OCR A Level ELSS - Entire Course 3 Flashcards
Cryospheric processes
-ablation is loss of ice from snow, ice sheets and glaciers due to a combination of melting, evaporation and sublimation
-meltwater is an important component of river flow in high latitudes and mountain catchments in spring and summer
-rapid thawing of snow in winter is a common cause of flooding in adjacent lowlands
physical (inorganic) pump?
-involves mixing of surface and deep ocean waters by vertical currents
-creates a more even distribution of carbon in oceans
-CO2 diffuses into the oceans from atmosphere
-surface currents transport dissolved CO2 polewards where it becomes dense and sinks (downwelling)
-individual carbon particles may remain deep in the ocean for many centuries
-eventually deep ocean currents transport carbon back up to the surface (upwelling)
-cold, carbon rich waters rise to the surface where CO2 diffuses back into the atmosphere
biological (organic) pump?
-50% of carbon fixation happens by photosynthesis in oceans
-50GT of carbon is drawn from atmosphere by biological pump each year
-marine organisms (phytoplankton) drive the pump
-phytoplankton floating near surface combine sunlight, water and CO2 into organic material
-whether consumed in the food chain or through natural death, carbon locked in phytoplankton accumulates on the ocean floor or is decomposed and released as CO2. or is used by organisms for shells and skeletons
-most CO2 ends up in sediments such as chalk and limestone
What is permafrost?
a thick subsurface layer of soil that remains frozen throughout the year, occurring chiefly in polar regions.
what is the active layer?
-The top layer of permafrost.
-melts
water cycle negative feedback loop
heavy rainfall = increased water infiltration = more water stored in aquifers = water table is raised = more water is returned to the surface as springs = water table returns to normal levels
carbon cycle negative feedback loop
burning of fossil fuels = increased atmospheric CO2 = photosynthesis stimulated = more CO2 removed form the atmosphere = CO2 levels restored
3 land use changes?
- urbanisation
- farming
- forestry
land use changes - urbanisation?
-farmland and woodland areas replaced by tarmac and brick
-artifical surfaces are impermeable and allow little water infiltration and provide minimal water storage capacity, giving rise to run off
-urban areas have drainage systems designed to remove water rapidly (gutters, pitched roofs) therefore water form precipitation flows quickly into streams and rivers, leading to a rapid rise in the water tables
-urbanisation also encroaches floodplains which are natural water stores
-overall, urbanisation reduces water storage capacity in drainage basins, increasing river flow and flood risks
land use changes - farming and the carbon cycle?
-clearance of forest for farming reduces carbon storage in above and below ground biomass
-soil carbon storage is reduced by ploughing and exposure of organic material to oxidation
-harvesting of crops returns only a small amount of organic matter to the soil
-soil erosion by wind and soil is most severe when crops have been lifted and have little protective cover
-carbon exchanges through photosynthesis are lower due to a lack of biodiversity and a short growth cycle
land use changes - farming and the water cycle?
-crop irrigation diverts surface water from rivers and groundwater to cultivated land
-interception of crops is less than of grasslands,
-evapotranspiration is reduced by crops
-ploughing increases evaporation and soil moisture loss
-heavy machinery compacts the soil which leads to more surface run off leading to peak flows higher in farmland ecosystems
-ploughing causes infiltration which means even more water is transferred to streams and rivers
land use changes - forestry plantations and the water cycle?
-there is a higher rate of rainfall interception in natural plantations
-preferred plantation species in the uk are conifers with needle like structures, evergreen habit and high density
-increased evaporation form water stored on leaf surfaces
-reduced run off and stream discharge due to high interception and transpiration rates
-clear felling of harvest timber creates a sudden change in the water cycle, increasing run off, reducing evapotranspiration and increasing stream discharge
land use changes - forestry plantations and the carbon cycle?
-in the uk a typical plantation contains 10x more carbon than grassland and 20x higher than heathland
-soil represents a large carbon pool - 500 tonnes/ha
-forest trees extract carbon for hundreds or years only after 100 years since planting
-balanced by litter inputs into the soil
what were the CO2 levels in the atmosphere 800,000 years ago compared to today (2016)?
