WCC: Water, Carbon and Climate - The Relationship Between the Water and Carbon Cycles in the Atmosphere

Question 1

Give 6 similarities between the water and carbon cycles.

Answer 1

• Natural systems.
• Exist in a state of dynamic equilibrium.
• Fragile and easily damaged by humans.
• Crucial to life on earth.
• Atmosphere, biosphere, hydrosphere and lithosphere crucial to both.
• Changes have a massive knock-on effect on life on Earth.

Question 2

Give 3 key links between the water and carbon cycles

Answer 2

Rainwater absorbs carbon.
Dissolved carbon is transported by rivers to the sea and used by marine organisms to build shells.
Some dissolved carbon in ocean and river water is returned to the atmosphere through diffusion.

Question 3

State and describe the pH of pure water.

Answer 3

7.0 - neutral

Question 4

State and describe the pH of natural unpolluted rainwater.

Answer 4

5.6 - mildly acidic

Question 5

Which 3 atmospheric substances make rainwater acidic?

Answer 5

CO2
Nitric acid
Sulphur dioxide

Question 6

Which greenhouse gas is the primary source of acidity in unpolluted rainwater?

Answer 6

CO2

Question 7

How much can polluted air affect the pH of rainwater?

Answer 7

Rainwater can become very acidic with a pH of 4 or lower

Question 8

Give evidence to show how acidic rainwater can become.

Answer 8

In 1982 a fog on the west coast of the US had a pH of 1.8

Question 9

What is carbonation?

Answer 9

The reaction between carbonic acid and calcium carbonate in rocks to create dissolved calcium bicarbonate

Question 10

How does acid rain increase the rate of weathering?

Answer 10

It increases the rate of carbonation through the presence of carbonic acid

Question 11

What is the most significant link between water and carbon in the atmosphere?

Answer 11

Changes in the carbon cycle can cause warming, allowing the atmosphere to hold more moisture.

Question 12

Why does the warming of the atmosphere not mean everywhere will experience more precipitation?

Answer 12

It may disrupt normal weather patterns which could lead to less rain in some regions

Question 13

What disruption in normal weather patterns could reduce rain in some regions?

Answer 13

Increased frequency of El Nino

Question 14

What is El Nino?

Answer 14

A pattern of unusually warm water stretching across the surface of eastern equatorial Pacific that occurs every 3-7 years.

Question 15

How is climate change likely to affect El Nino?

Answer 15

It may double the frequency of particularly strong ‘super’ El Nino events

Question 16

How will climate change increase the frequency of super El Nino events?

Answer 16

The eastern equatorial Pacific warms faster than the surrounding regions. Warming temperatures will therefore make it easier to have maximum sea surface temperatures in the eastern equatorial Pacific, increasing occurrences of extreme El Nino events.

Question 17

Why does the eastern equatorial Pacific warm faster than surrounding regions?

Answer 17

The natural temperature difference between surface waters in the eastern tropical Pacific and the western tropical Pacific makes the eastern waters easier to warm.

Question 18

Describe why surface waters of the western tropical Pacific are naturally warmer than those of the eastern tropical Pacific.

Answer 18

Trade winds blow east to west across the Pacific, pushing warm surface waters across. Warm water piles up on the west and in the east this water is replaced by the upwelling of cold water.

Question 19

How does the natural difference in temperature across the Pacific affect the climate?

Answer 19

Warmer water in the west heats the air causing increased cloud and rainfall. This air travels and cools before sinking in the east, creating an atmospheric circulation.

Question 20

How does the El Nino phenomenon occur?

Answer 20

Slow changes in the equatorial ocean can reverse the usual trade winds. This decreases the natural push of water to the west and upwelling in the east. The colder east Pacific warms, neutralising the normal temperature difference.

Question 21

What aspects of the global climate soes El Nino particularly affect?

Answer 21

Temperature
Rainfall
Tropical cyclones

Question 22

Give 2 examples of the impacts El Nino has on the global climate

Answer 22

It can increase droughts and wildfires in Australia
It can increase floods in Peru
It can change distribution of sea ice in Antarctica

Question 23

What percentage of the Earth’s greenhouse effect is caused by CO2?

Answer 23

20%

Question 24

What percentage of the Earth’s greenhouse effect is caused by water vapour?

Answer 24

50%

Question 25

If CO2 contributes less to the greenhouse effect than water vapour, why is it considered to be a more important greenhouse gas?

Answer 25

CO2 levels determine the temperature as they control the amount of water vapour in the atmosphere, and therefore the magnitude of the enhanced greenhouse effect.

Question 26

Which greenhouse gas has more impact over global temperature changes: CO2 or water vapour?

Answer 26

CO2

Question 27

Why is there a lag time between increased CO2 levels and increased warming?

Answer 27

The ocean soaks up heat

Question 28

What does the lag time between increased CO2 levels and increased warming mean for global climate?

Answer 28

The rise in temperature is not all the warming that will occur based on current CO2 concentrations - the Earth’s temperature will increase at least another 0.6C because of CO2 already in the atmosphere.