🔵Carbon Cycle

Question 1

What’s the cryosphere

Answer 1

Ice storage

Accounts for 1.7% of all water on earth

Question 2

Major cryospheric stores

Answer 2

Antarctic (90%) and Greenland (10%) ice sheets
Polar sea ice
Mountain glaciers

Question 3

Sea ice function (global climate )

Answer 3

While sea ice exists primarily in the polar regions, it influences the global climate. The bright surface of sea ice reflects a lot of sunlight out into the atmosphere and, importantly, back into space. Because this solar energy “bounces back” and is not absorbed into the ocean, temperatures nearer the poles remain cool relative to the equator.

When warming temperatures gradually melt sea ice over time, fewer bright surfaces are available to reflect sunlight back into the atmosphere. More solar energy is absorbed at the surface and ocean temperatures rise. This begins a cycle of warming and melting. Warmer water temperatures delay ice growth in the fall and winter, and the ice melts faster the following spring, exposing dark ocean waters for a longer period the following summer.

Question 4

What do changes in sea ice cause (globally)

Answer 4

Changes in the amount of sea ice can disrupt normal ocean circulation, thereby leading to changes in global climate. Even a small increase in temperature can lead to greater warming over time, making the polar regions the most sensitive areas to climate change on Earth.

Question 5

How much freshwater is stored in the cryosphere

Answer 5

70% worlds freshwater

Question 6

What would happen if the cryosphere melted fully

Answer 6

Rise in sea level - 70m

A significant amount of the UK, SW Europe, a large amount of Asian cities would be drowned including Singapore, Mumbai and Doha. All seaside cities and areas would be lost.

Question 7

Permafrost definition

Answer 7

Permafrost is a layer of frozen soil, composed of soil, gravel, and sand bound together by ice. Permafrost is found throughout the Arctic, as well in Eastern Europe and China. It can also be found below the ocean floor.

Question 8

Permafrost function

Answer 8

Permafrost contains a lot of carbon dioxide and methane that has been stored over thousands of years. Recent research shows that permafrost is thawing 70 years earlier than anybody thought it would. One potential consequence of the current rapid thawing is the release of this carbon dioxide and methane into the atmosphere.

Decreases in cryosphere - more GHG’s released (due to warming soil temperatures)

Question 9

What would happen if permafrost melted

Answer 9

Large amounts of GHG’s released

Homes, roads and schools to buckles and collapse, some communities have already had to relocate.

Landslides, floods, coastal erosion, decrease in wildlife and biodiversity.

Question 10

Glacial water - Himalayas

Answer 10

Himalayan Glaciers provide freshwater to Afghanistan, Pakistan, India, China, Nepal, Bhutan, Bangladesh and Myanmar.

More than 1.9 billon people rely on glacial melt water for drinking, agriculture and energy - however by 2050 1/3 of Asias glacier would have melted meaning many are left without freshwater supply’s.

Question 11

Main carbon stores - lithosphere (1)

Answer 11

1st
Marine sediments and sedimentary rocks (long term)

66,000-100,000 million billion metic tonnes of C.

The rock cycle and continental drift recycle the rock over time, but this may take thousands, if not millions of years.

Question 12

Main stores of carbon - hydrosphere

Answer 12

2nd
Oceans (dynamic / variable)

The second biggest store contains a tiny fraction of the carbon of the largest store - 38,000 billion metric tons of carbon.

The carbon is constantly being utilised by marine organisms, lost as an output to the lithosphere, or gains as an input from rivers and erosion.

Question 13

Main stores of carbon - lithosphere (2)

Answer 13

3rd
Fossil fuel deposits (long term but currently dynamic and variable)

Fossil fuel deposits used to be rarely changing over short periods of time, but humans have developed technology to exploit them rapidly, though 4000 billion metric tons of carbon remain as fossil fuels.

Question 14

Main stores of carbon - lithosphere (3)

Answer 14

4th
Soil organic matter (mid term)

The soil can store carbon for over a hundred years, but deforestation, agriculture and land use change are affecting this store. 1500 billion metric tons of carbon stored.

Question 15

Main stores of carbon - atmosphere

Answer 15

5th
Dynamic

Human activity has caused CO levels in the atmosphere to increase by around 40% since the industrial revolution, causing unprecedented change to the global climate. 750 billion metric tons of carbon stored.

Question 16

Main stores of carbon - biosphere

Answer 16

6th
Terrestrial plants - Mid term but dynamic

Vulnerable to climate change and deforestation and as a result carbon storage in forests is declining annually in some areas of the world. 560 billion metric tons ofB carbon.

