Carbon cycle and biofuels Flashcards
Describe combustion of fossil fuels
Coal is produced from wood so is a product of photosynthesis
Wood didn’t decay no CO2 released as when trees died they fell into conditions where bacteria cannot grow
Carbon remains locked in coal = carbon sink
Carbon released has been out of circulation for millions of years
Describe deforestation
forests are cut down in long term its equal in short term more is released than absorbed
Large trees and trunks are harvested
Branches/shrubs left decay or are burnt releasing CO2
What else could upset the CO2 balance?
Volcanoes may release CO2
CO2 lost to sediments in ocean by incorporate of carbon into CaCO3 skeleton but this is blanced by various erosion processes
Acid rain - CO2 released by erosion of limestone
Rising global temps-increased decomp and warmer oceans
What is a biofuel?
A biofuel is any source of energy produced, directly in plants or indirectly in animals
Provides a renewable energy source and is CO2 neutral
What are the reasons for using biofuels?
More sustainable
carbon neutral
produced quickly
economic influence
What are the reasons against using biofuels?
Still produces CO2 Takes up space habitats are destroyed food machinery transport
Describe reforestation
Planting of new trees in existing forests
little old wood and little decay so respiration will be less than photosynthesis so its a net absorber of CO2
Forests could soak up extra CO2 as increased CO2 and temp increase growth due to photosynthesis
Long term- more vegetation= more food =more animals = more decay = more CO2
Carbon sinks
Describe windfarms
produce energy with no CO2
danger to birds and installisation causes emissions
Describe mature forests
stable ecosystems and don’t accumulate biomass or become fossil fuels so they aren’t net absorbers of CO2
CO2 uptake = CO2 release
