Note to reviewers (March 2022). This is complete, but might have some typos. Please use the “contact” link above to let me know.

Link to the Greenhouse Effect and Climate Disruption Student Learning Guide

1. Introduction: Carbon cycle review

In the previous tutorial, you learned about the Carbon Cycle. Take the click-on quiz below to review.

[qwiz quiz_timer=”true” dataset=”Carbon Cycle Click On Dataset” dataset_intro=”false” qrecord_id=”sciencemusicvideosmeister1961-Carbon Cycle Click-On Review”]

[h] Carbon Cycle Click-On Challenge

[i]Notice the timer in the upper right corner. Your goal is to build mastery by working as quickly and accurately as possible.

[q json=”true” hotspot_user_interaction=”label_prompt” dataset_id=”Carbon Cycle Click On Dataset|212b1495ea1b9a” question_number=”1″] The carbon cycle. Click on the reservoir, flow, or its letter or number.

CO2 in the atmosphere

Awesome! CO2 is at number 1. 

HINT FOR NEXT TIME: Carbon dioxide has one carbon atom and two oxygen atoms.Where do you see a molecule like that? 
Photosynthesis

Excellent: “A” is photosynthesis.

HINT FOR NEXT TIME: Find an arrow that’s bringing carbon into plants. 
Respiration by plants

Exactly. “B” is respiration by plants.

HINT FOR NEXT TIME: Find an arrow that’s moving carbon from plants back to the atmosphere.
Ecological Producers

Exactly.  Plants, at “2” are ecological producers.

HINT FOR NEXT TIME:  Plants are ecological producers. 
Consumption

Fantastic. “C” is consumption.

HINT FOR NEXT TIME:  Consumption moves carbon-based compounds from plants to animals.
Ecological consumers

Good work: “3” represents ecological consumers.

HINT FOR NEXT TIME:  Animals are ecological consumers.
Death

Great! Death by animals is “E.” Death by plants is “F.”

HINT FOR NEXT TIME:  Find arrows moving from animals or plants to decomposers. Bacterial and fungi are decomposers.
Decomposers

Nice! The fungi and bacteria at “4” are decomposers.

HINT FOR NEXT TIME:  Fungi and bacteria are decomposers.
Fossil fuel formation

Outstanding! The arrow at “H” represents fossil fuel formation.

HINT FOR NEXT TIME:  Find the arrow that’s going from dead plants to the oil rig.
Fossil fuels

Superb! “5” represents fossil fuels.

HINT FOR NEXT TIME:  Coal, oil, and natural gas are fossil fuels.
Fossil fuel extraction (mining/drilling) and processing.

Terrific. Letter “I” represents fossil fuel extraction.

HINT FOR NEXT TIME:  Find a flow that would take oil/petroleum from the ground to machines.
Fossil fuel powered machines

That’s right. Number 6 represents fossil fuel powered machines

HINT FOR NEXT TIME:  A factory is (usually) either powered by fossil fuels, or by electricity from fossil fuels.
Combustion

Thumbs up! “J” represents combustion.

HINT FOR NEXT TIME:  Machines/factories (often) combust fossil fuels, which emits carbon dioxide into the atmosphere.
Respiration by decomposers.

Way to go! “G” represents respiration by decomposers.

HINT FOR NEXT TIME:  Decomposition involves cellular respiration, which releases carbon dioxide into the atmosphere. Find a flow from decomposers.

[/qwiz]

2. Through combustion of fossil fuels, humans have disrupted the carbon cycle

Over the past 200 years, humans have changed the Earth’s natural carbon cycle.  As you’ve learned, there are natural flows that take carbon dioxide out of the atmosphere (photosynthesis – letter “A” in the carbon cycle diagram above) and release carbon dioxide back into the atmosphere (plant and animal respiration – letters “B” and “D”, and decomposition – letter “G”).  But, through burning fossil fuels (letter “J”), humans have added enough carbon dioxide to the Earth’s system to change the balance. The result is to more carbon dioxide remaining in the atmosphere.

2a. Humans are adding enough  CO2 to the atmosphere to make a difference

How much carbon dioxide? Combustion of fossil fuels from CO2 adds about 3% to the natural flow of CO2 into the atmosphere.  While 3% might not sound like a lot, that CO2 has been accumulating for the last 200 years .

Think of all the cars and factories and power plants all over the world. Most of these are powered by fossil fuels. As a result, most of these are emitting carbon dioxide. To emit means to produce and release something into the environment. What gets emitted is called an emission. Combustion emits  carbon dioxide (and water vapor) into the air.

Here are a few examples of activities that result in carbon dioxide emissions.

  • Electrical power generation: When you open up your refrigerator, it might not feel like you’re burning anything. But the electricity that powers your refrigerator (and every other electrical appliance in your house) was probably generated in a power plant that made the electricity by burning coal or natural gas. That’s how 60% of the electricity in the United States is generated.
    Note that there are ways to make electricity that don’t result in carbon dioxide emissions. These include solar power, wind power, and hydroelectric power. We’ll briefly discuss these at the end of this tutorial.
  • Transportation: Unless it’s an electric vehicle, the energy that powers cars, buses, trucks and trains is a liquid fuel made from oil (petroleum). That includes the gasoline or diesel that we put in our cars. It also includes the jet fuel that powers airplanes. Even if you’re driving an electric car, the electricity itself might have been generated through combustion of fossil fuels.
  • Home heating and cooking: If you cook with gas, you’re burning what’s called natural gas. Many home heating systems work by burning natural gas. And, as with electrical vehicles, even if you cook with an electric stove, the electricity might come from a fossil fuel powered generating station.

 

You can see how much carbon dioxide humans have emitted into the air in the graph on the right. Note the increase between 1800, when the Industrial Revolution began, and now.

In 2020, global carbon dioxide emissions were 39 billion tonnes. A metric tonne is 2205 pounds: a bit more than the weight of a car. That’s a lot of carbon dioxide emitted into the air, every year.

 

2b. Emissions of CO2 are increasing the amount of CO2 in the atmosphere

Given all of the carbon dioxide we’ve been emitting into the atmosphere, it’s no surprise that the amount of CO2 in the air is going up.

Since 1958, scientists have been directly measuring the amount of carbon dioxide in the atmosphere. The gas is sampled at various sites around the globe. The most famous of these sites is the Mauna Loa Astronomical Observatory in Hawaii, which is where atmospheric carbon dioxide was first sampled. The scientist who began this effort was named Charles Keeling, and the line showing atmospheric carbon dioxide change is often called the Keeling Curve. 

