problem solving activity climate change and feedback loops answers

Climate Feedback Loops and Tipping Points

Feedback loops can be positive or negative.

The American Meteorological Society defines a feedback as a sequence of interactions determining the response of the system to an initial change. In the climate system, a feedback is a process that can work as part of a loop to either lessen or add to the effects of a change in one part of the system. When a process helps keep components of the system in balance, it sets up a negative, or balancing, feedback loop. When a change in one part of the system causes changes in the same direction in other parts of the Earth system, a positive, or reinforcing, feedback loop occurs.

A climate feedback is an important part of the Earth system and can set up a loop that influences the type of change. Negative feedback loops help maintain a fairly constant level within the system. Positive feedback loops accelerate or amplify a change.

UK Met Office

An example of a negative, or balancing, feedback loop is the ocean’s ability to store heat , which helps keep temperatures in a livable range across the planet. Another negative, or balancing, feedback loop is the ability of plants and soil to absorb carbon dioxide, removing it from the atmosphere. When discussing feedback loops in our climate system, the word “negative” can actually be a good thing!  An example of a positive feedback loop is the relationship between global warming and increased amounts of water vapor in the atmosphere. A warmer planet causes more water to be evaporated from the surface, resulting in increased heat-storing water vapor in the atmosphere, which leads to more warming in an ongoing, continually amplified cycle. The positive feedback loop between global warming and melting ice sets up another amplifying effect and is already accelerating change within the climate system.

The climate system contains many positive feedback loops, including the interaction between warmer temperatures and ice and snow melt. As the planet warms, ice sheets and sea ice melt, revealing darker land or ocean surfaces that absorb more heat and become warmer, which causes more snow and ice to melt, and the cycle continues. 

Crossing Tipping Points Is Dangerous

Tipping points occur when a positive feedback loop crosses a threshold that leads to large changes, that often can't be turned around or reversed. Essentially, the positive feedback loop becomes so strong, or the changes begin happening so quickly, that the impacts are like a snowball accumulating mass and rolling so quickly downhill that it can’t be stopped.

Tipping points within Earth’s climate system mark a threshold at which positive feedback loops can ‘tip’ an existing, predictable system into a profoundly different pattern.

Creative Commons Rauter et al.

Climate indicators that cross a tipping point mark a transition from an existing regime, or regular pattern, to a new state of the climate and a point of no return. Rising sea levels can be considered an example of this type of shift in conditions. As ice sheets melt , sea levels rise. If the melting of ice sheets crosses a tipping point to where the losses cannot be slowed down or reversed, an increased amount of sea level rise becomes unavoidable. Sea levels have already risen enough to have noticeable effects on many coastal areas. The rising seas represent a new “normal,” or new climate regime: no matter what we do, these changes cannot be easily reversed.

A new normal or new state of the climate might not sound like that much of a problem, but the observed 0.20-0.30 meter (8-12 inch) global average sea level rise is already having detrimental impacts. Many coastal cities are experiencing an increase in the number of days of nuisance tidal flooding each year. Nuisance flooding occurs during high tides (and is also sometimes known as high-tide flooding) and can inundate low-lying areas, close roads, and overwhelm storm drains. With the current and expected sea level rise, such flooding can be expected to continue (and worsen) in decades ahead. 

Nuisance tidal flooding has become more frequent in recent decades (shown in orange on the graph as the number of days experiencing flooding each year). Even under “lower emissions” scenarios, San Francisco could experience coastal flooding nearly every day by the end of this century.

NOAA/State Climate Summaries

• Earth as a System
• How Climate Works

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Lesson of the Day

Explore 7 Climate Change Solutions

In this lesson, students will use a jigsaw activity to learn about some of the most effective strategies and technologies that can help head off the worst effects of global warming.

By Natalie Proulx

Lesson Overview

Earlier this summer, a report issued by the Intergovernmental Panel on Climate Change , a body of scientists convened by the United Nations, found that some devastating impacts of global warming were unavoidable. But there is still a short window to stop things from getting even worse.

This report will be central at COP26 , the international climate summit where about 20,000 heads of state, diplomats and activists are meeting in person this week to set new targets for cutting emissions from coal, oil and gas that are heating the planet.

In this lesson, you will learn about seven ways we can slow down climate change and head off some of its most catastrophic consequences while we still have time. Using a jigsaw activity , you’ll become an expert in one of these strategies or technologies and share what you learn with your classmates. Then, you will develop your own climate plan and consider ways you can make a difference based on your new knowledge.

What do you know about the ways the world can slow climate change? Start by making a list of strategies, technologies or policies that could help solve the climate crisis.

Which of your ideas do you think could have the biggest impact on climate change? Circle what you think might be the top three.

