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Summary IB Geography Unit 2 Climate Change (full notes) CA$5.02   Add to cart

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Summary IB Geography Unit 2 Climate Change (full notes)

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This document includes all of the course content and case studies needed for the second core unit Climate change for IB Geography new syllabus whose first examination is in 2019 (mine). By using these notes I managed to get a 7 (84%) on my class test.

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  • March 31, 2019
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IB Geography notes

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Geography command terms


Unit 2 Climate change

, Geography command terms

Questions which begin with a command term in ​green (AO1)​ are descriptive and ​worth few marks in exams​: more time
should always be devoted to questions which begin with command terms in b​lue (AO2)​ or ​red (A03)​ which are more
analytical and are ​usually worth more marks​ on exams papers. Assessment Objectives written in black (AO4) refer to
drawing skills (annotated maps and diagrams, graphs)


● Analyze ​(AO2): Break down in order to bring out the essential elements or structure
● Annotate ​(AO4): Add brief notes to a diagram or graph
● Classify ​(AO2): Arrange or order by class or category
● Compare ​(AO3): Give an account of the similarities between two (or more) items or situations, referring to both (all)
of them throughout
● Compare and contrast​ (AO3): Give an account of similarities and differences between two (or more) items or
situations, referring to both (all) of them throughout
● Construct ​(AO4): Display information in a diagrammatic or logical form
● Contrast ​(AO3): Give an account of the differences between two (or more) items or situations, referring to both (all)
of them throughout
● Define ​(AO1): Give the precise meaning of a word, phrase, concept or physical quantity
● Describe ​(AO1): Give a detailed account
● Determine ​(AO1): Obtain the only possible answer
● Discuss ​(AO3): Offer a considered and balanced review that includes a range of arguments, factors or hypotheses.
Opinions or conclusions should be presented clearly and supported by appropriate evidence
● Distinguish ​(AO2): Make clear the differences between two or more concepts or items
● Draw ​(AO4): Represent by means of a labelled, accurate diagram or graph, using a pencil. A ruler (straight edge)
should be used for straight lines. Diagrams should be drawn to scale. Graphs should have points correctly plotted (if
appropriate) and joined in a straight line or smooth curve
● Estimate ​(AO1): Obtain an approximate value
● Evaluate ​(AO3): Make an appraisal by weighing up the strengths and limitations
● Examine ​(AO3): Consider an argument or concept in a way that uncovers the assumptions and interrelationships of the
issue
● Explain ​(AO2): Give a detailed account including reasons or causes
● Identify ​(AO1): Provide an answer from a number of possibilities
● Justify ​(AO3): Give valid reasons or evidence to support an answer or conclusion
● Label ​(AO4): Add labels to a diagram
● Outline ​(AO1): Give a brief account or summary
● State ​(AO1): Give a specific name, value or other brief answer without explanation or calculation
● Suggest ​(AO2): Propose a solution, hypothesis or other possible answer
● To what extent ​ (AO3): Consider the merits or otherwise of an argument or concept. Opinions and conclusions should
be presented clearly and supported with empirical evidence and sound argument

,Climate change
Part 1: Causes of climate change
- LT: To explain the atmospheric system, including the natural greenhouse effect and energy balance (incoming
shortwave radiation and outgoing longwave radiation)
- LT: To explain the changes in the global energy balance, and the role of feedback loops
- LT: To analyse the cause of the enhanced greenhouse effect
Part 2: Consequences of climate change
- LT: To examine the effects of climate change in terms of the water stored in ice and oceans, and changing sea
levels
- LT: To examine the effects of climate change in terms of the carbon dioxide stored in ice oceans and the
biosphere
- LT: To examine the effects of climate change in terms of the incidence of severity of extreme weather events,
including drought
- LT: To examine the effects of climate change in terms of the changes to agriculture, including crop yields, limits
of cultivation and soil erosion
- LT: To examine the effects of climate change in terms of spatial changes in biomes, habitats and animal
migration patterns
- LT: To synthesise information on the impacts of climate change and how they will affect people in different
regions around the world
Part 3: Responses to climate change
- LT: To examine government-led adaptation and mitigation strategies for global climate change
- LT: To explain the disparities in exposure to climate change risk and vulnerability
- LT: To examine a civil society and corporate strategy to address global climate change

