3.1.1 Water and Carbon Cycles Flashcards
how are models useful to a geographer?
-very visual
-simplify a complex world
-provide a starting point
-helps to predict and describe a possible sequence/consequence
-shows interrelated components
what are the inputs of the water cycle?
-precipitation
-autumn leaf fall
-seeds carried by wind & birds
what are the outputs of the water cycle?
-plants
-evaporation
-seed dispersal
what are the stores/components of the water cycle?
-water
-soil
-water soaking through the soil/rocks
what are the flows/transfers of the water cycle?
-photosynthesis
-infiltration
-transpiration
what do systems compromise of?
any set of interrelated components to form a working unit
what does a relationship mean in comparison to an interrelationship?
relationship means one way whereas an interrelationship means both ways
what are the different geological systems?
-hydrological cycle
-carbon cycle
-ecosystems
-oceanic circulation
-atmospheric circulation
what’s another name for the hydrological cycle?
water cycle
what is an ecosystem?
a system that models relationships and interactions between the various biotic and abiotic components making up a community of organisms and their surrounding physical environment
what’s an example of an ecosystem?
Sahara Desert
what’s an example of a biome?
all the hot deserts in the world
what are the four main biomes?
-hot desert
-cold desert
-temperate forest
-rainforest
what does desert mean?
lacks rain (dry)
what is a system?
an assemblage of interrelated parts that work together by way of some driving process
what are some common characteristics that most systems share?
- systems have a structure that is defined by its parts and processes
- systems are generalisations of reality
- systems tend to function in the same way- this involves the inputs and outputs of material
- the various parts of a system have functional as well as structural relationships between each other
5.flow and transfer of some type of energy and/or matter - systems often exchange energy and/or matter beyond their defined boundary with the outside environment
- functional relationships can only occur through various input and output processes
- the parts that make up a system show some degree of integration
within the boundary of a system what three properties can we find?
-elements
-attributes
-relationships
what are elements?
the kinds of parts that make up a system
what are attributes?
characteristics of the elements that may be perceived and measured
what are the relationships in a system?
the associations that occur between elements and attributes
what are the types of system?
-closed
-open
-isolated
-morphological
-cascading
-process response
-control
-ecosystem
what is a closed system?
system that transfers energy but not matter across its boundary to the surrounding environment
what is an open system?
system that transfers both energy and matter across its boundary to the surrounding environment
what is an isolated system?
a system that has no interactions beyond its boundary layer
what is a morphological system?
this is a system where we understand relationships between elements and their attributes in a vague sense based only on measured features and correlations
what is a cascading system?
when a change in one area of a system causes a change in another and another and another and another
what is a process-response system?
a system that integrates the characteristics of both morphological and cascading systems
what is a control system?
a system that can be intelligently manipulated by the action of humans
what systems are the carbon and water cycle?
they are both cascading systems but not control systems
what is positive feedback?
where a change causes a further effect accelerating the original change
what is negative feedback?
system acts by lessening the effect of the original change and ultimately reverses it
what is a positive feedback loop that increases global warming?
- temperatures warm
- sea ice melts and shrinks
- dark ocean waters absorb more solar radiation
- temperatures warm further
- sea ice melts more
- temperatures warm further still
what is a negative feedback loop that decreases global warming?
- surface temperature increases
- increased evaporation from oceans
- increased low cloud in atmosphere
- increased earths albedo
- decreased surface temperature (slightly)
- decreased evaporation from oceans
- decreased low clouds in atmosphere
- earths albedo decreases
what percentage of earths total global water is freshwater?
2.5%
what percentage of earths total global water is oceans?
96.5%
what percentage of earths freshwater is found in the ground?
30.1%
what percentage of earths freshwater is found in glaciers and icecaps?
68.7%
what percentage of earths freshwater is found on the surface?
1.2%
what percentage of earths surface water is in the atmosphere?
3.0%
what percentage of earths surface water is in living things?
0.26%
what percentage of earths surface water is in soil moisture?
3.8%
what percentage of earths surface water is in lakes?
20.9%
what percentage of earths surface water is in ground ice and permafrost?
69.0%
what type of water is most of the earths water?
salt water
is most of the earths water being salt water useful? why?
no, it’s useless because if you drink it you go mad, it clogs up machines and cannot be used to water crops as it kills plants
why does the ocean have differential areas of saltiness?
due to the amount of dissolvable rocks present and the flow of ice/glaciers into the sea which aren’t salty
how have Americans considered solving the California water shortage?
by iceberg harvesting
how far above ground is the water table in Wokingham?
about 20m above ground
how much of earths water is available for human use?
only three-tenths of a percent which is all we’ll ever have
where is 90% of the water that is locked in ice and glaciers found?
antarctica
how much of our water is used for growing food?
two thirds of our water
how much of the water we use on earth is used in industry?
80%
how much water does it take to produce one pound of beef?
1,837 gallons of water
how much water does it take to produce one cup of coffee?
37 gallons of water
how much of indoor water use is used for flushing the toilet in the US?
26%
how much of indoor water use is used for washing clothes in the US?
22%
how much of indoor water use is used for showering and bathing in the US?
19%
how much water do americans use on average per day?
100 gallons of water
how much water do millions of the worlds poorest persist on per day?
fewer than 5 gallons of water
how many people lack access to clean, safe water supply?
one billion people
by 2025 how many people will live where water is scarce?
1.8 billion people
how will water scarcity and global warming cause problems for the uk in the future?
due to global warming water will get more scarce so large amounts of people will migrate to countries that do not have a scarcity of water- e.g. the UK
how many swimming pools are there in the US?
8.8 million
how much of the human body is water?
66% of the human body is water
what is an aquifer?
a body of saturated rock through which water can easily move
what must happen in order for a well to be productive?
it must be drilled into an aquifer
why are rocks such as granite and schist generally poor aquifers?
they have a very low porosity
what is a well?
a hole drilled into the ground to penetrate an aquifer
there are a lot of aquifers underneath the amazon rainforest- is this helpful?
no because the water’s not being used as nobody lives there
why is it a good thing that there are aquifers under the sahara desert?
it means the water can be used for farming in the future
where is indonesias population ranked globally?
indonesia has the 4th largest population
what does it mean that areas have physical water scarcity?
they have a lack of water
what does it mean that areas have economic water scarcity?
they can’t afford to exploit water
what is an example of a continent that has low physical water scarcity but high economic water scarcity?
Africa
when countries are on a map and have no data collected- what are the reasons why that may happen?
-the country is at war
-there is no point as there’s a very small population
-there’s high levels of poverty so it’s not possible
what are the different ways that water is found in around the world?
-oceanic water
-cryospheric water
-terrestrial water
-atmospheric water
how much oceanic water is there?
-1,370,000,000 km³ with an average depth of 3,862m
-covers approximately 72% of the planets surface
in what forms are oceanic water?
divided into principal oceans and smaller seas
what are the key issues/changes with oceanic water?