Now, test your knowledge by taking this 2017 interactive quiz:

How Much Do You Know About Solving Global Warming?

A new book presents 100 potential solutions. Can you figure out which ones are top ranked?

After you’ve finished, reflect on your own in writing or in discussion with a partner:

What solutions to climate change did you learn about that you didn’t know before?

Were you surprised by any of the answers in the quiz? If so, which ones and why?

What questions do you still have about solving climate change?

Jigsaw Activity

As you learned in the warm-up, there are many possible ways to mitigate the worst effects of climate change. Below we’ve rounded up seven of the most effective solutions, many of which you may have been introduced to in the quiz above.

In this jigsaw activity, you’ll become an expert in one of the climate solutions listed below and then present what you learned to your classmates. Teachers may assign a student or small group to each topic, or allow them to choose. Students, read at least one of the linked articles on your topic; you can also use that article as a jumping-off point for more research.

Climate Change Solutions

Renewable energy: Scientists agree that to avoid the most catastrophic effects of climate change, countries must immediately move away from dirty energy sources like coal, oil and gas, and instead turn to renewable energy sources like wind, solar or nuclear power. Read about the potent possibilities of one of these producers, offshore wind farms , and see how they operate .

Refrigerants: It’s not the most exciting solution to climate change, but it is one of the most effective. Read about how making refrigerants, like air-conditioners, more efficient could eliminate a full degree Celsius of warming by 2100.

Transportation: Across the globe, governments are focused on limiting one of the world’s biggest sources of pollution: gasoline-powered cars. Read about the promises and challenges of electric vehicles or about how countries are rethinking their transit systems .

Methane emissions: You hear a lot about the need to reduce carbon dioxide in the atmosphere, but what about its dangerous cousin, methane? Read about ideas to halt methane emissions and why doing so could be powerful in the short-term fight against climate change.

Agriculture: Efforts to limit global warming often target fossil fuels, but cutting greenhouse gases from food production is urgent, too, research says. Read about four fixes to earth’s food supply that could go a long way.

Nature conservation: Scientists agree that reversing biodiversity loss is a crucial way to slow climate change. Read about how protecting and restoring nature can help cool the planet or about how Indigenous communities could lead the way .

Carbon capture: Eliminating emissions alone may not be enough to avoid some of the worst effects of climate change, so some companies are investing in technology that sucks carbon dioxide out of the air. Learn more about so-called engineered carbon removal .

Questions to Consider

As you read about your climate solution, respond to the questions below. You can record your answers in this graphic organizer (PDF).

1. What is the solution? How does it work?

2. What problem related to climate change does this strategy address?

3. What effect could it have on global warming?

4. Compared with other ways to mitigate climate change, how effective is this one? Why?

5. What are the limitations of this solution?

6. What are some of the challenges or risks (political, social, economic or technical) of this idea?

7. What further questions do you have about this strategy?

When you’ve finished, you’ll meet in “teaching groups” with at least one expert in each of the other climate solutions. Share what you know about your topic with your classmates and record what you learn from them in your graphic organizer .

Going Further

Option 1: Develop a climate plan.

Scientists say that in order to prevent the average global temperature from rising more than 1.5 degrees Celsius, the threshold beyond which the dangers of global warming grow immensely, we will need to enact all of the solutions you learned about — and more. However, the reality is that countries won’t be able to right away. They will have to consider which can have the biggest or fastest impact on climate change, which are the most cost-effective and which are the most politically and socially feasible.

Imagine you have been asked to come up with a plan to address climate change. If you were in charge, which of these seven solutions would you prioritize and why? You might start by ranking the solutions you learned about from the most effective or urgent to the least.

Then, write a proposal for your plan that responds to the following questions:

What top three solutions are priorities? That is, which do you think are the most urgent to tackle right away and the most effective at slowing global warming?

Explain your decisions. According to your research — the articles you read and the quiz you took in the beginning of the lesson — why should these solutions take precedence?

How might you incentivize companies and citizens to embrace these changes? For some ideas, you might read more about the climate policies countries around the world have adopted to help reduce greenhouse gas emissions.

Option 2: Take action.

Thinking about climate change solutions on such a big scale can be overwhelming, but there are things you can do in your own life and in your community to make a difference. Choose one of the activities below to take action on, or come up with one of your own:

Share climate solutions via media. Often, the news media focuses more on climate change problems than solutions. Counteract this narrative by creating something for publication related to one or more of the solutions you learned about. For example, you could submit a letter to the editor , write an article for your school newspaper, enter a piece in one of our upcoming student contests or create an infographic to share on social media .

Make changes in your own life. How can you make good climate choices related to one or more of the topics you learned about? For example, you could eat less meat, take public transportation or turn off your air-conditioner. Write a plan, explaining what you will do (or what you are already doing) and how it could help mitigate climate change, according to the research.

