Part 1. Causes of Global Climate Change

Conceptual Understanding:

Key Question:

How do natural and human processes affect the global energy balance?

Key Content:

  1. The atmospheric system, including the natural greenhouse effect and energy balance (incoming shortwave radiation and outgoing longwave radiation)
  2. Changes in the global energy balance, and the role of feedback loops, resulting from:
    • terrestrial albedo changes and feedback loops
    • solar radiation variations, including global dimming due to volcanic eruptions
    • methane gas release and feedback loops
  3. The enhanced greenhouse effect and international variations in greenhouse gas sources and emissions, in relation to economic development, globalization and trade

Synthesis, evaluation and skills opportunities

The complexity of the dynamic climate system and the spatial interactions of different processes and feedback mechanisms

Monday 25 October 2021

The Atmospheric System

Objective: To be able to describe the functioning of the atmospheric system in terms of the energy balance between solar and long wave radiation.

Lesson 1. The Atmospheric System (Google Doc)

Starter: Watch the video below about the Earth’s Atmosphere.

After watching the video, label the diagram in the Google Doc with the names of the five layers of the atmosphere!

Task 1. Watch the YouTube video below.

Now complete the wordfill exercise on the Google Doc using the words from the word bank.

Task 2. KeyTerms and Definitions

Match the key terms with the correct definition in the table on the Google Doc.

The Atmospheric Energy Budget 

The earth and its atmosphere constantly receives solar radiation but there are long and short term variations in the earth’s climate & recent decades have seen the general rise in global temperatures. This is global warming and will be covered a little later on in the unit. 

Task 3. Make a copy of the Atmospheric Energy Budget Diagram below. Then watch the video: How Does the Climate System Work? Use the information to make annotated (around the diagram) notes on how the energy budget works and transfers at each stage.

Task 4. Using the video above, answer the questions on your worksheet.

Task 5.  Click here to be taken to Cool Geography. Read the information carefully on the page before completing the four activities in full, at the bottom of the page. Make copies of the maps and diagrams where necessary.

Tuesday 26 October 2021

Starter: Quick Quiz: 5, 4, 3, 2, 1.

5 – Layers of the atmosphere.

4 – Reasons for energy surplus and deficit.

3 – Greenhouse gases.

2 – Types of radation.

1 – Definition of insolation.

Natural Causes of Climate Change

When explaining climate change it is important to make the distinction between the more recent industrial age, which only covers the last 200 years or so and the period preceding the industrial age. Temperature changes before the industrial age can only be explained by natural factors. There are many causes, but the ones that we are going to investigate are:

  1. Changes in Insolation (Milankovitch Cycles)
  2. Albedo Changes and Feedback Loops
  3. Sun Spot Activity
  4. Volcanic Eruptions

Cause #1. Changes in Insolation (Milankovitch Cycles)

Cause #1. Changes in Insolation (Google Doc)

Serbian scientist Milutin Milankovitch hypothesized the long-term, collective effects of changes in Earth’s position relative to the Sun are a strong driver of Earth’s long-term climate, and are responsible for triggering the beginning and end of glaciation periods (Ice Ages).

Specifically, he examined how variations in three types of Earth orbital movements affect how much solar radiation (known as insolation) reaches the top of Earth’s atmosphere as well as where the insolation reaches. These cyclical orbital movements, which became known as the Milankovitch cycles, cause variations of up to 25 percent in the amount of incoming insolation at Earth’s mid-latitudes (the areas of our planet located between about 30 and 60 degrees north and south of the equator).

The Milankovitch cycles include:

  1. The shape of Earth’s orbit, known as eccentricity;
  2. The angle Earth’s axis is tilted with respect to Earth’s orbital plane, known as obliquity; and
  3. The direction Earth’s axis of rotation is pointed, known as precession.

Task 1. Watch the videos below about the Milankovitch Cycles and then complete the wordfill exercise on the Google Doc.

Friday 29 October 2021

Starter: Quick Quiz… 5, 4, 3, 2, 1.

5 – Layers of the atmosphere.

4 – Natural causes of climate change.

3 – Milankovitch Cycles.

2 – Cycle intervals in the Milankovitch cycles. Ie: How many thousand years do the cycles occur?

1 – Definition of albedo.

Cause #2 Terrestrial Albedo Changes and Feedback Loops

Cause #2. Albedo Changes and Feedback Loops (Google Doc)

Task 1. Read the information below, and watch the two videos linked below. Use the information to answer the four questions set out on your worksheet.

Albedo

Albedo refers to the fraction of Sun’s radiation reflected from a surface. The term has its origins from the Latin word albus, meaning “white”. 

It is quantified as the proportion, or percentage of solar radiation of all wavelengths reflected by a body or surface to the amount incident upon it. An ideal white body has an albedo of 100% and an ideal black body, 0%.

The image below shows the albedo values for various surfaces.

