Teacher Preparation

Overarching learning goal: By participating in this activity students will understand the characteristics and effects of water vapour. They will observe and understand the effects of heating and cooling on water vapour and will recognise the role of water vapour in global warming.

Teacher content information: In debates around global warming water vapour is often cited as a villain. Skeptics have argued that water vapour is a more dangerous greenhouse gas than CO₂ and has a higher contribution to global warming than CO₂. The truth is that the relationship between CO_2, water vapour and climate change is complex:

MYTH: Water vapour is the most important, abundant greenhouse gas. So if we’re going to control a greenhouse gas, why don’t we control it instead of carbon dioxide (CO₂)?

FACT: Although water vapour traps more heat than CO₂, the relationship between CO₂, water vapour and climate change means that to fight global warming we need to focus on controlling CO₂. While atmospheric levels of CO₂ are determined by how much CO₂ we release, the “amount of water vapour in the atmosphere is not directly affected by human activities. It's controlled by atmospheric temperature – the higher the temperature, the more water the air can hold. When carbon dioxide – which is directly affected by human activities – is emitted into the atmosphere, the atmosphere warms slightly. But that modest amount of warming sets up a perverse amplification process: carbon dioxide emissions warm the atmosphere, which leads to more water vapour in the atmosphere, and thus more warming. It's a vicious cycle.” (from Environmental Defense Fund)

For more reliable information about climate change in Australia, visit the Climate Council.

The IPCC

The Intergovernmental Panel on Climate Change (IPCC) is the United Nations body for assessing the science related to climate change. It was created to:

provide policymakers (governments) with regular scientific updates about climate change;
highlight the impact climate change will have on the planet in the future; and,
offer some ideas about how to tackle the challenges of climate change's potential effects on the planet.

In 2021-22, the IPCC released their sixth assessment report. This is the most up-to-date physical understanding of the climate system and climate change.

The report makes a number of important points:

It is unequivocal that human influence has warmed the atmosphere, ocean and land.
Global surface temperature will continue to increase until at least mid-century under all emissions scenarios considered. Global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades (B1). The report describes five possible climate futures, where #1 is not great and #5 is extremely bad. If we want to keep global warming at less than two degrees, which the IPCC says is the best-case scenario, we need to reduce our CO2 and greenhouse gas emissions significantly and start right away.

'Net zero' or 'carbon neutral' are terms that refer to achieving an overall balance between greenhouse gas emissions produced and greenhouse gas emissions taken out of the atmosphere. Getting to net zero means we can still produce some emissions, so long as we're doing something else to reduce the greenhouse gases already in the atmosphere at the same time, kind of like balancing a set of scales (more info).

Psychological safety. The IPCC Report sets a hard challenge. While this real-world issue is essential for students to understand, there is no doubt it can make them feel sad or anxious about the future is becoming darker and scarier by the day. So, reassure students that we can have a hopeful and optimistic outlook on this report, rather than one of doom and gloom. Explain that optimism involves looking objectively at a situation and making a conscious decision to focus on the good (more info), and that hope is the belief that you can make an impact (more info). Explain to students that you are going to look ahead, identify what needs to be improved, and then work on the skills and confidence so that they can go out and do it. If you're interested in learning more about how to approach challenging topics around climate change and sustainability in your classroom through a Hope and Optimism lens, consider our PD course.

Student and classroom organisation

Step 1.

Begin the activity by asking students to read and respond to the quotes from We Are the Weather Makers on the Student Worksheet.

Ask students to share their responses with the class. What are some of the more unusual responses students had? For example, water vapour makes your hair go curly.

Step 2.

Students will conduct a simple experiment designed to demonstrate how water vapour responds to heating and cooling - or compression and decompression. Students can conduct this experiment in groups. Each group will need:

A glass jar
A rubber balloon with a wide neck OR a large rubber glove
Chalk dust

The steps for conducting this experiment are:

Put a few centimetres of water in the bottom of a jar.
Place a large rubber balloon or rubber glove over the mouth of the jar and leave for 10 minutes.
Remove the balloon and quickly drop some chalk dust into the jar before replacing the balloon.
Push the balloon into the jar a little way and hold there before quickly releasing it.

Another method for conducting this experiment is to use a rubber glove and insert your hand into the fingers in order to pull the glove in and out of the jar.

Students should observe that dust clouds form when the glove or balloon is pulled out of the jar (and the air has more room to move and becomes cooler) and disappear again when the air is again compressed.

Extension: This experiment can also be tried by dropping a lit match into the jar - although having students use chalk dust is probably safer.

Step 3.

In the next part of the activity students will investigate the relationship between water vapour and global warming. In preparation for this task, students will probably find a little research useful.

Before conducting any research, explain to students that climate skeptics have used misunderstanding around the role of water vapour as a contributor to global warming to diminish the role of humans in global warming.

For example a common MYTH and FACT about water vapour and global warming could be explained as:

MYTH: Water vapour is the most important, abundant greenhouse gas. So if we’re going to control a greenhouse gas, why don’t we control it instead of carbon dioxide (CO₂)?

FACT: Although water vapour traps more heat than CO₂, the relationship between CO₂, water vapour and climate change means that to fight global warming we need to focus on controlling CO₂. While atmospheric levels of CO₂ are determined by how much CO₂ we release, the “amount of water vapour in the atmosphere is not directly affected by human activities. It's controlled by atmospheric temperature – the higher the temperature, the more water the air can hold. When carbon dioxide – which is directly affected by human activities – is emitted into the atmosphere, the atmosphere warms slightly. But that modest amount of warming sets up a perverse amplification process: carbon dioxide emissions warm the atmosphere, which leads to more water vapour in the atmosphere, and thus more warming. It's a vicious cycle.” (from Environmental Defense Fund)

Students should then work independently to research 5 arguments that support or contradict the idea that water vapour is responsible for global warming. Students should be encouraged to explore a range of understandings on the subject. Remind students to include scientific evidence and references. Students can add their research to the table on the Student Worksheet. Some suggested resources are included on the Student Worksheet.

Once complete, ask students to share some of their responses with the class. Consider using the following questions:

Which was the most common argument?
Which argument was the least controversial?
Which argument was the most controversial?
Which line of argument do you think is most persuasive and why?

Step 4.

Ask students to complete the Cause and Effect table about the interaction between CO₂ warmth and water vapour on the Student Worksheet.

Reflection/Assessment

Ask students to create an infographic (DIY infographic background information) or short animation (e.g. Wideo or Animoto, animation should be a maximum 30 seconds) that describes the relationship between water vapour, CO₂ and climate change. Students can work independently or in groups.

Homework/Extension

1. Working from the Student Worksheet, ask students to imagine themselves as a water molecule. Ask students to describe their state in different parts of the globe at different times of the year: when are you gas, liquid, solid? Why? Students can record their responses as a short story or as an image.

2. Put water vapour on trial! Hold a mock court trial for water vapour in the class with a prosecutor, defence team, jury and scientific expert.

Weather Makers - Water vapour and CO2

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