The Carbon Cycle and Energy Security Flashcards
Define adaptation strategies
An approach to respond to future impacts of climate change
- What is carbon?
It is a chemical element that exists in its pure form or as a combination with other elements e.g. CO2
It forms the ‘building blocks’ of all life on earth and is moved around the earth via the carbon cycle.
Why is carbon so important?
- Economic development relies on fossil fuels
- Energy scarcity has led to hardship and conflict
- Combustion of carbon is changing the environment
- A desire for carbon is destroying ecosystems
What is the carbon cycle?
It’s a closed biochemical cycle that moves carbon between the different spheres of the Earth
What are the four spheres of the Earth?
- Lithosphere (largest)
- Hydrosphere
- Biosphere
- Atmosphere
How is carbon stored?
- Inorganic, found in rocks as bicarbonates and carbonate
- Organic, found in plant material
- Gaseous, e.g. carbon dioxide, methane, carbon monoxide
How is carbon stored in the biosphere?
In living and dead organisms
How is carbon stored in the hydrosphere?
As dissolved CO2
How is carbon stored in the lithosphere?
As carbonates in limestone and fossil fuel e.g. coal, oil & gas
How is carbon stored in the atmosphere?
As gases like CO2 and methane
What is carbon sequestration?
When carbon is captured from the atmosphere and stored e.g. through photosynthesis.
Define combustion.
The burning of fuels such as wood and coal, releasing CO2 into the atmosphere
Define decomposition
When organic substances are broken down into simpler matter i.e. they rot.
Define photosynthesis.
When plants remove CO₂ from the atmosphere to create carbohydrates for plant growth.
(CO₂ is stored in the structure of plants – also known as carbon sequestration.)
Define respiration.
When a plant/animal releases CO₂
Define ocean uptake.
When oceans absorb CO2 from the atmosphere.
- What are examples of fast carbon fluxes?
(seconds to minutes)
- Photosynthesis
- Respiration
What are examples of medium speed carbon fluxes?
(10-500 years)
- Decomposition
What are examples of slow carbon fluxes?
(millions of years)
- Sedimentation/lithification
Is the geological carbon cycle slow or fast? What is the reservoir turnover rate?
Slow.
Reservoir turnover rate of at least 100,000 years.
Is the biological carbon cycle slow or fast? What is the reservoir turnover rate?
Fast.
Reservoir turnover rate of a few years to a few millennia.
Define reservoir turnover.
The rate at which carbon enters and leaves a store is measured by the mass of carbon in any store divided by the exchange flux.
What are the main stores in the geological carbon cycle?
Rocks and sediments
What are the main stores in the biological carbon cycle?
Vegetation, soils, atmosphere, water
What are some examples of geological stores of carbon?
- Limestone (sedimentary carbonate rock made from when shell-building organisms form layers and turn into rock)
- Coal (a fossil fuel, biologically derived from decayed organisms)
- Shale (sedimentary rock, biologically derived from organisms embedded in mud)
- The Himalayas
- Coral (organisms cemented together over time to form limestone structures – coral reefs)
What exactly are sedimentary carbonate rocks made out of?
Calcium carbonate - CaCO₃ - shells and skeletons of marine creatures
By what process do marine sediments become sedimentary carbonate rock?
Lithification
What mountain range represents one of the earth’s largest carbon stores?
Himalayas
What % of carbon-containing rock in the ocean is biologically derived?
20%
How long ago did fossil fuels form in the UK?
320 millions years ago
What are oil and gas made out of?
Microscopic organisms called plankton
What is coal made out of?
The remains of trees, ferns and other plants
What are two processes in the geological cycle that last hundreds of millions of years?
Volcanic outgassing and Chemical Weathering
What are the three types of weathering?
Mechanical, Biological and Chemical
What is mechanical weathering?
Caused by physical changes such as changes in temperature, freezing and thawing, and the effects of wind, rain and waves. Can shatter and break rocks.
What is biological weathering?
Weathering caused by burrowing animals and roots of plants which can break rocks up.
What is chemical weathering?
Alters the chemical composition of rocks, through interaction with chemical compounds e.g. acid rain. Can dissolve rocks.
- What are carbon cycle pumps?
The processes operating in oceans to circulate and store carbon. They move carbon between the surface ocean and deep ocean.
What are the three pumps?
- The biological pump
- The carbonate pump
- The physical pump
What is the biological pump and how does it work?
- Phytoplankton sequester carbon from the atmosphere during photosynthesis in surface ocean waters.
- Carbon enters the food web as marine creatures consume each other.
- Most of the carbon is recycled in surface waters through respiration, decomposition and photosynthesis.
- A small amount of the carbon reaches the sea floor after dead plankton sink.
What are plankton?
Why are plankton important?
- They absorb more carbon than rainforests
- Essential for the food web
- Shells from plankton form sedimentary rocks.
- Oil is made from plankton.
What is the carbonate pump and how does it work?
The carbonate pump is part of the biological pump.
1. Organisms like corals and oysters use dissolved carbon to make their shells and skeletons.
2. When the organisms die, their calcium carbonate shells and skeletons sink to the ocean floor and accumulate as sediment.
3. Due to heat, time and pressure, these sediments will lithify to become sedimentary rock such as limestone.
What is the physical pump and how does it work?
Ocean currents and the thermohaline circulation move dissolved CO2 from surface ocean waters into the deep ocean and back again.
1. CO2 is diffused into oceans (ocean uptake) – the colder the water, the more CO2 it can hold
2. Water moves around the world horizontally (through ocean currents) and vertically (through upwellings and downwellings)
This global movement circulates carbon and regulates ocean temperatures and nutrient levels. The physical pump is vital to the biological and carbonate pumps – e.g. it brings nutrients to the surface leading to plankton blooms
What is the thermohaline circulation?