-the pH has fallen from about 8.25 in the last 250 years
-this change in pH is linked to the increase in atmospheric carbon and may have a profound influence on marine ecosystems
-it’s mostly salt water
how much cryospheric water is there?
-glacial land ice extends more than 50,000 km²
-greenland ice sheet extends about 1.7 million km²
in what forms is cryospheric water?
-the portions of the earths surface where water is in solid form
-sea ice
-ice sheets
-alpine glaciers
-ice caps
-permafrost
what are the key issues/changes of cryospheric water?
-ice sheets form in areas where snow that falls in winter does not melt entirely over the summer- causing layers of snow to pile up into thick masses of ice
-if greenland ice sheet melted the sea level would rise about six metres
-if the antarctic ice sheet melted, sea level would rise by 60m
how much terrestrial water is there?
-rivers make up only a small percentage of all water, covering just 1,000,000 km² with a volume of 2,120km³
in what forms is terrestrial water?
-surface water
-ground water
-soil water
-biological water
what are the key issues/changes of terrestrial water?
there is not much of this water
in what forms is atmospheric water?
-exists in all three states
-the most common is gas: water vapour
what are the key issues/changes of atmospheric water?
can not be used as it’s hard to collect
the oceans are the main store of saline water. can you account for the ‘other saline water’ stores?
saline aquifers and mangrove swamps
what are saline aquifers?
they exist where seawater has infiltrated into the rocks, often due to over abstraction
many of the worlds glaciers are melting, where do you think this freshwater is going?
ocean store (meaning it’s now saltwater)
why is ‘groundwater’ a more important fresh water source than ‘glaciers, ice caps and ice sheets’?
it’s not frozen, in more convenient locations, it’s held as ice
why do you think the atmosphere stores such a small amount of the worlds water?
water cycles quickly in and out of the atmosphere- the atmosphere can’t store it very effectively
what happens once aquifers under deserts have been used?
they won’t refill for a long time as there’s little rain, this means they could be infiltrated by seawater when they are empty
what is the availability of fresh, clean water affected by?
climate change, overuse and contamination
what are the four main stores of the water cycle?
-lithosphere (land)
-hydrosphere (liquid water)
-cryosphere (frozen water)
-atmosphere (air)
what is the cryosphere?
it contains the frozen parts of the earth
what does the cryosphere include?
-snow
-ice on land
-ice caps
-glaciers
-permafrost
-sea ice
describe the main positive feedback mechanism present in the cryosphere
melting reduces ice coverage, decreasing albedo, leading to more absorption of solar energy and further warming
describe the main negative feedback mechanism present in the cryosphere
increased snowfall in some areas due to warmer air holding more moisture can offset ice loss temporarily
what are ice caps?
when snow accumulates and compresses into ice, feeding the glaciers
what are glaciers?
frozen rivers move downhill due to gravity and weight
what is snow?
it covers mountains in ice sheets, playing a big role in reflecting solar energy
what is permafrost?
permanently frozen soil underground, thawing this could release greenhouse gases like methane
what are icebergs?
ice that has broken off from glaciers or ice-shelves
what is an ice shelf?
an extended piece of ice from a land based ice sheet
what is an ice sheet?
massive layers of ice covering land, such as Antarctica or Greenland
describe the composition of the earths atmosphere
-78% nitrogen
-21% oxygen
-0.9% argon
-the remaining gases, such as water vapour and CO2 are found in smaller quantities
what are the different layers of the earths atmosphere?
-troposphere
-stratosphere
-mesosphere
-thermosphere
-exosphere
describe the troposphere
-lowest level of the atmosphere, from the surface of the earth up to 9-17km
-densest atmospheric layer because of the weight of the layers above it
-contains 99% of all water vapour
describe the stratosphere
-extends up to 50-55km
-much warmer than the troposphere
-contains the ozone layer which absorbs radiation from the sun, protecting the surface
-not much weather occurs here
describe the mesosphere
-extends up to 80-85km
-reaches temperatures as low as -100 degrees
-water vapour is scarce but noctilucent clouds can form ice crystals
describe the thermosphere
-extends up to 500-1000km
-where the atmosphere begins to break down
-temperature rises as altitude increases; however, the air is so thin that although particles may have energy equivalent to a heat of 1500 degrees, it wouldn’t feel hot to touch
describe the exosphere
no well define upper limit as it merges with space where gases can escape earths gravity
what is the atmosphere?
a complex system of gases that surrounds the planet and is held in place by gravity
what are the functions of the atmosphere?
-life support
-temperature regulation
-UV protection
-weather and climate
-shield from space debris
how does the atmosphere support life?
it supplies oxygen for breathing and carbon dioxide for photosynthesis
how does the atmosphere regulate temperature?
acts as an insulating blanket, maintaining a habitable climate through the greenhouse effect
how does the atmosphere provide UV protection?
the ozone layer shields life from harmful ultraviolet radiation
how does the atmosphere impact weather and climate?
drives global weather systems and patterns through interactions between air, water and sunlight
how does the atmosphere shield from space debris?
burns up meteoroids before they reach the surface
what is the lithosphere?
the rocky outer part of the earth, it is made up of the brittle crust and the top part of the upper mantle- it is the coolest and most rigid part of the earth
what are the characteristics of the lithosphere?
-the rocks in the lithosphere are considered elastic and they are not viscous
-the asthenosphere is viscous and the lithosphere asthenosphere boundary is the point where geologists mark the difference in ductility between the two layers of the upper mantle
-the lithosphere is far less ductile than the asthenosphere
what are the types of lithosphere?
-oceanic lithosphere (associated with oceanic crust)
-continental lithosphere (less dense than the oceanic lithosphere)
what tectonic plates make up the lithosphere?
North American, Caribbean, South American, Scotia, Antarctic, Eurasian, Arabian, African, Indian, Philippine, Australian, Pacific, Juan de Fuca, Cocos and Nazca
what is the movement of tectonic plates possible by?
the thermal energy from the mantle part of the lithosphere
how does thermal energy impact the rocks of the lithosphere?
thermal energy makes the rocks more elastic
how does the lithosphere interact with other sphere?
-enormous, hard rocks of the lithosphere may be ground down to powder by the powerful movement of a glacier (cryosphere)
-weathering and erosion caused by wind (atmosphere) or rain (hydrosphere may also wear down rocks in the lithosphere
what are the functions of the biosphere?
-support life
-nutrient cycling
-climate regulation
-habitats and biodiversity
how does the biosphere support life?
the biosphere provides the necessary conditions for all living organisms to survive
how does the biosphere cycle nutrients?
it supports the circulation of essential nutrients through ecosystems
how does the biosphere regulate climate?
through processes like photosynthesis, respiration and water cycles
how does the biosphere provide habitats and biodiversity?
it offers countless habitats for a vast variety of plant, animal, and microorganism species, promoting biodiversity
why is protecting the biosphere important?
the biosphere is crucial for sustaining life, ensuring ecosystem balance, and maintaining the overall health of out planet
what is the biosphere?
the main part of the earth where all organisms live
what is the hydrosphere?
the total amount of water on a planet, this includes water that is on the surface of the planet, underground and in the air
how does liquid water exist on the surface of the earth?
in the form of oceans, lakes and rivers
how does liquid water exist below the ground of the earth?
as groundwater in wells and aquifers
when is water vapour most visible?
when its as clouds and fog
what is the frozen part of the hydrosphere made of?
ice: glaciers, ice caps and iceburgs
what is the name given to the frozen part of the hydrosphere?
the cryosphere
how does water move through the hydrosphere?