Carbon dioxide makes up only a small fraction of our atmosphere: much less than one percent. By contrast, nitrogen gas makes up about 78% of the molecules in the air, and oxygen makes up about 21%.  Because there’s so little carbon dioxide, its level is measured in parts per million (ppm). For example, in 1960, the carbon dioxide level was 320 ppm. That means that for every million molecules of gas making up the atmosphere, there were 320 molecules of carbon dioxide. In percentage terms, 320 ppm is 0.032%.

Study the graph above. Over the past 60 years, the fraction of carbon dioxide in the atmosphere has steadily increased. In 2013, the level of carbon dioxide passed 400 ppm. In 2021, the level reached 419 ppm. That’s a 30.9% increase in 60 years.

If you look closely at any year on the Keeling curve, you’ll note that there’s a seasonal rise and fall. That rise and fall is related to the carbon cycle, and two features of the Earth.

  1. The Earth has more land mass north of the equator than south of the equator.
  2. Enormous forests blanket much of the northern part of the Earth (think of the forests of Canada and Russia).

During the Northern summer, the trees in the northern forests are doing photosynthesis. That pulls carbon out of the air through carbon fixation, pulling the Earth’s carbon dioxide level down. In the winter, those trees can’t do very much photosynthesis (because of the short days). These plants keep themselves alive by doing cellular respiration. That increases the Earth’s carbon dioxide level.

Ice core from a glacier. source: NASA.

We know the level of carbon dioxide in the air since 1958 through direct measurements of the air. But the record of carbon dioxide levels goes back hundreds of thousands of years. That’s because of air bubbles trapped in glaciers. The air in these bubbles can be hundreds of thousands of years old. Measuring the amount of carbon dioxide in those air bubbles tells us how much carbon dioxide was in the air before 1958.

Based on these samples, it’s been determined that the amount of carbon dioxide in the atmosphere at the start of the Industrial Revolution was 280 ppm. That means that combustion of fossil fuels has increased the Earth’s carbon dioxide level by just under 50% during the past 200 years.

In the next section, we’ll see the effect that this increase in carbon dioxide levels has had upon the Earth’s systems for regulating climate. But first, consolidate your understanding of the terms and concepts above with a set of flashcards.

3. Altering the Carbon Cycle: Flashcards

[qdeck qrecord_id=”sciencemusicvideosmeister1961-Altering the Carbon Cycle (FC)”]

[h]Altering the Carbon Cycle

[i]

[q]Fill in the blanks in the sentences below.

The main way that humans have altered the carbon cycle has been through….That’s because ….

[a]The main way that humans have altered the carbon cycle has been through burning fossil fuels. That’s because combustion of fossil fuels releases carbon dioxide into the atmosphere. 

[q]List three examples of everyday activities that probably involve combustion of fossil fuels.

[a]Three everyday activities that probably involve combustion of fossil fuels include:

  • Any use of electricity (because most electricity is generated by burning fossil fuels).
  • Almost any form of transportation (because most cars, buses, and trucks are powered by engines that burn fossil fuels).
  • Heating your home or cooking food (because heating furnaces  burn natural gas or fuel oil, and many stoves and ovens use natural gas.

Many other answers are possible.

[q]List the general formula for combustion

[a]A general formula for combustion is

FUEL +  oxygen →  energy (heat) + carbon dioxide + water

[q]The three-letter abbreviation for the concentration of carbon dioxide in the air is _________. This stands for …

[a]The three-letter abbreviation for the concentration of carbon dioxide in the air is ppm. This stands for parts per million. 

[q]The graph below shows how the amount of _________ released by ___________________has ___________ during the past 200 years.

[a]The graph below shows how the amount of CO2 released by combustion of fossil fuels has increased during the past 200 years. 

[q]The graph below shows how the amount of ________________ in the atmosphere has increased from about __________ in 1960 to about __________ in 2020.

[a]The graph below shows how the amount of carbon dioxide in the atmosphere has increased from about 320 ppm in 1960 to about 420 ppm in 2020.

[q]This is important enough to memorize: The amount of carbon dioxide in the atmosphere in 2020 is about _____________. In 1960 it was about ______________. Before the industrial revolution, it was ___________.

[a]The amount of carbon dioxide in the atmosphere in 2020 is about 420 ppm. In 1960 it was about 320 ppm. Before the industrial revolution, it was 280 ppm.

[q]he overall trend in carbon dioxide levels is up. But within that trend, there’s a seasonal cycle. Explain.

[a]The seasonal cycle is related to the fact that there are more forests in the Northern hemisphere. As a result

  • Increased amounts of photosynthesis/carbon fixation happen every summer in the Northern Hemisphere, pulling carbon dioxide levels down.
  • Decreased photosynthesis/carbon fixation and increased plant cellular respiration happens every winter in the Northern hemisphere, pushing carbon dioxide levels up.

[q]How do we know that amount of carbon dioxide in the air since 1960? How do we know the amount going back hundreds or thousands of years?

[a]Since about 1958, the amount of carbon dioxide in the air has been directly sampled in many places. The most famous of these is the astronomical observatory at Mauna Loa in Hawaii, where the air has been sampled every year since 1958.

Going back further in time, tiny bubbles of air trapped in the ice in glaciers can tell us what the carbon dioxide level in the air was like in the past. That record goes back 800,000 years.

[q]The graph below is saying that…

[a]The graph below is saying that the level of carbon dioxide in the atmosphere has increased from 278 ppm before the industrial revolution to about 417 ppm in 2020. That’s almost a 50% increase, caused by human emissions of carbon dioxide.

[/qdeck]

4. Understanding the Greenhouse Effect

Among the planets in the solar system, the Earth has a uniquely moderate temperature. The Earth has some hot places and some cold places, but  if you averaged out all the temperatures around the globe, you’d find that the Earth’s average temperature is 59 °F (15 °C).

The Earth has several systems that control average temperature. One of the most important of these is called the Greenhouse effect.

Why is it called the greenhouse effect?  A greenhouse is a special structure for growing plants. The roof and walls are made of glass or plastic, which let light from the sun enter. The windows also trap heat, which usually warms the greenhouse to a comfortable, plant-friendly temperature, even in the winter.

The greenhouse effect involves the same process of letting light through and trapping heat, but on a planetary scale. Here’s how it works.

4a. CO2 and Methane are Greenhouse Gases

In the diagram to your right, “1” represents  the sun. Number 2 represents the sun’s energy. When the sun’s energy strikes the Earth (“3”), two things happen.

First, some sunlight is reflected back out into space. Light reflected from the Earth is represented by arrow # 4.

Second, some of the sun’s energy is converted into heat energy, which is represented by arrow # 5. If you’ve ever walked on hot sand on a beach or hot pavement on the street, then you’ve experienced how the sun’s energy can heat the Earth’s surface.

