Human Factors Changing Carbon Cycle Flashcards
Name 4 ways humans change carbon cycle.
Burning / extracting fossils fuels.
Farming practices.
Deforestation.
Urban growth.
Where does the most human caused carbon release come from ?
According to IPCC 90% comes from combustion of coal, oil and natural gas.
What helps to mitigate against this big surge of co2 from combustion?
Vegetation and oceans which reabsorb 50% of this.
Rest absorbed by atmosphere.
How much have co2 levels risen by in last 50 years ?
80ppm
Process of burning ?
Most of worlds has/oil comes from rocks that are 70-100 million years old.
Carbon remains locked up in these deposits for all that time.
When burnt to generate energy the stored carbon is released into atmosphere mainly as co2.
What does combustion of hydrocarbon release ?
Carbon dioxide and water vapour into atmosphere.
How much co2 does the cement industry produce.
5% of all human induced global co2 emissions.
50% of which comes from heating of calcium carbon and 40% from burning of fuel to power the process
How much cement produced for how much co2 released?
For every 1000kg of cement produced.
900kg of co2 released into atmosphere
Which fossil fuel generates most co2 emissions?
In 2013
43% coal
33% oil
Is global co2 emissions from fossil fuel use and cement increasing or decreasing ?
Increasing.
In 2013 it topped 36 GtC which is 61% higher than in 1990
Which countries release most co2?
2013 Dominated by China - 28% USA - 14% India -7% All NEEs
What is the greatest source of carbon emissions in agriculture?
Enteric fermentation - methane belched by livestock during digestion.
How much does enteric fermentation release ?
In 2011 it made up 39% of all agriculture carbon emissions.
Increased by 11% since 2001 - 2011
What happens when soil is ploughed?
Soil layers invert with each other allowing air to mix in.
As a result soil microbial activity increases resulting in more soil organic matter being decomposed.
As a result more co2 lost to atmosphere along with co2 produced by farm trackers doing ploughing in first place.
What happens in rice paddies?
Biological processes in rice paddies generate methane which makes up 10% of all agriculture carbon emissions
What % does burning of tropical grasslands make up ?
5%
How much carbon dioxide is released from land use change
30% for deforestation for all human induced emissions.
What is logging ?
They remove forests.
Some act illegally building roads to access remove forests.
Why else does deforestation occur?
Result of urban sprawl.
Wildfires / overgrazing prevent reestablishment of younger trees.
Conversion to pasture : agriculture.
When forests are cleared for conversion to agriculture what happenes?
Large proportion of above ground biomass May be burned leading to huge release of co2
What does forest clearing also accelerate ?
The decay of dead wood, little and below ground organic carbon
What long term negative impacts does deforestation have on carbon cycle ?
Forest souls are moist but without shade from trees they soon dry out.
Trees maintain water cycle by returning vapour back to atmosphere through transpiration.
Former forest land quickly turn into barren deserts.
What has planting of trees resulted in?
A reduced net loss of total forest area.
How much forest has been lost ?
3% of forests were lost between 1990 and 2005 at a rate of 200km2 per day meaning forests could vanish completely within 100 years.
Over 50% of worlds population , lives where ?
Urban areas Z
Urban areas decrease or increase ??
Expected to reach 60% by 2030.
Growing 1.3 million people per week
What happens when cities grow ?
Land use changes from natural vegetation to a one being built on.
Where are most carbon emissions concentrated highly around ?
Polluting cities. The worst 21 polluting cities contribute 10% of all energy related carbon emissions.
How will polluting cities become worse?
By 2030 the worst 10 polluting cities will contribute to the same 10% of all energy related carbon
Animal store
Fossil fuels are intercepted and stored in plants.
Animals will then eat plants and will have a larger store of carbon.
When animals die they decay and the amount of carbon is realised will be a high amount.
Ocean species
when organisms die they sink to bottom of ocean floor and over time become cemented together creating sedimentary rocks which means they store carbon as stone.
(Biological pump)
Pollution and fish
Fish becoming more threatened as more plastic enter ocean by humans.
Fish eat this or become trapped in it and die.
This will then release co2 and reduce the biological pump
Positive feedback.
Climate
An increase in burning fossil fuels means the climate becomes warmer as there is more carbon emissions suspended in atmosphere.
This will then increase surface temp of oceans.
Which will increase evaporation from oceans.
More water vapour in atmosphere.
This enhances the greenhouse effect causing more warming
Negative feedback climate.
An increase in burning fossil fuels means the climate becomes warmer as there is more carbon emissions suspended in atmosphere.
Meaning more trees growth and more photosynthesis occurs.
This increases the biosphere carbon store as trees act as natural carbon store taking in co2 from atmosphere.
Potentially nullifying affects of extra carbon.
(However, Warmer temps can lead to desertification of landscapes, reaching number of trees taking in carbon. Less biosphere store and more co2 In atmosphere)
Transport -cars
More cars = more wealth = more materialism meaning more road networks/ congestion and in then co2 emissions increase.
However, in modern society more electric cars are being made which helps decrease carbon emissions but to power cars the powers is generated using carbon so in turn shifts the problem.
Transport - airports
More airports = more wealth = advanced technology.
Means more area cleared and less trees.
This not only reduces natural store of carbon in biosphere but more aeroplanes means large source of carbon emissions given off
Agriculture - trees 2 plants
Brazil where slash and burn / clearing methods remove forest for land use whether that’s for infrastructure/ livestock / agriculture.
It means less carbon is able to store in biosphere as trees absorb the most co2 from atmosphere then smaller plants.
More co2 in atmosphere as less photosynthesis- more cc
Agriculture - grass 2 crops
In cases were natural grasslands have been now used for crops or afforestation this in turn implements a carbon store as they take in more co2 into their leaves when growing.
Residential
Increase in population = increase demand in housing.
Meaning vegetation/ trees are removed and replaced by impermeable surfaces. Reduction in biosphere store. Less photosynthesis.
More housing = more power = more carbon transferred from lithosphere to atmosphere due to combustion of fossil fuels.
(More trees planted as decoration - reduce noise/ protection so absorb lots of co2 when growing)
Commercial
More factories = more co2 emissions from combustion of fossil fuels = more co2 transferred from lithosphere into atmosphere - cc
More workers = more waste into ocean = co2 would then diffuse into hydrosphere = contaminate water / poison sea life = death of sea life releases co2 back into atmosphere
what is Carbon sequestration ?
Capturing co2 and storing in long term storage.
What is geological sequestration?
Carbon captured at source such as power plants and then injected into liquid form underground storage.
Depleted at oil / gas reservoirs / deep ocean
Experimental
What is biological sequestration
Capturing carbon long term from atmosphere within plants.
Stores it in stems and roots as well as soil
Reduces co2 in atmosphere and would mean ecosystems would be positive leading to enrichment of wildlife - negative feedback effect
However plants and trees can be lost to fires
Ocean sequestration
Carbon stored in oceans due to large surface area
Sinks within weeks and months and it’s long term
Strategies
Renewable energy - wind/ solar.
Public transport
Walking / cycling
Flying less - employees don’t travel to other place to discuss work they just FaceTime
Disadvantages of land based plantations?
Slow growing
Active monitoring
Management for lifetime of plantation