In the water cycle; hot air rises as water vapour condenses into a solid or liquid form, they create droplets that precipitate back onto the earths surface as rain or snow, precipitation that falls onto land flows into rivers, streams or lakes, and some of it seeps into the soil where it is held underground as groundwater. When warmed by the sun, water on the surface of oceans and freshwater bodies evaporates, forming a vapour. This then rises into the atmosphere again and the cycle repeates.
what are some inputs into the hydrosphere?
precipiation
what are some stores in the hydrosphere?
-surface water
-groundwater
-oceans
-clouds
-biomass
what are some outputs to the hydrosphere?
-plants
-evaporation
-biomass
what is sublimation?
solid to gas
what is deposition?
gas to solid
how was antarctica formed?
due to deposition, as the air (saturated with water vapour) hits the cold ground it freezes immediately
define pressure
the weight of air on the earths surface
what is the global average atmospheric pressure?
1 bar or 1000 millibars
why can the atmosphere not sustain large changes in pressure gradients?
because the atmosphere is a gas it cannot sustain large changes in pressure gradients
why does air get colder as it rises?
this is because it gets less dense as it rises so it doesn’t trap heat- less insulation
what is the environmental temperature?
the temperature at any particular height in the atmosphere
why are tropical rainforests on the equator not hotter than deserts on cancer and capricorn?
they are cooler because the process of creating rain takes up heat energy and due to cold air falling it has a cooling effect on the ground
what does high pressure mean?
no space for hot air particles to rise, particles fall and heat up, becomes dry air = deserts
what does low pressure mean?
space for hot air particles to rise = rain
describe the atmospheric circulation model
- suns rays are more concentrated at the equator therefore making it warmer (it only has to heat a small area and the suns rays also have to pass through less atmosphere)
- hot air rises off the equator, this creates low pressure and therefore rain
- as the air rises it gets colder and small- the water gets squeezed out of it forming condensation nuclei in the atmosphere (the air contracts, causing water vapour to cool and condense), this starts to form clouds at dew point
- falling air- warms up- expands- no rain = hot deserts
5.temperate regions- same as equation but less hot - regions- higher pressure- no rain = cold deserts
what does the atmospheric circulation model look like?
see paper flashcard
what does the ITCZ stand for?
Inter Tropical Convergence Zone
where is the ITCZ?
in the middle when its in between the equinox and solstice
when does the ITCZ move north?
in summer
when does the ITCZ move south?
in winter
what is the residence time of the ocean?
up to 4,000 years
what is the residence time of the glaciers?
up to 1000 years
what is the residence time of groundwater?
2 weeks-1000 years
what is the residence time of soil?
2 weeks-1 year
what is the residence time of the atmosphere?
10 days
what is the residence time of lakes?
10 years
what is the residence time of rivers?
2 weeks
what is the residence time of swamps?
1-10 years
what is the amount of water held in each store in the water cycle determined by?
the transfer processes that act as inputs and outputs
how long ago was the last ice age?
18,000 years ago
what happened at the peak of the last ice age?
about 1/3 of the earth’s land area was covered by glaciers and ice sheets
what is the driving force for the movement of clouds?
the global atmospheric circulation model
what does the global atmospheric circulation model demonstrate?
variations in time and space of the water cycle transfer process
what is the equilibrium line?
on a glacier, this marks the altitude where the annual accumulation and melting are equal
what has happened to the equilibrium line in the recent decade as the climate has warmed?
the equilibrium line has moved to higher altitudes so most glaciers are now shrinking and retreating
what is the global atmospheric circulation model also called?
latitudes affect on climate
why are black clouds black?
as there’s lots of water which stops sunlight from going through
which cells in the atmospheric circulation model are the weakest?
the polar cells
how much rainfall must a place get to be a desert?
less than 500mm of rain
what does residence time mean?
the length of time water remains in the store
what is calving?
when the snout of a glacier falls off into the sea
where’s 95% of the water that’s stored in ice stored?
ice sheets covering Antarctica and Greenland
how old is some ice in ice sheets?
400,000 years old
how much could the sea level rice due to melting of polar ice sheets?
by 60m
how much of the 60m rise in sea level due to melting of polar ice sheets is actually due to thermal expansion?
80%
what is the equilibrium line?
this marks the altitude where the annual accumulation and melting (ablation) are equal
why does soil have the second shortest residence time in the water cycle?
due to the uptake of water through the roots and evaporation from surface of soil
why does deep groundwater have the longest residence time in the water cycle?
due to the fact there are no rocks to uptake water, and friction and impermeable rocks
how is snow formed?
by deposition and is it falls it does not melt
how is hail and sleet formed?
they are formed by deposition but as they fall they melt then rise again into colder air and re-freeze- this is how they then fall
what is the name for clouds on the ground?
dew
what is the name for frozen clouds on the ground?
frost
explain the role of cryospheric change in the water cycle
-cryospheric change has a regulatory role in sea levels
-the cyrosphere is a major store of water
-in a period of cooling the cryosphere will grow in size, this is because the water cycle is slowed considerably as the ice restricts the return of the water to the sea and ocean
-in a period of warming the cryosphere will add water to the cycle, as the water cycle restarts more of the ice melts and return water to the sea
-this increased the size of ocean store causing sea levels to rise through thermal expansion
define water table
point at which the ground becomes saturated with water
where does through flow take place?
above the water table but below the surface
how do rivers erode and when do they stop eroding?
rivers erode vertically until they hit the water table where they stop eroding
explain why the drainage basin hydrological cycle can be described as an open system
-it has energy transfers due to the suns rays
-it has transfers of matter (water) due to evaporation and transpiration which leaves the drainage basin and enters the atmosphere
what are four ways that water reaches a river channel in a drainage basin?
-directly from the atmosphere as precipitation
-surface runoff
-water infiltrates through the ground as throughflow
-water percolates through the ground as baseflow
suggest how hydrological cycle operations might differ between a mountainous region and a lowland forest region
-the mountainous region is colder so there would be little evaporation whereas the lowland forest would be hotter so there would be more evaporation
-the mountain area would have less trees so there would be more surface runoff as there’s no interception from trees or uptake from the roots whereas in a forest there are lots of trees so there would be limited surface runoff due to the interception of the leaves
what are two ways humans can impact the hydrological cycle?