Join a movement. This guest essay urges people to focus on systems, not themselves. What groups could you get involved with that are working toward some of the solutions you learned about? Identify at least one group, either local, national or international, and one way you could support it. Or, if you’re old enough to vote, consider a local, state or federal politician you would like to support based on his or her climate policies.

Want more Lessons of the Day? You can find them all here .

Natalie Proulx joined The Learning Network as a staff editor in 2017 after working as an English language arts teacher and curriculum writer. More about Natalie Proulx

LEARNING TOOL

• Feedbacks of Ice and Clouds

Students use interactive computational models to explore how light-colored surfaces such as snow, ice, and some clouds have a cooling effect on Earth. Then they interpret real-world data to examine the positive feedback loop between ice coverage and temperature.

Earth Science, Climatology

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Learning materials

• NASA: Global Climate Change | Vital Signs of the Planet

This activity is part of a sequence of activities in the What Is the Future of Earth's Climate? lesson. The activities work best if used in sequence.

Preparation

• Interactions Within Earth's Atmospheres
• Sources, Sinks, and Feedbacks
• Required Technology: internet access; 1 computer per classroom; 1 computer per learner; 1 computer per small group; projector
• Physical Space: classroom; computer lab; media center/library
• Groupings: heterogeneous grouping; homogeneous grouping; large-group instruction; small-group instruction

Solar radiation consists of visible light, infrared radiation (heat), and ultraviolet radiation. When solar radiation encounters Earth's atmosphere and surface, it can be reflected (sent back into space) or absorbed. Energy that is absorbed becomes heat in Earth's surface. This heat can be re-radiated into space. Light-colored surfaces reflect more solar energy than dark-colored surfaces.

Infrared radiation is emitted by Earth's surface. Instead of the infrared radiation being allowed to exit Earth's atmosphere into space, greenhouse gases absorb it and re-emit it, keeping more heat in the atmosphere. Greenhouse gases include carbon dioxide, methane, and water.

Clouds can have a cooling effect or a warming effect, depending on their makeup and position in the atmosphere. High-level clouds have a net cooling effect as they reflect incoming solar radiation. Low-level clouds have a net warming effect as they prevent infrared radiation from escaping into space.

Learning Objectives

Students will:

• explain why light-colored surfaces have a cooling effect on Earths' temperature
• describe the positive feedback loop between temperature and ice cover
• describe the negative feedback loop between cloud cover and temperature
• describe the uncertainty about the feedbacks of temperature, water vapor, and cloud cover that complicate scientists' ability to predict future climate conditions

Teaching Approach: learning-for-use

Teaching Methods: discussions; multimedia instruction; visual instruction; writing

Skills Summary

This activity targets the following skills:

• Learning and Innovation Skills: Critical Thinking and Problem Solving
• Global Awareness
• Analyzing; Evaluating; Understanding

1. Activate students' prior knowledge about reflection and absorption.

Show the photos of the Bear Glacier in Alaska (1909 and 2005, shown above). Tell students that some surfaces reflect light more than others and that more reflective surfaces have a higher albedo. Ask:

• Which photo shows surfaces with higher albedo? (The 1909 photo shows surfaces with a higher albedo. There is more snow and ice in that photo than in the 2005 photo.) 
• Which photo shows surfaces that would absorb the most solar radiation? (The 2005 photo shows surfaces that would absorb the most solar radiation. The ice and snow in the 1909 photo would reflect most of the solar radiation.) 
• Why does a dark-colored surface feel much hotter than a light-colored surface in the sunshine? (The dark-colored surface absorbs more radiation than the light-colored surface. The absorbed radiation becomes heat energy in the surface.)

2. Discuss the role of uncertainty in the scientific process.

Tell students that science is a process of learning how the world works and that scientists do not know the “right” answers when they start to investigate a question. Let students know they can see examples of scientists' uncertainty in climate forecasting.

Show the Global Temperature Change Graph from the 1995 IPCC (Intergovernmental Panel on Climate Change) report and tell them that this graph shows several different models of forecast te mperature changes. Ask:  Why is there more variation (a wider spread) between the models at later dates than at closer dates?  (There is more variation between the models at later dates than at closer dates because there is more variability in predicting the far future than in predicting the near future.)

Tell students that the ability to better predict near-term events occurs in hurricane and tropical storm forecasting as well. Project The Definition of the National Hurricane Center Track Forecast Cone  and show students the “cone of uncertainty” around the track of the storm. The cone shows the scientists' uncertainty in the track of the storm, just as the climate models show the scientists' uncertainty in how much Earth's temperature will change in the future. Ask: When are scientists most confident in their predictions? (Scientists are most confident in their predictions when they have a lot of data. This is why the forecast for near-term events is better than forecasts of longer-term events, both in storm forecasting and in climate forecasting.)