Question 17

Main carbon stores - cryosphere

Answer 17

Very little carbon stored

Question 18

Transfers in the carbon cycle - photosynthesis

Answer 18

Carbon Dioxide + Water —> (Light Energy) —> Oxygen + Glucose

By removing CO: from the atmosphere, plants are sequestering carbon and reducing the potential impacts of climate change.

During the day, plants photosynthesise, absorbing significantly more CO2 than they emit from respiration. During the night they do not photosynthesise but they do respire, releasing more CO2 than they absorb. Overall, plants absorb more CO2 than they emit, so are net carbon dioxide absorbers (from the atmosphere) and net oxygen producers (to the atmosphere).

Question 19

Transfers in carbon cycle - respiration

Answer 19

Oxygen + Glucose —> Carbon Dioxide + Water

Question 20

Transfers in carbon cycle - combustion

Answer 20

When fossil fuels and organic matter such as trees are burnt, they emit CO2 into the atmosphere, that was previously locked inside of them. This may occur when fossil fuels are burnt to produce energy, or if wildfires occur.

Question 21

Transfers in carbon cycle - decomposition

Answer 21

When living organisms die, they are broken down by decomposers (such as bacteria and detritivores) which respire, returning CO2 into the atmosphere. Some organic matter is also returned to the soil where it is stored adding carbon matter to the soil.

Question 22

Transfers in carbon cycle - diffusion

Answer 22

The oceans can absorb CO2 from the atmosphere, which has increased ocean acidity by 30% since pre-industrial times. The ocean is the biggest carbon store, but with carbon levels increasing seawater becomes more acidic which is harming aquatic life by causing
coral bleaching. Many of the world’s coral reefs now under threat.

Question 23

Transfers in carbon cycle - weathering and erosion

Answer 23

Rocks are eroded on land or broken down by carbonation weathering. Carbonation weathering occurs when CO2 in the air mixes with rainwater to create carbonic acid which aids erosion of rocks such as limestone. The carbon is moved through the water cycle and enters the oceans. Marine organisms use the carbon in the water to build their shells. Increasing carbon dioxide levels in the atmosphere, may increase weathering and erosion as a result, potentially affecting other parts of the carbon cycle.

Question 24

Transfers in carbon cycle - burial and compaction

Answer 24

When shelled marine organisms die, their shell fragments fall to the ocean floor and become compacted over time to form limestone. Organic matter from vegetation and decaying marine organisms is compacted over time, whether on land or in the sea, to form fossil fuel deposits.

Question 25

Transfers in carbon cycle - carbon sequestration

Answer 25

Transfer of carbon from the atmosphere to other stores and can be both natural and artificial. A plant sequesters carbon when it photosynthesises and stores the carbon in its mass. Factories are also starting to use carbon sequestration in the form of Carbon Capture and Storage (CCS). CO? is captured and transported via pipeline to depleted gas fields and
saline aquifers.

Question 26

CCS advantages

Answer 26

Can be fitted to existing coal power stations.
Captures 90% of CO produced.

There is a demand for CO2 (Coca-Cola, Plant Growth, Beer etc.), so transport systems via pipeline in liquid form already exist.

Potential to capture half the world’s CO emissions.

Question 27

CCS disadvantages

Answer 27

High cost is the main restriction to the growth of CCS.

Increases energy demand of power stations.

May not be space to fit it to existing power stations.

Economically viable in some cases as it is used to push oil out the ground, thus further increasing fossil fuel usage.

Question 28

Define a sere

Answer 28

A sere is a stage of a vegetation succession and can relate to specific environments. A vegetation succession occurs when a plant community develops and becomes more complex over time.

The carbon cycle occurs on a local scale in a plant, or in a sere.

Question 29

Changes to carbon cycle - NATURAL wildfires

Answer 29

Carbon transferred from biosphere to atmosphere due to combustion.

This burning can encourage the growth of plants in the long term.

(Man made fires - 90% all fires, so theres dramatically change the carbon storage balance)

Question 30

Changes to carbon cycle - NATURAL volcanic activity

Answer 30

Carbon stored within the earth is released during volcanic eruptions, mainly as CO2 gas. They contribute a relatively low proportion of CO to the overall carbon cycle.

The1815 Mt Tambora eruption in Indonesia produced sulphur dioxide gas, which then entered the
atmosphere, blocking radiation from the sun and lowering global temperatures by 0.4 - 0.7°C in 1816.

In this way volcanoes can influence the carbon cycle by reducing photosynthesis rates, which will then also affect the water cycle.