-building impermeable surfaces increase surface runoff and increasing flooding
-cutting down trees reduces interception so also increases surface runoff
how is the water table affected in summer?
it’s lower in summer
how is the water table affected in winter?
it’s higher in winter
what is throughflow?
the flow through the ground above the water table
what is infiltration?
when water breaks through permeable surfaces
what is groundwater flow?
flow through the ground in the water table
what is channel flow?
flow of a river
what is river runoff?
when water leaves the drainage basin system
is evaporation or transpiration largely dependent upon absorption of water from the soil?
transpiration
is evaporation or transpiration a physical process that occurs on any free surface?
evaporation
is evaporation or transpiration that the formation of vapour continues for some time even after the saturation of outside air?
transpiration
is evaporation or transpiration if it varies directly according to the velocity of the wind?
both
is evaporation or transpiration if it is a physiological process and occurs in plants?
transpiration
is evaporation or transpiration if living cells are involvedq?
transpiration
is evaporation or transpiration if any liquid can evaporate- the living epidermis and stomata are not involved?
evaporation
is evaporation or transpiration if various forces such as vapour pressure and osmotic pressure are involved?
transpiration
is evaporation or transpiration if not many forces are involved?
evaporation
is evaporation or transpiration if the water moves through the epidermis with its cuticle or through the stomata?
transpiration
is evaporation or transpiration the rate is slightly lower than evaporation under the influence of wind velocity because it lowers the leaf temperature?
transpiration
is evaporation or transpiration if it stops when the air is fully saturatedq?
evaporation
is evaporation or transpiration if it can occur from both living and non living surfaces?
evaporation
is evaporation or transpiration if it continues as long as water is available on the surface?
evaporation
what is soil moisture utilisation?
as it warms up potential evapotranspiration exceeds precipitation- the water store is being used by plants (utilisation)
what is soil moisture defecit?
there is a defecit of soil water, plants either wilt or have adaptations to survive dry conditions
what is soil moisture surplus?
precipitation is greater than potential evapotranspiration, all space in the soil has been filled and so it is in surplus, groundwater gets recharged, overland flow can occur leading to floods
what is soil moisture recharge?
precipitation is greater than potential evapotranspiration, the soil water will start to fill again (recharge) until it gets back to its normal level
what is the water balance?
the balance between inputs and outputs in a drainage basin, usually shown on a graph
why is storage expressed with a +/- in the water balance equation?
because of drought/flooding
what places can precipitation end up?
-evapotranspiration
-streamflow
-storage
describe the UK climate
-precipitation exceeds evapotranspiration
-during the winter months when precipitation is high and evapotranspiration and temperatures are low, there is a soil moisture surplus
-but summer can lead to a soil moisture defecit
what areas of a water balance graph should be the same size?
soil moisture utilisation and soil moisture recharge
what can be done in soil moisture utilisation?
-plants
-agriculture
-humans
what is the field capacity of soil?
the soil becomes as saturated as it can be
what two things should you always think about when describing a water balance graph?
-always look at the key carefully
-look at where the place is in the world e.g. a desert and if the graph doesn’t match this then you are reading it wrong
what does the word ‘compare’ mean in a question?
give similarities and differences
what does the word ‘contrast’ mean in a question?
just give differences
what is a river regime?
the pattern of seasonal variation in the flow of a river (discharge)
what are river regimes related to?
-the geology and soils (so the amount of precipitation that finds its way to the river depends on: steepness of slope; permeability of the rocks and soils and vegetation cover)
-climate (the precipitation, temperature and evaporation rate)
-additionally (streams with many tributaries may have a different regime from streams with few)
what are the different types of river regimes?
simple and complex
describe a simple regime
-these show times of high water levels followed by lower levels, one cycle per year
-they exist as a result of glacier melt, snow melt or seasonal rainfall such as monsoons
why do most British rivers have a simple regime?
-they are relatively short
-there is the same climate throughout the British Isles
describe a complex regime
-if a river has more than one period of high water levels and/or low water levels [er year
-more common on large rivers that flow through a variety of relief and receive their water supply from large tributaries
-and through various climate zones
what factors affect the shape of the hydrograph?
-drainage basin shape and size
-steepness of land
-vegetation
-carbon land use
-deforestation
how does the drainage basin shape and size affect the shape of the hydrograph?
If there is a big drainage basin it will mean the river discharge is quicker. However, it will mean that the lag time will be longer as there is a bigger volume of water and there is a higher chance of interception.
how does the steepness of land affect the shape of the hydrograph?
If it is steeper there is a quick water runoff meaning that there is a shorter lag time.
how does the amount of vegetation affect the shape of the hydrograph?
Precipitation is intercepted by the plants so it takes longer for it to get to the river as the vegetation has taken up/ in the water. Water is lost by evaporation and transpiration also.
how does carbon land use affect the shape of the hydrograph?
Agriculture have a variety of effects among which are ploughing that breaks up the top soil and allows greater infiltration, subduing the hydrographs. This can be enhanced by contour ploughing.
how can you find out the discharger of a river?
multiply the velocity of the river, measured in metres per second by the cross-sectional area of the river measured in square metres
what is the discharge of a river measured in?
cumecs (cubic metres per second)
what does a storm hydrograph show?
how the drainage basin helps to respond to a period of rainfall
what is bankfull discharge?
when the river is at maximum capacity (up to the river bank)
what does the hydrograph allow us to examine a relationship between?
the rainfall event and the discharge- it shows the discharge before, during and after the storm
what is bankfull?
the maximum discharge that a river channel is capable of carrying without flooding
what is discharge?
the amount of water in a river flowing past a particular point expressed m³ s⁻¹ (camecs)
what is a flashy drainage basin?
it leads to flooding
what is peak discharge?
the point on a flood hydrograph when river discharge is at its greatest
what is storm flow?
discharge resulting from storm precipitation involving both over land flow, through flow and ground water flow
what is lag time?
the time between peak rainfall and peak discharge
what does it mean the longer to lag time?
the longer the lag time the lower the peak flow, this is because the water molecules arrive to the river at different times
what is baseflow?
water trickling out of the ground from bed and banks of river
what factors affect discharge?
-weather
-drainage basin
-vegetation
-geology and soils
-land use
-agriculture
-construction
how does weather affect discharge?
-snow slows down
-precipitation, intensity and duration
-temperature, evaporation reduces discharge
how does the drainage basin affect discharge?
-shape, rounder=higher discharge
-size, smaller increases discharge
-slope, step slope means water reaches river more quickly
-drainage density
what is drainage density?
the number of river/ stream channels in a square km
how does vegetation affect discharge?
more trees can reduce infiltration due to higher interception, higher evapotranspiration and more uptake
how does geology and soils affect discharge?
impermeable rocks increase surface runoff and humous soils absorb more water
how does land use affect discharge?
-urbanisation
-drainage
-deforestation
how does agriculture affect discharge?
removes vegetation and ploughing creates mini drainage basins in the fields
how does construction affect discharge?
-dams
-levees
-afforestation
what are dams used for?
to moderate the flow of the river
what’s an example of a levee that failed?
