About This Module

Topics: volcanoes, volcanic gases, eruptions, climate change, greenhouse effect

Grade Levels: 5-8



Scenario



Eruption of Mt. Stromboli, Italy

Volcanoes are the most dramatic and rapid agents of geologic change. An erupting volcano can eject vast amounts of ash and gases into the atmosphere, and cover the ground with tons of lava flows and ash. Eruptions create new mountains, and tear down old ones as we watch. Large eruptions are dangerous, sometimes killing tens of thousands of people at one time. But the most extreme impact of eruptions is their affect on Earth’s climate.

Our planet’s climate results from a complex and always changing mixture of processes and events. The basic source of energy is radiation from the Sun. The incoming radiation interacts with the Earth’s atmosphere and surface, so that changes to either can affect the climate. For example, a dark lava flow absorbs more of the solar energy than a desert soil, so a large enough lava flow could warm a local region. But a much larger influence on climate comes from volcanic gases erupted into the atmosphere that spread out and encircle the planet.

The most abundant gas typically erupted is water vapor, which has been measured to be as high as 97% of gases erupted from some volcanoes. The water has very little impact on climate because it usually rains out of the atmosphere fairly quickly. In fact, it is very common to find volcanic ash deposited that preserve rainfall splash marks.



1991 Eruption of Mount Pinatubo, Philippines

The greenhouse gas carbon dioxide (CO 2 ) is the second most common gas (varying from 1% to 50% in different types of eruptions). Carbon dioxide is heavier than air and commonly ponds in low-lying areas; it can poison and kill animals that breathe it. The CO 2 does not significant influence climate because volcanic CO 2 is only about 1% of what is released by burning of fossil fuels.

The gas that does have a noticeable climate impact is sulfur dioxide (SO 2 ). Unlike greenhouse gases, SO 2 cools the atmosphere. Magma contains a small amount of SO 2 , typically less than 10% by volume. Large eruptions thrust the SO 2 into the upper atmosphere (the stratosphere) where it is transported around the planet. Contact with abundant water changes the SO 2 gas into sulfuric acid (H 2 SO 4 ) droplets called aerosols. Even though they are microscopic, there are billions of such aerosols following a big eruption, so that they actually affect the climate. Each aerosol absorbs some of the radiation from the Sun, and thus heats itself and the surrounding stratosphere. But each ray of Sunlight that hits an aerosol does not strike the Earth, robbing the surface of that small amount of heat. During the 1900s there were three large eruptions that caused the entire planet to cool down by as much as 1°C. Volcanic coolings persist for only 2 to 3 years because the aerosols ultimately fall out of the stratosphere and enter the lower atmosphere where rain and wind quickly disperse them.

Although scientists understand the basic mechanism of cooling due to eruptions there are many details still to be investigated. Here are some questions for you to consider:

Not all volcanic eruptions seem to effect climate. What are the characteristics, other than bigness, of those that do?

How can geologists predict which volcanoes are likely to impact the climate when they erupt?

What would be the climate effect if a series of large eruptions occurred over 10 years?

For further information:

Volcanic Gases and Climate Change Overview Volcanic Gases and Climate Change Overview (U.S. Geological Survey)

http://volcanoes.usgs.gov/hazards/gas/climate.php

Volcanic Gases and Their Effects (U.S. Geological Survey)

http://volcanoes.usgs.gov/hazards/gas/index.php

Task

Keely sat in the airport terminal waiting for the announcement that their plane could finally take off. Flights had been canceled due to a volcano eruption, for pete’s sake! She and her family had been sitting around now for 2 days, sleeping on the floor, washing off in the bathroom sinks, and eating at fast food stands.

They weren’t alone, of course. There were many people at the airport—all stuck in the same situation. The volcano wasn’t even near the airport! Surely, it would be safe to start flying again soon!

Another family moved to seats near Keely and she started a conversation with a boy that looked to be about her age just to relieve the boredom. They started talking about the volcanic ash that was delaying their trip. Jake said that his father had explained that even though the volcanic eruption had occurred thousands of miles away, it had thrown the ash high into the atmosphere and wind currents were carrying the ash around the world. Flights in the path of the ash had to be canceled or delayed for safety reasons.

