Predicting Human Population Change Part 3: Environmental Impact
Lesson 7 of 10
Objective: Students will be able to predict three nations' future environmental impact by analyzing current data on population growth rate and current CO2 emissions.
This lesson looks specifically at the environmental impact of population growth as measured by the CO2 emissions of the three countries student groups had studied in the 2 previous lessons.
Like the other lessons in this sequence, this lesson requires your students to use computers to collect data from internet databases. While it may be possible for them to do so using smartphones or tablets, I recommend using computers if they're available since some of the online resources have interactive components that function much better on desktops or laptops. We have access to a computer cart in my classroom, but if that is a resource you share with other teachers or you have a more traditional computer lab, you may want to make sure to make arrangements to use those computers ahead of time.
Connection to Standards:
In this lesson, students will follow a complex, multi-step procedure, integrate multiple information resources to address a problem, develop claims supported by evidence, conduct research, and model with mathematics to arrive at a better understanding of cause and effect relationships in complex systems.
There isn't as much warm up necessary as the previous lesson because this is a direct continuation of the previous lessons in the sequence. Still, it's helpful to go over a few terms and concepts that will be necessary to complete the activity.
I ask the following questions to begin the lesson:
- "Why are per capita CO2 emissions a good measure of a nation's environmental impact?", A: CO2 is a greenhouse gas. The more CO2 emitted to the atmosphere, the greater the increase in global temperature.
- "What does 'per capita' mean?", A: it means an amount per person in a population.
Once we have gone over this quick review, I ask students to work with the same partner as the previous lessons and have one partner get and set up one computer for the pair. I ask the other partner to pick up the activity instructions, a sheet of graph paper, and a box of colored pencils.
Since this is the 3rd lesson in the sequence, students should be familiar with the drill: collect data on their chosen countries from an online database.
Before we begin any new data collection for this lesson, students will need to transfer data on projected population growth from the previous lesson to the table at the top of their activity worksheet.
In this lesson, we will use the World Bank's database on per capita Carbon emissions.
The database students use in this lesson is much simpler to use than any of the online resources in previous days. Still, I do use the projector to show my class how to use it.
I ask them all to navigate to the World Bank's database on per capita Carbon emissions. I ask them to call out a country. As they do this, I scroll to find the country and show them that the information is very plainly available to them. In addition to the per capita Carbon emissions data, I demonstrate that clicking on the name of a country goes to that country's information page.
Once the guided practice is done, I move around the room to help students troubleshoot the website and/or help them with any problems interpreting the data they collect.
In this lesson, students will actually make two graphs:
- The first is projected population growth and will use data collected in the previous lesson
- The second is projected additional CO2 emissions. It's important for students to understand the distinction that this graph is neither the per capita CO2 emissions, nor the total CO2 emissions, but rather the additional CO2 emissions if the per capita emissions are stable and the population grows as projected. In other words, this is a graph of how much more each country will contribute to global warming.
To make sense of these graphs, they must be viewed side by side, which is why I encourage students to complete them on the same sheet of graph paper. They need to be viewed side by side because only then can students see that a country's population can grow fairly dramatically compared with another nation, but that their environmental impact may or may not change that much depending on the CO2 emissions of that country.
I think this is a very important point to make as so much of the rhetoric around population growth seems to point the blame on developing nations. Although it is true that developing nations' populations are growing fastest, their CO2 emissions are so low compared to developed nations that it is more accurate to say that it is in the developed nations where population growth has the most environmental impact, despite lower numbers of growth. Students will have the opportunity to explore this concept in more personal detail in the "What's Your Ecological Footprint?" lesson later in this unit.
Like the previous lessons, I use the last 20-30 minutes checking on students interpretations of the data they’ve collected.
Although some students will be eager to ask you questions, it’s important to engage all student groups in guiding dialogue to make sure they are critically considering their data as they interpret it. Otherwise, this lesson becomes simply collecting and compiling data. The learning objectives are met when they consider what this data means. A few suggestions for helping students to dig deeper into the data they're collecting:
- The "little boxes" data tables on the activity worksheet are intentionally made to visually distinguish the information there from the rest of the page. When I walk around to a group, I look to the data table as an easy way to find a discussion point. I find this essential because every group has different countries and I can't come to each group with the same questions because the data won't necessarily be consistent from group to group. For example, the first data table on this worksheet is about projected growth for each of the three countries. Looking at this data (largely gathered from the previous lesson), you might ask students why a particular country is expected to grow more than another. Is it because the country has a high growth rate? Is it because the country is already so large that even at a small growth rate, it is growing quickly? Answers to these questions can be used to guide a short dialogue with the individual group. (e.g., "Why do you think that country is growing at its rate?", "Which country is projected to grow the least? Does that country have a high or a low growth rate?", "Where is that country located?", "What do you know about countries from that part of the world?", etc.)
- Follow up questions can also relate one data table to the next. For example, if a country is expected to grow a lot, you might then ask students if that means that growth will have a very large impact on the environment. In their answers, you could direct their attention to the next data table about CO2 emissions and then ask if the country with the most growth already has the most CO2 emissions. You might ask students to clarify what "per capita" means to make sure they understand that they're not looking at total CO2 emissions, but rather the environmental impact of the average individual of that country (students will have an opportunity to calculate and compare their own environmental impact in the Ecological Footprint lesson). A basic question of clarification could be to ask students why CO2 emissions are an indicator of environmental impact, which students can hopefully answer is a way to measure consumption of resources, or more specifically, energy resources. You might then ask students to discuss greenhouse gases and the role of CO2 in global climate change. Again, the idea is to help each group "connect the dots" with their data rather than tell the whole class the "answer".
- A deceptively simple question that can really generate a good dialogue with a particular group is "What trends do you see in this data?". This question really asks students to carefully consider data from multiple tables and, likely, from the earlier lessons in this sequence.
- If you want students to have the vocabulary to place this activity in the context of the characteristics of developing versus developed nations, you might decide to teach this lesson after the Demographic Transition lesson.
- Even more so than in the previous lessons, truly interpreting the data requires careful comparisons of the graphs the students make. (e.g., in the student work example, it shows that while China's population growth will be several times that of the U.S., their projected additional CO2 emissions will be about the same. The most basic question then is, "What conclusions can you draw from this projection?" A: people in the U.S. use too much energy. Our environmental impact is equal to the biggest county in the world)
During the last 10-15 minutes, I ask for groups to volunteer answers to the final questions and to support their answers with specific data they gathered during the activity. It's important to have multiple groups contribute to this discussion, so use the discussions you have had with individual groups during the course of the activity to help you call on groups that might add something significant to the conversation (whether that's to support a general trend or provide a contrast).
Again, since each group is working with different data than their classmates, I use a document reader to project student graphs onto the board as a way for all students to really see the information a particular group is referencing to draw their conclusions.