Tell students that they will be asked questions about the certainty of their predictions and that they will need to think about what scientific data are available as they assess their certainty with their answers. Encourage students to discuss the scientific evidence with each other to better assess their level of certainty with their predictions.

3. Discuss the role of systems in climate science.

Tell students that forecasting what will happen in Earth's climate system is a complicated process because there are many different interacting parts. Scientists think about how one part of the system can affect other parts of the system. Give students a simple example of a system, as described in the scenario below.

On an island, there is a population of foxes and a population of rabbits. The foxes prey on the rabbits. Ask:

• When there are a lot of rabbits, what will happen to the fox population? (It will increase because there is an ample food supply.) 
• What happens to the fox population when they’ve eaten most of the rabbits? (The foxes will die of starvation as their food supply decreases.) 
• What happens to the amount of grass when the fox population is high? (The amount of grass will increase because there are fewer rabbits to eat the grass.)
• If there is a drought and the grass doesn’t grow well, what will happen to the populations of foxes and rabbits? (The rabbit population will decrease because they have a lesser food supply. The fox population should also decrease as their food supply decreases.)

Humans introduce dogs to the island. The dogs compete with the foxes over the rabbit food supply. Ask: What will happen to the populations of foxes, rabbits, and grass after the dogs are introduced? (The foxes will decrease because they are sharing their food supply, the rabbits will decrease because they have more predators, and the grass will do well because of the lowered impact of the smaller rabbit population.)

Tell students that they will be exploring cause-effect and system feedback relationships between carbon dioxide and water vapor in this activity. Ask students to think about how each piece of the system affects other pieces of the system.

4. Introduce and discuss the use of computational models.

Introduce the concept of computational models, and give students an example of a computational model that they may have seen, such as forecasting the weather. Project the NOAA Weather Forecast Model , which provides a good example of a computational model. Tell students that:

• scientists use information about the past to build their climate models.
• scientists test their climate models by using them to forecast past climates.
• when scientists can accurately forecast past climates, they can be more confident about using their models to predict future climates.

5. Have students launch the   Feedbacks of Ice and Clouds   interactive.

Provide students with the link to the Feedbacks of Ice and Clouds interactive. Divide students into groups of two or three, with two being the ideal grouping to enable sharing computer workstations. Tell students they will be working through a series of pages of models with questions related to the models. Ask students to work through the activity in their groups, discussing and responding to questions as they go.

Note: You can access the Answer Key for students' questions—and save students' data for online grading—through a free registration on the  High-Adventure Science portal page .

Tell students this is Activity 5 of the lesson What is the Future of Earth's Climate?

6. Have students discuss what they learned in the activity.

After students have completed the activity, bring the groups back together and lead a discussion focusing on these questions:

• What is the relationship between ice cover and temperature?  (When there is a lot of ice cover, the temperature is low. This is because the solar radiation is reflected into space r ather than absorbed.)
• In the model of the Earth system with clouds   (Model 7) , how did clouds affect the temperature?  (In the model, clouds have a cooling effect.)
• Is this model (Model 7) realistic?  (The model is realistic, but it is not complete. Clouds can have cooling effects or warming effects depending on the location and makeup of the clouds. This model only shows high clouds that reflect sunlight back into space.)
• What would happen to ice cover if greenhouse gas concentrations increase?  (Ice cover would decrease. This is because greenhouse gases trap heat energy in the atmosphere, causing the ice to melt because of the increased temperature. As the ice melts, more radiation is absorbed because there are fewer light-colored surfaces to reflect the radiation, leading to further warming.)
• What type of feedback is the relationship between clouds and temperature?  (This is a negative feedback relationship. The cloud cover increases with increasing water vapor, but the cloud cover serves to reduce incoming solar radiation which leads to cooling. The stimulus is counteracted by the response.)
• What type of feedback is the relationship between ice and temperature?  (This is a positive feedback relationship. The melting ice leaves a darker surface that absorbs more solar radiation, leading to more heating, leading to more melting. The stimulus is reinforced and accelerated by the response. Similarly, when the temperature is cold, more ice forms, which reflects more solar radiation, which leads to less heat absorption, which leads to further ice formation.)

Informal Assessment

1. Check students' comprehension by asking them the following questions:

• How do ice, snow, and clouds affect temperature?
• Why is it colder on clear nights than on cloudy nights?
• If the sea ice melts, how might that affect global temperature and the atmospheric concentrations of carbon dioxide and water vapor?

2. Use the answer key to check students' answers on embedded assessments.

Tips and Modifications

• To save your students' data for grading online, register your class for free at the High-Adventure Science portal page .
• This activity may be used individually or in groups of two or three students, or as a whole class activity. If using as a whole class activity, use an LCD projector or interactive whiteboard to project the activity.