-260 ppm 800,000 years ago
-400.5 ppm 2016
-small changes over 800,000 years due to glacials and interglacials
what were the CO2 levels in the atmosphere in 1700 compared to 2016?
-most people lived in rural areas in 1700
-1800 - the industrial revolution and CO2 levels rapidly increased due to coal use
-1910 - the first production line car
-1913 - coal extraction
-1960 - increase in car use and central heating fitted in homes
-1700 - 310 ppm
-2016 - 400.5 ppm
changes in the CO2 levels in the past two years?
-400.5 ppm
-in spring and summer there is less CO2 in the atmosphere due to more vegetation therefore increased photosynthesis
-in winter there is increases in CO2 due to more use of heating inn homes
-increased in 5 ppm in two years
energy consumption overtime?
-oil (496 GT) and coal (673 GT) are the largest carbon emission sources
-coal has been used since the industrial revolution and oil has been used since 1920s
-since 1970s there has been an increase in use of nuclear and hydroelectric sources
-overall global energy consumption has increased rapidly since the 1960s with coal and oil being the main sources
3 stages involved in CCS?
- separate CO2 from power station emissions
- CO2 is compressed and transported to storage areas
3.injected into porous rock underground and stored permanently
what is the impact and plans of CCS?
-plays an important role in reducing CO2 and other emissions
-in USA, 40% of all carbon emissions could be reduced by 80-90%
-in the UK a CCS project is underway in peterhead, north east Scotland which is going to capture 2 million tonnes of CO2
-plan for carbon to be transported by pipeline to the North Sea and stored in depleted gas resevoirs
Why is the CCS limited?
-involves big capital costs
-uses large amounts of energy (compress and transport CO2)
-requires storage in specific geological locations
in 2013 what percentage did fossil fuels account for the overall energy consumption?
87% fossil fuels
what sources were used the most in 2013 for global energy consumption?
-oil (37%)
-natural gas (27%)
-coal (23%)
where have most of our carbon emissions come from (1750 - 2012)?
-coal - 673GT
-land use - 590GT
where have our carbon emissions gone (1750 - 2012)?
-atmosphere (879GT)
-ocean (590GT)
-land (528GT)
how many tonnes of CO2 is released into the atmosphere annually?
-10 billion tonnes
-increases the CO2 concentration over 1 ppm
impact of anthropogenic carbon emissions in the atmosphere?
-since 1750, 879GT of anthropogenic co2 emissions have remained in the atmosphere, tasing co2 concentrations from 280 ppm - 400 ppm
-co2 levels today have been the highest for 800,000 years
what is the impact of anthropogenic carbon emissions?
-compromise only 10% of the natural influx of from the biosphere, oceans and atmosphere
-however they impact significantly on carbon stores
-despite international efforts used to reduce carbon emissions, between 2000 and 2009 they grew faster than in any other decade
-without increased absorbtion of CO2 from oceans and biosphere, atmospheric concentrations would exceed 500 ppm
groundwater
water stored underground in permeable and porous rocks know as aquifers
aquifer
a water bearing band of porous or permeable rock
artesian aquifer
a confined aquifer containing groundwater under pressure, which will rise to the surface under its own pressure
artesian pressure
The hydrostatic pressure exerted on groundwater in a confined aquifer occupying a synclinal structure.
abstraction
the extraction of water from rivers and boreholes for public demand
impact of water extraction?
-rates of extraction have exceeded rates of discharge
-lower flows have reduced flood risk and temporary areas of standing water on floodplains
-lower groundwater levels ave caused springs to dry up and reduce the instance of saturated overground flow on chalk
the water table?
-the level below which the ground is saturated with water.
changes that occur in the water table levels?
-water table heights fluctuate seasonally by periods of lots of rainfall, drought and abstraction
-in normal years in southern England, the water table falls between march and September due to rising temperatures and increased evapotranspiration
-recharge resumes in late autumn
artesian basins
-when sedimentary rock forms a syncline, a downloaded basin like geological structure
-confined between layers of impermeable rock (clay)
-may contain groundwater under artesian pressure
-when groundwater is tapped by a well or borehole water will flow to its surface under its own pressure
what is remote sensing?
the scanning of the earth by satellite or high-flying aircraft in order to obtain information about it.
what is GIS?