A key driver in global oceanic circulation.
In colder waters, it is saltier and denser meaning more carbon can be stores and contains lots of nutrients.
In warm waters, water rises to the surface. It stores less carbon than cold and nutrients rises to the surface.
Upwelling brings carbon from deep ocean into atmosphere, downwelling takes carbon out of the atmosphere and moves it into the deep ocean.
How does terrestrial sequestration work?
- CO2 is taken in by plants for photosynthesis and turned into carbohydrates.
- Plants release CO2 through respiration.
- The carbon taken in by plants is then eaten by animals.
- Animals release CO2 through respiration.
- Animals (and plants) die and their remains are fed on by microbes.
- These microbes also release CO2 through respiration.
Define primary producers.
Organisms such as green plants and phytoplankton which photosynthesise and produce carbohydrates to fuel growth.
AKA autotrophs
Describe the stores in mangrove ecosystems.
-Thick, organic layers of litter, humus, peat which has lots of carbon
-3-4 times more carbon than other tropical forests
-Submerged twice a day by tides so anaerobic soils i.e. no oxygen so slow decomposition
-Store it for a long time
Describe the stores in tropical rainforest ecosystems.
- One of the largest organic carbon stores on earth
- Carbon is mainly stored in the biomass (trees), not the soil
- Soils are thin & lack nutrients because litter layers decompose quickly due to high temperatures and humidity, and nutrients are consumed by vegetation
Describe the stores in tundra ecosystems.
- Carbon is stored in permafrost
- Contains twice as much carbon as the earths entire atmosphere
- Half of all soil carbon is stored in permafrost
- It is locked there for thousands of years
- Very few plants, litter, organisms or decomposition
Describe the fluxes in tundra ecosystems.
- Very little photosynthesis.
- Dying plants form peat.
Describe the fluxes in tropical rainforest ecosystems.
- Take in more CO2 than any other terrestrial biomes (land based biome).
- Decomposition is fast.
Describe the fluxes in mangrove ecosystems.
- Take in 1.5 metric tonnes of carbon per hectare per year
- Slow decomposition – thousands of years
Describe the threats and impacts on the carbon cycle in mangrove ecosystems.
- Mangroves are being cleared for tourism, shrimp farms and aquaculture
- 1.9% of mangrove cover is being lost each year
Describe the threats and impacts on the carbon cycle in tropical rainforest ecosystems.
- Deforestation
- 30-60% of carbon is lost to atmosphere during deforestation due to combustion (burning)
Describe the threats and impacts on the carbon cycle in tundra ecosystems.
- Global warming
- Permafrost melts
- Carbon lost in to the oceans/atmosphere
- How might increasing carbon emissions affect the oceans?
- They absorb more carbon and become more acidic
- More acidic waters mean that sea shell creatures struggle to build their shells
- Will slow down and reduce sequestration
- Will alter the marine ecosystem and food web
Why is a balanced carbon cycle important?
- A balanced carbon cycle is important in sustaining other earth systems.
- It plays a key role in regulating the Earth’s global temperature and climate, which then affects the hydrological cycle.
- Ecosystem development also depends on the carbon cycle.
- The system is being increasingly altered by anthropogenic actions.
Define greenhouse effect.
Warming of the atmosphere due to greenhouse gases absorbing heat energy radiated from the Earth.
What is the enhanced greenhouse effect?
The increase in the natural greenhouse effect, said to be caused by human activities that increase the quantity of greenhouse gases in the Earth’s atmosphere
What is the natural greenhouse effect?
1 – Short-wave solar radiation passes through the atmosphere. Some solar radiation is reflected by the atmosphere and the Earth’s surface.
2 – Some short-wave energy is absorbed and is converted into long-wave (heat) radiation. This warms the Earth.
3 – Some long-wave radiation passes back into space.
4 – Some long-wave energy is absorbed and re-emitted by the greenhouse gases back to Earth, heating Earth up.
What are the anthropogenic causes of increased greenhouse gases?
Burning fossil fuels, jet engines, rice paddies, cattle ranching, burning to clear vegetation, deforestation leads to lower levels of sequestration but does not in itself release CO2, sewage farms, landfill sites etc.
What is renewable energy?
Energy from continuous flows of nature which can be constantly reused.
5 - What different types of energy sources are there?
- Renewable
- Non-renewable
- Recyclable
What is non-renewable energy?
Finite energy sources where exploitation and use of stocks will eventually lead to their exhaustion
What is recyclable energy?
The use of energy that would otherwise go to waste e.g. reprocessed uranium from nuclear power plants, heat recovery systems
Define energy mix.
The combination of different primary energy sources used to meet a country’s energy demand.
Define primary energy sources.
Natural energy resources that have not been converted into another energy source.
Define secondary energy.
This is what primary energy sources are converted into e.g. electricity.
Define domestic resources.
The energy resources (of any type) within a country’s borders
Name 3 countries which rely completely on fossil fuels.
- South Sudan
- Qatar
- UAE
Why do some countries rely completely on fossil fuels?
Mostly because these countries have a lot of oil so it is convenient and available.
Name 3 countries that rely completely on renewables.
- Iceland
- Ethiopia
- Norway
Why can some countries rely completely on renewables?
They have good sources of renewables
E.g. Nile in Ethiopia and geothermal in Iceland
Which country is mostly reliant on nuclear energy and what % of their electricity comes from it?
France - 74%
What is the USA’s energy mix?
60% fossil fuels
19% nuclear
21% renewables
What factors affect access to and consumption of energy? (Name 5)
- Physical availability
- Cost
- Technology
- Public perception
- Economic development
- Environmental priorities
- Climate
- Politics
What are the largest sources of energy in Norway and why?
What are the largest sources of energy in the UK and why?