Question 31

Changes to carbon cycle - HUMAN fossil fuel use (combustion)

Answer 31

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

Question 32

Changes to carbon cycle - HUMAN deforestation

Answer 32

Often used to clear land for farming/housing, rapidly releases carbon stored in plants using slash and burn techniques and interrupting the forest carbon cycle.

Question 33

Changes to carbon cycle - HUMAN farming practices

Answer 33

Pastoral farming releases CO2 as animals respire, affecting the carbon cycle.

Ploughing can release CO stored in the soil. Farm machinery such as tractors may release CO2.

Question 34

Define the carbon budget

Answer 34

Balance between carbon inputs and outputs to a store at any scale. Includes the balance and exchanges between the 4 major carbon stores.

Carbon source - store that emits mire carbon than it absorbs.

Carbon store - store that absorbs more carbon than it emits.

Question 35

Impact of the carbon cycle on tropical rainforests

Answer 35

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

Deforestation reduces photosynthesis and respiration, further reducing humidity and cloud cover and decreasing precipitation.

Question 36

Impact of carbon cycles on oceans

Answer 36

Warmer oceans cause more plankton growth and through plankton chemical production, cause clouds to potentially form.

Warm oceans also store less COz, as carbon sequestration is dependent on a cooler ocean. This means higher temperatures could lessen the effects of oceans as carbon sinks.

Note how warmer, equatorial oceans are classed as CO sources. This sets up : positive feedback loop where the greenhouse effect is heightened further.

Question 37

The enhanced greenhouse effect

Answer 37

Process causing global warming due to abnormally high levels of GHGs produced by humans that trap large amounts of radiation from the sun - causing climate change.

Increases in global temperature due to alteration of the carbon cycle will have significant impacts on the water cycle, leading to greater levels of evapotranspiration. The increase in global temperatures may make summer storms more likely but decrease the amount of rainfall in summer on average, yet increase the average winter rainfall.

Question 38

Radiative forcing

Answer 38

Refers to the difference between incoming solar radiation absorbed by the Earth and the energy radiated back out into space. This has increased in the recent years, leading to more heat being trapped. CO is the single most important anthropogenic greenhouse gas in the atmosphere, contributing around 65% to radiative forcing by greenhouse gases.

Question 39

Land use changes - effect on carbon budget

Answer 39

Accounts for a tenth of carbon release annually and impacts on short-term stores in the carbon cycle, such as the soil and atmosphere. For example:

Farming Practices: In the Amazon, around 70% of deforestation is for cattle
ranching. Cattle produce significant amounts of methane, further contributing to global warming. Scientists are considering whether feeding cows different foods would help to reduce their methane emissions.

Fertilisers are a significant source of greenhouse gases as well as rice padi fields, from which methane emissions have increased as a result of increased productivity due to higher CO2 levels. More sustainable grains and seeds like quinoa are being considered as substitutes, which require less water to grow.

Question 40

Deforestation - effect on carbon budget

Answer 40

In total, deforestation accounts for about 20% of all global greenhouse emissions.

The main impact is when the cycle is interrupted and the land is used for other purposes, which then reduces carbon sequestration and land becomes a carbon source rather than a carbon sink.

Question 41

Urbanisation - effect on carbon budget

Answer 41

This is the process of replacing countryside with buildings and other similar infrastructure. It affects the local and global carbon cycles, by replacing vegetation and covering soils.

Urban areas occupy 2% of the world’s land mass, but
these areas account for 97% of all human caused global CO emissions.
Cement is an important building material, but releases carbon dioxide during production, contributing 7% to global carbon dioxide emissions each year, so sustainable options for recycling concrete are being developed.

Question 42

Mitigating climate change - mitigation

Answer 42

Setting targets to reduce greenhouse gas emissions.

Switching to renewable sources of energy.

‘Capturing’ carbon emissions and/or storing or burying them (sequestration).

Question 43

Mitigating climate change - global intervention (COP21 Paris Climate Deal)

Answer 43

Aim to limit the increase of global temperatures to 2°C above pre-industrial levels.

Support for developing countries.

Public interaction and awareness schemes.

Meet every 5 years to review and improve goals.

Question 44

Mitigating climate change - regional intervention (EU 20-20-20)

Answer 44

20% reduction in GHG emissions and commitment to 20% of energy coming from renewable sources and 20% increase in energy efficiency by 2020.

EU has suggested it will increase its emissions reduction to 30% if major GHG producing countries also improve their targets.