-Geographic Information System.
-A computer that can capture, store, query, analyze, and display geographic data.
-analyses layers, spacial location and identifies any anomalies and trends
what are diurnal changes?
-significant changes that occur within a 24 hour period
-lower temperatures at night reduce evaporation and transpiration
-during the day convectional precipitation is dependent on direct heating of ground surface by the sun
-flows of carbon are reversed at night compared to day
what are seasonal changes?
-seasons are controlled by the variations in solar radiation
-in uk, solar radiation peaks in mid June (800 w/m2) in southern england
-compared to input of (150 w/m2) in December
-80% of precipitation is lost to evaporation in driest parts of lowland England, which exhausts soil moisture and river flows are lowest in late summer
how are seasonal changes reflected in the carbon cycle?
-month-month changes in the net primary productivity (NPP)
-in middle and high latitudes day length of photoperiod drive seasonal changes in NPP
-similar variations occur in tropics, but there main cause is water availability
carbon dioxide flows in the summer?
-net flow of CO2 from atmosphere to biosphere
-causes CO2 levels to fall by 2ppm
-at end of summer flow is reversed by natural decomposition releasing CO2 back to atmosphere
what are seasonal fluctuations in global CO2 flux explained by?
-concentration of continental land masses in the northern hemisphere
-during growing season, ecosystems such as boreal and forests extract huge amounts of CO2
from atmosphere which has a huge global impact
what happens during seasonal changes to phytoplankton in the oceans?
-in oceans phytoplankton are stimulated to photosynthesise by rising water temperatures, more intense sunlight and the lengthening photoperiod
-in northern Atlantic, ever year there is an explosion of microscopic ocean activity, resulting in algal blooms which peak in mid summer
impact of long term changes - how many major glacial cycles in the last 400,000 years?
-4 major glacial cycles in the last 400,000 years
-each last around 100,000 Years
-followed by warmer interglacials
temperatures at the height of the last glacial?
-20,000 years ago
-temperatures on average 5 degrees lower than they are today at the peak of the last glacial
what happened during the last glacial to most of the UK?
-scotland, Wales and Northern Ireland were submerged in ice up to 1km thick
impact on water cycle during glacial periods (sea level and sea ice)?
-in glacials sea level falls by 100-130m
-ice sheets expand over one third of the continental land mass
-ice sheets destroy forests and grasslands as they expand towards the equator
-lower rates of evapotranspiration reduces flows of water in the cycle
-overall water cycle decreases
impact on carbon cycle during glacial periods (temperature and CO2 concentration, oceans and phytoplankton ) ?
-dramatic reduction in CO2 in atmposphere
-glacial maxima concentrations fall to 180 ppm
-warmer interglacials they were 100 ppm higher
-close correlation between temperature and CO2 concentration
-more CO2 dissolves in oceans at lower SST as lower temperatures make the sea more soluble
-ocean circulation brings nutrients to the surface and stimulates phytoplankton growth
-overall a slowing carbon flux and smaller amounts of CO2 returned to atmosphere by decomposition
how are carbon and water cycles linked by the atmosphere?
-atmospheric CO2 has a greenhouse effect
-CO2 plays role in photosynthesis for plants and phytoplankton
-plants extract water from soil and transpire it to the atmosphere
-water is evaporated from the oceans to the atmosphere which causes CO2 to be transferred between both stores
how are carbon and water cycles linked by the ocean?
-ocean acidity increases when CO2 stores are unbalanced
-solubility of CO2 increases with lower SST
-CO2 levels influence SST, thermal expansion, air temperatures, melting of ice and sea level
how are carbon and water cycles linked by vegetation and soils?
-water availability influences photosynthesis, NPP, inputs of organic material and transpiration
-increased inputs of organic material to the soil increases the soils water storing capacity
-temperatures and rainfall affects decomposition and release of CO2
how are carbon and water cycles linked by cryosphere?
-CO2 levels determine the intensity of the greenhouse effect and melting of ice sheets, glacials and sea ice
-melting of ice exposes land which increases the absorption of solar radiation which increases temperatures
-melting of permafrost exposes dead organic material to decomposition and oxidation
-run off, river flow and evaporation respond to temperature change
what 4 anthropogenic factors have impacted the water and carbon cycles?