Keely had heard the same explanation from her parents so she agreed with Jake until he started to talk about what else his parents had told him. They had also explained that erupting volcanoes had other far-reaching and more serious effects than just delaying air flights. Volcanoes emitted gases, such as carbon dioxide and sulfur dioxide that absorb energy from sunlight and raise Earth’s temperatures. Jake said that he learned in school that Earth’s temperatures have been rising. His parents had also told him that volcanoes with greenhouse gases are just one of the factors that increase Earth’s global temperatures. Jake didn’t like cold temperatures so he didn’t think that sounded that bad until his parents added that increasing global temperatures are linked to severe weather events, ice cap melting, and sea level rise. Jake took it a lot more seriously after hearing all that.

Keely told Jake that her parents had discussed the volcanic eruption with her as well. But they said that volcanic eruptions lower global temperatures! Her parents had explained that active volcanoes emit particles that can block sunlight and therefore lower temperatures.

Both opinions made sense and both were based on the science of volcanoes and eruptions.

Who is correct? Keely or Jake? Do volcanoes increase or decrease temperatures on Earth? Do volcanoes cause climate changes?

Sample Rubrics

The developing rubrics page in the Problem Based Learning section provides a content-specific rubric for the Volcanoes module under the Sample Rubrics heading.

Skill Building Activities

Tropical Atlantic Aerosols

http://mynasadata.larc.nasa.gov/lesson-plans/?page_id=474?&passid=56

(Right) Image courtesy NASA Visible Earth

Purpose: Students will use real satellite data to determine where the greatest concentrations of aerosols are located during the course of a year in the tropical Atlantic region and their source of origin.

Grade level: 8

Estimate Time for Completing Activity: 50 minutes

Learning outcomes:

Students will explore data and draw conclusions about aerosol transport.

Students will learn about the radiation budget effects of aerosols.

Students will consider explanations linking tropical Atlantic aerosols to Atlantic hurricane strength.

Using My NASA Data to Determine Volcanic Activity

http://mynasadata.larc.nasa.gov/lesson-plans/?page_id=474?&passid=40

(Right) Image courtesy Vulcani and Vulcani Online

Purpose: Students will use MASA satellite data of optical depth as a tool to determine volcanic activity on Reunion Island during 2000-2001.

Grade level: 8-12

Estimated time: One 50-minute class period

Learning outcomes:

Understand how aerosols are used in science to indicate volcanic activity

Understand how biomass burning affects global aerosol activity

Access data and import into MS Excel

Use graphical data to make inferences and draw conclusions



Science Project: What Color Is Your Sky?

http://mynasadata.larc.nasa.gov/what-color-is-your-sky/

(Right) Image courtesy Forrest M. Mims III

Purpose: Students will learn about characteristics of the sky they see every day. The activity will explain why the sky is not always blue and will provide some ideas for science projects that will give students a better appreciation of the sky.

Age range: 11 years to adult

Estimated time: You can learn the basic facts about sky color in half an hour. You can then enhance your knowledge by observing the sky every time you have the opportunity. You can share with family members and friends what you have learned about sky color while looking out a window or walking outside. And you can teach students the basic facts about sky color in two brief sessions of 5 to 10 minutes each. For best results one session should be indoors and the other outdoors or in a room with a window or windows having an unobstructed view of the sky. For best results spend time with your students so they can more fully appreciate, understand, and discuss the appearance and color of the sky.

Sky Color for Kids

http://mynasadata.larc.nasa.gov/804-2/sky-color-for-kids/

(Right) Image courtesy Forrest M. Mims III

Purpose: Students will be introduced to the colors of the sky and will learn why the sky has such a wide range of colors.

Age range: 6-10 years

Estimated time: You can teach children just the basic facts about sky color in two brief sessions of about 10 minutes each. For more understanding spend some time observing the sky and looking into why sky colors change with your students.





Learning Objectives

Alignment of Learning Objectives and Standards - Volcanoes and Climate Change