Heat energy is also called infrared radiation. You can’t see infrared radiation (except with special goggles). But you can feel it. That infrared radiation warms the atmosphere and heads back out into space. In the diagram, the atmosphere is represented by number 8, and heat from the Earth is represented by arrow number 5.

Our atmosphere is mostly made out of nitrogen and oxygen gas, which make up 78% and 21% of the gases in the air. Nitrogen and oxygen let infrared radiation pass right through the atmosphere. However, a few other gases are greenhouse gases. These are represented by number 9 in the diagram. Note that in reality, they don’t form a layer, but are mixed throughout the atmosphere.

The most important greenhouse gases are carbon dioxide (CO2) and methane (CH4). We’ve talked a lot about carbon dioxide in the context of the carbon cycle. Methane is produced naturally by bacteria that live in the guts of animals like cows, sheep and people. Every time a cow or sheep (or person) farts or belches, methane is released into the air. Methane is also naturally produced by bacteria in swamps or lakes. In addition, many human activities also produce methane. These activities include coal mining, waste-water treatment, landfill emissions and industrial processes.

4b. Greenhouse Gases Trap the Earth’s Heat

When infrared radiation from the Earth hits greenhouse gas molecules, those molecules absorb the energy, and then re-emit that energy. Some of that energy goes out into space (arrow number 6). Some of the energy gets sent back down into the Earth’s atmosphere (arrow number 7).

Arrow number 7 is what the greenhouse effect is all about. The greenhouse effect traps some of the Earth’s heat, and sends it back to the Earth’s surface. It’s estimated that without the greenhouse effect, the Earth’s average temperature would be -15 °C (5 °F). The Earth’s surface would be frozen solid.

So, the greenhouse effect is a good thing. It’s responsible for the mild temperatures that support life on Earth, and which make civilization possible. We’ll see below, however, that human activities — especially human-caused emissions of carbon dioxide and methane — have altered the natural greenhouse effect in a way that is disrupting our climate. We’ve taken the natural greenhouse effect, and created an intensified greenhouse effect.

But first, take the quiz below to make sure that you really understand the diagram and information above.

4c. Understanding the Natural Greenhouse Effect

[qwiz qrecord_id=”sciencemusicvideosmeister1961-The Natural Greenhouse Effect”]

[h]Understanding the Natural Greenhouse effect

[q] In the diagram below, energy from the sun heading towards the Earth is represented by number

[textentry single_char=”true”]

[c]ID I=[Qq]

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[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50IGZvciBuZXh0IHRpbWUuICYjODIyMDsxJiM4MjIxOyByZXByZXNlbnRzIHRoZSBzdW4uICYjODIyMDszJiM4MjIxOyByZXByZXNlbnRzIHRoZSBFYXJ0aC4gRmluZCBhbiBhcnJvdyB0aGF0IHJlcHJlc2VudHMgc29tZXRoaW5nIGNvbWluZyBvdXQgb2YgdGhlIHN1biBhbmQgaGVhZGluZyB0b3dhcmQgdGhlIEVhcnRoLg==[Qq]

[q] In the diagram below, the surface of the Earth is represented by number

[textentry single_char=”true”]

[c]ID M=[Qq]

[f]IEV4Y2VsbGVudC4gJiM4MjIwOzMmIzgyMjE7IHJlcHJlc2VudHMgdGhlIHN1cmZhY2Ugb2YgdGhlIEVhcnRoLg==[Qq]

[c]ICo=[Qq]

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[q] In the diagram below, light reflected by Earth that heads back into space is represented by

[textentry single_char=”true”]

[c]ID Q=[Qq]

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[c]ICo=[Qq]

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[q] In the greenhouse effect, energy from the sun gets absorbed by the Earth. The Earth then emits heat. Heat emitted by the surface of the Earth is represented by

[textentry single_char=”true”]

[c]ID U=[Qq]

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[c]ICo=[Qq]

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[q] In the greenhouse effect, heat emitted by the surface of the Earth is absorbed by Greenhouse gases, which re-emit that heat. Some of that heat gets radiated out into space. Heat from greenhouse gases heading out to space is represented by

[textentry single_char=”true”]

[c]ID Y=[Qq]

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[c]ICo=[Qq]

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[q] In the greenhouse effect, heat emitted by the surface of the Earth is absorbed by greenhouse gases, which re-emit that heat. Some of that heat gets radiated back to the Earth. Heat from greenhouse gases getting sent back to the Earth is represented by

[textentry single_char=”true”]

[c]ID c=[Qq]

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[c]ICo=[Qq]

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[q] In the diagram below, the atmosphere is represented by

[textentry single_char=”true”]

[c]ID g=[Qq]

[f]TmljZSEgJiM4MjIwOzgmIzgyMjE7IHJlcHJlc2VudHMgdGhlIGF0bW9zcGhlcmUu[Qq]

[c]ICo=[Qq]

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[q] In the diagram below, greenhouse gases are represented by

[textentry single_char=”true”]

[c]ID k=[Qq]

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[c]ICo=[Qq]

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[q] If you had to choose one number from the diagram below to represent the greenhouse effect, what number would it be?

[textentry single_char=”true”]

[c]ID c=[Qq]

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[c]ICo=[Qq]

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Cg==

W3Jlc3RhcnRd[Qq]

[/qwiz]

5. Combustion of CO2, release of methane, and other changes are creating an Intensified Greenhouse Effect

Let’s look at the carbon cycle and the greenhouse effect side by side. That will enable us to see how human changes to the carbon cycle have changed the greenhouse effect. Those changes are making the greenhouse effect more intense. That is changing the Earth’s  climate system.

Here’s a short list of some of human-caused changes that are intensifying the greenhouse effect.

5a. Increasing the density of the Earth’s Greenhouse Gas Layer

Look at the left side of the carbon cycle diagram. Since 1800, humans have been burning fossil fuels (“J”) to power the generators and other machines  (“6”) that have become the basis of our civilization. Combustion of fossil fuels has increased the amount of carbon dioxide in the atmosphere.

Now look at the greenhouse effect diagram. Carbon dioxide emissions have increased the density of the greenhouse gas layer (number 9) in the Earth’s atmosphere (8). That’s increased the amount of heat reflected back to the Earth by greenhouse gases (the arrow at 7). It’s as if you were cold at night, and put on a thicker blanket. The blanket would trap more heat. By releasing more carbon dioxide from combustion of fossil fuels, we’ve thrown a thicker blanket over the Earth, trapping more heat. That’s the intensified, greenhouse effect. That’s increasing temperatures.

Emissions of methane have added to this effect. While methane is much less abundant than carbon dioxide, it’s 80 times more powerful as a greenhouse gas. Since the Industrial Revolution, methane levels have soared, increasing about nine times from their pre-industrial levels.