, Climate change


Part 1: Causes of global climate change


LT: To explain the atmospheric system, including the natural greenhouse effect and energy balance (incoming
shortwave radiation and outgoing longwave radiation)


- The atmosphere is like a thin film around the earth
- Incoming solar radiation is known as insolation
- The atmosphere is an open energy system




The atmosphere energy budget
The earth's atmosphere constantly receives solar energy, and until recently the atmosphere was not getting hotter.
There was a balance between the inputs (insolation) and the outputs (outgoing radiation)


Under ‘natural conditions’ the balance is achieved in 3 main ways:
● Radiation​: ​The emission of EM waves such as X-rays, shortwaves and long waves (the sun is a hot body)
● Convection​: ​The transfer of heat by the movement of a gas or a liquid
● Conduction​: ​Transfer of heat by contact




LT: To explain the changes in the global energy balance, and the role of feedback loops

,The climate is not static, it is dynamic​. ​The natural greenhouse effect would always be constant but it is not
Natural causes include changes in levels of solar activity, volcanic activity and variations in the earth's orbit

Radiative forcing​: ​Any change in the balance between insolation and energy being radiated back into space
Positive forcing warms the earth as there is more insolation received than lost
Negative forcing cools the atmosphere as less insolation is being received than the amount lost

Forcing agents​: ​Pressure and processes that cause radiative forcing
Some are external (not originating from planet earth) e.g change in the earth's orbit
Others are internal (originating from planet earth) e.g volcanic eruptions

Feedback loops​:
➢ Negative and positive feedback systems keep a system in dynamic equilibrium
➢ Negative feedback tend to dampen or buffer changes; this tends to hold a system to some equilibrium state
making it more stable.
➢ Positive feedback enhance or amplify changes; this tends to move a system away from its equilibrium state
and make it more unstable and will not go back to its original state.
Sunlight, also known as solar radiation is beneficial to almost all living things on Earth. Solar radiation is all the light
and energy that is emitted from the sun. Although it is important, too much or too little sunlight can be harmful.


One of the main causes to the world's temperature change is a ​change in the input of energy from the Sun.

Global Dimming
● This is a decrease in the amount of of solar radiation reaching the Earth’s surface.
● Since 1950, there has been a 22% average drop in the sun’s energy reaching earth.

Cause:
● The burning of fossil fuels has been identified as one of the major causes of global dimming. As these particles
fill the air, they absorb solar energy from the atmosphere, and reflects radiation back into space before it can
reach the planet’ surface.
● Volcanic activity is another cause as ash clouds can prevent insulation from reaching the earth

Effects:​ ​The pollutants that cause global dimming also leads to ​acid rain​, ​smog​ and respiratory diseases in humans.
This has also lead to water in the northern hemisphere to become colder Thus, affecting evaporation and the amount
of rainfall per year resulting in droughts and famine. Global dimming is also known to cause heat waves, and wildfires


Solar Evolution
● 4.5billion years ago the sun was about 8% smaller and about 3% less radiant than now.
● The sun is getting brighter and hotter, therefore there is more radiation hitting the earth.

,Cause:​ ​The size of the sun has inevitably grown since the star’s birth 4.5 billion years ago. The sun’s core contains
hydrogen, which it has been burning up for years. ​As the hydrogen burns, helium ashes are left behind which are
much denser than, thus raising the sun’s pressure, brightness, and size.

Effects:​ ​The sun’s growth has made for a lot more heat radiation to be directed towards Earth. This has resulted in
several harmful temperature changes. One example of this is the rise in sea level due to melting ice.



Changes In the Earth’s Orbit
● The earth’s orbit deviates, causing the amount of insolation the earth receives to change.
● Earth's orbit change causing more insolation or less depending on how it changes.
● The orbital cycle of the earth usually makes the earth slowly get closer to the sun, leading to more solar
radiation hitting earth, which then leads to an increase in the earth's temperature.

Cause: the gravitational pull of the sun that causes the earth to slowly move closer to it.


Sunspot Cycles & Solar Cycles
● Solar maximum​: When the sun's magnetic fields are strongest leading to more sunspots and more radiation.
● Solar minimum: ​When the sun’s magnetic fields are weakest, leading to less sunspots and less radiation.
● The solar cycles change about every 11 year (it is not known why they change)
● Sunspots are colder patches on the sun's surface that are created because of variations in magnetic activity
Cause: the magnetic cycles of the sun causing large patches on the sun's surface to cool down.


