C13.3 - Greenhouse gases

Question 1

Why can media reports be misleading?

Answer 1

Media reports can be misleading, because they are sometimes:
1. Biased
Or,
2. Over-simplified

Question 2

What are the main ‘greenhouse gases’ in the Earth’s atmosphere?

Answer 2

The main ‘greenhouse gases’ in the Earth’s atmosphere are:

1. Carbon dioxide
2. Methane
3. Water vapour

Question 3

Greenhouse gases

Answer 3

Greenhouse gases are gases that contribute to the greenhouse effect by absorbing infrared radiation

Question 4

Without carbon dioxide in the Earth’s atmosphere, what would the average temperature on Earth be?

Answer 4

Without carbon dioxide in the Earth’s atmosphere, the average temperature on the Earth would be about -19 degrees Celsius

Question 5

What is the Earth heated by?

Answer 5

The Earth is heated by the Sun

Question 6

The Earth is heated by the Sun.

How much of the energy reaching the Earth warms up our planet?

Answer 6

Not all of the energy reaching the Earth warms up our planet

Question 7

Example of short-wavelength electromagnetic radiation

Answer 7

An example of short-wavelength electromagnetic radiation is ultraviolet (UV) light

Question 8

What do greenhouse gases let pass through?

Answer 8

Greenhouse gases let short-wavelength electromagnetic radiation pass through

Question 9

How does the surface of the Earth cool down?

Answer 9

The surface of the Earth cools down by emitting longer wavelength infrared (thermal) radiation

Question 10

The surface of the Earth cools down by emitting longer wavelength infrared (thermal) radiation.
However, what do greenhouse gases absorb?

Answer 10

Greenhouse gases absorb infrared radiation

Question 11

The surface of the Earth cools down by emitting longer wavelength infrared (thermal) radiation.
However, greenhouse gases absorb infrared radiation.
What does the radiation do?

Answer 11

The radiation stimulates the bonds in these molecules to:
1. Vibrate
2. Bend
3. Stretch
more vigorously

Question 12

The surface of the Earth cools down by emitting longer wavelength infrared (thermal) radiation.
However, greenhouse gases absorb infrared radiation.
The radiation stimulates the bonds in these molecules to vibrate, bend and stretch more vigorously, raising their temperature.
So, what happens?

Answer 12

1. Some of the energy radiated from the surface of the Earth gets trapped in the atmosphere
2. The temperature rises

Question 13

What happens the higher the proportion of greenhouse gases in the air?

Answer 13

The higher the proportion of greenhouse gases in the air, the more energy is absorbed

Question 14

What do the molecules of a ‘greenhouse gas’ do?

Answer 14

The molecules of a ‘greenhouse gas’ absorb the energy radiated by the Earth as it cools down at night

Question 15

The molecules of a ‘greenhouse gas’ absorb the energy radiated by the Earth as it cools down at night.
What does this do?

Answer 15

This:

1. Increases the store of energy of the gases in the atmosphere
2. Warms the Earth

Question 16

Over the past century, what has the amount of carbon dioxide released into the atmosphere done?

Answer 16

Over the past century, the amount of carbon dioxide released into the atmosphere has greatly increased

Question 17

What are used more than ever to make electricity, heat homes and run cars?

Answer 17

More fossil fuels than ever are used to:

1. Make electricity
2. Heat homes
3. Run cars

Question 18

More fossil fuels than ever are used to make electricity, heat homes and run cars.
What has this enormously increased?

Answer 18

This has enormously increased the amount of carbon dioxide produced

Question 19

Why has more fossil fuels being used than ever to make electricity, heat homes and run cars enormously increased the amount of carbon dioxide?
What happens when you burn fossil fuels?

Answer 19

When you burn fossil fuels, carbon that has been locked up for hundreds of millions of years in fossil fuels is released as carbon dioxide into the atmosphere when used as fuel

Question 20

How does methane get into the atmosphere?

Answer 20

Methane gets into the atmosphere from:

1. Swamps
2. Rice fields

Question 21

Methane gets into the atmosphere from swamps and rice fields.
What is another source of methane?

Answer 21

Another source of methane is emissions from:

1. The growing number of grazing cattle
2. Their decomposing waste

Question 22

Methane gets into the atmosphere from swamps and rice fields.
Another source of methane is emissions from the growing number of grazing cattle and from their decomposing waste.
The increasing human population produces more what?

Answer 22

The increasing human population produces more waste to dispose of in landfill sites

Question 23

The 3 sources of methane

Answer 23

The 3 sources of methane are:

1. Swamps and rice fields
2. The growing number of grazing cattle and from their decomposing waste
3. Waste in landfill sites

Question 24

What is there no doubt of amongst scientists?

Answer 24

There is no doubt of amongst scientists that the levels of greenhouse gases, especially carbon dioxide, in the atmosphere are increasing

Question 25

There is no doubt of amongst scientists that the levels of greenhouse gases, especially carbon dioxide, in the atmosphere are increasing. So, what are you experiencing?

Answer 25

You are experiencing an enhanced greenhouse-effect

Question 26

The overall trend in the carbon dioxide proportion and the year

Answer 26

The overall trend in the: 1. Carbon dioxide proportion 2. Year has been upwards

Question 27

Examples of 'CO2 sinks'

Answer 27

Examples of 'CO2 sinks' are: 1. Tropical rainforests 2. The oceans

Question 28

What is the balance between the carbon dioxide produced and the carbon dioxide absorbed by 'CO2 sinks' affected by?