Here are some activities that have increased atmospheric methane.

  1. Mining coal, oil and natural gas all cause methane to leak into the atmosphere.
  2. More livestock. As human population has increased and eating patterns have changed, more cattle and sheep are being raised than ever before. The Earth has over billion cattle. That number has been constant since about the 1970s, but it’s much more than the Earth had in 1960 (about 750 million (source)), or in 1900 (about 460 million (source)). That’s a lot of additional methane released into the air from animal farts and belches. On top of that, ranches are often on land that used to be forest. That means that the carbon that was locked up in the trees is now in the atmosphere, and the remaining plants are doing much less photosynthesis.
  3. More landfills and more wastewater treatment.

5b. Deforestation reduces carbon fixation

Deforestation involves cutting down the trees in a forest. The purpose of deforestation can be to harvest wood (logging), or to clear the land for for other uses (usually for farming and ranching). Deforestation removes or reduces the size of the plant carbon reservoir at “2,” and reduces the amount of carbon fixation from the atmosphere into plants (at “A”). Because carbon dioxide isn’t being pulled out of the atmosphere, deforestation has the effect of increasing the density of the Earth’s greenhouse gas layer.

5c. Changes to the Earth’s surface that reflect less light and create more heat.

Cities have a lot of concrete and pavement which absorb light and convert it into heat. That makes each city is a kind of “heat island:” cities are a few degrees hotter than the surrounding countryside. That means that more of the sun’s light becomes heat, and that adds to greenhouse effect.  In terms of the diagram, that would make the arrow at “5” thicker.

Melting ice (which we’ll discuss more below) causes less light to be reflected from the Earth into space. When ice is replaced by seawater or land, that land converts the light into heat, which warms the atmosphere. In the greenhouse effect diagram, that makes the arrow at “4” smaller, and the arrows at “5,” “6,” and “7” bigger. We’ll discuss this more below.

5d. Intensifying the Greenhouse Effect: Checking Understanding

Answer the questions below.

[qwiz qrecord_id=”sciencemusicvideosmeister1961-Intensifying the Greenhouse Effect”]

[h]Intensifying the Greenhouse Effect

[q labels = “top”]Melting ice has ______________ the arrow at 4, and ____________ the arrows at “5,” “6,” and “7.”

[l]increased

[fx] No, that’s not correct. Please try again.

[f*] Good!

[l]decreased

[fx] No. Please try again.

[f*] Correct!

[q labels = “top”]More livestock produces lots of ______________, which has ______________ the density of the _____________________ layer at 9, which has _____________ the arrow at 7.

[l]decreased

[fx] No, that’s not correct. Please try again.

[f*] Good!

[l]greenhouse gas

[fx] No. Please try again.

[f*] Correct!

[l]methane

[fx] No. Please try again.

[f*] Correct!

[l]increased

[fx] No. Please try again.

[f*] Excellent!

[q labels = “top”]Burning  ______________ has _______________ the density of the __________________ layer at 9, which has _____________ the arrow at 7.

[l]decreased

[fx] No, that’s not correct. Please try again.

[f*] Good!

[l]fossil fuels

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[l]greenhouse gas

[fx] No. Please try again.

[f*] Correct!

[l]increased

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[q labels = “top”]Deforestation has  ______________ the amount of  __________________ by plants. That has _____________the amount of ____________________ removed from 9. That has _______________ the Greenhouse Effect represented by the arrow at 7.

[l]decreased

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[l]increased

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[l]carbon dioxide

[fx] No, that’s not correct. Please try again.

[f*] Excellent!

[l]photosynthesis

[fx] No, that’s not correct. Please try again.

[f*] Good!

[/qwiz]

6. Consequences of Disrupting the Carbon Cycle and Intensifying the Greenhouse Effect

We’ve seen above how human changes to the carbon cycle (and other changes to the planet) are intensifying the greenhouse effect.

  • As humans emit more carbon dioxide and methane into the atmosphere, the layer of greenhouse gases at “9” is becoming denser. That’s increasing the arrow at “7,” trapping more heat in the Earth’s atmosphere.
  • The arrow at “4” is getting smaller as ice melts and cities spread. That’s increasing the arrows at “5,” “6,” and “7,” also trapping more heat within the atmosphere.

Here are some of the consequences.

6a. Rising temperatures and Climate Disruption

Trapping more heat in the atmosphere is causing the Earth to warm up. Scientists have accurate records of the Earth’s temperature going back to 1880. During that time, the Earth’s average temperature has risen about 2 °F (slightly more than 1 °C). The rate of temperature increase has doubled in the last 50 years(source). The hottest seven years on record have all occurred since 2015 (source).

Climate is the long-term weather conditions in an area. The increase in average planetary temperatures is referred to as

  • Global warming
  • Climate change
  • Climate disruption

A 1 °C increase in average temperature  might not seem like a big deal. But that 1 °C of warming has already caused serious consequences around the globe. If humanity can limit the total amount of warming to 1.5 °C, the consequences will be continue to be serious, but not catastrophic. A 2 °C (3.6 °F) increase is widely thought to be the level that could generate a  climate catastrophe that would affect billions of people.

The consequences will vary around the globe. Not all of them are negative.

In some areas that were formerly too cold for farming, agriculture might become possible (see How Russia Wins the Climate Crisis).

In other parts of the globe, the effects will be less beneficial. These include

  • More droughts and heat waves
  • Stronger and more frequent hurricanes
  • Increased wildfires

Temperature changes are altering the habitats that wild animals and plants depend on. This is adding to an ongoing extinction crisis. If you want to learn more about ecosystem disruption (caused by climate change and other human activities), you can do so at this tutorial in our AP Biology Curriculum. 

6b. Rising Sea Levels

As the atmosphere has warmed up, the oceans have warmed up too. All liquids (including water) expand when they are warmed up. As a result, the warming seas are rising.

According to Climate.gov, the website of the U.S. National Oceanic and Atmospheric Administration (NOAA), “sea level has risen 8-9 inches (21 – 24 cm) since 1880.” A new record was set in 2020, and the rate of increase is accelerating.

What’s the problem with sea level rise? Most people in the world live close to the coastlines. As sea levels rise, coastal cities and towns will face increasing flooding and damage from storms.

How much will sea level continue to rise in the future? It depends on us. If humans continue to emit high levels of of carbon dioxide and methane, the rise could be from 0.6 to 1.0 meters by 2100.  That level of sea level rise will have significant consequences for many coastal towns and cities.

In some predictions, sea level rise could be much worse. If the large glaciers in Greenland and Antarctica melted, sea levels around the world could rise by many meters. According to the United States Geological Survey, this would flood “every coastal city on the planet.”