New Orleans levee
what is a storm hydrograph?
a graph of discharge of a river over a period when the normal flow of the river is affected by a storm event
what does ephemeral mean?
name given to a river that only flows in winter (baseflow gets to zero in summer)
what has to happen for a river to stop flowing?
the water has to drop below the water table
how do you describe a hydrograph?
-The rising limb is described as…
-The falling limb is described as…
The lag time for _____ is…
-The peak discharge for _____ is…
-Some of the reasons of this shape include… because…
during a drought would you expect more clouds or less clouds?
less clouds even though there is increased evaporation
why do less clouds form during drought?
because the air is hotter- this increases the capacity of the air because it expands, this means the air can hold more water vapour which means the air does not condense and form clouds
draw and label the water cycle
see paper flashcard
how does agriculture affect the water cycle?
-farmers are able to control the local water cycle through irrigation or land drainage
-soils covered with plants have higher infiltration and soil water rates and therefore reduced runoff
how does urbanisation affect the water cycle?
water cannot infiltrate the soil as it has been covered with impermeable concrete or tarmac, which increases overland flow and makes flooding more likely- soil water and groundwater stores are reduced
how does water abstraction affect the water cycle?
-Colorado river became ephemeral due to water abstraction which has meant it doesn’t reach the sea all year round
-when water is abstracted aquifers become depleted, they can also become contaminated by inflowing saltwater if the water table drops below sea level
-abstraction can result in low flow conditions in rivers which can have harmful impacts on ecosystems
how does soil drainage affect the water cycle?
-the water table is lowered, changing rates of infiltration and evaporation creates dry peat that is friable and vulnerable to erosion
-dry peat can also ignite which releases carbon
-land drainage causes nitrate loss which can lead to eutrophication (algae grows a lot due to fertiliser which suffocates fish)
-the dry topsoil can be subject to wind erosion
how does irrigation affect the water cycle?
irrigation has a significant impact on water stores and transport processes, aquifers are in serious danger of being depleted
how does deforestation affect the water cycle?
-leading to surface runoff and soil erosion and reducing soil water stores
-less trees means new vegetation generally has fewer leaves and shallower roots which means it uses less water than the forest it replaces
-the result is that less water evaporates from the land; more water runs off the land and stream flow is increased
what are the top four greenhouse gases that contribute to the greenhouse effect?
- water vapour
- methane
- carbon dioxide
- nitrous oxide
how does the ozone layer relate to climate change?
the ozone layer is not related to climate change at all
what would happen if we didn’t have the greenhouse effect?
earth would be too cold and no life would exist
describe the role of photosynthesis in the carbon cycle
the sun sends energy and plants take in the energy and converts it along with carbon dioxide into forms of energy called carbohydrates such as glucose and sucrose
what happens when plants are decomposed?
it releases carbon back into the atmosphere
what are fossil fuels?
previously dead living organisms that have been compressed under high pressure
what fossil fuels do rainforests become?
coal
what fossil fuels do marine organisms become?
oil and gas
what has industrialisation caused?
it has burned excess fossil fuels which has caused an imbalance
how does humans breathing out carbon dioxide play a part in global warming?
humans breathing out carbon dioxide plays no part in global warming
what is sustainable technology?
one where it’s inputs are equal to it’s outputs
what did Boserupp say that can be used in a 20 marker?
necessity is the mother of all invention
what is carbon?
a basic chemical element needed by all plants and animals to survive
what are the roles of carbon?
-it’s recycling it essential for life on earth
-enables food to be provided for plants/animals
-enables energy sources to be created for industrial development
where is most of the carbon stored in the world?
lithosphere- the rocks and the soil
what is the carbon cycle?
the carbon flows between each of the stores in a complex set of exchanges
what is an example of a fast element of the carbon cycle?
trees
what is an example of a slow element of the carbon cycle?
carbon being locked in the ground
what are the different stores of carbon?
-biosphere
-atmosphere
-pedosphere
-fossil fuels
-hydrosphere
-lithosphere
how many billions of tonnes of carbon is stored in the biosphere?
560
describe the biosphere as a store of the carbon cycle
Vital for life on Earth by converting energy from the sun into carbohydrates that support life. Can store carbon for many years and transfer carbon into the soil. However through deforestation this carbon can be released back into the atmosphere very quickly.
how much of a humans body is carbon?
18%
why do you rarely find carbon in its pure form?
carbon bonds easily with other molecules
what is a storm hydrograph, and why is it importnat?
A graph showing river discharge over time during a storm event. Helps analyse factors affecting river flow and is a common exam topic in hydrology
What is baseflow in a storm hydrograph?
Normal river discharge before a storm.
What is the rising limb in a storm hydrograph?
The steep increase in discharge after rainfall begins.
What is peak discharge?
The maximum river flow after a storm
What is lag time in a storm hydrograph?
The delay between peak rainfall and peak discharge
What is the falling limb in a storm hydrograph?
The gradual decline in discharge back to baseflow
What is direct channel input?
Rain falling directly into the river
What is interception?
Water absorbed by vegetation before reaching the ground.
What is infiltration?
Water soaking into the soil (fastest in grassland, slowest in bare soil/rock)
What is percolation?
Water moving deeper into underground rock layers (aquifer).
What is overland flow?
Water running over the ground surface to the river
What is infiltration-excess flow?
When rainfall exceeds the infiltration rate (common in summer).
What is saturation-excess flow?
When the soil is already saturated, causing runoff (common in winter).
What is throughflow?
Water moving laterally through unsaturated soil to the river.
What is baseflow in terms of water movement?
The slowest process, where water seeps from underground into the river.
How does drainage basin size affect hydrographs?
Smaller basins = shorter lag time, higher peak discharge.
How does basin shape affect hydrographs?
Circular basins = shorter lag time; Elongated basins = longer lag time.
How do steep slopes affect hydrographs?
Faster flow, shorter lag time, higher peak discharge.
How does precipitation type affect hydrographs?
Intense/prolonged rain = higher peak, shorter lag time.
How does rock permeability affect hydrographs?
: Impermeable rock = faster runoff, higher peak discharge.
How does vegetation affect hydrographs?
More vegetation = slower flow, lower peak discharge.
How does soil type affect hydrographs?
-Sandy soils = more infiltration, lower peak.
-Clay soils = less infiltration, higher peak.
How does urbanisation affect hydrographs?
More concrete & drains = faster runoff, higher peak discharge.
How does deforestation affect hydrographs?
Less interception = more runoff, higher peak discharge.
Where is the River Ribble?
Located in Lancashire, UK, draining 2,182 km².
Where does the River Ribble start?
In the Pennines at 442m elevation.
How does rainfall vary in the River Ribble basin?
1775mm at the source, 890mm at the estuary.
How does rock type affect the River Ribble’s flow?
-Millstone Grit (impermeable) → rapid overland flow.
-Limestone → throughflow via joints and bedding planes.
How has human activity affected the River Ribble?