Connections to National Standards, Principles, and Practices

National Science Education Standards

• (5-8) Standard A-1 : Abilities necessary to do scientific inquiry
• (5-8) Standard A-2 : Understandings about scientific inquiry
• (5-8) Standard B-1 : Properties and changes of properties in matter
• (5-8) Standard B-3 : Transfer of energy
• (5-8) Standard D-1 : Structure of the earth system
• (5-8) Standard E-1 : Abilities of technological design
• (5-8) Standard E-2 : Understandings about science and technology
• (5-8) Standard F-5 : Science and technology in society
• (5-8) Standard G-1 : Science as a human endeavor
• (9-12) Standard A-1 : Abilities necessary to do scientific inquiry
• (9-12) Standard A-2 : Understandings about scientific inquiry
• (9-12) Standard B-5 : Conservation of energy and increase in disorder
• (9-12) Standard D-1 : Energy in the earth system
• (9-12) Standard E-1 : Abilities of technological design
• (9-12) Standard E-2 : Understandings about science and technology
• (9-12) Standard G-1 : Science as a human endeavor
• (9-12) Standard G-2 : Nature of scientific knowledge

Common Core State Standards for English Language Arts & Literacy

• Reading Standards for Literacy in Science and Technical Subjects 6-12: Craft and Structure, RST.6-8.4
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Key Ideas and Details, RST.6-8.3
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Key Ideas and Details, RST.9-10.3
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Craft and Structure, RST.9-10.4
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Key Ideas and Details, RST.6-8.1
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Key Ideas and Details, RST.11-12.1
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Key Ideas and Details, RST.11-12.3
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Craft and Structure, RST.11-12.4
• Reading Standards for Literacy in Science and Technical Subjects 6-12: Key Ideas and Details, RST.9-10.1

ISTE Standards for Students (ISTE Standards*S)

• Standard 3: Research and Information Fluency
• Standard 4: Critical Thinking, Problem Solving, and Decision Making

Next Generation Science Standards

• Crosscutting Concept 2 : Cause and effect: Mechanism and prediction
• Crosscutting Concept 3 : Scale, proportion, and quantity
• Crosscutting Concept 4 : Systems and system models
• Crosscutting Concept 5 : Energy and matter: Flows, cycles, and conservation
• Crosscutting Concept 7 : Stability and change
• HS. Earth and Human Activity : HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.
• HS. Earth and Human Activity : HS-ESS3-5. Analyze geoscience data and the results from global climate models to make an evidence-based forecast of the current rate of global or regional climate change and associated future impacts to Earth systems.
• HS. Earth's Systems : HS-ESS2-6. Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.
• HS. Earth's Systems : HS-ESS2-4. Use a model to describe how variations in the flow of energy into and out of Earth's systems result in changes in climate.
• HS. Earth's Systems : HS-ESS2-2. Analyze geoscience data to make the claim that one change to Earth's surface can create feedbacks that cause changes to other Earth systems.
• MS. Earth and Human Activity : MS-ESS3-5. Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.
• Science and Engineering Practice 1 : Asking questions and defining problems
• Science and Engineering Practice 2 : Developing and using models
• Science and Engineering Practice 4 : Analyzing and interpreting data
• Science and Engineering Practice 6 : Constructing explanations and designing solutions
• Science and Engineering Practice 7 : Engaging in argument from evidence
• Science and Engineering Practice 8 : Obtaining, evaluating, and communicating information.

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This Overlooked Feedback Loop Is Accelerating Climate Change

By Tufts University March 16, 2024

Climate models must account for numerous factors, including overlooked natural processes like soil degradation. Soil, holding 80% of the Earth’s carbon, releases greenhouse gases under drought conditions, potentially exacerbating climate change. New research highlights the importance of incorporating soil health into climate predictions and advocates for sustainable land use to mitigate these effects. Credit: USDA

Scientists at Tufts University state that soil, which contains 80 percent of the Earth’s carbon, emits more greenhouse gases as droughts cause soils to crack due to drying.

The precision of climate models is influenced by numerous elements, including greenhouse gas emissions stemming from industrial operations and transportation, emissions from farm animals, the expansion of urban areas and the reduction of forests, as well as the reflection of solar rays off snow and other ground surfaces. Additionally, natural occurrences such as volcanic eruptions play a role and are factored into these models.

However, some other natural processes have been overlooked. Farshid Vahedifard, professor and Louis Berger Chair in civil and environmental engineering, points to an important one that lies directly beneath our feet and covers most of our planet above water.

