The Carbon Cycle
- Created by: carlajokic
- Created on: 14-03-18 11:43
Introduction
The carbon cycle:
a biogeochemical cycle where carbon is stored and moved between spheres through flows/fluxes.
It is a closed system
Stores ADD carbon to the atmosphere
Sinks REMOVE carbon
Flux: movement of organic compound through an ecosystem
The carbon cycle must be balanced to support planetary health
Terrestrial Carbon Stores
Geological has the slowest turnover rate, carbon enters and leaves very slowly.
It is stored in rocks and sediment and leaves through volcanic emissions or weathering
Biological cycle has a faster turnover, carbon is not sequestered for long, between the oceans, atmosphere and vegetation
Sequestering: the natural storage of carbon by physical or biological processes (e.g. Photosynthesis)
Stores of Carbon:
Limestone & Shale
Fossil Fuels
Coal
Coral
Formation of Fossil Fuels
Oil & Natural Gas:
-formed from remains of aquatic animals & plants
-gas & oil occur in pockets in rocks
Coal
-formed from remains of trees, ferns & other plants
-4 main types of coal; Anthracite, Bituminous, Lignite & Peat
Volcanic Outgassing:
-pockets of CO2 escaping from the earth's crust from volcanic activity or earthquakes
-outgassing occurs at; active/passive volcanoes with tectonic plate boundaries
-plates with no current volcanic activity e.g. hot springs or geysers
-emissions from fractures in the earth's crust
Carbon Pumps
Biological pump: organic sequestration of CO2 to oceans by Phytoplankton
-carbon passed up the food chain by fish & zooplankton which release CO2 into the water & atmosphere
Carbonate pump: inorganic carbon sedimentation
-marine life use Calcium Carbonate to form shells & skeletons e.g. corals, oysters etc.
-when organisms die & sink, shells dissolve and carbon is released
Physical Pump: oceanic circulation of water upwelling/downwelling & thermohaline current
-the colder the water, the more CO2
-warm waters release more, cold take in more
Thermohaline circulation: global system of surface & deep water ocean currents driven by temperature & salinity differences between areas of the ocean
Biological processes
Biological processes sequester organic carbon on land- quickest part of the cycle
1. primary producers (plants) remove carbon through photosynthesis & release through respiration
2. consumers (insects) eat plants, carbon becomes part of their fat/protein
3. Microorganisms (beetles) feed on waste material from animals & gain carbon
4. storage of carbon is mainly in plants/soils, the largest in trees, the least in animals
Terrestrial Carbon Stores
Amazon Rainforest; absorb more than they release, regulate global carbon levels
Mangroves; most carbon rich species on the planet, double those of forests
Tundra Soils; natural carbon stores, form at high latitudes in cold temperatures
Arctic Permafrost; stores carbon, released as they melt
A balanced carbon cycle
The Greenhouse effect:
- heat energy comes from the sun through SHORT WAVE radiation
-it has a lot of energy to pass through the atmosphere
-on reaching the earth's surface, it is either absorbed or reflected (albedo)
-at night, earth's surface cools & heat energy is released in LONG WAVE radiation
-this has less energy to escape & is absorbed by Greenhouse gas molecules
This sustains warm temperatures on earth, allowing humans to survive
Changing levels of CO2 over time:
-levels of carbon naturally fluctuate due to volcanic outgassing, solar flares & amounts of vegetation
-carbon levels have increased more rapidly recently due to burning fossil fuels
Impacts of burning fossil fuels
Fossil fuel combustion releases carbon into the atmosphere
-combustion has altered the carbon balance, flows have greatly increased
-rising levels of CO2 have lead to an increase in temperature
-annual precipitation will increase
-extreme weather events are more likely
Arctic: warming 2X as fast as global average
melting permafrost releases CO2, sea ice melts, habitats lost
Hydrological cycle:
change in rainfall patterns
more floods in winter, more droughts in summer
Energy Security
Energy security: the uninterrupted availability of energy sources at an affordable price
4 aspects of energy security:
-availability -accessibility -affordability -reliability
Energy intensity: a measure of how efficiently a country uses energy
HIGH intensity means high price of converting energy into GDP
energy intensity DECREASES with economic development
Factors affecting the consumption of energy
environmental priorities
-renewable energy is expensive
physical availability
-energy has to be imported if not available, consumer cost increased, air miles
climate
-colder climates require more energy e.g. heating, low consumption in Africa
economic development
-richer countries can afford more energy, opposite for poorer; prices are relative to economy
cost
-delivery to consumer, processing (primary to secondary), physical exploitation
Energy Players