-Urbanisation → Rapid runoff from built-up areas.
-Agriculture → Overgrazing & burning increase erosion & runoff.
Name three ways humans reduce river discharge.
- Water extraction from rivers/boreholes.
- Reservoirs storing water, preventing floods.
- Afforestation increasing interception.
Name three ways humans increase river discharge.
- Sewage & industrial waste adding water.
- Inter-basin transfers bringing water from other areas.
- Deforestation reducing interception → faster overland flow
Where does the Mississippi River rank in terms of drainage basin size?
It is the 4th largest drainage basin in the world (~1.2 million square miles).
How do water transfers and stores in the Mississippi River change?
They change naturally and due to human impact.
How much precipitation is lost to evapotranspiration in the Mississippi Basin?
> 75% of annual precipitation is lost through evapotranspiration.
How does evapotranspiration affect different regions of the basin?
-Arid western areas → little runoff due to high evapotranspiration.
-Wetter eastern areas → main source of river flow
How does seasonal variation affect runoff in the Mississippi Basin?
-Winter → More precipitation, higher runoff.
-Summer → Less precipitation, lower runoff.
How does rainfall distribution affect the Mississippi River’s flow?
Uneven rainfall across the basin changes flow patterns throughout the year.
How do storms affect runoff in the Mississippi Basin?
Storms saturate soil, leading to increased surface runoff & higher discharge.
How do droughts impact river discharge?
-Initially → Lower discharge.
-Later → Hardened soil increases rapid runoff & flooding after rain.
How does agriculture impact runoff in the Mississippi Basin?
-92% of the USA’s agricultural exports come from the basin.
-Irrigation stores water in reservoirs, reducing natural surface flow.
-Increases evapotranspiration.
How do dams affect runoff in the Mississippi Basin?
-43 dams hold back water.
-6% of runoff lost due to evaporation from reservoirs.
What increases water demand in the Mississippi Basin?
Growing demand for domestic, urban, and industrial water use.
How will climate change affect rainfall in the Mississippi Basin?
Expected 5-inch (12.7 cm) annual rainfall reduction in lower Mississippi Basin.
How will climate change affect river flow in the Mississippi Basin?
Less rainfall + higher evapotranspiration → decreased runoff & river flow.
How could climate change impact irrigation?
Increased irrigation demand could worsen water shortages.
what percentage of the earths carbon is made up of the biosphere?
0.0012%
how many billions of tonnes of carbon is stored in the atmosphere?
750
describe the atmosphere as a store of the carbon cycle
Carbon is held in the form of carbon dioxide and methane. In recent decades the amount has increased due to emissions from power stations, transport and deforestation. This had contributed to the enhanced greenhouse effect and climate change.
what percentage of the earths carbon is made up of the atmosphere?
0.0017%
how many billions of tonnes of carbon is stored in the pedosphere?
1500
how many billions of tonnes of carbon is stored in fossil fuels?
4000
how many billions of tonnes of carbon is stored in the hydrosphere?
38000
how many billions of tonnes of carbon is stored in the lithosphere?
100000
describe the pedosphere as a store of the carbon cycle
Decomposition of dead organic material creates carbon store for hundreds of years. Deforestation and land use change can release carbon very quickly.
describe fossil fuels as a store of the carbon cycle
Hydrocarbons such as coal, oil and gas are long term stores of carbon. Since the industrial revolution they have been exploited for heat and power. The resulting combustion has pumped huge volumes of carbon dioxide into the atmosphere contributing to climate change.
describe the hydrosphere as a store of the carbon cycle
Very important carbon store. Carbon dioxide is absorbed from the air and river water discharges carbon carried in solution. Since the industrial revolution more carbon dioxide has been absorbed due to emissions.
describe the lithosphere as a store of the carbon cycle
The largest store of carbon. Long term store taking millions of years to form.
what percentage of the earths carbon is made up of the pedosphere?
0.003%
what percentage of the earths carbon is made up of fossil fuels?
0.004%
what percentage of the earths carbon is made up of the hydrosphere?
0.038%
what percentage of the earths carbon is made up of the lithosphere?
99.9%
over the last century how much has the carbon dioxide in the atmosphere increased by?
36%
what is soil composed of?
broken up lithosphere (regolith) and dead organic matter
what leads to the formation of fossil fuels?
burial and compaction
what is most of the carbon in the ocean in the form of?
bicarbonate
What is carbon’s role in living organisms?
Carbon is a core element in sugars, starches, fats, and proteins, making up about half of the dry mass in living things
What are the four major carbon pools?
Atmosphere, Oceans, Earth’s Crust, and Terrestrial Ecosystems
How much carbon is stored in the Earth’s atmosphere?
Approximately 750 PgC (mostly CO2)
What processes have increased atmospheric CO2 from its natural level of ~560 PgC?
Fossil fuel combustion and deforestation
How much carbon is held in the Earth’s oceans?
Approximately 38,000 PgC, mostly in deep waters
What is the primary form of stored carbon in deep ocean waters?
Dissolved inorganic carbon and carbonates.
How much carbon is stored in the Earth’s crust?
Approximately 100,000,000 PgC in sedimentary rocks and an additional 4,000 PgC in fossil fuels.
How does photosynthesis contribute to the carbon cycle?
It removes ~120 PgC/year from the atmosphere, converting CO2 into plant material.
How much carbon is released by respiration in plants and soil organisms?
Approximately 60 PgC/year for each process
What role does decomposition play in the carbon cycle?
It releases CO2 as bacteria and fungi break down organic material
How does the ocean-atmosphere exchange affect carbon levels?
Through diffusion, oceans absorb ~92 PgC/year and release ~90 PgC/year.
How much carbon is released by fossil fuel combustion each year?
Approximately 6-8 PgC/year.
What is the estimated carbon release from deforestation and land change?
~1.5 PgC/year.
What has caused CO2 levels to rise ~30% above natural levels?
Human activities such as burning fossil fuels and deforestation
What is the greenhouse effect?
The process by which gases like CO2 trap heat in the Earth’s atmosphere, contributing to global warming.
What is a carbon sink?
A system that absorbs more carbon than it releases, such as forests or oceans.
What is a carbon source?
A system that releases more carbon than it absorbs, such as fossil fuel burning.
What is carbon sequestration?
The process of capturing and storing atmospheric CO2.
What are anthropogenic emissions?
Human-made emissions from sources like industry and vehicles
What is decomposition?
The breakdown of organic material by microorganisms, releasing carbon back into the atmosphere.
What is the greenhouse effect?
The warming of Earth due to heat-trapping gases like CO2, methane, and water vapor
What are boreal forests?
Forest areas in the northern temperate zone dominated by coniferous trees such as spruce, fir, and pine.
What is biogeochemistry?
The study of natural processes that recycle nutrients from the environment, to organisms, and back to the environment.
What is an ice core?
A vertical section of ice removed from glaciers or ice sheets to study past climate patterns.
What is a greenhouse gas inventory?