Feedback Loops

What are Feedback Loops?

Negative and positive feedback systems keep a system in dynamic equilibrium. A negative feedback decreases the amount of change by reducing some of the inputs, returning the system to stability. Positive feedback is less common. It increases the amount of change. This leads to an imbalance. 

Negative Feedback Example: 

A good supply of grass for rabbits to eat will attract more rabbits to the area, which puts pressure on the grass, so it dies back, so the decreased food supply leads to a decrease in population because of death or out migration, which takes away the pressure on the grass, which leads to more growth and a good supply of food which leads to a more rabbits attracted to the area which puts pressure on the grass and so on and on…. 

Positive Feedback Example: 

  1. Polar ice reflects light from the sun. As this ice begins to melt, less sunlight gets reflected into space. It is instead absorbed into the oceans and land, raising the overall temperature, and fueling further melting. This results in a positive feedback loop called ice albedo feedback, which causes the loss of the sea ice to be self-compounding. The more it disappears, the more likely it is to continue to disappear.
  2. Methane and carbon dioxide are very powerful greenhouse gases (GHG’s) which contribute to climate change. is a very, very powerful greenhouse gas. In the Arctic, methane and carbon can be found in permafrost, as well as in frozen peat bogs and under sediment on the sea floor. As these bogs and permafrost thaw thanks to climate change, the methane and carbon within are released into the atmosphere, adding yet more GHGs that can lead to further global warming. More warming results in more permafrost loss, adding yet more GHGs to the atmosphere to create even more warming and more melting permafrost, and on and on.

Cause #3 Solar Radiation Variation from Sunspots

Cuase #3. Solar Radiation Variation from Sunspots (Google Doc)

Task 1. Conduct some research into sun spots, starting with the videos below, and explain how they are linked to the amount of short wave energy that the earth receives.

Task 2. Using the graph below, answer the questions on the Google Doc.

  1. Describe the pattern of sunspot activity between 1960 and 2010. 
  2. Is there a relationship between sunspot activity and global temperatures? (don’t forget to look for anomalies)
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Task 3. Click on this link from the BBC and print out and read the article carefully. 

  1. What is the Maunder Minimum?
  2. What is blocking?​
  3. Outline the impacts of sunspots on continental Europe and its populations. 

Monday 01 November 2021

Starter: Complete this online crossword.

Cause #4 Volcanic Eruptions

​Focus: Mount Pinatubo.

Eruption: 1991 in the Philippines. 

Task 1. Familiarise yourself with this specific eruption by clicking on this link. Create a 5 W’s graphic organiser for the eruption (who, what, where, why, when).

Picture

Task 2. Using the information within this Live Science Link, particularly focusing on the section entitled ‘Pinatubo’s global reach’, the section above on Global Dimming and the graph below, explain how volcanic eruptions can influence climate.

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Tuesday 02 November 2021

Starter: Play key term dominoes!

The Enhanced Greenhouse Effect

The enhanced greenhouse effect, is 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 earths atmosphere since the industrial revolution.

The increase in world’s greenhouse gases is linked to industrialisation, trade and globalisation. As industrialisation has increased so too has the increase of atmospheric CO2.

Common Misconception!

Do not confuse the enhanced greenhouse effect with the greenhouse effect! The greenhouse effect is vital for life on Earth!

TOK Link: Although it is widely accepted that the enhanced greenhouse effect is causing a rise in global temperatures, there is much debate over who is causing it, who suffers the most, and what is being done to solve it.

International variations in greenhouse gas sources and emissions…

Task 1: Using the videos above, and the spatial data sets linked below, create a piece of commentary that addresses the international variations in greenhouse gas sources and emissions according to the 4P’s. You may use the questions below to help you with your commentary…

1. Place – Which countries emit the largest/smallest quantities of C02? Can they be categorised by level of economic development? Are there differences between overall emissions and those per capita? 

2. Processes – How are these emissions created? Do the emissions just affect the emitting countries or are there processes in place that disperse the problem?  What’s the link to the Enhanced Greenhouse Effect? Think about globalisation & trade.

3. Possibility – What could future patterns in emissions and targets be? (Think about SDG’s) How can we reduce emissions and reduce impacts on MIC’s & LIC’s?

​4. Power – Who are those that aim to change these patterns? (Think about SDG’s, Climate Change Deals etc) as well as those governments who are promoting economic growth through industrialisation and processes of globalisation. 

Who emits the most CO2 today?

Where in the world do people emit the most CO2?

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Assessment 2.1 Carbon Sources Report

Study the map below (by clicking it) and write a report on the spatial variation in carbon sources and emissions. Focus on

  • Extraction, emissions, consumption as sources for greenhouse gases
  • CO2 per capita
  • Emissions change

Use screenshots in your report.

Homework:

Read pages 426 – 435 and answers the 10 Check Your Understanding questions on page 435.