With lower emissions, the level of sea level rise could be less.

6c. Ocean Acidification

The white coral in the foreground has been “bleached” by ocean acidification.

Over the past two hundred years, a lot of the carbon dioxide that humans have emitted into the atmosphere has been absorbed by the oceans. When carbon dioxide dissolves in seawater, it becomes a weak acid called carbonic acid. As carbonic acid has built up in the oceans, the oceans have become more acidic. Since the Industrial Revolution began, the pH of the oceans has fallen by 0.1. That’s a 30% increase in acidity (source: NOAA).

This is a challenge for many ocean species, especially those with shells. Around the planet, the dual threat of warming temperatures and ocean acidification is endangering coral reefs, which are the most diverse ecosystem in the oceans.

The death of the coral that make up coral reefs is called coral bleaching. You can learn more about coral bleaching on Wikipedia, or from this article from the Woods Hole Oceanographic Institution.

6d. Positive feedback loops are causing more changes

Human-caused emissions from fossil fuel combustion have caused the atmosphere to warm up. This warming can unleash positive feedback loops, causing other changes to the Earth’s systems which can wind up making the problem much worse.

A positive feedback loop is a system that feeds back on itself in a way that increases the output of the system. In the diagram above, increased temperature causes sea ice to melt (step 1). The darker sea water absorbs more sunlight, causing more warming (2). That warming feeds back to the system, causes more melting (3). Now we’re back to 1, but there’s less ice, which will lead to more melting, which leads to less ice.

Positive feedback loops can lead things to change very quickly. When a positive feedback loop has a harmful consequence, it’s called a vicious cycle. Unfortunately, when it comes to climate change, there could be many such vicious cycles awaiting us.

Source: Professor Merritt Turetsky, Institute of Arctic and Alpine Research, University of Colorado, Boulder.

Another feedback loop involves permafrost and methane. Places like Russia, Canada, and Alaska have huge areas covered with permafrost. Permafrost is ground that remains frozen throughout the year. A lot of permafrost has been frozen since the end of ther last Ice Age, about 10,000 years ago. As the temperature rises, the permafrost melts. As the permafrost melts, bacteria in the soil become active and release carbon dioxide and methane into the air. As more carbon dioxide and methane are released, temperatures rise even faster, melting more permafrost, releasing more methane and carbon dioxide, causing more global warming.

Source: Skeptical Science

Here’s a third positive feedback loop. The oceans store huge amounts of carbon dioxide. As the Earth warms, so does the water in the oceans. Warm water can hold less carbon dioxide than cold water. As the oceans warm, they release their carbon dioxide. That increases the greenhouse effect, which warms the oceans even more.

 

6e. Carbon Cycle and Greenhouse Effect Disruption Consequences: Checking Understanding

[qdeck qrecord_id=”sciencemusicvideosmeister1961-Carbon Cycle/Greenhouse Effect Disruption”]

[h]Carbon Cycle and Greenhouse Effect Disruption Consequences

[i]Work with the flashcards below until you can answer each question with confidence. Getting them right the first time is not the goal. The goal is the have mastery by the time you’re done.

[q]List five harmful consequences of disruption of human-caused intensification of the greenhouse effect, and one beneficial effect (note: in this card, just list them. You’ll expand on them in other cards).

[a]Negative consequences of human-caused intensification of the greenhouse effect include

  1. Rising temperatures and disruption of climate.
  2. Rising sea levels.
  3. Ocean acidification.
  4. Disruption of wildlife habitat, increasing the extinction crisis.
  5. Unleashing positive feedback loops/vicious cycles that will lead to more intensification of the greenhouse effect.

One positive effect is that in some areas that were formerly too cold for farming, farming may become possible.

[q]The graph below is saying that … The consequence is …

[a]The graph below is saying that global average temperatures have increased by about 2 °F (slightly more than 1 °C) since 1880. The consequence is climate change (also known as global warming, or climate disruption).

[q]What are some consequences of climate change (also known as climate disruption or global warming)?

[a]Some consequences of climate change include

  • The possibility of farming in areas that were formerly too cold for farming.
  • More droughts and heat waves.
  • Stronger and more frequent hurricanes.
  • Increased wildfires.
  • Disruption of wildlife habitat, increasing extinction.

[q]The graph below is saying that …. The consequence is ..

[a]The graph below is saying that global sea levels are rising. The consequence is that coastal cities, towns, and wildlife habitats will face increasing flooding and damage from storms.

[q]What is ocean acidification? What are its consequences?

[a]A lot of the carbon dioxide that humans have emitted has been absorbed by the oceans. When carbon dioxide dissolves in water, it becomes a weak acid called carbonic acid. Increased carbonic acid has made the oceans more acidic, a process called ocean acidification.

Ocean acidification is destroying coral reefs — the ocean’s most diverse ecosystems —by making it impossible for corals to build shells.

[q]What is a positive feedback loop? What’s the name for a positive feedback loop with harmful consequences? In terms of the intensified greenhouse effect, what would be the consequence of a positive feedback loop?

[a]A positive feedback loop is a system that feeds back on itself in a way that increases the output of the system. A positive feedback loop with a negative consequence is called a vicious cycle. In the context of the intensified greenhouse effect, positive feedback loops make the intensified greenhouse effect even more intense. 

[q]List three positive feedback loops connected to the intensified greenhouse effect.

[a]Three positive feedback loops connected to the intensified greenhouse effect are

  • Melting sea ice is replaced by darker seawater. This darker seawater converts more of the sun’s energy to heat, melting more sea ice.
  • Melting permafrost increases decomposition by soil bacteria in the melted permafrost, releasing carbon dioxide and methane. These gases intensify the greenhouse effect, melting more permafrost.
  • Rising ocean temperatures decreasing the amount of carbon dioxide stored in the oceans. As the oceans release carbon dioxide, the greenhouse effect is intensified, warming the oceans.

[/qdeck]

7. Solutions are possible, but humanity has to act fast

Humanity has been aware of the intensification of the greenhouse effect and its consequences for over 40 years. Yet despite numerous studies, conferences, and agreements by the highest levels of world leadership, emissions of greenhouse gases are rising at an accelerating rate.

According to the latest report from the United Nations Intergovernmental Panel on Climate Change,  40% of the world’s population lives in situations and places that are “highly vulnerable to climate change.” Climate change is already causing death and suffering around the world from heatwaves, catastrophic forest fires, flooding, and severe storms. If we allow global average temperatures to rise beyond 1.5 °C  above their pre-industrial levels, the positive feedback loops described above might lead to irreversible and catastrophic change.

What actions could reverse our current direction?

