Water and Carbon Cycles

Question 1

What is an input?

Answer 1

Where matter or energy is added to the system.

Question 2

What is an output?

Answer 2

Where matter or energy leaves a system.

Question 3

What is a store?

Answer 3

Where matter or energy builds up in a system.

Question 4

What is a flow?

Answer 4

Where matter or energy moves in a system.

Question 5

What is an open system?

Answer 5

A system that has inputs and outputs of energy and matter.

Question 6

What is a closed system?

Answer 6

No matter can be an input or an output, only energy.

Question 7

What is an isolated system?

Answer 7

A system where there is no input of energy or matter.

Question 8

What is dynamic equilibrium?

Answer 8

Where the volume of input is the same as the volume of output despite changing conditions.

Question 9

What is positive feedback?

Answer 9

When a change in conditions causes a further change that amplifies the original change.

Question 10

What is negative feedback?

Answer 10

When a change in conditions causes a further change which nullifies the original change.

Question 11

What is photosynthesis?

Answer 11

Plants convert CO₂ from the atmosphere into glucose for them to grow.

Question 12

What is respiration?

Answer 12

Living organisms convert glucose into carbon dioxide.

Question 13

What is combustion?

Answer 13

Where organic matter is burned. This releases CO₂ into the atmosphere.

Question 14

What is decomposition?

Answer 14

Decomposers like bacteria break down dead organisms which returns CO₂ to the atmosphere.

Question 15

How can the oceans reduce CO₂ levels?

Answer 15

They absorb the CO₂ from the atmosphere which causes them to become more acidic.

Question 16

What is burial and compaction?

Answer 16

Shelled organisms die, fall to the ocean floor and become compacted to form limestone and fossil fuels.

Question 17

What is carbon sequestration?

Answer 17

Where carbon is captured from the atmosphere and stored.

Photosynthesis is a type of carbon sequestration.

Question 18

What is a carbon sink?

Answer 18

A store that takes in more carbon than it emits.

Question 19

What is a carbon source?

Answer 19

A store that emits more carbon than it stores.

Question 20

What are the four main stores of carbon?

Answer 20

The lithosphere - rocks like calcium carbonate and fossil fuels.
The hydrosphere - dissolved carbon dioxide in bodies of water.
The biosphere - animals and plants (dead and living).
The atmosphere - gases like carbon dioxide.

Question 21

What are two natural processes that cause changes in the carbon cycle?

Answer 21

Wildfires and Volcanoes.

Question 22

How do wildfires cause a change in the carbon cycle?

Answer 22

It transfers carbon from the biosphere to the atmosphere as plants are being burned.

Question 23

How do volcanoes cause a change in the carbon cycle?

Answer 23

Carbon stored within the lithosphere is released into the atmosphere during an eruption.

Question 24

What are three ways humans have changed the carbon cycle?

Answer 24

Burning fossil fuels

Deforestation

Farming

Question 25

How has burning fossil fuels changed the carbon cycle?

Answer 25

Combustion transfers CO₂ to the atmosphere from a long-term carbon sink.

Question 26

How has deforestation caused a change in the carbon cycle?

Answer 26

It prevents photosynthesis from occurring. Slash and burn causes CO₂ to be released.

Question 27

How can farming practices change the carbon cycle?

Answer 27

Animals release CO₂ into the atmosphere.

Question 28

What is the carbon budget?

Answer 28

The maximum amount of anthropogenic carbon dioxide that can be released to reach climate goals.

Question 29

What is the enhanced greenhouse effect?

Answer 29

Abnormally high levels of greenhouse gases trap radiation from the sun which causes the temperature to rise.

Question 30

What is radiative forcing?

Answer 30

The ratio of incoming solar radiation from the sun and the energy radiated back into space.

Question 31

How can tropical rainforests impact the climate?

Answer 31

High rates of photosynthesis and respiration in forests lead to greater humidity, cloud cover and precipitation. Deforestation reduces photosynthesis and respiration, further reducing humidity, cloud cover and precipitation.

Question 32

What are two positive feedback loops in the carbon cycle?

Answer 32

Wildfires are more likely to occur in hotter and drier climates created by global warming. Wildfires release large amounts of CO₂ into the atmosphere, which causes an increase in the warming effect. Permafrost melts which causes CO₂ and methane to be released. This causes an increase in the enhanced greenhouse effect and a higher temperature causing more permafrost to melt.

Question 33

What are two negative feedback loops in the carbon cycle?

Answer 33

Higher CO₂ levels cause phytoplankton to grow. They photosynthesise and so carbon dioxide levels decrease. Higher CO₂ levels means that plants photosynthesise faster. This decreases the CO₂ levels.

Question 34

What are two examples of positive feedback cycles between the water and carbon cycles?

Answer 34

As increased carbon dioxide warms the atmosphere, evaporation rates increase and cause a wetter atmosphere. As water vapour is a greenhouse gas, this leads to further warming. Warmer oceans release dissolved carbon dioxide, transferring carbon dioxide into the atmospheric store, increasing greenhouse gases in the atmosphere and leading to further warming.

Question 35

How have humans intervened in the carbon cycle to mitigate the impacts of climate change?

Answer 35

The Paris Agreement in 2015 legally bound countries to reducing their greenhouse gas emissions to limit global warming to 2 degrees. This includes reducing reliance on fossil fuels (more renewable energy), encouraging public transport use, reducing deforestation and improving energy efficiency.