Chapter 8 Dynamics of Climate Change

Chapter 8: Dynamics of Climate
Economy and Environment
8.1 Energy Transfer in the Climate
• Open system: The human body
receives food, water, and
nutrients and releases waste
products and heat
• Closed system: The atmosphere
allows energy to enter but
restricts other materials from
entering or exiting.
Feedback Loops in the Earth’s Closed
• Earth being a closed system, it must circulate
all of its matter within its boundary.
– The interactions between the earth’s materials
create a feedback loop
(i.e. A impacts B which impacts C impacting A again)
Positive Feedback Loops
• A positive feedback loop is a feedback system
where each of the items on the loops will
increases its effects every cycle
in albedo
Increase in
Increase in
the rate of
melting ice
Negative Feedback Loops
• A negative feedback loop is a feedback system where
each cycle brings the system closer towards
– Each cycle will decrease the effects of the items in the loop
Decrease in
Increase in
time studying
Decrease in
Increased test
sleep time
Energy and Heat on Earth
• The earth has 3 main types of energy transfer that help to heat the
Radiation: Electromagnetic radiation in the form of waves emitted by a heat
- Radiation can be either absorbed, reflected or refracted.
Conduction: The transfer of energy between two objects
Convection: The transfer of energy due to moving objects (e.g. liquid, gas [not
Conduction, Convection, Radiation
Conduction, Convection, and Radiation
in the Earth’s Atmosphere
• On Board (Figure 8.4)
Earth’s Energy Budget
• Energy is either:
 absorbed by the clouds,
atmosphere or land (70%)
 reflected by the clouds,
atmosphere, or land (30%)
• The measure of the clouds
and land structures (ice,
snow) ability to reflect
solar radiation is known as
its albedo.
Values for
Global Warming and Albedo
• Dark coloured earth structures mainly absorb
radiation = low albedo
• Light coloured structures reflect radiation = high
– The more ice that melts the greater amount of radiation
will be emitted resulting in increased temperatures.
– However, increased temperatures cause more evaporation,
which increases cloud cover, which increases albedo
Energy Transfer in the Oceans
• Ocean circulation occurs due to the thermohaline
circulation (affected by temperature and salt)
– The current is referred to as “the great ocean conveyer belt”
– Water at the poles is colder/saltier = more dense = sinking
– As cold water sinks, warm water rises to the surface creating a
warm surface flow.
– In this manner energy is transferred throughout the oceans
Global Warming and Thermohaline
• Global warming causes an increase the overall
– Leads to melted ice at the poles = less saline water =
less dense water = does not sink
– Leads to increased evaporation at the tropics = more
saline water = more dense = sinking
• These effects may reverse the thermohaline
circulation or stop it entirely resulting in uneven
distribution of energy in the ocean
In Class Work Time
8.2. Greenhouse Gases and Human
• Carbon dioxide in the
Earth’s atmosphere is
currently approximately
370 ppm
• What does this mean?
• It means that of every one
million parts in the
atmosphere, 370 are
carbon dioxide
Atmosphere Composition
• 90% of the atmosphere is made up of N2
(nitrogen) and O2 (oxygen)
– These are not greenhouse gases
• Greenhouse gases are water vapour, carbon
dioxide, methane, nitrous oxide, ozone.
• Source: Processes that add greenhouse gases
• Sinks: Processes that remove greenhouse gases
Sources and Sinks
• The source of carbon dioxide in the atmosphere
is primarily due to animal respiration.
– Human’s burn fossils which also contributes to
carbon dioxide
• Plants/phytoplankton remove carbon dioxide
making them carbon sinks
• Common to bogs and swamps (e.g. wetlands)
• Cattle contribute a large portion of the
methane production through gas release.
• Waste products (manure) also contributes to
methane production.
Nitrogen Oxide
• From damp tropical soils and the oceans
• Anthropogenic sources: Chemical fertilizers,
manure, vehicle exhausts
Ozone (O3)
• Occurs naturally in the atmosphere
• Blocks harmful UV radiation
Ozone Depletion
• Ozone has been depleting for the last 30 years
• Depleted ozone allows for harmful UV radiation to
pass through the atmosphere
– Increases cancers of the skin
• Caused by chlorine containing gases
Ground Level Ozone
• Ozone can also be found at ground level due
in the form of smog
– Smog is composed of sunlight and vehicle exhaust
– Smog causes damage to the lungs and heart
• Are carbons bound by halogens
• Most common halocarbon found in the
atmosphere is chlorofluorocarbons (CFC’s)
– Are gases that have depleted the ozone over
– Found in solvents, cleaners, old refrigerators
Global Warming Potential (GWP)
Reducing Greenhouse Gases
• Conserve electricity:
– Energy efficient lights, new appliances, conserve.
• Improve home heating
– Update furnace, retrofit (windows and seals)
• Reduce, re-use, and recycle
– Be frugal in using products, reuse products, and
dispose in the correct bins.
8.3 Jigsaw Activity
• In this activity groups of four will be made
• Each student within the group will be given a number
(i.e. 1, 2, 3, 4)
• Each student must read these pages and summarize the
key ideas to the group along with any figures
– Student 1: Read pages 333-334 ( up to “The Global Carbon Budget”)
– Student 2: Read page 334 (“The Global Carbon Budget”) and page 335
(The carbon cycle)
– Student 3: Read page 336 (“How human act…) and page 337
– Student 4: Read pages 338-339.

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