ACTION # 1: Aggressive reduction of human-caused greenhouse gas emissions through switching from fossil fuel consumption to use of renewable, carbon-free energy sources. Instead of combusting fossil fuels, we’d have to power our civilization through electricity generated by wind, solar energy, hydroelectric generators, and geothermal energy.

Action # 1 is far more important than anything else. But the next moves are important too.

ACTION # 2: Reforestation: Caring for current forests, and replanting forests that have been destroyed. New trees could soak up billions of tons of carbon dioxide.

ACTION # 3: Making agriculture less carbon-intensive.  Changing our eating patterns — eating less meat — and raising cattle in ways that reduces their methane output are important moves in reducing climate disruption. That’s because cattle are responsible for about 14.5% of the world’s greenhouse gas emissions. In addition, new methods of farming are being developed that keep more carbon in the soil.

ACTION # 4: Improving our buildings.  Buildings contribute about 33% of worldwide greenhouse gas emissions. The key is to improve insulation and overall energy efficiency.

ACTION # 5:  Reduce fossil fuel powered transportation. In 2019, transportation accounted for 29% of US greenhouse gas emissions. Improving public transportation, moving closer to work, biking instead of driving are all key steps toward a carbon neutral future.

These five are just the beginning. For a more comprehensive approach, take a look at the Stabilization Wedges Approach from Princeton University’s Carbon Mitigation Initiative.

8. The Greenhouse Effect and Climate Disruption Cumulative Quiz

The quiz below will test you on everything above. If you don’t know the answer, take a hint, or guess. The goal is to know all the material by the end. You can do it!

[qwiz qrecord_id=”sciencemusicvideosmeister1961-Climate Disruption Cumulative Quiz”]

[h] The Greenhouse Effect and Climate Change: Cumulative Quiz

[i]

[q] [hangman] of fossil fuels has increased the amount of [hangman] dioxide in the atmosphere.

[c]IGNvbWJ1c3Rpb24=[Qq]

[f]IENvcnJlY3Qh[Qq]

[c]IGNhcmJvbg==[Qq]

[f]IENvcnJlY3Qh[Qq]

[q]Label the reservoir at “5” and the flow at “j.”  Number 5 is two words.

[hangman]
[hangman]

[c]IGNvbWJ1c3Rpb24=[Qq]

[f]IEdvb2Qh[Qq]

[c]IGZvc3NpbCBmdWVscw==[Qq]

[f]IENvcnJlY3Qh[Qq]

[q multiple_choice=”true”] CO2 levels are currently (in 2022) at about

[c]IDI4MCBwcG0=[Qq]

[f]IE5vLiBUaGF0IHdhcyB0aGUgbGV2ZWwgYXQgdGhlIHN0YXJ0IG9mIHRoZSBpbmR1c3RyaWFsIHJldm9sdXRpb24u[Qq]

[c]IDM1MCBwcG0=[Qq]

[f]IE5vLiBUaGF0IHdhcyB0aGUgbGV2ZWwgaW4gdGhlIDE5ODBz[Qq]

[c]IDQyMC BwcG0=[Qq]

[f]IFllcy4gQ08=Mg==IGxldmVscyBhcmUgYXQgYWJvdXQgNDIwIHBwbS4=[Qq]

[c]IDUwMCBwcG0=[Qq]

[f]IE5vLiBXZSYjODIxNztyZSBub3QgYXQgdGhhdCBsZXZlbCB5ZXQu[Qq]

[q] Every year during the Northern Winter,[hangman] by plants in the Northern hemisphere causes the Earth’s CO2 level to increase. That increase is shown in the red line below. During the Northern spring and summer, [hangman] pulls the level of carbon dioxide down. But despite what happens during the seasons,emisssions from fossil fuel [hangman] is causing the black line to always go up.

[c]IHJlc3BpcmF0aW9u[Qq]

[f]IEdvb2Qh[Qq]

[c]IHBob3Rvc3ludGhlc2lz[Qq]

[f]IEdvb2Qh[Qq]

[c]IGNvbWJ1c3Rpb24=[Qq]

[f]IEdyZWF0IQ==[Qq]

[q labels = “top”]This is important enough to memorize: The amount of carbon dioxide in the atmosphere in 2020 is about __________ ppm. In 1960 it was about ___________ ppm. Before the industrial revolution, it was ________ ppm. Between the start of the industrial revolution and today, we’ve increased atmospheric carbon dioxide by ______ percent.

[l]50

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[l]280

[f*] Great!

[fx] No. Please try again.

[l]320

[f*] Great!

[fx] No, that’s not correct. Please try again.

[l]420

[f*] Excellent!

[fx] No. Please try again.

[q] If you had to choose one number from the diagram below to represent the greenhouse effect, what number should it be?

[textentry single_char=”true”]

[c]ID c=[Qq]

[f]IEZhYnVsb3VzISAmIzgyMjA7NyYjODIyMTsgcmVwcmVzZW50cyB0aGUgZ3JlZW5ob3VzZSBlZmZlY3Q6IGhlYXQgZnJvbSB0aGUgRWFydGggZ2V0dGluZyBhYnNvcmJlZCBhbmQgcmUtZW1pdHRlZCBieSBncmVlbmhvdXNlIGdhc2VzIGJhY2sgdG8gdGhlIEVhcnRoLg==[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50IGZvciBuZXh0IHRpbWUuIEdyZWVuaG91c2UgZ2FzZXMgYWJzb3JiIHRoZSBFYXJ0aCYjODIxNztzIGhlYXQsIGFuZCB0aGVuIHJlLWVtaXQgdGhhdCBoZWF0LiBUaGUgaGVhdCB0aGF0IGNvbWVzIGJhY2sgdG8gRWFydGggaXMgdGhlIGVzc2VuY2Ugb2YgdGhlIGdyZWVuaG91c2UgZWZmZWN0LiBXaGljaCBhcnJvdyByZXByZXNlbnRzIGhlYXQgZnJvbSBncmVlbmhvdXNlIGdhc2VzIGNvbWluZyBiYWNrIHRvIEVhcnRoLg==[Qq]

[q] The gases at “9” that absorb heat from the Earth and then re-emit that heat (some of which goes back down to the Earth) are known as [hangman] gases. In addition to carbon dioxide, one of these gases is [hangman], with formula CH4.

[c]IGdyZWVuaG91c2U=[Qq]

[f]IEV4Y2VsbGVudCE=[Qq]

[c]IG1ldGhhbmU=[Qq]

[f]IEV4Y2VsbGVudCE=[Qq]

[q labels = “top”]As sea ice melts and is replaced by darker seawater, some aspects of the greenhouse effect are changing. Drag the labels to the correct location to show this change.

 

[l]decrease

[f*] Correct!

[fx] No, that’s not correct. Please try again.

