1. Earth Science Chapter 11.2
Climate Change

2. Climate Change
Climate change = the change in long-term weather patterns in certain regions.
‘Global warming’
one aspect of climate change
world-wide increase in average temperature
Causes & effects of global warming are unknown and controversial.

3. Greenhouse Effect
As greenhouse gases increase, they absorb more heat reflected back from the earth, warming the atmosphere.
Human activities increase some greenhouse gases.
Greenhouse gases include water vapour, CO2, N2O, CH4, & CFC’s.

4. Carbon Dioxide
CO2 levels have increased greatly in the past 200 years.
Since the Industrial Revolution, we have greatly increased our use of fossil fuels, which release CO2 when burned.
Deforestation has changed carbon sinks, such as forests, into carbon sources.

5. Methane Methane traps thermal energy. 25X more efficient than CO2
produced by bacteria breaking down wastes in oxygen- free environments, animals digesting plant matter, rice paddies (and other natural wetlands), & the burning of fossil fuels.

6. Nitrous Oxide and Ozone
Nitrous oxide (N2O) = the 3rd largest contributor to the greenhouse effect.
there are only small amounts but 300X more global warming potential than CO2.
comes from bacteria, fertilizers, & improper disposal of human and animal waste.
Ozone
At upper altitudes, an important UV radiation blocker
But, at lower altitudes, a very powerful greenhouse gas
comes from solar radiation reacting with pollution (from the burning of fossil fuels, photocopiers and certain air conditioner use)

7. CFC’s (Chlorofluorocarbons)
Halocarbons, used as refrigerants, are strong greenhouse gases.
Best known = Chlorofluorocarbons (CFC’s)
Lead to ozone layer depletion.
Cooling Units Use CFC’s Some Aerosols Use CFC’s

8. Albedo (reflectivity) and Climate
Changes could result in climate change
Examples:
Polar ice caps melting
snow cover melting earlier than it did previously
deforestation as forests emit large amounts of water vapour, which reflects solar radiation back into space.

9. Global Impacts of Climate Change

10. Impact of Climate Change on
Average temperature increase = 0.5ºC to 1.5ºC
Arctic regions are losing permafrost & Arctic Ocean ice cover
Longer growing seasons
Heavier spring rains
Severe droughts
Rise in sea levels
Glaciers are melting (less drinking water)
Fisheries could be very negatively affected
Pollution  health issues

11. Temperature Change Predictions for Canada

12. Climate Change in B.C.

13. Action Plan
Improving our environmental approach will help, no matter how dramatic climate change actually is.
Not acting could result in huge problems.
The United Nations suggests “better safe than sorry.”
Relatively small changes could have large positive impact:
Reduce vehicle greenhouse gas emissions.
Reduce industrial greenhouse gas emissions.
Increase use of energy-efficient products.
Improve indoor air quality.
Take the Section 11.2 Quiz