Published on EGEE 401: Energy in a Changing World (https://www.e-education.psu.edu/egee401)

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Introduction

Unit 2: Environmental Challenges – Lesson 4: Processes of Climate Change

About Lesson 4

In the previous lesson, we learned about the environmental changes currently challenging our planet—what they are, the science behind them and their current and future impacts. In this lesson, we are going to look closely at the processes that cause the environmental changes and the role of human activity. As a means of introduction, here's a good overview from the Environmental Protection Agency:

The Earth’s climate is changing. In most places, average temperatures are rising. Scientists have observed a warming trend beginning around the late 1800s. The most rapid warming has occurred in recent decades. Most of this recent warming is very likely the result of human activities. Many human activities release “greenhouse gases” into the atmosphere. The levels of these gases are increasing at a faster rate than at any time in hundreds of thousands of years. We know that greenhouse gases trap heat. If human activities continue to release greenhouse gases at or above the current rate, we will continue to increase average temperatures around the globe. Increases in global temperatures will most likely change our planet’s climate in ways that will have significant long-term effects on people and the environment.

The Earth’s greenhouse effect is a natural occurrence that helps regulate the temperature of our planet. When the Sun heats the Earth, some of this heat escapes back to space. The rest of the heat, also known as infrared radiation, is trapped in the atmosphere by clouds and greenhouse gases, such as water vapor and carbon dioxide. If all of these greenhouse gases were to suddenly disappear, our planet would be 60°F colder and would not support life as we know it.

Human activities have enhanced the natural greenhouse effect by adding greenhouse gases to the atmosphere, very likely causing the Earth’s average temperature to rise. These additional greenhouse gases come from burning fossil fuels such as coal, natural gas, and oil to power our cars, factories, power plants, homes, offices, and schools. Cutting down trees, generating waste and farming also produce greenhouse gases. Many greenhouse gases, like water vapor and carbon dioxide (CO2), occur naturally. Fuel burning and other human activities are adding large amounts of carbon dioxide and other gases to the natural mix at a faster rate than at any other time on record. Other important greenhouse gases produced by human activity include methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6).

Source: Environmental Protection Agency, Frequently Asked Questions About Global Warming and Climate Change: Back to Basics [1]

In this passage, you saw the term "very likely." You'll remember that this phrase has specific meaning as set forth by the IPCC. The passage above is from a 2009 EPA publication. I continue to use it in this class because of its broad and clear perspective. Since this document was published, however, the IPCC has put forth an updated finding concluding that it is "extremely likely" that human influence has been the dominant cause of observed warming since the mid-20th centruy. (Human influence on climate clear, IPCC report says [2], Sept 2013). This transition in confidence is very important in the case for action.

Whether we use "IMHO" (in my humble opinion) or a statistical level of confidence, we can contribute to the quality of public conversation (debate) by carefully separating fact from opinion and dealing openly with uncertainty. The IPCC does this explicitly. Fortunes and power entangle the climate change discussion especially, inviting loud voices to try to drown out quiet facts for economic gain. We can help by handling data and opinion forthrightly and approaching all new information with a critical eye--is it a fact, whose fact, and why? (Well, IMHO anyway!)

What will we learn in Lesson 4?

With the successful completion of this lesson, you will be able to:

  • draw a diagram depicting and quantifying the greenhouse effect;
  • understand the carbon cycle and its role in climate change;
  • relate energy consumption to greenhouse gas emissions;
  • differentiate between greenhouse gases and their respective impact on the environment.

Approach for Lesson 4 Activity

For this lesson especially, I suggest you begin by looking at the Activity questions on page 4, then read and view all the assigned material. By looking at the questions first, you'll know the kind of information and data to watch for while you read. For most questions, a good answer will involve a synthesis of material from different sources. For example, individual greenhouse gases are explained and described at various levels of detail by several sources assigned for this Activity.

What is due for Lesson 4?

The table below provides an overview of the requirements for Lesson 4. For details regarding the assignment, refer to the page(s) noted in the table.

Please refer to the Calendar in CANVAS for specific time frames and due dates.

Lesson 4 Requirements
REQUIREMENT LOCATION SUBMITTED FOR GRADING?
Viewing: (Greenhouse Effect): Interactive presentation from National Geographic and related materials (as designated) Page 2 No
Reading: (Greenhouse Effect): Department of Energy, "Energy Explained" (designated sections) Page 2 No
Reading: (Greenhouse Effect): Visionlearning, The Carbon Cycle: What Goes Around Comes Around Page 2 No
Viewing: (Greenhouse Effect): NASA, "Six Decades of a Warming Earth" Page 2 No
Reading: (Greenhouse Gases): US Environmental Protection Agency, "Climate Change" (designated sections) Page 3 No
Reading: (Greenhouse Gases): Arbor Day Foundation, "Plant Hardiness Zones" Page 3 No
Reading: (Greenhouse Gases): US Environmental Protection Agency, "Inventory of Greenhouse Gas Emissions and Sinks: 1990-2011 APRIL 2013" (designated sections) Page 3 No
Lesson 4 Activity: Complete Lesson 4 Activity (It's in CANVAS, in the Unit 2 Module.) Page 4 Yes
Unit 2 Discussion Forum: "Biggest Loser!" Cutting your greenhouse gas emissions (It's in CANVAS, in the Unit 2 Module.) Page 5 Yes

Questions about EGEE 401?

If you have any questions, please post them to our Questions about EGEE 401? Discussion in CANVAS. Use this Discussion for general questions about course content and administration. I will check it daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate or have a related question.

 


Source URL: https://www.e-education.psu.edu/egee401/node/1766

Links
[1] https://nepis.epa.gov/Exe/tiff2png.cgi/P1003EIP.PNG?-r+75+-g+7+D%3A%5CZYFILES%5CINDEX%20DATA%5C06THRU10%5CTIFF%5C00000388%5CP1003EIP.TIF
[2] https://www.ipcc.ch/news_and_events/docs/ar5/press_release_ar5_wgi_en.pdf