Systems (The Carbon Cycle)

Question 1

Define “The Carbon Cycle”

Answer 1

The movement of carbon through several stores via pathways and flows eg: respiration, photosynthesis.

Question 2

What type of system is the carbon cycle?

Answer 2

An closed system. (Just Energy is transferred)
1. Stores- where carbon is held eg: plants, coal, gas.
2. Flows- how carbon moves from one store to another
3. Processes- the physical ways flows happen
CARBON MEASURED IN PETAGRAMS (PgC)
Fluxes- measurements of the rate of flow of material between stores.

Question 3

What is methane?

Answer 3

Methane= an important compound of carbon (CH4) a greenhouse gas produced by landfill and cows. Also released from the cryosphere.

Question 4

What are hydrocarbons?

Answer 4

Any compounds of carbon that are found in sedimentary rocks. Crude oil and natural gas also.

Question 5

What is calcium carbonate?

Answer 5

Common compound found in rocks, main component of the shells of living organisms= compacted to form limestone.

Question 6

What is a carbon sink?

What is a carbon source?

Answer 6

The inputs are greater than outputs.

The outputs are greater than the inputs

Question 7

Name three uses of the element carbon?

Answer 7

1. The control rods for nuclear reactors.
2. Carbon fibre as a strong yet lightweight material.
3. Within iron and steel industries

Question 8

Describe the global distribution of carbon?

Answer 8

Lithosphere- sedimentary rocks such as limestone, marine sediments, hydrocarbons = 99.9% -absorbs 34% of ANTHRPOGENIC EMISSIONS
Hydrosphere- carbonate ions, bicarbonate ions, dissolved C02 = 0.04%
Cryosphere= 0.0018
Atmosphere= 0.001
Cryosphere= 0.01%

Question 9

Photosynthesis and Respiration (processes that allow fluxes of carbon to take place LOCALLY and not and over a LONG/SHORT TIME) (s+t)

Answer 9

Photosynthesis
6C02 + 6H20 = C6+H6+O6+ 6O2

Respiration
C6+ H6+ O6+ 6O2 =6CO2 +6H20
Deforestation means decreased carbon sequestration
Most takes place in LIC’s such as Brazil
Due to agriculture, resources, land use, housing developments

Question 10

Define carbon sequestration?

Answer 10

The process where CO2 is captured and put into long term storage eg: plants, sedimentary rock.

Question 11

Key points regarding the “Greenhouse Effect”

Answer 11

Without greenhouse gasses the planet would be too cold to support life and too much solar radiation would be lost.
The NATURAL GREENHOUSE EFFECT allows organic life to survive on earth through absorbing long wave radiation.
The HUMAN ENHANCED GREEHOUSE EFFECT is down to human activities as C02 too efficient at holding in long wave radiation.

Question 12

What is the slow carbon cycle?

What is the fast carbon cycle?

Answer 12

Can take millions of years and is the movement of carbon through the lithosphere- sedimentary rocks and marine sediments- released by weathering (IN SITU).

Movement of carbon through food chains. Photosynthesis and intake of C02 can take a few mins

Question 13

Can we go back to a Carbon Cycle in Equilibrium?

KYOTO PROTOCOL

Answer 13

Japan, 1997 by United Nations (UN)
Aimed to decrease emissions generally by 5.2%
Each country had a specific goal eg: USA 7%, Iceland 10%
–Only focused on already developed nations.
–USA didn’t comply and Canada withdrew in 2012.

Question 14

Human changes to the carbon cycle?

Answer 14

• The burning of fossil fuels (oil, coal, gas) has lead to an upset of the equilibrium.
• Deforestation of carbon sinks and replacing them with urban areas/crop land/ agriculture.
• “slash and burn” -combustion of fossil fuels= acid rain.(water vapour + carbon = carbonic acid)

+afforestation can increase carbon sinks
+alternative energy eg: wind, tidal, solar

Question 15

Natural changes to the carbon cycle?

Answer 15

Weathering/ soil erosion.
Volcanic activity.
Forest fires- dry, hot, lightning.
Storm events/ natural disasters.

Question 16

Processes- WEATHERING

Answer 16

Involves the breakdown of rock in situ, as the rock breaks apart carbon inside is released.
-ACID RAIN- carbonic acid- reacts with minerals in unstable rocks to release component ions. These are transported to oceans and dissolved.
Dissolved carbonate ions are used to build shells of marine organisms that are compacted= sedimentary rocks.
-FREEZE THAW

Question 17

Processes- PHOTOSYNTHESIS

Answer 17

Plants use the suns energy to form carbohydrates in the form of glucose, whilst also sequestering CO2.
CO2 reacts with chlorophyll to create c.h.d
Used to aid plant growth or stored as starch.

Question 18

Processes- RESPIRATION

Answer 18

The opposite of photosynthesis.

Plants use stored glycose for energy source, whereas animals eat plants and convert them into their own energy.

Question 19

Process- CARBON SEQUESTRATION

Answer 19

Geological Sequestration- CO2 is captured at it’s source and injected deep into the ground eg: gas and oil reservoirs. Still experimental stage and costs alot.

Terrestrial sequestration- the use of plants ON LAND to capture CO2 from the atmosphere. Good for wildlife and conservation, but slow growing and requires a lot of management. -Peat, Soil humus.

Question 20

Process- DECOMPOSITION

Answer 20

When organisms die they are consumed by decomposers- body returned as carbon dioxide. However, some material is returned to the atmosphere as C02 and stores for hundreds of years.

Question 21

Processes- BURIAL AND COMPACTION

Answer 21

Organic matter dies, buried by sediments and becomes compacted. Over millions of years these organic sediments that form carbon= HYDROCARBONS.
eg: shelled organisms take up dissolved CO2 ions and turn it into calcium carbonate to build shells. When they die the shells are compacted= LIMESTONE.

Question 22

Define Geo-sequestration?

Answer 22

The technology of capturing greenhouse gas emissions from power stations and pumping them unto underground reservoirs.

Question 23

Define radiative forcing?

Answer 23

The difference between the incoming solar energy absorbed by the earth and the energy radiated back to space.
Some sunlight is reflected back to space (30%) and the rest is absorbed by the planet.
Current level is 1.6watts/m2

Question 24

The Carbon Budget?

Answer 24

The finite amount of gg we can emit to limit global temperature rise by 2 degrees Celsius.
Effects in Australia if we blow it:
-Great barrier reef destroyed by bleaching-oceans rise and become deeper decreasing sunlight.
-Double temperature related deaths
-3x increase in forest fires

Question 25

CASE STUDY: The Paris Agreement

Answer 25

December of 2015 at the UNFCCC’s COP21 held in Paris, France.
195 governments have agreed there’s a need to limit temperature rise to 2 degrees Celsius
67% change of accomplishing this
Scientists say if rise exceeds this amount then accelerated temps will be irreversible.

Question 26

Paris agreement advantages and disadvantages?

Answer 26

+more international consensus than Kyoto
+gained support from fossil fuel companies such as Chevron and Shell

• countries have only made pledges so far
• Rivalries and diplomatic tension makes the “balance of inequalities” portion of the Paris Agreement particularly hard to implement. For instance, the U.S. agreed to voluntarily pay $3 billion dollars under the commitments made by President Obama.

Question 27

Positive feedback example?

Answer 27

Enhanced greenhouse effect ——- increased surface temperature of oceans——- increased evaporation from the oceans——– increased amounts of water vapour in atmosphere.

Question 28

Negative feedback example?

Answer 28

Enhanced greenhouse effect——— increased warmth globally——— increased plant growth——– increased terrestrial sequestration———- reduced greenhouse effect.