Water & Carbon Systems Flashcards
What’s an input?
- Material or energy moving into the system from outside
What’s an output?
- Material or energy moving from the system to outside
Energy
- Power or driving force
Stores/Components
- The individual elements or parts of a system
Flows/transfers
- The links/relationships between the components
Positive feedback
- Cyclical sequence of events that amplifies or increases change.
- Positive feedback loops exacerbate the outputs of a system, driving it in one direction and promoting environmental instability
Negative feedback
- Cyclical sequence of events that damps down or neutralizes the effects of a system
- Promoting stability and a state of dynamic equilibrium
Dynamic equilibrium
- Represents a state of balance within a constantly changing system
What are the Earth’s subsystems? [5]
Cryosphere - cold enough to freeze
Lithosphere - outermost part of Earth e.g. crust & upper mantle
Biosphere – where all living things are found
Hydrosphere - includes all the water on Earth
Atmosphere - layer of gas between Earth’s surface & space
What % of carbon is stored in sedimentary rocks e.g. limestone?
99.9%
What % of the carbon in the earth is stored in fossil fuels?
0.004%
What % of carbon is stored in the cyrosphere?
0.01%
What % of carbon is stored in the atmosphere?
0.001%
What type of system is the carbon cycle and why?
Closed system:
There are inputs & outputs of energy, but the amount of carbon in the system remains the same.
Name the stores of the carbon cycle [7]
- Atmosphere
- Vegetation
- Soils
- Fossil fuels
- Earth’s crust
- Oceans
- Sediments
What are the fast carbon flows? [4]
- Photosynthesis
- Respiration
- Combustion
- Decomposition
What is sequestration? [2]
- Carbon from the atmosphere can be sequestered (captured & held) in sedimentary rocks or as fossil fuels- dead animal & plant material = compacted
- Carbon in fossil fuels is sequestered until we burn them
What is photosynthesis? [2]
- Transfer of carbon stored in the atmosphere to biomass
- Plants convert co2 into glucose & oxygen
What is respiration? [2]
- Transfers carbon from living organisms to the atmosphere
- Plants & animals release carbon dioxide & methane
What is combustion? [2]
- Transfers carbon stored in biomass into the atmosphere by burning
- Wildfires can cause carbon flow
What is decomposition? [2]
- Transfers carbon from dead biomass into the atmosphere & soil
- After death bacteria & fungi break organisms down - releases co2
What is ocean uptake & loss? [2]
- CO2 is directly dissolved from the atmosphere into the ocean
- CO2 is transferred from the ocean to the atmosphere when carbon-rich water from deep oceans rises and releases CO2
What is weathering? [4]
- Transfers CO2 from atmosphere -> hydrosphere -> biosphere
- Atmospheric carbon reacts w/ water vapour to form acid rain
- Acid rain dissolves the rocks & molecules from this reaction may wash into the sea
- Molecules react with CO2 dissolved in water to form calcium carbonate which is used by sea creatures e.g to make shells
What are the main carbon flows at plant scale? [2]
- Respiration
- Photosynthesis
What are the main carbon flows at ecosystem scale?
- Combustion
- Decomposition
What are the main carbon flows at continental scale?
- Sequestration
How can wildfires affect the magnitude of carbon stores? [3]
- WF’s rapidly transfer large quantities of carbon from biomass into the atmosphere
- Loss of vegetation decreases photosynthesis so less carbon is removed from the atmosphere
However in long term: fires can encourage new plant growth = neutral effect on amount of atmospheric carbon
How can volcanic activity affect the magnitude of carbon stores? [3]
- Carbon stored w/i Earth in magma is released during eruptions
- Majority of carbon enters the atmosphere as co2
- Recent eruptions have released much less co2 than human activities - however there’s potential for a large eruption to disrupt the carbon cycle significantly
What has happened since the industrial revolution? [2]
- Human impact on the carbon cycle has dramatically increased
- Causing carbon flows from lithosphere and biosphere to the atmosphere to happen much faster than they would naturally
How has hydrocarbon (fossil fuel) extraction & use affected the carbon cycle? [2]
- Extracting + burning of fossil fuels releases co2 into atmosphere
- W/o human intervention, the carbon would remain sequestered in the lithosphere for millions of years
How has deforestation affected the carbon system? [2]
- Clearance reduces the size of the carbon store
- If cleared forests are burnt, there’s a rapid flow of carbon from the biosphere into the atmosphere
How have farming practices affected the carbon system [3]
- Agricultural activities release co2 into the atmosphere:
Animals release CO2 and methane
Ploughing can release CO2 stored in soil
Growing rice in paddies releases methane
Will increase impact as world’s population increases.