A statistical compilation of greenhouse gases emitted by a community, state, or country.
What is the Intergovernmental Panel on Climate Change (IPCC)?
An organization that assesses scientific information related to climate change and advises governments.
What is the Kyoto Protocol?
An international agreement to reduce worldwide greenhouse gas emissions.
What is longwave radiation?
Radiation emitted from the Earth and atmosphere, often referred to as infrared radiation.
What is soil carbon?
Carbon stored in soil, largely from organic material, which plays a key role in the carbon cycle.
what are the different ways that carbon moves through the slow carbon cycle?
-carbon dioxide in the atmosphere reacts with water vapour to form carbonic acid, this causes slightly acidic rainfall to fall onto the rocks and into the ocean which causes chemical weathering
-this chemical weathering releases carbon back into the atmosphere and the rocks storing carbon are also transported into the ocean through run off
-carbon dioxide from the atmosphere also diffuses into the ocean
-this carbon dioxide is taken into shells as calcium carbonate
-the marine organisms die and fall to the sea bed where they compact down to form sedimentary rock- this can then be converted to fossil fuels by heat and pressure and is stored in the lithosphere
-the carbon dioxide in the lithosphere is then released on destructive plate boundaries through volcanic eruptions
how much carbon dioxide do volcanoes release per year?
about 200 million tonnes of carbon dioxide per year
how long can it take for a molecule of carbon to go through the whole of the slow carbon cycle?
between 100 and 200 million years
how old is the earth?
4.6 billion years old
what is the governing factor for the location of biomes?
latitude
what trees are found in boreal forests?
evergreens e.g. pine trees
define carbon source
a store in which the release of carbon occurs at a faster rate than it is absorbed
define carbon sink
a store in which the absorption of carbon occurs faster than it is released
define fast carbon cycle
rapid transfer of carbon compounds over years, decades and centuries
define slow carbon cycle
slow transfers, up to millions of years
what are the main transfers operating in the carbon cycle?
-respiration
-decomposition
-combustion
-photosynthesis
-burial and compaction
-carbon sequestration
-weathering
describe respiration as a transfer in the carbon cycle
-chemical process that happens in cells
-glucose is converted into energy that can be used for growth
-carbon dioxide is then returned to the air
describe decomposition as a transfer in the carbon cycle
-when organisms die they are consumed by decomposers
-during this process of decomposition, carbon from their bodies are returned to the atmosphere as carbon dioxide
-some organic matter passes into the soil where it may be stored for hundreds of years
describe combustion as a transfer in the carbon cycle
-organic matter in the presence of oxygen is converted into energy
-the carbon dioxide is released into the atmosphere
describe burial and compaction as a transfer in the carbon cycle
-where organic matter is buried by sediments and becomes compacted
-over millions of years there organic sediments containing carbon may from hydrocarbons such as coal and oil
-some of the carbon dissolves releasing carbon dioxide, the rest becomes compacted to form limestone
describe carbon sequestration as a transfer in the carbon cycle
umbrella term used to describe transfer of carbon from the atmosphere to plants, soil, rocks and oceans
describe weathering as a transfer in the carbon cycle
-involves the break down and decay of rocks at or close to the surface
-through chemical reactions, the rocks will slowly dissolve with the carbon being held in solution
-can then be transported via the water cycle
what are the factors in the slow carbon cycle?
-carbon sequestration
-burial and compaction
-chemical weathering
how much carbon does the fast carbon cycle move in comparison to the slow carbon cycle?
moves 100 to 1000 times more carbon than the slow carbon cycle
does the fast or slow carbon cycle contain more carbon?
the slow carbon cycle
describe the flows in the fast carbon cycle
-flow of carbon from atmosphere to biosphere through plants photosynthesising
-in the ocean phytoplankton also take in carbon from the atmosphere through photosynthesis
-the carbohydrates the plants produced when the photosynthesised are consumed when animals eat the plants as they do this they release carbon dioxide from respiration and methane gas from digestion
-when animals die and decompose by bacteria and fungi which break down the carbohydrates releasing carbon dioxide and methane back to the atmosphere
-some of the carbon remains in the soil as humus
-fire (combustion) releases carbon dioxide back into the atmosphere
what are peat bogs?
soil, dead organic matter and humus have decayed and become rich with water which stores massive amounts of carbon
why do peat bogs have little oxygen?
because the soil is so wet there’s little oxygen in the soil so plants don’t decompose fully
how long can plants be in peat bogs?
plants can be in the peat for hundreds of years and not rot away which traps massive amounts of carbon
how could global warming affect peat bogs?
global warming could mean peat bogs absorb more carbon or if decomposer organisms in the soil work faster and return more carbon dioxide into the atmosphere
how is carbon transferred to the soil in the carbon cycle?
-decomposition of leaf litter
-root cell respiration and death
how is carbon released to the atmosphere in the carbon cycle?
-plant respiration
-respiration by decomposers
if the leaf litter was burned in a fire, what impact would this have on the carbon cycle?
this would release massive amounts of carbon dioxide into the atmosphere and prevent carbon dioxide from entering into the soil as leaf decay
what are the factors of the fast carbon cycle?
-photosynthesis
-respiration
-decomposition
-combustion
what is one of the key carbon stores on earth?
the cryosphere
describe the positive feedback loop of carbon in the Siberian Tundra
-warmer air
-permafrost melting
-dark rock exposed
-lower albedo rate
-more sunlight absorbed by the earth
-warmer earth
what happens when permafrost melts in the tundra (negative feedback loop)?
-stored carbon dioxide is released (in form of methane)
-methane is more potent to absorb atmospheric heat (20 times more potent than carbon dioxide)
-this contributes to further global temperature increase
-warmer conditions
-more plant growth
-more carbon dioxide stored by the vegetation
what’s some evidence showing climate change is caused by humans?
-Vostok ice core, 1998, found 420,000 year old ice that was in an ice core that was 3,623m (this showed 4 climate cycles- 4 ice ages and 4 interglacial)
-EPICA core was 800,000 years old and mirrored Vostok data
-IPCC (Intergovernmental Panel on Climate Change) said that humans are majorly responsible for climate change
what are the human factors driving change in the carbon cycle?
-fossil fuel combustion
-cement production
-land use change: deforestation
-land use change: urbanisation
-farming practices
what percentage of anthropogenic emissions is cement production?
1%
how much of the CO2 emissions is anthropogenic and how much is natural?
5% is anthropogenic and 95% is natural
how does fossil fuel combustion change the carbon cycle?
