1.1 What causes climate change?

Information for Planning & Teaching

Background Knowledge - Correlation and Causation

Correlation and causation are two different concepts that teachers should understand when discussing data with their students. Correlation refers to a relationship or connection between two variables where they tend to move together in a certain direction. For example, there might be a correlation between the amount of time students spend studying and their grades; as study time increases, grades might also increase. However, this does NOT mean that one causes the other. When two variables show a correlation, it does not automatically imply that one variable is causing the change in the other. There could be other factors at play, or it could even be a coincidence. 

Causation, on the other hand, implies that one event is the result of the occurrence of the other event; in other words, one variable directly affects the other. For instance, if a student receives direct instruction on a specific topic and then performs better on a test about that topic, we might infer causation. It’s important to note that while correlation can suggest a possible relationship, it does not prove causation. Understanding this distinction helps prevent misconceptions and promotes more accurate interpretations of data.

Background Knowledge - Carbon Cycle

The carbon cycle is a fundamental concept in understanding Earth's ecosystems, and it's essential for middle school students to grasp its significance. The carbon cycle describes the movement of carbon atoms through various components of our planet, including the atmosphere, oceans, soil, and living organisms. Carbon is a key element in many biological processes, such as photosynthesis, respiration of animals and plants, and the food chain.

Photosynthesis is the process by which plants, algae, and some bacteria convert carbon dioxide (CO₂) from the air and water from the soil into glucose and oxygen using the energy from sunlight. This process not only provides the primary source of energy for plants but also produces the oxygen that animals and humans need to breathe. The carbon in glucose becomes part of the plant's structure, fueling its growth and development.

Respiration is a process that occurs in both plants and animals, where glucose and oxygen are converted back into carbon dioxide and water, releasing energy that the organism can use for its vital functions. In animals, this process takes place in the cells' mitochondria, providing the energy needed for movement, growth, and repair. Plants also respire, using the energy produced to support their growth and reproduction, particularly at night when photosynthesis cannot occur.

The food chain is another critical part of the carbon cycle. When animals eat plants, they take in the carbon stored in the plant's tissues. This carbon becomes part of the animal's body and can be passed along to other animals when they are eaten. At each stage of the food chain, respiration returns some of this carbon to the atmosphere as carbon dioxide. When plants and animals die, decomposers like bacteria and fungi break down their bodies, releasing carbon back into the soil and atmosphere.

Fossil fuels, such as coal, oil, and natural gas, are formed from the remains of ancient plants and animals that were buried and subjected to intense heat and pressure over millions of years. When humans extract and burn these fuels for energy, carbon that has been stored for eons is released back into the atmosphere as carbon dioxide. This process significantly impacts the carbon cycle, contributing to increased atmospheric CO₂ levels and influencing global climate patterns. Understanding these processes helps students appreciate the delicate balance of the carbon cycle and the effects of human activities on our planet

Lesson Timing

Student Ideas & Experiences

Students have experiences with energy use and CO2 emission in various ways. Students use electricity to power their house and classrooms. They may see their parents getting gas for their vehicles. They may have experience power loss due to extreme weathers, which provide insights into the importance of energy. Through discussion, teachers will learn students' prior knowledge and experiences associated with energy use, CO2 emission, and climate change. Teachers can use and build from students' knowledge during class discussions to piece together a cohesive understanding of the carbon cycle and energy sources.

We provide a series of images for students to discuss. 

(1) How do they think the picture is (or is not) related to CO2 emission?

(2) How do they think the picture is (or is not) related to energy use? and 

(3) How do they think the picture is related to their life.

Through these questions, teachers will be able to understand students' experiences with energy use and Carbon Dioxide emission. 

We hope that students can understand that almost every aspect of their life requires energy, even if some of the energy use seems not directly related to them. There is an indirect relationship with our everyday lives. For example, for students who live inland, it may seem that large ships are not directly related to their daily life. However, many of the items they purchase in stores are transported from other countries by these ocean freighters. 

Science Practices

Modeling

Teaching Cases