Unit 1: Energy and Environment

How and Why We Use Energy

Welcome to Unit 1. In this first unit, we will present content in text and video showing the immense value we get from energy, where we get most of our energy, why the energy system must change eventually, and why a faster change would help us.

Each module of the course includes links to topic-related video clips taken directly from Earth: The Operators' Manual, a three-hour miniseries funded by the US National Science Foundation and viewed by millions of people nationwide on PBS. The conceptual foundations of this course were built on the principles and materials created for ETOM.

In addition, the course includes integrated video-enhanced graphics—clicking on many of the images and tables will open a short narrated video from Dr. Alley, explaining the key points. We hope that these will greatly enhance your level of understanding of key concepts presented.

  • Why Energy Matters (Module 1)
  • What is Energy? (Module 2)
  • Oil, Coal & Natural Gas | Drilling, Fracking & Reserves (Module 3)
  • The Physics of Global Warming (Module 4)
  • The History of Global Warming (Module 5)

Earth: The Operators' Manual: Humans and Energy - To get started, please watch the video below. This particular video will give you a glimpse into what the world's energy usage currently is and what it might be in the future. The video is a little over 4 minutes and 30 seconds long. Click the arrow to start the video.

Humans and energy video
Click Here for Transcript for video

(Richard Alley) Humans need energy. We always have, and always will. But how we use energy is now critical for our survival. It all began with fire...Today, it's mostly fossil fuels. Now we're closing in on seven billion of us and the planet's population is headed toward 10 billion. Our cities and our civilization depend on vast amounts of energy. Fossil fuels-- coal, oil and natural gas--provide almost 80% of the energy used worldwide. Nuclear is a little less than 5%. Hydro-power a little under 6.

And the other renewables--solar, wind and geothermal about 1% but growing fast. Wood and dung make up the rest. Using energy is helping many of us live better than ever before. Yet well over a billion and a half are lagging behind, without access to electricity or clean fuels.

In recent years, Brazil, has brought electricity to ten million, but in rural Ceará some still live off the grid. No electricity, no running water, and no refrigerators to keep food safe. Life's essentials come from their own hard labor. Education is compulsory, but studying's a challenge when evening arrives. The only light is from kerosene lamps. They're smoky, dim and dangerous. Someday, this mother prays, the electric grid will reach her home. (translator) The first thing I'll do when the electricity arrives in my house will be to say a rosary and give praise to God. (Richard Alley) More than half of China's 1.3 billion citizens live in the countryside. Many rural residents still use wood or coal for cooking and heating, although most of China is already on the grid. China has used energy to fuel the development that has brought more than half a billion out of poverty.

In village homes there are flat screen TVs and air conditioners. By 2030, it's projected that 350 million Chinese, more than the population of the entire United States, will move from the countryside to cities... a trend that's echoed worldwide. Development in Asia, Africa, and South America will mean three billion people will start using more and more energy as they escape from poverty. Suppose we make the familiar if old-fashioned 100 watt light bulb our unit for comparing energy use. If you're off the grid, your share of your nation's energy will be just a few hundred watts, a few light bulbs. South Americans average about 13 bulbs. For fast developing China, it's more like 22 bulbs. Europe and Russia, 5,000 watts, 50 bulbs. And North Americans, over ten thousand watts, more than 100 bulbs.

Now let's replace those light bulbs with the actual numbers. Population, shown across the bottom and energy use, displayed vertically, off the grid to the left, North America to the right. If everyone, everywhere, started using energy at the rate North Americans do, the world's energy consumption would more than quadruple, and using fossil fuels, that's clearly unsustainable. No doubt about it, coal, gas and oil have brought huge benefits. But we're burning through 'em approximately a million times faster than nature saved them for us, and they will run out. What's even worse, the carbon dioxide from our energy system threatens to change the planet in ways that'll make our lives much harder. So why are fossil fuels such a powerful, but ultimately problematic, source of energy?

Credit: Earth: The Operators' Manual

Unit Goals

Upon completion of Unit 1, students will be able to:

  • Recognize the natural and human-driven systems and processes that produce energy and affect the environment
  • Explain scientific concepts in language non-scientists can understand
  • Find reliable sources of information on the internet
  • Use numerical tools and publicly available scientific data to demonstrate important concepts about the Earth, its climate, and resources

Unit Objectives

In order to reach these goals, the instructors have established the following objectives for student learning. In working through the modules within Unit 1, students will:

  • Recognize that even really smart people have failed when climate changed
  • Explain how machines and trade have helped other people avoid catastrophe
  • Describe how we have burned through energy sources in the past
  • Show that people can make money and save the world at the same time
  • Recall that using energy doesn’t make it go away, it is just converted into a less useful form
  • Recognize the many units of energy and power
  • Show that the amount of energy used by people around the world is much larger than the 100 watts inside most people converted from food
  • Recall that around 85% of the energy we use is derived from fossil fuels
  • Analyze energy use and production in a country other than the United States
  • Recall that oil, coal and natural gas are produced naturally by well-understood processes
  • Evaluate the effects of technology, economics, and population growth on fossil fuel production using computer models
  • Demonstrate that our current consumption of fossil fuels is not sustainable by exploring future scenarios with computer models
  • Recall that carbon dioxide has a well-understood and physically unavoidable warming influence on Earth’s climate
  • Recognize that positive feedbacks amplify changes, and negative feedbacks reduce them
  • Recall that multiple independent records from different places using different methods all show that both CO2 and temperature are rising
  • Explain that patterns of global warming in the past century can only be reproduced by considering both natural and human influences on climate
  • Use a model to show that global climate always finds a steady state, but certain factors may influence how long it takes to get there
  • Demonstrate that greenhouse gases are the most significant factor controlling surface temperature
  • Summarize how the Earth’s history confirms the warming influence of carbon dioxide
  • Recognize that past climate changes have greatly affected plants and animals, usually in unpleasant ways
  • Recall that future rise in CO2, and therefore surface temperature is likely to be much worse than what we have experienced in the past 100 years
  • Explain how small amounts of climate change are worse for poor people, and larger amounts are bad for everyone
  • Assess what you have learned in Unit 1


Assessment title and type, by module
Module Assessment Type
1. Why Energy Matters Get Rich and Save the World Blog: Find an Article
2. What is Energy? Energy Use Around the World Blog: Search and Compare
3. Oil and Coal and Natural Gas Peak Oil Model Stella Model
4. Global Warming: Physics Global Climate Model Stella Model
5. Global Warming: History Learning Outcomes Survey Self-Assessment