Question 45

Mitigating climate change - national intervention (climate change act 2008 UK)

Answer 45

Legally binding target for the UK to reduce GHG emissions by 80% of 1990 levels by 2050 with a target of 26% by 2020 which has recently increased to 34%.

Created national carbon budgets and the Independent Committee on Climate Change to help the government and report on progress that is being made.

Question 46

Mitigating climate change - local scale

Answer 46

Recycling.

Using energy more wisely and use of smart meters and using public transport or car sharing schemes and calculating personal carbon footprints.

Question 47

Biological carbon pump

Answer 47

Decomposition - release co2 into atmosphere through respiration of decomposers.

Ocean - absorb co2 (dissolves in cool water)

Photosynthesis - absorbs co2 from atmosphere

Question 48

Carbon pump - transfers to and from atmosphere

Answer 48

Ocean - warmer ocean (diffuse out) / cooler ocean (diffuse in)

Respiration - release co2

Decomposers - release co2

Volcanoes - release co2 / ch4

Wildfires / combustion of fossil fuels - release co2

Photosynthesis - absorb co2

Question 49

Name countries with the largest deforested areas

Answer 49

1. Russia
2. Brazil
3. China
4. Canada
5. USA
6. DRC
7. Australia
8. Indonesia

Question 50

Enhanced greenhouse effect

Answer 50

Process thats currently causing global warming as abnormally high levels of GHGs are being produced by humans and trapping radiation.

Radiative forcing - CO2 contributes to 65% of radiative forcing.

Question 51

Effect of increased temperature on C cycle

Answer 51

Greater levels of evapotranspiration.

Summer storms more likely but decrease the amount of rainfall in summer on average.

Increased winter rainfall.

Question 52

Milankovitch Cycles

Answer 52

Describes the collective effects of changes in the Earth’s movements on its climate over thousands of years.

Question 53

What does Vostok ice core data from Antarctica show.

Answer 53

Suggests that in the past temperature change has occurred before co2 levels have risen.

Question 54

It’s possible that variations in the earths orbit cause periods of time where we experienced greater heating effect from the sun…

Answer 54

Increasing global temperatures, causing glaciers to melt that therefore increases flows in the C cycle.

Allows more CO2 to enter the atmosphere and for global temperatures to rise further (+ve feedback).

Question 55

Impact of the C cycle on tropical rainforests

Answer 55

Higher rates of photosynthesis and respiration, further increasing lead to greater humidity and cloud cover increasing precipitation.

Deforestation reduced p/s and respiration reduce humidity and cloud cover decreasing precipitation

Question 56

Impact of C cycle on oceans

Answer 56

Warmer oceans cause more plankton growth and through plankton chemical production, causes clouds to potentially form.

Warm oceans also store less CO2. (CO2 can start diffusing out of oceans).

Question 57

Positive feedback - wildfires

Answer 57

Wildfires are more likely to form in hotter and drier climates created by global warming, which releases large amounts of CO2 which increase warming.

Question 58

Positive feedback - ice melting

Answer 58

Ice reflects radiation from the sun, reducing surface warming. As sea temperatures rise and ice melts, warming effect amplified as less sea ice to reflect radiation.

Question 59

Positive feedback - permafrost thawing

Answer 59

Higher temperatures thaw permafrost releasing CO2 and CH4 causing warming locally and globally. Process repeats.

Question 60

Negative feedback - increased p/s

Answer 60

Increased p/s by plants and rising global temperatures allows vegetation to grow in new areas so absorbs CO2 and reduces effect of global warming.

Question 61

Negative feedback - phytoplankton growth

Answer 61

Causes phytoplanktons growth as they feed off CO2 and take in in by p/s.

Question 62

Negative feedback - phytoplankton + clouds

Answer 62

Higher temperatures cause phytoplankton and phytoplankton cause in increase in formation of clouds. Therefore cloud coverage increases and radiation form the sun is less able to reach oceans, reducing temperatures and decreasing cloud cover.

Question 63

Define moorland

Answer 63

Moorland (peatland) is an expanse of waterlogged, acidic soil and peat.

Moorlands are major carbon stores (largest terrestrial C store.)

Waterlogged grounds reduced plant growth.

Question 64

Land drainage in moorland areas

Answer 64

Many moorlands have been drained by large channels and converted into highly productive farmlands due to their fertile soils.

This has caused an increased flood risk in local areas as surface storage is reduced.

Question 65

How does drainage of moorland increase effect C cycle

Answer 65

Moorland is drained

Water table is lowered affecting flows in the water cycle.

Dry peat degrades easily.

As the water table lowers, air is able to aid decomposition of peat releasing CO2.