How have land use changes affected the carbon cycle? [2]
- Vegetation is removed to make way for buildings - reducing carbon stores
- Concrete production releases lots of CO2, especially in urban areas
What is the carbon budget?
- The difference between inputs of carbon into a subsystem and outputs of carbon from it.
Name some inputs of the carbon system? [3]
Volcanic eruptions
Burning fossil fuels
Ocean loss
Name some outputs of the carbon system?
- Photosynthesis
- Sequestration
- Decomposition
- Chemical weathering
- Ocean uptake
What’s a carbon source?
- The outputs of carbon outweighs the inputs
What’s a carbon sink?
- The inputs of carbon outweigh the outputs, so it absorbs more carbon than releases
What’s the impact of the carbon cycle on the atmosphere? [3]
- Carbon cycle affects the amount of gases containing co2 in the atmosphere (greenhouse gases, trap sun’s energy)
- As concentrations increase temperatures are expected to rise - global warming
- Changes in temp. will affect other aspects of climate, e.g. more tropical storms.
What’s the impact of the carbon cycle on land? [3]
- Allows plants to grow - with no CO2, no photosynthesis or decomposition
- Changes in cycle can reduce amount carbon stored in land e.g. melting of the permafrost releasing carbon into atmosphere
- An increase in global temps could increase frequency of wildfires
What’s the impact of the carbon cycle on oceans? [5]
- CO2 is dissolved directly into oceans from the atmosphere
- > used by organisms e.g. phytoplankton & seaweed during photosynthesis to form skeletons
- Increased CO2 in ocean can increase ocean acidity, damaging marine line
- Global warming could kill organisms e.g. phytoplankton
- Warmer water less able to absorb CO2 so less can be dissolved in the sea decreases
What contains carbon?
All living things
How do plants form the base for food chains? [2]
- When photosynthesis occurs they use energy to convert co2 to biomass
- Requires inputs of both water and carbon - photosynthesis.
What is water present in the atmosphere as?
Water vapour and water droplets
What is carbon present in the atmosphere as?
Carbon dioxide and methane
What do water & carbon in the atmosphere cause?
A natural greenhouse effect that prevents some energy from escaping to space & reflects it back to Earth -> higher temperatures
What is an enhanced greenhouse effect?
- Where additional greenhouse gases reflect more energy back to Earth than in the natural greenhouse effect, so temp. increases even further
Example of positive feedback in the carbon cycle [4]
Temperatures rise -> Evaporation increases
-> Amount of water vapour in atmosphere increases -> Greenhouse effect increases
Name 3 greenhouse gases
- Water vapour
- Carbon dioxide
- Methane
Example of a negative feedback loop in the water cycle [5]
Temperatures rise-> evaporation increases
- > amount of water vapour in atmosphere increases, causing more clouds to form
- > increased cloud cover reflects more of sun’s energy back to space
- > temperatures fall
Example of a positive feedback loop within the carbon cycle [4]
Temperatures rise-> plant respiration rate increases
-> amount of co2 in atmosphere increases -> greenhouse effect increases ->
Example of a negative feedback loop within the carbon cycle [5]
CO2 in atmosphere increases -> Extra CO2 causes plants to increase growth
- > Plants remove and store more CO2 from atmosphere
- > Amount of CO2 in atmosphere reduces
How do the carbon & water cycles depend on each other? [3]
- Carbon combines with water in the atmosphere - allows chemical weathering, which removes carbon from atmosphere
- Water is needed for photosynthesis, which removes carbon from the atmosphere
- Amount of CO2 in the atmosphere affects global temperature, which affect the amount of evaporation that can take place, which affects the amount of precipitation
How might climate change affect precipitation?