In a study published in Environmental Research Letters , Vahedifard notes that soil stores 80 percent of carbon on Earth, and with increasing cycles and severity of droughts in several regions, that crucial reservoir is cracking and breaking down, releasing even more carbon dioxide and other greenhouse gases into the atmosphere. In fact, it may be creating an amplified feedback loop that could accelerate climate change well beyond current predictions.

“This process has not been sufficiently evaluated in the existing literature or incorporated into models,” said Vahedifard. “If we don’t consider the interplay of drought, soil desiccation cracking, and CO 2 emissions, that could result in significant inaccuracies when modeling and predicting climate change. There are other repercussions as well. Poorer soil health can lead to reduced photosynthesis and lower carbon dioxide uptake, and it can compromise the structural integrity of earthen dams that protect against floods.”

Additional Feedback Loops and Climate Change

There are also other amplifying feedback loops that may not have been fully accounted for in climate change models, he said. These include melting of sea ice and exposure of darker ocean surfaces that absorb more heat from the sun. The increase of wildfires due to warm, dry conditions releases a lot of carbon dioxide into the atmosphere, which in turn creates hotter, drier weather more conducive to fires.

Another amplified feedback loop is the thawing of Arctic and sub-Arctic permafrost, which also releases carbon dioxide into the atmosphere and raises climate temperature, leading to more melted permafrost.

Cycle of drought, drying and cracking soil, and ground carbon release creates and amplified feedback loop that has not been accounted for in most models of climate change. Credit: Farshid Vahedifard, Tufts University

But soil changes caused by drought could be as significant, if not more significant, than any of those factors. Drought, manifested by long periods of low soil moisture content and high temperature, leads to cracking in fine-grained soils, sometimes extending meters below the surface. The cracks result in more exposure to the air, increased microbial activity and breakdown of organic matter, released carbon dioxide, and loss of nutrients and ability to support plant growth, reducing carbon dioxide sequestering.

The deep cracks expose much older reserves of carbon that had previously been stable and protected. The permeation of air into the soil accelerates the release of not only carbon dioxide from organic matter but also other greenhouse gases like nitrous oxide .

Small animals like earthworms and millipedes that help turn the soil over are also affected by the reduced moisture and increased air exposure, being less able to play active roles in nutrient cycling and soil structure maintenance. That, in turn, increases the likelihood of soil cracking and aeration.

“The amplifying effect of soil carbon feedback loops and its interactions with other loops could carry us across tipping points and lead to even more severe and permanent shifts in climate,” said Vahedifard.

He noted that government agencies and policymakers need to promote sustainable land use, “which can include adoption of precision irrigation techniques and water conservation practices, and use of drought tolerant crops,” he said. “Organic fertilizers and compost can enhance soil organic matter content and improve soil water-holding capacity. Of course, this can only help if it’s part of a comprehensive effort to reduce greenhouse gas emissions from all human activity.”

Reference: “Amplifying feedback loop between drought, soil desiccation cracking, and greenhouse gas emissions” by Farshid Vahedifard, C Clay Goodman, Varun Paul and Amir AghaKouchak, 5 March 2024, Environmental Research Letters . DOI: 10.1088/1748-9326/ad2c23

The study was funded by the U.S. National Science Foundation.

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1 comment on "this overlooked feedback loop is accelerating climate change".

“Small animals like earthworms and millipedes that help turn the soil over are also affected by the reduced moisture and increased air exposure, …”

What role does moisture play in the bacterial decomposition of organic material in soil? I suspect it is significant with every day experience of how moisture accelerates rot in most things. Also, increased exposure to air will reduce methane production, which is touted as having a higher potential global warming impact than CO2.

Yes, Carbon Cycle models leave a lot to be desired. They leave out a lot of anthropogenic emissions [ http://wattsupwiththat.com/2015/05/05/anthropogenic-global-warming-and-its-causes/ ] and they appear to do a poor job of estimating respiration from the roots of seasonally-dormant trees, particularly Boreal trees south of the tundra. The recent Carbon Cycle models show plant respiration at about half of photosynthesis, and only include CO2 from terrestrial volcanoes.

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Activity 10: Feedback Loops Applied

Cameron Weiner - Undergraduate - Middlebury College, [email protected]

Lisa Gilbert - Professor of Geosciences and Marine Science - Williams-Mystic, [email protected]

This activity was selected for the On the Cutting Edge Exemplary Teaching Collection

Resources in this top level collection a) must have scored Exemplary or Very Good in all five review categories, and must also rate as "Exemplary" in at least three of the five categories. The five categories included in the peer review process are

For more information about the peer review process itself, please see https://serc.carleton.edu/teachearth/activity_review.html .

Students apply the vocabulary and concepts from the Activity 9: Feedback Loop Introduction to assess and create earth science feedback loops with the LOOPY online modeling program. (Optional) The students then engage in a discussion of the limitations of the LOOPY program to create feedback loop diagrams.