[l]increase

[f*] Good!

[fx] No. Please try again.

[q]In the diagram below, number 9 is what layer HINT: It’s two words that begin with the same letter.

[hangman]

[c]IGdyZWVuaG91c2UgZ2Fz[Qq]

[f]IENvcnJlY3Qh[Qq]

[q multiple_choice=”true”] Human changes to the greenhouse effect have caused the average temperature on Earth to increase by

[c]IDAuNiDCsEM=[Qq]

[f]IE5vLiBJdCYjODIxNztzIGFib3ZlIHRoYXQu[Qq]

[c]IDEg wrBD[Qq]

[f]IFllcy4gVGhhdCYjODIxNztzIGJlZW4gdGhlIGFtb3VudCBvZiB3YXJtaW5nIHNvIGZhci4=[Qq]

[c]IDLCsEM=[Qq]

[f]IE5vLiBXZSYjODIxNztyZSBub3QgYXQgdGhhdCBsZXZlbCB5ZXQu[Qq]

[q multiple_choice=”true”] Based on our best understanding of the Earth’s climate system, which of the following levels of global average temperature increase might unleash catastrophic consequences.

[c]IDAuNiDCsCBD[Qq]

[f]IE5vLiBIdW1hbml0eSBoYXMgYWxyZWFkeSBpbmNyZWFzZXMgdGhlIGNsaW1hdGUgYmV5b25kIHRoYXQgbGV2ZWwu[Qq]

[c]IDEgwrAgQw==[Qq]

[f]IE5vLiBUaGF0JiM4MjE3O3MgYmVlbiB0aGUgYW1vdW50IG9mIHdhcm1pbmcgc28gZm9yLiBUaGUgY29uc2VxdWVuY2VzIGFyZSBzdGFydGluZyB0byBiZSBzZXJpb3VzLCBidXQgbm90IGNhdGFzdHJvcGhpYy4=[Qq]

[c]IDEuNcKwIEM=[Qq]

[f]IE5vLiBUaGUgZ29hbCBvZiBtb3N0IGNsaW1hdGUgYWdyZWVtZW50cyBpcyB0byBsaW1pdCB3YXJtaW5nIHRvIHRoaXMgbGV2ZWwuIFRoZSBjb25zZXF1ZW5jZXMgd2lsbCBiZSBzaWduaWZpY2FudCwgYnV0IHdlIG1pZ2h0IGF2b2lkIGEgY2xpbWF0ZSBjYXRhc3Ryb3BoZS4=[Qq]

[c]IDLC sEM=[Qq]

[f]IFllcy4gSWYgd2UgcmFpc2UgdGhlIHRlbXBlcmF0dXJlIGJ5IHRoaXMgYW1vdW50LCB3ZSBtaWdodCB1bmxlYXNoIGEgc2VyaWVzIG9mIHBvc2l0aXZlIGZlZWRiYWNrIGxvb3BzIHRoYXQgd2lsbCBjYXVzZSB0ZW1wZXJhdHVyZSB0byBpbmNyZWFzZSBieSBtdWNoIG1vcmUsIHdpdGggY2F0YXN0cm9waGljIGNvbnNlcXVlbmNlcy4=[Qq]

[q multiple_choice=”true”] Which of the following types of countries might benefit from climate change?

[c]IENvdW50cmllcyBpbiB0aGUgZmFyIG5vcnRo LCBsaWtlIENhbmFkYSBhbmQgUnVzc2lhLg==[Qq]

[f]IFllcy4gSW4gc29tZSBub3J0aGVybiBhcmVhcyB0aGF0IHdlcmUgZm9ybWVybHkgdG9vIGNvbGQgZm9yIGZhcm1pbmcsIGFncmljdWx0dXJlIG1pZ2h0IGJlY29tZSBwb3NzaWJsZQ==[Qq]

[c]IElzbGFuZCBuYXRpb25zIGxpa2UgdGhlIFBoaWxpcHBpbmVzIG9yIHRoZSBEb21pbmljYW4gUmVwdWJsaWMu[Qq]

[f]IE5vLiBJbiBpc2xhbmQgbmF0aW9ucywgcmlzaW5nIHNlYSBsZXZlbHMgd2lsbCBsZWFkIHRvIGZsb29kaW5nIG9mIGJlYWNoZXMgYW5kIGNvYXN0YWwgYXJlYXMsIGNhdXNpbmcgc2VyaW91cyBwcm9ibGVtcy4=[Qq]

[c]IENvdW50cmllcyBhdCBtaWRkbGUgbGF0aXR1ZGVzLCBsaWtlIHRoZSBVbml0ZWQgU3RhdGVzLCBTcGFpbiwgYW5kIENoaW5h[Qq]

[f]IE5vLiBDb3VudHJpZXMgYXQgbWlkZGxlIGxhdGl0dWRlcyB3aWxsIHNlZSBtb3JlIGRyb3VnaHRzIGFuZCBoZWF0IHdhdmVzLCBzdHJvbmdlciBhbmQgbW9yZSBmcmVxdWVudCBodXJyaWNhbmVzLCBhbmQgaW5jcmVhc2VkIHdpbGRmaXJlcy4=[Qq]

[q] All liquids (including water) [hangman] when they are warmed up. As a result, the warming seas are [hangman].

[c]IGV4cGFuZA==[Qq]

[f]IENvcnJlY3Qh[Qq]

[c]IHJpc2luZw==[Qq]

[f]IEdyZWF0IQ==[Qq]

[q] As sea levels rise, coastal cities and towns will face increasing [hangman] and damage from storms.

[c]IGZsb29kaW5n[Qq]

[f]IEV4Y2VsbGVudCE=[Qq]

[q] Human caused emissions of carbon dioxide have caused a lot of carbon dioxide to be absorbed by the oceans. This is causing ocean [hangman], which is destroying coral [hangman].

[c]IGFjaWRpZmljYXRpb24=[Qq]

[f]IEdyZWF0IQ==[Qq]

[c]IHJlZWZz[Qq]

[f]IEdvb2Qh[Qq]

[q] A [hangman] feedback loop is a system that feeds back on itself in a way that increases the output of the system. When these feedback loops have harmful consequences, they’re called [hangman] cycle.

[c]IHBvc2l0aXZl[Qq]

[f]IENvcnJlY3Qh[Qq]

[c]IHZpY2lvdXM=[Qq]

[f]IEdvb2Qh[Qq]

[q] One positive feedback loop associated with global warming involves the melting of frozen soil called [hangman]. As this frozen soil melts, decomposition by bacteria releases more of the [hangman] gases that are warming the atmosphere, which leads more of this frozen soil to melt.