- Wet areas are expected to get wetter & dry areas are expected to get drier
- Could lead to conflicts in future
How might climate change affect weather events?
- Extreme weather events may get more frequent (e.g. tropical storms)
- Less developed countries will be worst affected as may be unable to deal with impacts
How might climate change affect agricultural productivity?
It will decrease in some areas, which could lead to food shortages
How may climate change affect sea levels?
- Sea levels are expected to rise further.
- This will flood coastal & low-lying areas
How may climate change affect some species? [2]
- Geographical range of some species may change e.g. migrating birds
- The arrival of new species in an area may damage the ecosystem, and some species may become extinct
How may climate change affect plankton?
- Plankton numbers may decline if temperatures increase, which will have a knock-on effect on marine food chains
How much more CO2 is there than in 1750?
40% more in the atmosphere
What is the IPCC?
Intergovernmental Panel on Climate Change
- international organisation set up by UN to share knowledge about climate change
How can individuals mitigate climate change? [2]
- People can choose to use their cars less and buy fuel efficient cars
- Make homes more energy efficient e.g. double glazing
How can regional/national governments mitigate climate change? [4]
- Governments can reduce reliance on fossil fuels and reduce costs of renewable energy sources e.g. wind
- Afforestation and restoring degraded forests can increase carbon uptake
- Improving public transport (reduce car use) and creating more green spaces
- CCS (Carbon capture and storage) - CO2 is captured and stored underground
How can we mitigate climate change globally? [2]
- Kyoto Protocol 1997 & Paris Agreement 2015 - International treaties to control emission limits
- International carbon trading schemes- countries & businesses are given a limit on the emissions they can produce
What is the Amazon Rainforest? [3]
- World’s largest tropical rainforest, covers 40% of South America
- Home to up to 1 million plant species, 500 mammals and over 2000 species of fish
- Endangered species e.g. Black caiman, pirarucu
What is the average rainfall in the Amazon basin?
3000mm/year
How is the Amazon a carbon sink?
It stores a lot of carbon in its vegetation and soil
What has the increasing concentration of CO2 in the atmosphere led to in the Amazon?
Increased productivity in the Amazon rainforest because the vegetation is able to access more CO2 for photosynthesis
What has increased biomass in the Amazon rainforest caused?
The amount of CO2 sequestered by the rainforest has increased, making it an even more important carbon store.
What has happened to trees in the rainforest? [2]
Growing more quickly
Dying younger
How is human activity affecting the carbon cycle? [3]
- Without roots to hold soil together, heavy rain washes away the nutrient-rich top layer of soil -> transferring carbon stored in the soil to the hydrosphere
- Deforestation = less leaf litter so soil can’t support new growth, limits carbon being absorbed
- Trees remove CO2 from the atmosphere & store it, so fewer trees means more atmospheric CO2 - enhances greenhouse effect
How can climate change impact the Amazon Rainforest? [3]
- Temperature increasing and rainfall increasing leads to droughts, e.g. in 2005
- Many species die in dry weather due to moist adaptation
- A 4 degrees temp. rise could kill 85% of the rainforest -> lots of carbon into atmosphere
How can selective logging limit human impacts on the Amazon? [2]
- Only some trees are felled - most are left standing
- Less damaging than felling all the trees, forest is able to regenerate
How can replanting limit human impacts on the Amazon? [2]
- New trees are planted to replace ones cut down
- Variety of trees is maintained as same types are replanted
How can Environmental Laws limit human impacts on the Amazon? [2]
- Laws ban excessive logging
- Laws that control land use e.g. the Brazilian Forest Code - says landowners have to keep 50-80% of land as a forest
How can protection limit human impacts on the Amazon? [2]
- Many countries have set up national parks & nature reserves to protect rainforests, e.g. the Central Amazon Conservation Complex in Brazil 2003 - protects biodiversity
