3a- human factors can influence the cycles Flashcards
what is dynamic equilibrium (example from carbon and water)
system naturally responds to change
water- after heavy rain plants will intercept water and then EVTP which returns it to the atmosphere
carbon- co2 increases, plants grow and more PS so less CO2
positive feedback loops in the cycles
as temperature increases so does EVTP and so more H2O in the atmosphere - global warming so temperature increases
as temperature increases permafrost melts so CO2 and CH4 are released which means temperature increases
as temperature increases, there is more decomposition so more CO2 in the atmosphere therefore temperature increases
Negative feedback loops in the cycles
more vapour creates cloud cover which reflects more radiation so the average global temperatures fall
As CO2 increases more PS is stimulated so more plant growth and more carbon is stored in biomass than in the atmosphere
how does fossil fuel consumption impact the carbon cycle
burning fossil fuels releases CO2 into the atmosphere (getting worse as pop grows) and Causes global warming due to the greenhouse effect. However when more CO2 is produced PS is stimulated and takes CO2 out of the atmosphere
how does carbon sequestration impact the carbon cycle
takes carbon from factories and pumps it into porous rocks so less atmospheric CO2. Is limited by cost and energy needed to transport the CO2 also relies on the right geological conditions but factories built on the right geology would reduce this
how does growth in urban areas impact the cycles
Carbon- increase in pop means more CO2 is produced (cars, oil, gas). Deforestation has to occur so less PS so more CO2 in the atmospheric store.
Water- due to more concrete there is less infiltration, less trees means less interception so a greater flood risk. Drainage systems to remove surface water like gutters create a quick run off and increase the water level in rivers.
how does farming impact the cycles
carbon- clearing forests decreases carbon store. Soil carbon is reduced by ploughing and exposure to oxidation.
Water- crop irrigation diverts water and most of it is lost to soil drainage, farming intercepts less water than forests. Ploughing creates channels so when there is heavy rain there is an increase rate of water in streams and rivers
how does forestry impact the cycles
carbon- forests store 10X more carbon than grassland, PS takes CO2 from the atmospheric store into the biomass store
Water- forests intercept lots of water and lots of it is EVTP into the atmosphere. Interception means less run off so a longer lag time and decreased flood risk
how do Aquifers/artisan impact the cycles
carbon- climate change will increase the evaporation
water- large store of water but replenished slowly, especially in deserts where it rains less than 200mm/year e.g Las Vegas. Overuse of aquifers means that stores will run out as outputs are larger than inputs.
naturally output water due to pressure- springs
in summer water table decreases due to warmer temperatures as more evaporation, and the water table is recharged in later autumn. Heavy rain and drought will impact the water table
water flows to the surface under pressure like in London. overexploitation in the 19th century caused a drastic fall in the water table but due to irrigation in the last 50 years the table has been allowed to recover