-urbanisation
-rapid population change
-deforestation
-economic change
=they have changed the size of stores and impacted most at local and regional scales
what has created shortages in the water cycle?
-rising demand for water for agriculture, irrigation and public supply
-human impact most evident on rivers and aquifers
what effect do anthropogenic factors have on the water cycle?
-decrease through flow
-lower water tables
-increase run off
-reduce evaporation and precipitation
where have human activities had a detrimental impact on the water cycle - examples?
-colorado basin, southwest USA
-surface supplies diminished as more water extracted from rivers
-huge amount evaporated from reservoirs in Lake mead and Powell
-bangladesh
-excessive water pumping of aquifers led to inclursions of salt water which makes the water unfit for drinking and irrigation
what are the impacts of deforestation?
-impact areas like Amazonia as forest trees play a huge role in the water cycle
-deforestation has decreased evapotranspiration therefore precipitation, breaking the cycle in some places which stops forest regeneration
how is human actives impacting the carbon cycle? (3)
-extracted billions of tonnes of carbon from the geological store
-the world relies on fossil fuels for 87% of the worlds total energy consumption
-land use changes, deforestation transfers 1 billion tonnes of carbon to atmosphere annually
-more CO2 absorbed by oceans due to more CO2 in atmosphere
-increases ocean acidity which kills phytoplankton
-soil degraded by erosion caused by deforestation and agricultural mismanagement
why has exploitations of coal, oil and gas stores increased rapidly recently?
exploitations of coal, oil and gas has increased rapidly due to the increasing industrialisation in India and china
Carbon cycle: burning fossil fuels transfers ____________________ of carbon to the atmosphere
8 billion tonnes
Carbon cycle: land use changes (deforestation) transfers ____________________ carbon to the atmosphere
1 billion tonnes
Carbon cycle: ocean acidification
-Ocean acidity increases when exchanges of CO2 aren’t in balance
-more CO2 dissolves into oceans when more co2 is in the atmosphere
-acidification kills phytoplankton
Carbon cycle: soil is degraded by erosion caused by what? (2)
deforestation and agricultural mismanagement
Carbon cycle: why are carbon stores in wetlands depleted?
When the wetlands are drained for cultivation and urban development they dry out and are oxidised
global warming leads to increased —– in the atmosphere?
leads to increased water vapour in the atmosphere
impact of long term changes on the water cycle?
-more water vapour in the atmosphere is a natural GHG
-vapour releases heat when it evaporates, cools and condenses which increases frequency of tropical storms
-global warming also accelerates melting of glaciers which transfers water from cryosphere to oceans + atmosphere
What does water release as it evaporates, cools and condenses?
heat
What could global warming increase the prevalence of and why?
hurricanes as they rely on warmer water
long term impacts of climate change on the carbon cycle - What does global warming lead to?
-higher temperatures increases rate of decomposition
-therefore accelerates flows of carbon from biosphere to atmosphere
-carbon stored in permafrost released to atmosphere
-acidification of oceans due to excess co2 in atmosphere kills phytoplankton, reducing rate of photosynthesis which limits oceans capacity of storing carbon
what changes occurs in stores of carbon due to long term impacts of climate change?
-less carbon stored in biosphere and ocean stores
-more carbon stored in the atmosphere
why is more carbon released to the atmosphere because of global warming? (2)
-higher decomposition rates
-melting of permafrost
Negative Feedback
A cycle that returns a system back to its normal (equilibrium) state
Positive Feedback
A ‘runaway’ system loop where the system moves further and further from equilibrium
Dynamic Equilibrium
The steady, balanced state of a system
Aquifer
Underground rock which can store and transmit water in sufficient quantities to extract for our benefits
Artesian Basin
Pressurised groundwater found where permeable rock is overlain by impermeable rock, trapping water below, which entered at higher elevation
Diurnal
Changes in the temperature between day and night - warmer during the day, and coolest during the night.
Seasonal Change
Alteration of the weather, temperature and precipitation throughout the year, as a result of the Earth’s tilt.
Long Term
Time period spanning millions of years, for example.
