The carbon cycle and energy security

Question 1

Petagram

Answer 1

A trillion kg

PgC = Petagram of carbon

Question 2

Anthropogenic

Answer 2

Human influenced

Question 3

The carbon cycle

Answer 3

Bio-chemical cycle by which carbon fluxes from one sphere to another. It’s a closed system so the total amount of carbon is constant.

Question 4

Residency time

Answer 4

How long carbon stays in one sphere

Question 5

Biggest carbon stores (PgC)

Answer 5

Sedimentary rock - 83m
Intermediate & deep ocean - 37,000
Soil - 2,000
Ocean floor ooze - 1,750
Permafrost - 1,700

Question 6

Biggest carbon fluxes
(PgC)

Answer 6

Photosynthesis - 123
Respiration & fire - 120
Atmosphere to ocean - 80
Ocean to atmosphere - 78
Fossil fuels and cement - 8

Question 7

Oil and natural gas formation

Answer 7

Phytoplankton and sea plants die and are covered by silt and sand. If organic content >= 2%, then over millions of years, heat, pressure and anaerobic processes creates oil/gas.

Question 8

Formation of sedimentary rocks

Answer 8

Made of calcium carbonate, formed from shells/skeletons and coral.

Question 9

How do volcanoes release CO2

Answer 9

CO2 is released from sedimentary rocks and water through subduction

Question 10

What happens to sedimentary rocks like limestone

Answer 10

Buried
Melted
Pushed up into terrestrial sphere

Question 11

Biological pump

Answer 11

-Phytoplankton photosynthesise
-Passed through food chain and respired
-Carbon moves through the ocean via feeding, waste and decomposition

Question 12

Carbonate pump

Answer 12

-Organisms use calcium carbonate to build their shells and create marine snow when they die
-Many shells dissolve, releasing carbon into ocean currents
-Shells that don’t dissolve build up on the sea floor and turn into limestone via high heat and pressure

Question 13

Thermohaline conveyor

Answer 13

-Primary mechanism for distributing heat globally
-Water heats and rises at equator, releasing CO2
-Travels to poles, where it cools and sinks
-Travels back to equator through deep ocean, CO2 stays here for hundreds of years

Question 14

Why are warming oceans an issue

Answer 14

-Water absorbs less CO2, enhancing GW
-Marine heatwaves that disrupt carbon cycle and marine life

Question 15

Why is the thermohaline conveyor failing and why’s it bad

Answer 15

-Water doesn’t sink at the poles as much, so less circulation
-Less oxygen reaches deep sea, marine life at risk
-Less CO2 absorption via biological/carbonate pumps
-Since 1990, circulation has slowed by a third

Question 16

Net Primary Productivity

Answer 16

The balance between energy captured by photosynthesis and released by respiration

Question 17

How does permafrost trap carbon

Answer 17

Too cold for microbes to decompose organic matter

Question 18

Permafrost positive feedback loop

Answer 18

-Climate warms
-Permafrost thaws
-CO2 and CH4 released
-Climate gets warmer

Question 19

Greenhouse effect

Answer 19

-Incoming short wave radiation from sun
-Some outgoing long wave radiation radiated back to space
-Some heat trapped by GrGases

Question 20

Natural systems and threshold risk

Answer 20

Stable state
>Positive feedback processes increase risk
>Reaches threshold (irreversible)
>New stable state (more risk)

Question 21

Formation of peatlands

Answer 21

Decomposing organic matter accumulates in watery environment without oxygen. Temps must be warm enough for plant growth but cold enough so microbes can’t break down plant matter. Takes thousands of years.

Question 22

Why are peatlands important

Answer 22

-30% of soil carbon store
-Home to endangered species
-Source of 70% of drinking water

Question 23

Primary energy

Answer 23

Natural resources that haven’t been converted to energy. Fossil fuels, nuclear, renewables

Question 24

Secondary energy

Answer 24

What primary energy is converted into (electricity)

Question 25

Problems with fossil fuels

Answer 25

-Environment -Finite -Become more expensive to extract -Most countries must import them, so are less energy secure

Question 26

Problems with wind and solar energy

Answer 26

-Don't produce energy 24/7 -Can't be stored efficiently -Sudden spikes can't be met

Question 27

Pros/cons of nuclear energy

Answer 27

Pros: -Uranium will last 1000 years -Less vulnerable -Low emissions Cons: -Chernobyl (public perception) -Nuclear waste can't be dealt with long term -High tech needed

Question 28

Biomass

Answer 28

Organic matter used as fuel. eg wood or methane

Question 29

Biofuel

Answer 29

Fuel derived from biological carbon fixations. eg sugar cane

Question 30

Biomass pros/cons

Answer 30

Pros: -Renewable -Not dependant on technology -Carbon neutral Cons: -Takes land away from farming -Encourages deforestation -Reduces biodiversity -Uses fossil fuels in transportation and 'kick start burning'

Question 31

Carbon capture and storage (CCS)

Answer 31

-Can capture up to 90% of CO2 from fossil fuels -Transported by pipeline or ship -Stored in depleted oil and gas fields or geological rock formations

Question 32

Decentralisation of energy

Answer 32

Generating electricity where it will be used, avoiding transport and less vulnerable

Question 33

What is ocean acidification

Answer 33

CO2 dissolving in the ocean, making its pH closer to 7. By 2100, will be 150% more acidic than in 1861.

Question 34

Impacts of ocean acidification

Answer 34

-Weakens coral -Loss of pteropods which are the main food source for marine creatures -Algal blooms