Carbon Cycle

Photosynthesis

Atmosphere to biomass - used to create glucose for growth

Respiration

Biosphere to atmosphere - break down glucose for energy - release carbon dioxide and methane

Combustion

Lithosphere / biosphere to atmosphere - burnt to release energy - release CO2 and other pollutants

Decomposition

Biosphere to atmosphere and lithosphere - bacteria / fungi break down dead organism - releases carbon dioxide and methane

Ocean uptake and loss

Atmosphere to hydrosphere - warm water absorbs carbon dioxide - carbon move to the deep waters when cool - warms and rises again

Weathering

Atmosphere to hydrosphere / biosphere - atmospheric carbon reacts with water vapour to form carbonic acid - reacts with calcium carbonate rocks to form calcium bicarbonate - dissolved into the seas

Sequestration

Atmosphere to lithosphere - natural and human - compacted dead organic matter and carbon capture and storage

Carbon Capture and Storage / Carbon Sequestration

Carbon is captured from the factories - turned into a liquid - stored underground

Rock requirements for Carbon Capture and Storage

Porous rock surrounded by impermeable rock

Atmosphere carbon store

CO2 and methane - 0.001% of the Earth’s carbon - over 400ppm

Cryosphere

Carbon stored in the permafrost - anaerobically released - less than 0.0001%

Hydrosphere

Carbon dissolved in oceans, rivers and lakes - 0.04% - most found in deep ocean

Biosphere

Carbon stored in the tissues of living organisms - 0.004% - mostly in soil

Lithosphere

Carbon stored in sedimentary rocks - over 99.9% - 0.004% in fossil fuels

Wildfires

Natural process - biosphere to atmosphere - released through burning - can encourage plant growth

Volcanic activity

Natural process - carbon is released from underground during eruptions

Fossil Fuel usage

Human process - Combustion transfers carbon to atmosphere - 90% of all carbon in the atmosphere

Deforestation

Human process - clear land by slash and burn - interrupt the forest carbon cycle

Farming Practices

Human process - Ploughing can release carbon in soil - arable farming releases carbon as animals respire

Carbon Source

Emits more carbon than it absorbs

Carbon Sink

Absorbs more carbon than it emits

Cement manufacture

Human process - Calcium carbonate is heated releasing CO2 - every 1000kg of cement produces 900kg of CO2

Land Use Change

Human process - Urban areas have less photosynthesis, more cars and more cement - responsible for 47% of all emissions in 2012

Terrestrial Carbon Sequestration

The use of plants to capture Carbon Dioxide from the atmosphere

Positive climate feedback - permafrost thaw

Surface temperatures increase - permafrost thaws releasing ch4 and co2 - greenhouse gas concentrations increase - more solar radiation trapped - increased surface temperatures

Negative climate feedback - vegetation growth

co2 used for photosynthesis - carbon locked up in biomass - less co2 in the atmosphere - less photosynthesis

The Carbon budget

The carbon that is emitted compared to what is absorbed by nature / captured by people

Enhanced greenhouse effect

The increase in the effects of global warming due to human activities

Blue carbon

Carbon sequestered in coastal ecosystems such as mangroves and salt marshes - has a higher storage capacity - 3-5 times greater than terrestrial forests

Carbon capture and storage - definition

Carbon gas is captured and compressed into a liquid - injected into suitable underground areas - deposits of fossil fuels

Carbon capture and storage - effects / mitigation

CO2 is not entering the atmosphere (moving to the lithosphere) preventing excess greenhouse gases - expensive and not fully trusted by environmental activists

Carbon capture and storage - Example

The Boundary Dam Power station in Canada burns through enough coal to power 100000 homes but captures 90% of carbon emissions

Modification of deforestation - definition

Reducing the rate at which deforestation is occurring by promoting the sale of sustainably grown timber, carbon offset payments and selective logging

Modification of deforestation - effects / mitigation

Tree is replanted - selective logging allows for some trees to remain in place

Modification of deforestation - example

By 2030, the Great Green wall aims to restore 100 million hectares of land and sequester 250 million tonnes of carbon

Paris Agreement / COP 26 - definition

195 countries agreed to limit and control the global climate by limiting temperature rises to 1.5c - report to one another on progress

Paris Agreement / COP 26 - effect / mitigation

Countries are now focussed on limiting CO2 outputs therefore reducing the overall amount that ends up in the atmosphere

Paris Agreement / COP 26 - example

2025, Donald Trump withdrew from the Paris Agreement within 1hr of being president

Government Policy in Brazil - definition

80% of all virgin forests per owner must be reserved - encourage farmers to be more productive with their land

Government Policy in Brazil - effect / mitigation

A decrease in deforestation from brazil reduces the total volume of CO2 released into the atmosphere - more trees allows for more CO2 to be absorbed from the atmosphere

Government Policy in Brazil - example

Brazil has been able to reduce deforestation by 75% since 2009 - increased in 2018 due to an emphasis on economic growth

Protecting mangroves - definition

Mangrove forests absorb more CO2 than terrestrial forests but have been cut down to provide access to the coast for economic growth / subsistence fishing

Protecting mangroves - effect / mitigation

Mangrove forests absorb 3-5 times more CO2 from the atmosphere - cannot burn making them immune to wildfires so cannot release more CO2 back into the atmosphere

Protecting mangroves - example

Sri Lanka has protected all of the mangroves (21000 acres) and plans to replant 9600 more acres

Changing rural land use - definition

Farming practices (carbon farming) can reduce the volume of CO2 - grassland and forested land can absorb more CO2

Changing rural land use - effects / mitigation

Certain crops absorb more CO2 than others - grasslands absorb up to 810 million tonnes of CO2 - limiting overgrazing and controlled irrigation can encourage plant activity decreasing atmospheric carbon stores

Changing rural land use - example

Tropical afforestation and reforestation could absorb and sequester 44% more CO2 from the atmosphere - grassland can absorb up to 810 million tonnes of CO2 up until 2030

Improved aviation practices - definition

Reducing the weight of aircraft and increasing the engine efficiency can reduce the CO2 emissions - flight management can also reduce emissions

Improved aviation practices - effect / mitigation

Design changes can make them more sustainable - flight management maximising the value of the fuel burnt by increasing occupancy and matching aircraft type to route

Improved aviation practices - example

In 2013, 3 billion passengers produced 705 million tonnes of CO2