Lesson 8: It Starts With Us


In the last lesson, you saw that human forcing is a major input to climate change. You have also looked at the potential impacts of climate change, especially for the Colorado Plateau. Today you will:

8a. Carbon Footprints

Carbon Footprint

Let's start by looking at your carbon footprint. A carbon footprint estimates the amount of CO2 you produce. Many parts of your life produce carbon, from the carbon used to make your toothbrush to the carbon you use to heat your home, run your appliances, and drive your car. A carbon footprint is measured in tons of CO2 generated per year.

How do you think your carbon footprint compares with your classmates? Or other Americans? Or the average for the world? In small groups, discuss these questions plus the 3 questions below. Write your ideas to them in your science notebook.

  1. What do you think are the three biggest sources of your carbon footprint?
  2. Do you think your family has a larger or smaller footprint than most of the other families you know? Why or why not?
  3. Can you name three significant things you could do to reduce your carbon footprint?

By understanding the main factors that contribute to your carbon footprint you can take thoughtful action to reduce it. While you may think your actions are too small to make a difference, your choices influence others and add up to make a difference.

8b. Carbon Calculator

You will use a carbon calculatorn from the Nature Conservancy to get your carbon footprint.

This carbon calculator is for educational purposes, and is not meant as an endorsement of The Nature Conservancy.

Answer the following questions in your notebook.

  1. In which category (home energy, driving and flying, etc.) do you contribute the most carbon?
  2. How does your carbon footprint compare to the average American? Why do you think your footprint is larger or smaller than the average American's?
  3. How does your carbon footprint compare to the world average? Why do you think your footprint is different from the world average?
  4. Name three changes you could make that would reduce your footprint according to this carbon calculator.
    1. Could the changes be made fairly easily?
    2. Test the changes with the carbon calculator. How much did the three changes reduce your carbon footprint?
  5. Did the carbon calculator point to any unexpected sources of carbon in your footprint? What were they and why did they surprise you?

The image below shows the "per capita" carbon dioxide emissions from countries around the world in the year 2000. Per capita means the average amount used by one person in that country. Red shows countries with the highest energy use per person. As you can see, an average American has a larger "carbon footprint" than someone living in other countries. Anyone, however, who is living without electricity or without as many modern appliances will have a smaller carbon footprint. Because Americans are the largest contributors to increasing atmospheric carbon, some people feel we also have a responsibility to become leaders in solutions to reduce the global carbon footprint.

Carbon Map

Average carbon emissions for each person living in each country in a typical year. Dark red shows countries that use a lot of energy, white shows countries where people use little energy.

8c. Classroom and Home Carbon

Look around your classroom. Do you see ways of reducing the carbon footprint of your classroom? Discuss what you see and your ideas with your class.

Some of the same ideas you came up with for your classroom would also work for your home. You can reduce your home energy use by making some small improvements to your existing home. And there are local groups and programs that provide free or reduced cost materials to help you. For example, you may be able to insulate walls, and seal windows and doors. On average, these small changes are termed retrofits. They can reduce family energy bills, energy consumption, and greenhouse gas emissions by about 33%. Retrofits can save your family over $400 a year on energy bills!

Light Bulbs

Two bulbs rated 60 Watts. Which uses more energy?

Does your family use Compact Florescent Lights (CFL's)? Here is a quick experiment: With a partner, screw in two light bulbs, one CFL and one incandescent. Now one of you put on a blindfold and the other put their hand near — but not on — each bulb. Note the difference. This tells you which one uses more energy. From the difference, which one uses more energy and why?

Energy efficient CFL's cuts greenhouse gas emissions and energy use 75% in comparison to incandescent light bulbs. This equals about 680 fewer pounds of CO2 emissions per bulb. Plus, a CFL bulb lasts ten times longer and saves families an average of $47 in energy costs over the lifetime of each bulb. They may cost more in the beginning, but they save a lot more in both CO2 and dollars in the end!

8d. Energy Use Monitor

Energy Monitor

Energy Monitor

You can also compare the energy used for a CFL bulb with an incandescent bulb with the Kill-a-Watt meter that you have been using to measure energy use of your appliances. Discuss the following questions with your team and write your answers in your notebook.

  1. How much more energy does the incandescent bulb use than the CFL when it is "on"?
  2. Is there a difference between how much energy the two bulbs draw when they are "off"?
  3. What appliances used the most energy when they were on?
  4. What appliances still used some energy even when they were not being used? Some people call this "phantom" or "vampire" electricity.

8e. Summary

You now have some ideas of how to reduce your carbon footprint, both in your classroom and your home. Talk to your family tonight and see if they want to try to reduce energy use in your household. Maybe they will also give you some other ideas for reducing how much carbon we use! Anyone older than you will have grown up in a time when there were fewer modern appliances. Listen — they might have some ideas.