Expand for more detail and links to related resources

Activity Classification and Connections to Related Resources Collapse

Grade level.

This activity is intended for a middle school science course. Materials presented here are designed to be implemented in a remote learning environment, either as part of an entirely online or hybrid course.

Skills and concepts that students must have mastered

Students need background information on systems thinking vocabulary and feedback loops (reservoir, flow, equilibrium/nonequilibrium or stable/unstable).

How the activity is situated in the course

This activity is designed to be taught following Activity 9: Feedback Loop introduction to apply feedback loops to course relevant material. This activity is additionally best taught in conjunction with the Systems Thinking vocabulary Activity 1 and the equilibrium experiment Activity 8 (the instructor can pick and choose the vocabulary elements from these activities).

Content/concepts goals for this activity

• Students apply feedback loop vocabulary and concepts to earth science systems.
• Students assess earth science system feedback loops.
• Students create earth science system feedback loops.
• (Optional) Students discuss the limitations of modeling feedback loops with LOOPY.

Higher order thinking skills goals for this activity

Other skills goals for this activity, description and teaching materials.

• Zoom meeting or other online platform (with breakout groups enabled)
• Make a single copy for Instructor use
• Give students access to their own copies to fill out individually
• LOOPY diagrams (linked in the Student Handout and Instructor Guide)
• Student/Instructor Resource: LOOPY instructional Video

Activity Description (total time: 20-30 min)

Part 1 - Applying Feedback Loops to Earth Science Systems (20 min)

Students complete Student Handout Activity 10 , applying the feedback loop vocabulary and concepts from Activity 9 to the following feedback loop examples:

• Plastic Bottle Use Feedback Loop : This LOOPY shows the reinforcing feedback loop of people demanding plastic bottles, companies making plastic bottles for people to purchase, companies selling plastic bottles, and people purchasing, using, and throwing those bottles away.
• Thermohaline Ocean Current Feedback Loop : This LOOPY shows the balancing ocean temperature regulation feedback loop of warm surface water flowing to the poles, cooling, freezing and sinking, and cool deep ocean currents bringing water back towards the equator, and warming and rising. The background information provided to students from this YouTube video . 
• Students create their own LOOPY model of the Hadley cell or the mantle convection balancing feedback loop. The background information provided to students from this YouTube video (same as in C above).

(Optional) Part 2 - LOOPY Limitations Discussion (10 minutes)

As students create their own feedback loops on LOOPY (Part D of the Student Handout), they may become frustrated that they cannot create their feedback loop model exactly how they would like to or the model they make may not represent the feedback loop system perfectly.

The instructor can share their screen and present the discussion prompts using the Discussion Activity 10 Powerpoint with discussion prompts and/or provide students with the Discussion Notes Activity 10 Google Doc which contains the prompts and space for notes.

Slide 1: Assessing the limitations of LOOPY

Slide 2//Discussion Question 1 (5 min): How did LOOPY help you create your feedback loop?

Slide 3//Discussion Question 2 (5 min): How did LOOPY make it difficult to create your feedback loop?

Alternatively: A question about the limitations of the loopy diagrams students created could also be added to the student handout instead of completing a class discussion:

• What are the limitations of LOOPY? (i.e. How did LOOPY make creating your feedback loop challenging?)

Alternatively: Activity 7 provides students with the framework to assess the limitations of a systems diagram (like these feedback loop diagrams) that could also be substituted for Part 2 of this activity.

Teaching Notes and Tips

The feedback loop examples in the student handout can easily be substituted for examples that fit better into the instructor's science course. These examples could also be modified to fit skills, history, or english courses. Here are some other example feedback loops:

• Mice and Birds of Prey Populations mini ecosystem - More mice, more birds of prey; fewer mice, fewer birds of prey
• Reservoir Water Cycle : Simplified water cycle diagram with inflows (precip/snowmelt/groundwater), reservoir (lakes, oceans, glaciers), and outflows (rivers, evaporation, human use, groundwater)
• Other ideas: Homeostasis, Sustainable Farming

Reinforcing

• Water Demand : People demanding more and more water with no change in inflow
• Water Pollution : Untreated water flowing into waterways and building up in water bodies
• Social Media Algorithms - Newsfeed shows you what you react to, hides what you don't.
• Ice Cover and Climate Change (Albedo) - The more ice the cooler the earth gets, the cooler the earth gets the more ice; the less ice the warmer the earth gets - the warmer the earth gets the less ice there is.
• Other ideas: Impacts of Systemic Racism, Farming and Soil Degradation, Addiction

Activity 7 provides students with the framework to assess the limitations of a systems diagram (like these feedback loop diagrams) that could also be substituted for Part 2 of this activity.

