The Costs and Benefits of Environmental Changes

The Costs and Benefits of Environmental Changes

This idea set explores unexpected and often obscured effects of human modifications of the environment. Challenge students to think about their own habits of consumption as well as the habits of human society as a whole with these activity ideas.


5 - 8


Earth Science, Geography, Social Studies

Dams, like this, the first dam on the Mekong River in Zaduo, China, are just one of the ways humans modify the natural environment.
Photograph by Michael S. Yamashita
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Morgan Stanley

One challenge of measuring the environmental impact of human modifications to Earth is quantifying the effects that are often invisible to the vast majority of the world’s people. Aside from locals who are experiencing change firsthand, many people are mostly unaware of the environmental impact of oil spills, removing a dam, or even buying certain products. This idea set dives into these environmental modifications and explores the varied, widespread, and often obscured effects of human life on the environment while encouraging students to analyze their own habits through their learning.

While dams can protect communities from potentially harmful flooding, these artificial structures can also be harmful to the environment. Here, extreme low water is downstream of Nepal's hydropower dam at the Kali River.
A Dam Do or Do Not: Debating Dam Removal

Dams change a landscape’s ecosystem and waterways permanently—unless they are removed. Sometimes, however, the removal causes just as many problems as keeping the dam in place. Weigh the pros and cons of dam removal with students. First, have students read two articles about dam removal: Removing a Dam, River Revives After Largest Dam Removal in U.S. History, and The Pros and Cons of Dam Removal. After dividing students into two groups, giving one group the position of “pro dam removal” and assign the other group “against dam removal.” Have students research their positions and prepare for a debate to defend their position. Then hold a debate between the two sides, letting each student share one of their points. At the end of the debate, have students share which side they personally fall on, after hearing both sides and doing research.

To extend this activity, review the section on the Argo Dam in The Pros and Cons of Dam Removal article as a counter argument. Finally, have students do more research and debate the removal of the Argo Dam, or write a persuasive essay of their opinion.

Deforestation, cutting down the trees in forests is a common way humans modify their environments. Shown here are logs cut from trees taken from South Africa's Kruger National Park.
The Daily Impact of Deforestation

While students may think that cars, machinery, and other large items are the main threat to trees, smaller items that people use everyday can also contribute to worldwide deforestation. Have students consider their impact on the environment by researching the origins of the products they use. First, have students read articles on some of the causes of deforestation: WWF’s Timber Introduction, Palm Oil Scorecard 2016, and FAO: Commercial agriculture accounted for almost 90 percent of deforestation globally. Then brainstorm a list of products that students use everyday, even those that are seemingly not connected to trees (including beauty and food products). Have each student pick one of the items listed and research the environmental impact of those products on deforestation. Instruct students to take notes on their chosen item and create an informational pamphlet or handout about their findings, giving their product a letter grade on its tree-friendliness. Finish the activity by having each student present their findings and letter grade, and compiling a class list of products by letter grade to distribute to other students in the school.

Humans not only farm the land but also the water using aquiculture. Here, catfish are being harvested from a fish-farm pond in Itta Bena, Mississippi, United States.
Aquiculture: Pros and Cons

Aquiculture is a type of farming, most often used in the food industry, where fish and other aquatic animals are raised in oceans and waterways. While there are aquiculture methods that are more sustainable, there are still some environmental impacts. Investigate the pros and cons of aquiculture with students by reading Seafood Month: Aquaculture Allure. As a class, make a T chart with Pros on one side, Cons on the other, and fill out the chart with information students read in the article. Then share the graphic The Mangrove Ecosystem. Read the infographic aloud, and using the shrimp farming inset, add additional pros and cons to the class list. In a class discussion, ask students to further analyze the rest of the infographic and hypothesize about other possible positive or negative outcomes of increasing the use of aquiculture farming. Then, ask students to imagine they are citizens who live near the mangrove ecosystem. Ask them to draft a letter to a local or state government official, arguing for or against increasing the amount of aquiculture that is happening in their area.

Extracting fossil fuels, like oil, have huge environmental impacts. The huge price paid by this process is made most obvious by underwater oil spills, like on oil rigs.
Oil Spill in the Gulf

Oil spills can have disastrous effects on plants and wildlife, especially when the spill is underwater. Investigate these effects with National Geographic’s The Gulf of Mexico: Layers of Life infographic. Share the infographic with students and have them read aloud the key sections about the effect of oil spills on the Gulf of Mexico. Assign each student one of the “layers of life” from the infographic, including the above-ground mangrove forests and shoreline. Have students use the infographic and additional resources from the library or online to research plants and animals that live in the layer assigned to them, as well as the short- and long-term effects oil can have on them. Also ask students to look for ways to rehabilitate the area to bring back the flora and fauna in their layer. Then bring students together into groups, making sure each layer was researched by at least one student in the group, and have them share their work with each other, creating a master list of the negative effects of an oil spill on the Gulf’s flora and fauna. Together in their groups, students will imagine a plan to rehabilitate the Gulf, then write a brief plan for a campaign to spread awareness of how to improve the Gulf’s ecosystem. The plan may include local outreach, national coverage in the press, social media messaging, and more.

Studies show artificial light can have profound effects on nearby animals, disrupting their natural cycles. Photographs taken from space highlight the change urban areas have on the night sky.
Reducing Light Pollution

Light pollution is an often-overlooked area of humanity’s effect on the environment. Start an investigation of this topic by having students read this article on Light Pollution. Guide students to take notes on the different effects light pollution can have on an environment and the people within it. As a class, discuss the points most relevant to students’ neighborhoods and region, such as effects on specific local animals and humans. In pairs, have students create a locally-focused marketing campaign around reducing light pollution, with tips for family homes or businesses. Ask students to create at least three different forms of media or outreach (such as flyers, social media posts, scripts for television commercials or radio ads, and special events). Have each pair present their marketing campaign to the class, explaining who the campaign is geared toward and why they think their messaging will be effective.

To extend the activity, have students choose one part of their campaign to implement locally. Have students contact local leaders (in government, local news, local interest groups, etc.) to help them reach their intended audience.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Tyson Brown, National Geographic Society
National Geographic Society
Production Managers
Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Clint Parks
Last Updated

March 13, 2024

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