Ch. 11.2 Human Activity and Climate Change Note Outline
Climate change à ______.
• ______refers to a world-wide increase in average temperature, but is only one aspect of climate change.
• Several ______have occurred in the past million years.
• Both the causes and effects of ______are unknown and controversial.
Greenhouse Effect
§ As greenhouse ______, they absorb more heat reflected back from the earth, warming the atmosphere.
§ ______increase some greenhouse gases.
§ Greenhouse gases include water vapour, ______, N2O, CH4, and CFC’s.
Carbon Dioxide
§ CO2 levels have ______greatly in the past ______.
§ Since the Industrial Revolution, humans have greatly increased their overall use of ______, which release CO2 when burned.
§ Deforestation has changed ______, such as forests, into ______.
§ Many people are attempting to reduce CO2 emissions by using ______sources or by ______.
§ Carbon offsets, such as ______, can be purchased to offset CO2 emissions.
Methane
§ Methane is very efficient at trapping ______.
§ 25X more efficient than ______.
§ ______is produced by ______in oxygen-free environments, animals digesting plant matter, rice paddies (and other natural wetlands), and the burning of fossil fuels.
Nitrous Oxide and Ozone
• ______N2O, is the third largest contributor to the greenhouse effect.
§ Even though there are only small amounts, it has ______potential than CO2.
§ ______comes from bacteria, fertilizers, and improper disposal of human and animal waste.
§ ______is an important UV radiation blocker in the stratosphere. At lower altitudes, however, it is a very powerful ______.
§ This ozone comes from ______reacting with pollution from the burning of fossil fuels, and is released from photocopiers and certain air conditioners.
CFC’s (Chlorofluorocarbons)
§ ______, used as refrigerants, are strong greenhouse gases.
§ ______(CFC’s) are the best-known halocarbons.
§ Halocarbons à ______.
§ ______and some ______use CFC’s.
Albedo and Climate
§ The ______at Earth’s surface affects the amount of solar radiation that a region receives.
§ Changes in a region’s albedo - for example, snow cover melting earlier in the season than it did previously - Could result in ______.
§ ______have a low albedo. ______increases albedo.
§ Forests also emit large amounts of water vapour, which reflects ______
______back into space.
§ ______effects on climate change are unknown.
Role of Science
Computer models of Earth’s climate.
§ Most show that a ______is necessary to stop the apparent global warming trend.
§ ______(GCM’s) use data from multiple locations over long periods of time.
o Can look at ______in greenhouse gases, albedo, ocean currents, winds and surface temperatures.
o Can forecast weather, analyse climate and make ______.
o Use past information to predict ______.
Global Impacts of Climate Change
Impact of Climate Change on Canada
§ Temperatures are ______(average increase = 0.5ºC to 1.5ºC).
§ ______are losing permafrost and ice cover on oceans.
§ Growing seasons are ______and ______precipitation is falling in the spring (possible drought in later summer).
§ Rise in ______.
§ Glaciers are ______(less drinking water).
§ Fisheries could be very ______affected.
§ Pollution à ______.
Strategies for Addressing Climate Change
§ Although ______is a controversial issue, our actions now are important.
§ Improving our ______approach will help, no matter how dramatic climate change actually is.
§ Not acting could result in ______.
§ The United Nations suggests the precautionary principle, “______.”
§ Relatively ______changes could have large ______impact on the climate in Canada.
§ Reduce vehicle ______emissions.
§ Reduce industrial ______gas emissions.
§ Increase use of ______products.
§ Improve indoor ______.