Answer Key Student Handout Activity 10

References and Resources

This systems thinking module is based on the undergraduate Systems Thinking module on InTeGrate, created by Lisa A. Gilbert, Deborah S. Gross & Karl J. Kreutz. This feedback loop activity relates to Unit 4: Feedbacks in a System .

Online Feedback Loop Diagramming Tool: Loopy by Nicky Case: https://ncase.me/loopy/

Systems Thinking Vocabulary Glossary

Why teach systems thinking in Middle School?

"Appendix G - Crosscutting Concepts." 2013. Next Generation Science Standards. https://www.nextgenscience.org/sites/default/files/Appendix%20G%20-%20Crosscutting%20Concepts%20FINAL%20edited%204.10.13.pdf

Learn about why we should teach Systems Thinking in Earth Science:

• Lisa A. Gilbert, Deborah S. Gross & Karl J. Kreutz (2019): Developing undergraduate students' systems thinking skills with an InTeGrate module, Journal of Geoscience Education, https://doi.org/10.1080/10899995.2018.1529469
• SERC's page on Complex Earth Systems: An explanation of the different types of systems thinking involved in Earth's systems  

Learn more about teaching systems thinking: 

• Q Design Pack Systems Thinking. Institute of Play. http://educators.brainpop.com/wp-content/uploads/2014/07/IOP_QDesignPack_SystemsThinking_1.0.pdf
• Mambrey, Sophia, Justin Timm, Jana Julia Landskron, and Philipp Schmiemann. 2020. "The Impact of System Specifics on Systems Thinking." Journal of Research in Science Teaching , July, tea.21649. https://doi.org/10.1002/tea.21649

Learn more about systems thinking:

• Meadows, Donella H., and Diana Wright. 2008. Thinking in Systems: A Primer . White River Junction, Vt: Chelsea Green Pub. https://wtf.tw/ref/meadows.pdf  

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Climate Emergency Feedback Loops Permafrost Video

Susan Gray, Bonnie Waltch, Barry Hershey, Moving Still Productions

The video provides a comprehensive overview of what permafrost is and why it matters in the context of climate change. The video includes: The definition of permafrost, the geographic extent, defines the problem of warming and melting permafrost, compares the amount of permafrost carbon content to all the world's forests, describes how carbon dioxide and methane are released when permafrost melts, includes visuals showing feedback loop, shows field work being done in Alaska and subsequent lab analysis of permafrost cores, and shows time release images of ground collapse on a slope due to permafrost melting.

Notes from our reviewers

The CLEAN collection is hand-picked and rigorously reviewed for scientific accuracy and classroom effectiveness. Read what our review team had to say about this resource below or learn more about how CLEAN reviews teaching materials .

• Teaching Tips Consider using this video to introduce topics related to permafrost and positive feedback loops. This video may also be useful in introducing subjects such as microbial metabolism, restoration practices, and the differences in carbon sources. This resource could also be used to highlight how decomposers are involved in the global carbon cycle. This video is focused on negative aspects of climate change. Teachers may want to supplement with discussion about how to look at and work through the issue presented. There could also be much more discussion about what permafrost is, where it's located, and how it's formed.
• About the Science This video uses expert scientists from places like the University of Cambridge to explain how microbial activity of thawing permafrost contributes to increased greenhouse gas emissions in arctic climates of the world. Accelerating positive feedback loops may also release pools of methane gas as permafrost thaws. Of special interest are the scenes showing scientists in the field collecting samples and later in the lab analyzing the samples / discussing the data. Although the video includes important scientific information, the provided solutions that include "greening the earth" are oversimplified and lack nuance. Teachers may want to supplement through discussion. Passed initial science review - expert science review pending.
• About the Pedagogy Foundational science concepts related to systems are presented in the video. Students will need to have an understanding of feedback loops in order to fully understand the visuals of feedback loops shown in the video. Students will also need to have an introduction to atmospheric chemistry to understand heat trapping and residence times. This video contains a "permafrost discussion guide" under educational materials in the menu tab. The guide provides a summary of the video information and supports a discussion about how to proceed and manage permafrost in a time of climate change. It's not obvious where to find the teacher guide so teachers may want the direct link [link https://feedbackloopsclimate.com/educational-materials/.] This video and the accompanying materials present a challenging issue to discuss, permafrost melting, because we can do nothing about it directly. The best solution is to stop climate change. Digging into this more along with associated issues might make for an interesting class. The intro video would be helpful for students and educators to watch before diving into this video [link https://feedbackloopsclimate.com/introduction/]
• Technical Details/Ease of Use Educational materials are hard to find but direct links are provided in the related URLs and pedagogy boxes. Educational materials are only available in PDF format.