Albedo:​ ​ ​The reflection of a radiant light of a surface usually a planet.
Ongoing feedback loop-​ ​Temperature of an area near the poles rises and the albedo decreases, more insolation is
absorbed by the ground which causes the temperature to rise further as the air above the warmer ground is also heated
Amplifying feedback loop-​ ​If a forcing agent triggers the cooling of an area near the poles, the albedo rises as the ice
caps expand thus, ​more radiation is reflected back into space, the ground absorbs less radiative energy causing the air
temperature to drop further, leading to another cycle and so on.The repeated looping increases and perpetuates the
impact of the initial trigger.
- Oceans​ ​keep​ ​the earth warm because they cover 71% of the earth and have an albedo of (roughly) 0.05, so they
retain most of the radiation. The warming increases the quantity of water in the sea due to the melting of ice
which results in an increase of water vapour which is a greenhouse gas thus increasing the global temperature as
an amplifying feedback loop since it increases the initial trigger

, - Changes to Snow cover -​ ​snow has a high albedo of (roughly) 0.8 to 0.9 which means that it reflects a lot of
the radiation directed towards it which (as for example in the ice age) decreased the temperature and then was
the amplifying feedback loop as more ice was produced
- Twice a year there are albedo peaks​, ​firstly during the antarctic winter maximum and secondly when the
Northern hemisphere experiences snowfall
- Deforestation​ ​plays a large role in increasing the earth's albedo as the cut down forests as the albedo of trees is
generally lower than topsoil.
- Desertification​ ​is where the climate increases which dries out areas of the earth and therefore the surface of
sand or bare earth increases and the albedo also increases. Land vegetation dries out → albedo increases, more
sunlight radiation is absorbed



LT: To analyse the cause of the enhanced greenhouse effect


The warming occurs due to additional heat being retained in the atmosphere as a result of increases in greenhouse
gases that humans have released


Enhanced greenhouse effects: ​The impact on the climate from the additional heat retained due to the increased
amounts of carbon dioxide and other greenhouse gases that humans have released into the Earth’s atmosphere

, Cattle Ranching
- Cows flatulate and release methane into the environment.
- Methane is a greenhouse gas
- Therefore, increased cattle ranching as a result of greater demand for meat is damaging to the environment

Rice Paddies
- Methane is produced by rice paddies when there are high levels of CO​2​ in the atmosphere

Fertilisers
- They release nitrous oxide which is a greenhouse gas
- Since 1750 the nitrous oxide levels have increased by 20%

Wastefills
“ Waste prevention and recycling (including composting) divert organic wastes from landfills, reducing the methane
released when these materials decompose” Nearly a fifth of of methane emissions come from landfills. Global
methane emissions from landfill are estimated to be between 30 and 70 million tonnes each year. Methane escapes
from landfills either directly to the atmosphere or by diffusion through the cover soil. Trash in landfills releases
methane gas by dumping our trash in landfills landfill methane is released this has a big impact on the climate

Deforestation​: ​The damaging/cutting of forests by humans resulting in a negative impact in the atmosphere.
Cutting down forests means there is erosion, no oxygen production, no carbon dioxide storage, no climate control and
no air purification. Forests have trees in a high concentration, therefore these trees are able to absorb excess carbon
dioxide through respiration leaving oxygen. Cutting down of these trees leave carbon dioxide in the atmosphere
causing a ​CO​2​ buildup. Burning or cutting of these trees can lead to an increase in the carbon dioxide in the air. Thus
cutting the trees leads to the increase in the temperature. Deforestation results in loss of water vapor because it’s an
essential part of plant transpiration. This transpiration replenishes the clouds, instigating rains, to replenish forests
(negative feedback) also deforestation causes CFC in the atmosphere since trees were the main absorbers.


Globalisation​ accelerates and amplifies the enhanced greenhouse effect. It is the interdependence of national
economies, business and trade in a world-wide scale

Evidence to suggest that globalisation is happening:
❏ Multinationals (environmental)
❏ Embassies (political)
❏ Funds from other countries (political / economical)
❏ International schools
❏ Westernisation of culture
❏ Tourism (economic)
❏ Internet

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