Nature's Role in the Greenhouse Effect

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From the course by University of Pennsylvania

English for Science, Technology, Engineering, and Mathematics

548 ratings

University of Pennsylvania

English for Science, Technology, Engineering, and Mathematics

548 ratings

Welcome to English for Science, Technology, Engineering, and Mathematics, a course created by the University of Pennsylvania, and funded by the U.S. Department of State Bureau of Educational and Cultural Affairs, Office of English Language Programs. To enroll in this course for free, click on “Enroll now” and then select "Full Course. No certificate." This course is designed for non-native English speakers who are interested in improving their English skills in the sciences. In this course, you will explore some of the most innovative areas of scientific study, while expanding your vocabulary and the language skills needed to share scientific information within your community. In unit 1, you will learn how to preview texts and practice some of the language used to make comparisons when talking about global warming and climate change. In unit 2, you will examine the chemistry of climate change and the language of cause and effect. In Unit 3, you will learn about some of the impacts of Climate Change and the language used to describe these effects. In Unit 4, you will learn reading strategies that can help you explore the science behind some new energy systems. In the final unit, you will investigate practical advances in Nanotechnology that help slow down climate change, while developing your own research skills in English. Anyone may take this course for free and get a generic Statement of Accomplishment issued by the University of Pennsylvania. If you want to get a Coursera Verified Certificate for free, please fill out the Financial Aid form. Unless otherwise noted, all course materials are available for re-use, repurposing and free distribution under a Creative Commons 4.0 Attribution license. Supplemental reading materials were provided by Newsela, which publishes daily news articles at a level that's just right for each English language learner.

From the lesson

Unit 2: The Greenhouse Effect

What is the Greenhouse Effect?4:22

Greenhouse Gases5:33

Unlockable Achievement 30:09

Nature's Role in the Greenhouse Effect6:19

Language Focus: Present Progressive4:15

Meet the Instructors

Jack Sullivan
Director of Programs
English Language Programs
Alyssa Swanson
Intensive Program Manager
English Language Programs

Hello, in an earlier video, we learned about greenhouse gases,

water vapor, carbon dioxide, methane, and nitrous oxide.

In this video, we will learn how nature plays a role in either increasing or

decreasing the amount of greenhouse gases in the atmosphere.

We will look specifically at the carbon cycle and what we call sources and sinks.

Nature plays a role in the greenhouse effects, because trees, soil, and

oceans all release greenhouse gases into the atmosphere.

Nature also stores elements or

compounds of greenhouse gases in different parts of the earth.

Any process or

activity that releases a greenhouse gas into the atmosphere is called a source.

Let's look at some of the natural sources of carbon dioxide.

One source is animal and plant respiration.

What's that?

Well, for animals and people that's breathing.

We take in oxygen and we breathe out carbon dioxide.

For plants, it's not breathing the same way humans do, but it does involve

taking in oxygen and letting out carbon dioxide in order to release stored energy.

Another natural source of carbon dioxide to the atmosphere is soil respiration and

decomposition.

What do we mean by soil respiration or soil breathing?

Well, when we mention soil respiration, the dirt itself doesn't breathe,

but all the living things in the dirt do,

things like plant roots, or tiny, little insects, bugs and bacteria.

When they are alive and respire in the soil, we have soil respiration.

When they die in the soil, they begin decomposition.

To decompose is to be destroyed or

broken down into simpler compounds by microbes, worms and insects.

One of the products of decomposition is carbon dioxide.

Animal and plant respiration account for

almost 29% of carbon dioxide in the atmosphere.

Soil respiration and decomposition also account for

about 29% of the carbon dioxide in the atmosphere.

But the largest natural source of carbon dioxide in the atmosphere,

at about 43%, is the ocean atmosphere exchange.

Exchange is when you give one thing and receive another in return for it.

In the ocean atmosphere exchange, the oceans and

the atmosphere continuously exchange carbon dioxide and oxygen with each other.

That means they both give carbon dioxide and

oxygen to each other and take carbon dioxide and oxygen from each other.

In the oceans, like in the soil, a lot of carbon dioxide is

produced from the plants and animals that live beneath the waters.

So those are the natural sources of carbon dioxide.

What are the sinks?

A sink is something that absorbs or

takes in the greenhouse gases from the atmosphere and stores it.

One example of a sink would be trees absorbing carbon dioxide and

then releasing oxygen.

It is the reverse of respiration.

We call this photosynthesis.

As you can see, things can be sources and sinks.

We mentioned earlier that trees and plants were sources.

They are, they are both sources and sinks.

They put some carbon dioxide into the atmosphere at night, but

they absorb much more of it during the day.

You can say the same thing about the oceans, they are both sources and sinks.

As we explained in describing the ocean atmosphere exchange, the oceans not only

produce some of the carbon dioxide that goes into the atmosphere, they also store

a massive amount of carbon dioxide in the water in the plants that live in it.

This exchange of carbon dioxide between the sources and

sinks is called the carbon cycle.

The climate that we and all other living things on Earth are now comfortable with

is created in part by this exchange.

But now experts say the climate is changing

because humans are putting more carbon dioxide into the atmosphere

than what occurs naturally between the sources and the sinks.

We will learn that even small changes to these natural cycles

can cause large impacts.

In this video, we learned how nature plays a role in both increasing or

decreasing the amount of greenhouse gases in the atmosphere.

We specifically looked at the carbon cycle in what we call sources and sinks.

In the next video, we will look at how the human activity

of burning fossil fuels can threaten the balance of the carbon cycle.

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