[c]IHBlcm1hZnJvc3Q=[Qq]

[f]IEdyZWF0IQ==[Qq]

[c]IGdyZWVuaG91c2U=[Qq]

[f]IEdvb2Qh[Qq]

 

[q hotspot_user_interaction=”label_prompt”]

This human-caused flow is what’s disrupting the natural greenhouse effect.

Yes. Human combustion of fossil fuels is what’s changing the natural greenhouse effect. 

HINT FOR NEXT TIME: Which arrow represents combustion?
This flow increases when permafrost melts.

Nice! When permafrost melts, bacteria in the soil increase their rate of decomposition, increasing flows of carbon dioxide (and methane) into the air.

HINT FOR NEXT TIME: When permafrost melts, decomposition increases. Look for respiration by decomposers.
Reforestation would increase this flow, which decreases the greenhouse effect.

Good work. Reforestation increases photosynthesis, which increases carbon fixation, which pulls carbon dioxide out of the air.

HINT FOR NEXT TIME. You’re looking for  photosynthesis, which increases carbon fixation, which pulls carbon dioxide out of the air.

[x]

[restart]

[/qwiz]

9. Questions you (and everyone) should be able to answer about climate disruption

[qdeck qrecord_id=”sciencemusicvideosmeister1961-Climate Disruption Cumulative Flashcards”]

[h]Questions you should be able to answer about climate disruption

[i]Work on these flashcards until you can answer them fluently and confidently.

[q]1. What are greenhouse gases? 2. What are the two main greenhouse gases? 3. What human activities have directly or indirectly increased greenhouse gas levels.

[a]

  1. Greenhouse gases trap heat within the Earth’s atmosphere.
  2. The two main greenhouse gases are carbon dioxide and methane.
  3. We’ve increased carbon dioxide by burning fossil fuels and by deforestation. We’ve increased methane by releasing it to the atmosphere during fossil fuel mining, extraction, and storage, and by agricultural practices (large-scale animal farming) that release methane.

[q]1. What is the natural greenhouse effect? 2. How have humans disrupted it?

[a]

  1. The natural greenhouse effect involves greenhouse gases such as carbon dioxide (and methane). Greenhouse gases absorb heat emitted from the Earth’s surface, and re-emit it back to Earth. That creates a kind of insulation that is responsible for the Earth’s moderate, life-supporting temperatures.
  2. Humans have disrupted the greenhouse effect by releasing carbon dioxide and methane, which has increased the density of the greenhouse gas layer, trapping more heat.

[q]What are the three primary fossil fuels?  What are some activities that rely on fossil fuels? What are some alternatives to fossil fuels.

[a]

  1. The three primary fossil fuels are coal, oil (petroleum) and natural gas.
  2. Almost any energy-consuming activity (using electricity, driving, home heating, cooking) directly or indirectly involves fossil fuel combustion.
  3. Alternatives to fossil fuels include carbon-free energy sources such as wind power, solar power, hydroelectric power, and geothermal power, all of which are in increasing use.

[q]Because of consumption of fossil fuels, atmospheric carbon dioxide levels have ____________. The level before the industrial revolution was ___________. In 1960, it was __________. Now it’s __________.

[a]Because of consumption of fossil fuels, atmospheric carbon dioxide levels have INCREASED. The level before the industrial revolution was 280 ppm. In 1960, it was 320 ppm. Now (in 2022) it’s 420 ppm.

[q]What are some consequences of human-caused disruption of the carbon cycle and the natural greenhouse effect? Divide your answer into harmful and beneficial effects.

[a]Harmful consequences:

  • Rising temperatures and disruption of climate.
  • Rising sea levels
  • Ocean acidification
  • Disruption of wildlife habitat, increasing the extinction crisis.
  • Unleashing positive feedback loops/vicious cycles that will intensify the greenhouse effect.

One beneficial effect is that in some areas that were formerly too cold for farming, farming may become possible.

[q]What are three positive feedback loops that could make climate disruption much worse.

[a]

  1. Melting sea ice is replaced by darker seawater. This darker seawater converts more of the sun’s energy to heat, melting more sea ice.
  2. Melting permafrost increases decomposition by soil bacteria in the melted permafrost, releasing carbon dioxide and methane. These gases intensify the greenhouse effect, melting more permafrost.
  3. Rising ocean temperatures decreasing the amount of carbon dioxide stored in the oceans. As the oceans release carbon dioxide, the greenhouse effect is intensified, warming the oceans.

[q]Since the 1880s, temperatures have risen by about ___ °F (about ___ °C). It’s widely agreed that catastrophic positive feedback loops will be unleashed if warming exceeds ____°F (___ °C).

[a] Since the 1880s, temperatures have risen by about 2 °F (about 1 °C). It’s widely agreed that catastrophic positive feedback loops will be unleashed if warming exceeds 3.6 °F (2 °C).

[q]What are some moves that humanity must make soon in order to turn the tide on climate change?

[a]

  1. Reduction of human-caused greenhouse gas emissions by switching from fossil fuels to carbon-free or carbon-neutral renewable energy sources.
  2. Reforestation.
  3. Making agriculture less carbon intensive.
  4. Improving the efficiency of buildings
  5. Reducing fossil fuel powered transportation (and replacing it with electricity-powered transportation, including bicycles).

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10. Learn More About Climate Disruption and Solutions

I’m hoping that the material above has given you a solid foundation in terms of understanding climate disruption. If you want to learn more, here are a few links to get you started.

  1. United Nations Climate Action Page
  2. NASA’s  Global Climate Change Page
  3. The US Environmental Protection Agency’s Climate Change Page
  4. The US National Oceanic and Atmospheric Administration Climate Change Page. 
  5. Climate Resources from The US National Academy of Sciences 
  6. The Climate Challenge, from the UK Climate Change Committee
  7. Princeton’s Carbon Mitigation Initiative has developed an innovative Stabilization Wedges Approach to reducing carbon emissions. I found it so inspiring and hopeful that I wrote a song about it (see “50 Ways to Reduce Carbon” below.

11. Mr. W’s Climate Change Music Videos

Do you want to learn about climate change through music, rhyme, and animated diagrams? Try the videos below.

  1. Greenhouse Effect: How the natural greenhouse effect works, and how humans have disrupted it
  2. Keep Those Fossil Fuels in the Ground: The consequences of climate change.
  3. Seven Ways to Reduce Carbon: A guide to carbon reduction, based on Princeton’s Carbon Mitigation Initiative Stabilization Wedges Approach, sung to Paul Simon’s “50 Ways to Leave Your Lover.”
  4. Disrupt Climate Disruption: What we can do about climate change

12. What’s next?

  1. Ecosystems (HS Level) Main Menu
  2. Use the menus above to choose another tutorial.