Cryosphere
The ice which exists upon Earth
Vegetation
Plant life at the Earth’s surface
Climate Change
Alteration to long-term weather patterns, e.g. increased temperature and rainfall shifts occur naturally, but can be influenced by human activity
Atmosphere
The gaseous part of the Earth - ranging from the troposphere at ground level, to the exosphere, as far as 10,000km away.
Regulation
Keeping a natural system in check - for example, trees and oceans absorb carbon from the atmosphere, reducing the degree of warming to the planet.
Management Strategy
Set of rules and regulations governing the use of and protection of the natural world
Wetland Restoration
The reprovision of aquatic habitats - for example, in areas that were drained centuries ago for farming.
Carbon Trading
Countries are allocated rights to emit certain gases - if they produce too much, they can buy credits from countries producing less than their quotas.
International Agreements
Legally binding or voluntary set of rules that countries ratify across the globe, such as the Kyoto Protocol, or the Copenhagen Accord.
Drainage Basin Planning
Overarching control and strategies which oversee a catchment - to reduce flooding and ensure a variety of habitats, for example.
photosynthesis
process by which green plants convert water and CO₂ into starch and sugar in the presence of sunlight
respiration
the process in living organisms where the intake of oxygen oxidises organic substances to produce energy and release CO₂
transpiration
the evaporation of moisture from the pores on the leaf surfaces of plants
atmosphere
the thin envelope of gasses (mainly Nitrogen and Oxygen) that surrounds the earth
biosphere
the space at the Earth’s surface and within the atmosphere occupied by living organisms
precipitation
moisture (rain, snow, hail) falling from clouds towards the ground
evapotranspiration
combined loss of water at the surface through evaporation and transpiration by plants
run-off
the movement of water across the land surface
groundwater flow
the horizontal movement of water within aquifers
closed system
a system with inputs and outputs of energy, but without any movements of materials across system boundaries
open system
a type of system whose boundaries are open to both inputs and outputs of energy and matter
water reservoir
an area on the surface or within the ground where water is stored
atmopspheric water store
the total water stored in the atmosphere
land water store
the total water stored on land
ocean water store
the total water stored in the oceans
water flow
the movement of water between different stores
oxidation
a chemical process that weathers certain types of rock and involes the absorption of oxygen from either the atmosphere or water by rock minerals.
decomposition
the breakdown of a material into chemically altered forms
combustion
A rapid reaction between oxygen and fuel that results in fire
weathering
the decomposition or disintegration of material in situ
system
A group of interacting, interrelated, or interdependent elements or parts that function together as a whole
permeable rock
a type of rock that is penetrated by water, either through mineral pores (air spaces) or along joints, faults or fissures
water cycle budget
the annual volume of movement of water by precipitation, evapotranspiration, run-off etc. between stores such as oceans, permeable rocks, ice sheets, vegetation, soil, etc.
condensation
the phase change of water vapour (gas) to water (liquid)
sublimation
the phase change of water from ice to vapour
infiltration
the vertical movement of rainwater into and through the soil
aquifer
a water-bearing band or porous or permeable rock
groundwater
water stored underground in permeable and porous rocks known as aquifers
sink
anything that absorbs more of a particular substance than it releases, e.g. the oceans act as a sink for CO₂
carbonate rocks
rocks comprising carbonate materials (e.g. CaCO₃) such as limestone and chalk
slow carbon cycle
the slow movement of carbon between the atmosphere and rocks, sea floor sediments and fossil fuels over millions of years. Accounts for between 10 and 100 million tonnes per year
residence times
the length of time that a molecule of water or CO₂ etc. remains in natural storage (e.g. in the atmosphere or oceans)
subducted
the tectonic process found at convergent plate marigins where an oceanic plate descends into the Earth’s mantle and is destroyed
upper mantle
the layer of the Earth’s interior extending 75-200km below the surface (also known as the asthenosphere) The upper mantle is able to flow under pressure
sedimentary rock
A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together
tectonic plate boundary
active area in which tectonic plate can be subducted into the upper mantle before being vented into the atmosphere via a volcano
chemical weathering
the in situ breakdown (decomposition) of rocks by chemical processes such as oxidation, solution and hydrolysis
carbonaceous rocks
rocks mainly comprising the fossilised remains of plants, e.g. coal, lignite.
