.
11Carbon and Energy Taxes
Advantages and disadvantages
Advantages
• Simple to administer
• Clear price on carbon
• Covers all emitters
• Predictable revenues
Disadvantages
• Tax laws can get complex.
• Vulnerable to loopholes
• Doesn’t guarantee lower emissions
• Politically unpopular
12Cap-and-Trade Policies
Advantages and disadvantages
Advantages
• Clear legal limit on emissions
• Rewards cuts in emissions
• Record of success
• Low expense for consumers
Disadvantages
• Revenues not predictable
• Vulnerable to cheating
• Rich polluters can keep polluting
• Puts variable price on carbon
13Ozone Depletion in the Stratosphere: Causes
• Numerous persistent chemicals
• Former Uses of CFCs