Answer 28

The balance between the carbon dioxide: 1. Produced 2. Absorbed by 'CO2 sinks' is affected by human activity

Question 29

The balance between the carbon dioxide produced and the carbon dioxide absorbed by 'CO2 sinks' is affected by human activity. Examples

Answer 29

For example: 1. Deforestation 2. Temperature rising

Question 30

The balance between the carbon dioxide produced and the carbon dioxide absorbed by 'CO2 sinks' is affected by human activity. What happens as more trees are cut down for timber and to clear land (deforestation)?

Answer 30

As more trees are cut down for timber and to clear land (deforestation), the carbon dioxide removed from the air as the trees photosynthesise is reduced

Question 31

The balance between the carbon dioxide produced and the carbon dioxide absorbed by 'CO2 sinks' is affected by human activity. What happens as the temperature rises?

Answer 31

As the temperature rises, carbon dioxide gets less and less soluble in water

Question 32

What do most scientists agree?

Answer 32

Most scientists agree that a trend in global warming has started

Question 33

Most scientists agree that a trend in global warming has started. What are their views based on?

Answer 33

Their views are based on evidence presented in scientific journals

Question 34

Most scientists agree that a trend in global warming has started. Their views are based on evidence presented in scientific journals. What does such evidence have to be?

Answer 34

Such evidence has to be checked by other scientists working in the same area of expertise

Question 35

Most scientists agree that a trend in global warming has started. Their views are based on evidence presented in scientific journals. Such evidence has to be checked by other scientists working in the same area of expertise. However, what do a minority of scientists argue?

Answer 35

A minority of scientists argue that rises observed are due to natural variations that have always happened throughout the long history of the Earth

Question 36

What are scientists searching for?

Answer 36

Scientists are searching for 'hard' evidence of the link between the: 1. Levels of carbon dioxide 2. Climate

Question 37

Scientists are searching for 'hard' evidence of the link between the levels of carbon dioxide and the climate. What is one source?

Answer 37

One source is ice cores drilled from Greenland's ice sheet

Question 38

Scientists are searching for 'hard' evidence of the link between the levels of carbon dioxide and the climate. How are ice cores drilled from Greenland's ice sheet, which have gases trapped inside, one source of this?

Answer 38

Once source is ice cores drilled from Greenland's ice sheet, which have gases trapped inside, because scientists can analyse the trapped air to find out how the composition of the gases in the atmosphere has changed over time

Question 39

Scientists are searching for 'hard' evidence of the link between the levels of carbon dioxide and the climate. Once source is ice cores drilled from Greenland's ice sheet, which have gases trapped inside, because scientists can analyse the trapped air to find out how the composition of the gases in the atmosphere has changed over time. What does analysis suggest?

Answer 39

Analysis suggests that the current levels of carbon dioxide are higher than at any time in the last 440,000 years

Question 40

Despite advances in science, what can you not predict with certainty?

Answer 40

Despite advances in science, you cannot predict with certainty the effects of increasing levels of greenhouse gases

Question 41

Media reports can be misleading, because they are sometimes: 1. Biased Or, 2. Over-simplified, as they often seek out what?

Answer 41

Media reports can be misleading, because they are sometimes: 1. Biased Or, 2. Over-simplified, as they often seek out sensational headlines from scientific research without presenting the whole picture

Question 42

The Earth is heated by the Sun. Not all of the energy reaching the Earth warms up our planet. About 30% is what?

Answer 42

About 30% is reflected back into space from the: 1. Atmosphere 2. Surface

Question 43

The surface of the Earth cools down by emitting longer wavelength infrared (thermal) radiation. However, greenhouse gases absorb infrared radiation. The radiation stimulates the bonds in these molecules to vibrate, bend and stretch more vigorously, doing what?

Answer 43

The radiation stimulates the bonds in these molecules to: 1. Vibrate 2. Bend 3. Stretch more vigorously, raising their temperature

Question 44

Methane gets into the atmosphere from swamps and rice fields. Another source of methane is emissions from the growing number of grazing cattle and from their decomposing waste. The increasing human population produces more waste to dispose of in landfill sites, which are what?

Answer 44

The increasing human population produces more waste to dispose of in landfill sites, which are another source of methane

Question 45

There is no doubt of amongst scientists that the levels of greenhouse gases, especially carbon dioxide, in the atmosphere are increasing. You are experiencing an enhanced greenhouse-effect, greater than what?

Answer 45

You are experiencing an enhanced greenhouse-effect, greater than the warming effect in pre-industrial times

Question 46

The balance between the carbon dioxide produced and the carbon dioxide absorbed by 'CO2 sinks' is affected by human activity. As the temperature rises, carbon dioxide gets less and less soluble in water. This makes the oceans what?

Answer 46

This makes the oceans less effective as 'CO2 sinks'

Question 47

Scientists are searching for 'hard' evidence of the link between the levels of carbon dioxide and the climate. One source is ice cores drilled from Greenland's ice sheet, which have what trapped inside?

Answer 47

One source is ice cores drilled from Greenland's ice sheet, which have gases trapped inside

Question 48

Despite advances in science, you cannot predict with certainty the effects of increasing levels of greenhouse gases, even with what?

Answer 48

Despite advances in science, you cannot predict with certainty the effects of increasing levels of greenhouse gases, even with the aid of the most powerful computers