Main worldwide energy players:
-TNCs, OPEC, Governments, Energy companies & consumers/pressure groups
Consumers; highly price sensitive, can exert pressure on politicians
Energy TNCs; exploration for reserves, exploitation & refining
Scientists, R&D; research into alternatives fuels
OPEC; key role in global prices, manage production
Environmentalists; pressure to adopt renewables & reduce carbon intensity
Generators & distributors; national grid & power stations (infrastructure)
Governments; National energy mix, subsidies and grants
Energy mix: combination of different available energy sources used to meet a country's demand
Energy pathways - Mismatch between supply & demand
Energy pathways: the flow of energy from producer to consumer
-e.g. by pipelines, shipping, rail, road or transmission lines
What makes a good energy pathway?
-good relationships between countries
-pipelines will try to avoid using transit states to transport the energy
Transit state: country/state through which energy flows from producer to consumer
How pathways can be disrupted:
Disturbance at chokepoints- can be blocked, disrupted; causes prices to rise
Geopolitical conflict - fight to gain control over resources
Piracy- oil stolen by pirates
Natural Hazards - extreme weather can damage pipelines
Unconventional fossil fuels
unconventional fuels: deep water oil, oil shale, tar sands & shale gas
Recyclable and renewable energy: helps to reduce carbon levels
examples include: Wind turbines, Solar power, Hyrdo electric, nuclear energy & biomass
Nuclear energy is not a renewable energy source as it needs uranium (a finite resource)
deep water oil - found at considerable depths in the ocean
tar sands - a mixture of sand, water, clay & bitumen
shale gas - natural gas trapped in sedimentary rocks
oil shale - oil bearing rocks that are permeable enough to allow oil to be pumped out directly
Reliance on fossil fuels
renewable energy - capable of natural regeneration & provides continual flow of energy
e.g. water, wind, tidal, waves, geothermal & solar
recyclable energy - can be renewed but only as a result of human intervention
e.g. harnessing nuclear power or biofuel
Primary biofuels - organic matter (fuelwood, wood chips) used in unprocessed form for cooling, heating & electricity
Secondary biofuels - derived from processed biomass & include liquid biofuels such as ethanol and biodiesel
DIFFERENCE IS ONE OF PROCESSING ^^
Radical alternatives to reduce carbon emissions: Carbon capture and storage, hydrogen fuel cells, electric vehicles & solar cooking
Carbon & water cycles link to global climate
Growing demand for resources e.g. food, fuel & water has led to land conversion
land conversion: change from natural ecosystems to an alternative use; usually reduces carbon & water stores as well as soil health
countries with highest rates of deforestation:
Nigeria Indonesia North Korea Bolivia Papua New Guinea
Impacts of deforestation:
Water cycle - runoff increased, higher flood peaks, annual rainfall reduced (droughts)
Soil health - rapid soil erosion, minerals lost, biodiversity decreased
Atmosphere - reduced evapotranspiration, reduced shading (forest floor)
Biosphere - species diversity reduced, decrease in habitat
Impacts of human activity
Kuznet's environmental curve: hypothesised relationship between environmental quality & economic development
-as modern economic growth occurs, environmental degredation gets worse
afforestation - establishing new forests where there were no trees before
reforestation - replanting trees where they were previously
ecosystem reliance - the level of disturbance that ecosystem can cope with while keeping their original state
critical threshold - a point beyond where damage becoms irreversible
ocean acidification - when CO2 in the ocean increases, the ocean pH decreases- the ocean becomes more acidic
coral bleaching: when water becomes too warm, algae is effected & coral turns white
CORALS: shelter marine species, protect shorelines, support fishing, income for tourism
implications for human wellbeing from degradation
forests & human wellbeing:
Human wellbeing: everyone aspires to live well worldwide, regardless of age, culture, religion or political environment
provisioning services - food, water, wood, fuel
supporting services - soil formation, habitat production
regulating services - climate & flood regulation
cultural services - spiritual, aesthetic, educational
current biggest threat to forests is deforestation
factors affecting time of change:
-wealth -law enforcement -aid -influence of TNCs
-Education and knowledge
Kuznet's curve
3 stages : Pre industrial, Industrial & post industrial
stage 1 - rapid economic development occurs when demand for products has environmental impacts
stage 2 - concern at degredation leads to action to protect environment
stage 3 - reinforcement of stage 2 occurs with education & funding for environmental protection
continued.