fast carbon cycle
the rapid movement of carbon between the atmosphere, oceans, biosphere and soils
phytoplankton
tiny photosynthesising marine organisms in the surface waters of the oceans
natural sequestration
natural process by which carbon is captured and stored
Goldilocks zone
A place in the universe where conditions are right that liquid water can exist and humans could live.
water balance
the relationship between precipitation, streamflow, evapotranspiration and soil moisture and groundwater storage in a drainage basin over a year
dew point
the critical temperature at which condensation occurs
catchment
the area drained by a river and it’s tributaries i.e. a drainage basin
intensity
the amount of rainfall which falls in a given time
duration
the length of time something lasts
channel precipitation
rain which falls directly into the river channel
interception
the process by which water is stored temporarily on leaves stems and branches of vegetation
stemflow
the flow of water along the branches and stems of trees and other plants to the ground
overland flow
rainfall that runs off the ground surface either because the soil is saturated or the intensity of the rainfall exceeds the soil’s infiltration capacity
throughflow
water flowing horizontally through the soil to stream and river channels
base flow
water input to streams and rivers from natural resevoirs such as aquifers, peat bogs and soils
recharge
net input of water into an aquifer causing a rise in the water table
percolation
the movement of surface and soil water into underlying permeable rocks
capillary rise
The ability of a liquid to flow against gravity in narrow spaces, allowing water to transfer from groundwater up into soil moisture storage
evaporation
the phase change of water from liquid to gas
leakage
an output from groundwater stores within a drainage basin
river discharge
The volume of water that flows past a point in a river per second measured in cumecs (cubic metres per second)
cumuliform cloud
a cloud formed by convection with a rounded-top, lumpy appearance and flat base
stratiform cloud
clouds lying in a level sheet
advection
the horizontal movement of an air mass which often results in either heating or cooling
cirrus cloud
a high altitude, feather-like cloud made of ice crystals
dew
deposits of moisture on the ground and vegetation due to condensation caused by radiative cooling, most often at night
fog
cloud at ground level caused by radiative cooling and advection
adiabatic expansion
the expansion of a parcel of air due to a decrease in pressure. Expansion causes cooling
convection
the motion of a gas or liquid which when warmed rises until eventually it cools and sinks in a continuous circulation
lapse rate
the vertical distribution of temperature in the lower atmosphere and the temperature changes that occur within an air parcel as it rises vertically away from the ground
environmental lapse rate
the vertical temperature profile of the lower atmosphere at any given time. On average the temperature falls by 6.5°C for every km of height gained
dry adiabatic lapse rate
the rate at which a parcel of dry air (i.e. less than 100% humidity so that condensation is not taking place) cools as it rises through the atmosphere. Approximately 10°C/km
saturated adiabatic lapse rate
the rate at which a saturated parcel of air (i.e. one in which condensation is occuring) cools as it rises through the atmosphere. At around 7°C/km this is lower than the DALR
latent heat
heat absorbed or radiated during a change of phase at a constant temperature and pressure
atmospheric instability
the situation when air is at a different temperature to that around it resulting in air rising
atmospheric stability
occurs at high altitude where air cannot rise any further as it is not warmer than its surroundings
interception loss
rainwater stored temporarily on the leaves, stems and branches of vegetation which is evaporated and does not reach the ground surface
throughfall
rainfall initially intercepted by vegetation, which drips to the ground
infiltration capacity
the maximum rate at which water, under the pull of gravity, can soak into soil
saturated overland flow
the movement of water across the ground, often as a thin film, when the ground is saturated
ablation
the loss of ice and snow, especially from a glacier through melting, evaporation and sublimation
flux
the rate of energy transfer per unit area
anthropogenic
Human-induced changes on the natural environment
carbonation
a chemical weathering process by which carbon dioxide dissolves in rainwater forming weak carbonic acid which leads to decomposition of rock
freeze-thaw
a mechanical weathering process caused by water, confined in rock joints, expanding by 9% as it freezes, exerting 2,100 kg/cm² pressure, and as a result breaking rocks into smaller fragments
