- How Earth’s climate has changed
- Earth’s recent temperature trends
- Causes of long-term climate change
- Short-term climate changes and their causes
- Predicting future climate change
- Outline how Earth’s climate has changed over time.
- Identify causes and effects of climate change.
- Describe El Niño and La Niña.
El Niño: naturally occurring, short-term worldwide climate change that occurs when the Pacific Ocean is warmer than usual
global warming: recent increase in Earth’s temperature due mainly to human actions, especially the burning of fossil fuels
ice age: period when Earth’s temperatures are cooler than normal and glaciers spread to lower latitudes than usual
La Niña: naturally occurring, short-term worldwide climate change that occurs when the Pacific Ocean is cooler than usual
Introducing the Lesson
Share the following startling facts and figures about recent global climate change with your class. Then tell students they will learn more about climate change when they read this lesson.
- Earth's average temperature has risen by 1.4 °F over the past century and is projected to rise another 2 to 11.5 °F over the next century.
- In Alaska, western Canada, and eastern Russia, average temperatures have increased as much as 4 to 7 °F in just the past 50 years.
- Fourteen of the hottest years on record have occurred in the last 16 years.
- Small changes in the average temperature of the planet can translate into large and potentially dangerous shifts in climate and weather.
- The current pace of rising global temperatures puts as many as 30 percent of plant and animal species at significant risk of extinction.
Students will have a better understanding of El Niño by doing the hands-on activity at the first URL below. In the activity, they will use simple materials to model El Niño. Questions are provided to help students analyze their data, interpret the results, and draw conclusions. After the hands-on activity, students can go to the second URL below to track occurrences of El Niño through time with an interactive timeline.
You may want to have students explore the excellent EPA climate change learning module at the URL below. Using a variety of interactive multimedia, the module offers background information, online activities, and other resources on recent climate change, including its causes and impacts around the world.
Building Science Skills
In the activity at the following URL, students will examine graphs of greenhouse gas emissions and their increases associated with human activity. They will also calculate their personal contributions to CO2 emissions. By doing the activity, students will be able to identify sources of the major greenhouse gases and current trends in atmospheric concentrations. They will also be able to calculate greenhouse gas emissions on personal and larger scales.
Building Science Skills
Have students do the second activity (Part B) at the URL below. They will evaluate data and graphs depicting very long-term climate trends extending over hundreds or thousands of years to see what this information indicates about climate and climate change on Earth. The PDF document includes a student worksheet, discussion questions, and extension ideas.
Ask a pair of students to add the term global warming to the word wall. They should write the term and its definition on an index card. Suggest that they also list some of the major causes and effects of global warming on the card before posting it on the wall.
Have students think about the questions listed below. Then pair less proficient readers and English language learners with other students, and ask partners to share and discuss their answers to the questions.
- How has Earth’s average temperature changed since 1960?
- How has the amount of carbon dioxide in the atmosphere changed since 1960?
- How are the changes in temperature and carbon dioxide related?
Ask a few students to collaborate on creating a visual display, such as a slide show or PowerPoint presentation, on the Pleistocene ice ages. The display should include maps that show the extent of glaciation in North America during the epoch and images of typical vegetation and animals that lived in North America during that time. Schedule class time for the students to present their slide show or PowerPoint to the class.
The following simple experiment serves as an introduction to the greenhouse effect. Students can see for themselves the effects of a greenhouse on air temperature and relate it to what occurs in the atmosphere. Specific objectives include helping students understand the greenhouse effect as a physical phenomenon and developing their basic science skills of observing and recording data, using a control, using a model, and drawing conclusions from results.
There are many misconceptions about global warming. For example, some people think that it is caused by the hole in the ozone layer, which they believe allows more solar radiation to reach Earth’s surface. Stress that global warming is caused by increased greenhouse gases in the atmosphere. These gases include carbon dioxide and water vapor, which trap infrared radiation from the warmed surface of Earth so it doesn’t escape into space. Point out that, although the ozone hole does allow more UV light to reach the surface, this is not an important factor leading to increased temperatures on Earth. You can find additional misconceptions about climate change at these URLs:
Reinforce and Review
Copy and distribute the lesson worksheets in the CK-12 Earth Science for Middle School Workbook. Ask students to complete the worksheets alone or in pairs to reinforce lesson content.
Lesson Review Questions
Have students answer the Review Questions listed at the end of the lesson in the FlexBook® student edition.
Check students’ mastery of the lesson with Lesson 17.3 Quiz in CK-12 Earth Science for Middle School Quizzes and Tests.
Points to Consider
A place’s climate determines what kinds of plants and animals can live there. Would you expect similar plants and animals to be found in the same type of climate all over the world?
Besides climate, what factors might influence which plants and animals are found in a place?