impacts of rising temperatures on the water cycle:
-increased evaporation due to rising temperatures - increased drought
-more rainfall than snowfall
-earlier peaks in snowmelt, river flows effected - reduced availability of fresh water in summer
Risks of further planetary warning
changes to the Arctic - ocean currents, air circulation & sea level rise - flooding
GHG - gases are still added faster than carbon stores can take them in, they lead to further planetary warming & remain in the atmosphere for some time
factors influencing climate change rates -
population growth - growing demand for resources, causes strain on the environment
forests (deforestation) - less natural carbon sinks, increased carbon into the atmosphere
Sea level rise - ocean acidification & loss of biodiversity, also coastal flooding
economic change - as world economy grows, so does demand for resources, however wealthy countries often put measure in place to stop exploitation
technology - e.g. turbines and solar power help to diminish negative effects
continued . .
feedback mechanisms & tipping points -
peatlands - huge carbon sinks, cover 3% of global land surface, store soil for millenia
permafrost - GHG that have been stored in the ice for millenia is relased as the frost melts due to rise in temperatures
forest die back - caused by global warming & drought; many trees are lost as a result of this and therefore carbon sinks are lost
changes to thermohaline circulation - melting ice, increases amount of freshwater in the oceans, changes the salinity & could effect flows which could cause drastic temperature change in parts of Europe
How can people respond to climate change?
adaptation strategies: adopting new ways to live with the effects of climate change e.g.
solar radiation, resilient agricultural systems, water conservation & land use planning
mitigation strategies: re-balancing the carbon cycle and reducing any impacts of climate change e.g.
carbon capture storage, renewable switching, afforestation/reforestation, carbon taxation & energy efficiency
Kyoto Protocol - 2005, 192 member countries
-state parties must reduce GHG emissions - successful as emissions were reduced by 125%
Paris agreement - 2015, 175 member nations
-dealing with GHG emissions through adaptation, mitigation & finance; starts 2020
success as has bought many nations together HOWEVER the US may pull out
Adaptation strategies
water conservation & management - e.g. smart irrigation, reducing agricultural consumption
helps to conserve water, which is running out
expensive & challenging
resilient agricultural systems - growing crops without ploughing & fewer fertilisers
conserves water, controls erosion,
could decrease yields
land use planning & flood risk management - development of flood plains
low cost and effective
land may be needed for alternative things e.g. property
adaptation strategies cont.
energy efficiency - residential buildings to reduce energy consumption
helps to reform old builidings & makes them more efficient
some may be against the renovation
afforestation & reforestation - forest rehabilitation
prevents soil erosion & provision of carbon sinks & stores
often trees planted grow quickly but are not actually that effective at storing carbon
renewable switching - switching from fossil fuels to renewable energy
lowers carbon emissions effectively
can be expensive, some countries cannot afford this option
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