Teacher Preparation

Overarching learning goal: By participating in this activity students will understand how CO₂ is absorbed by sea water. They will design and conduct and experiment to demonstrate the role of water temperature in CO₂ absorption and will understand the cause and consequences of ocean acidification.

Teacher content information: Climate change is predicted to have a range of effects on our environment, some barely noticeable, others devastating. One of those predicted devastating effects is the impact on our oceans.

Carbon dioxide in the atmosphere and the oceans are exchanged at the surface layer between these two environments. When the concentration in the atmosphere increases, the ocean takes in much of it, sequestering the CO₂ from the atmosphere. In this way, the oceans are moderating the amount of greenhouse gases in the atmosphere. Without the oceans, atmospheric CO₂ levels would be even higher.

Unfortunately, this process may cause long-term damage to life in the oceans. As CO₂ is transferred into the ocean it lowers the pH and creates a more acidic environment. This already sounds pretty nasty, but when you think what it means for all those marine species whose bodies have calciferous parts (molluscs, plankton, sea stars, corals and other shell inhabiting creatures), you can begin to understand why rising acidity in our oceans is being recognised as one of the most significant environmental problems we will have to face.

ACID TEST: 3 Minute Science of Ocean Acidification from Tristan Bayer on Vimeo - https://vimeo.com/8990924

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 this activity by asking students to look at the image of ocean acidification on the student worksheet and respond to the relevant questions.

Engage students in a class discussion around their answers. Ask students to share their answers with the class.

Step 2.

In his book, Flannery says "Scientists are worried that changes in ocean circulation brought about by global warming might degrade the effectiveness of this 'carbon kidney'. There are many ways that this could happen, one of which you can see in a warm can of soft drink. That fizz on opening the can fades - indicating that the liquid has quickly released the CO₂ that gives it is sparkle. Cold drinks hold their fizz longer. Cold sea water can hold more carbon than sea water, so as the ocean warms it becomes less able to absorb the gas." (p. 30)

Working in groups, ask students to design and conduct an experiment to show what Flannery means. Students may choose to interpret Flannery literally and use soft-drink cans in their experiment or devise a more complex simulation of this idea. It would be advisable to have some soft-drinks and ice on hand if students want to demonstrate their experiment to directly mirror Flannery's comments.

Students should use the Predict, Observe, Explain table to record their experiment before, during and after the experiment. Although students should design and conduct this experiment in groups, they should answer the questions in the table independently.

Reflection - Keep Our Oceans Cold

Students should work collaboratively to create a video commercial for an advertising campaign called: Keep Our Oceans Cold. Commercials should:

Include reasons for the focus on ocean temperatures and persuasive arguments for its importance;
Include scientific facts and figures;
Be no more than one minute in length;
Include supporting music and images.

Weather Makers - Understanding ocean acidification

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