90% of anthropogenic carbon release comes from combustion of fossil fuels- the remaining 10% comes from land use change, such as deforestation, land drainage and agricultural practices
how have carbon dioxide concentrations increased?
since the 1960s global concentrations of carbon dioxide have increased dramatically from about 320ppm to just over 400ppm, the highest levels ever recorded
why have fossil fuels been burnt in increasing quantities?
because it’s been driven by the rapid industrialisation of developing nations (including china)
where has carbon dioxide levels been measured?
the Hawaiian Volcanic Observatory
why have carbon dioxide emissions been measured in the Hawaiian Volcanic Observatory?
because it’s quite isolated so carbon dioxide values won’t be effected by changes in industry (more consistent measurements) and it’s part of the USA so has enough money to do it
how does cement production change the carbon cycle?
for every 1000kg of cement produced, 900kg of carbon dioxide is released into the atmosphere
describe the make up of cement industry emissions
50% comes from the heating of calcium carbon and 40% from the burning of fuel to power the process
how has land use change changed the carbon cycle?
through the use of machinery, tree decomposition and slash & burn which all release CO2
how have rising temperatures affected the amazon rainforest?
it has caused parts of the amazon to dry out (these absorb less CO2 and are more susceptible to fires) this creates a positive feedback loop
how much forestry land is cut down each year and changed to other uses?
13 million hectares
what does forest clearing accelerate?
the decaying of dead wood, litter and below ground organic carbon
what does deforestation lead to?
-forest soils are moist but without the shade of trees they soon dry out
-trees also help maintain the water cycle by returning vapour back to the atmosphere through transpiration
how does deforestation cause less carbon dioxide to be stored in the soil?
because there’s less trees so less burial and compaction so less biomass in soil
how much of the worlds population lives in urban areas?
over half the worlds population
how do farming practices change the carbon cycle?
When soil is ploughed, the soil layers invert with each other (allowing air to mix in). As a result, soil microbial activity dramatically increases, resulting in more soil organic matter being decomposed. As a result, more carbon is lost to the atmosphere.
how much of agricultural emissions does rice paddies generate?
10%
list some figures about meat production and carbon dioxide
-producing 1 kilo of beef generates 65 times more CO2 than producing 1 kilo of potatoes
-US produces 40.9m tonnes of meat a year
-EU produced 44.5m tonnes of meat per year
-China produces 78.1m tonnes of meat per year
-if we were to eat half the amount of meat we would reduce greenhouse gas emissions from farming by 42%
what are the physical factors driving change in the carbon cycle?
-volcanoes
-natural cycles
-wildfires
-carbon sequestration
how has volcanic activity caused change in the carbon cycle?
-volcanic activity returns to the atmosphere carbon that has been trapped for millions of years in rocks deep in the earths crust
-volcanoes also erupt lava, which contains silicates that will slowly weather, this converts carbon dioxide in the air to carbonates in solution- in this way carbon dioxide is absorbed very slowly from the atmosphere
how much CO2 is emitted from volcanoes in comparison to human emissions?
human activities emit between 100 and 300 times more CO2 than volcanoes
how have volcanoes reduced the amount of CO2 in the atmosphere?
The warming effect of CO2 emitted by volcanoes is counterbalanced by the large amount of sulphur dioxide also given out. Conversion of this sulphur dioxide to sulphuric acid which forms fine droplets, increases the reflection of the radiation from the sun back into space, cooling the Earth’s lower atmosphere.
what are the three different Milankovitch cycles?
-eccentricity cycle
-obliquity cycle
-precession of the equinoxes
how have wildfires caused changes in the carbon cycle?
-wildfires can be started naturally
-every year they burn 3 to 4 million km^2 of land
-wildfires turn carbon sinks to carbon sources
what does carbon sequestration involve?
involves capturing CO2 from the atmosphere and putting it into long term storages
what are the types of carbon sequestration?
-geological sequestration
-terrestrial/biological sequestration
what is geological sequestration?
CO2 is captured at its source and injected as a liquid deep underground in a variety of stores (depleted oil/gas reservoirs, uneconomic coal seams, underground salt formations or the deep ocean)
why is the ocean good at absorbing carbon?
due to its sheer size
what is the advantage of the ocean as a carbon sink?
An advantage of ocean carbon sequestration is that it “sinks” to great depths within weeks or months of being captured at the surface. Once in the deep ocean, it is in a circulatory system measured in thousands of years. This happens quickly but it keeps it for a long time.
what is terrestrial/biological sequestration?
this involves the use of plants to capture CO2 from the atmosphere, carbon is then stored in the stems and roots of the plants (as well as in the soil)
what are the six stores of carbon?
-atmosphere
-lithosphere
-biosphere
-pedosphere
-cryosphere
-hydrosphere
which sphere is the carbon budget calculated for a why?
the atmosphere because this is what’s causing humans the most problems
what are the different impacts of changes in the carbon cycle on oceans?
-ocean acidification
-ocean warming
-melting sea ice
-ocean salinity
-sea level rise
how and why are coral reefs affected by ocean acidification?
-CO2 diffuses into the ocean through direct chemical exchange which creates carbonic acid, this makes the ocean less alkaline
-carbonic acid reacts with carbonate ions in the water to form bicarbonate, this reduces the carbonate ions available which animals like coral and many plankton species need to create their shells
-as a result the shells und up being thinner and more fragile
what is the global carbon budget?
the amount of carbon gained and lost in the natural and manmade workings of the world
what does the carbon budget contain?
-inputs
-outputs
-balance
-deficit
-surplus
why do we study the carbon budget?
it’s essential for understanding how carbon dioxide emissions are contributing to changes in the Earth’s environment in the present day
what is carbon commonly measured in?
petagrams (Pg)
what are the different impacts of changes in the carbon cycle?
-land (fast and slow carbon cycle)
-ocean (ocean acidification, ocean warming, melting sea ice, ocean salinity, sea level rise)
-atmosphere (tundra, carbon stored in vegetation)
what does ocean acidification cause?
coral bleaching and bad for biomasses
what two things cause ocean currents?
ocean warming and ocean salinity
suggest reasons why the “Net increase is soil carbon” is a variable value
because it depends on where the tree is planted as if it’s planted on concrete then leaves can’t decay and it depends on climate also (hot and wet)
how have land use decisions affect CO2 uptake?
-more wildfires leads to increased atmospheric CO2
-farmland replaces trees which means less carbon is stored
-more CO2 available in atmosphere as more photosynthesis from plant growth
-increased temperatures have led to increased length of growing season so may plants photosynthesise for longer
-increased temperatures have caused ice to melt which releases CO2 and methane into the atmosphere
-agriculture has become more intensive so more crops means less trees to take in CO2
what are the key stores of carbon in the carbon cycle?
-lithosphere
-hydrosphere
-biosphere
-atmosphere
what are the different ways carbon can move through the carbon cycle?
-geological cycle
-photosynthesis
-respiration
-decomposition
-combustion
-oceanic carbon pumps
how does carbon move through the geological cycle?
Carbon moves via weathering, burial, subduction, and volcanic eruptions
how does carbon move through photosynthesis?
Plants absorb CO2 to produce oxygen and carbohydrates
how does carbon move through respiration?
Plants and animals release CO2 back into the atmosphere
how does carbon move through decomposition?
Organic matter breaks down, returning carbon to soil/atmosphere
how does carbon move through combustion?
Organic materials burn, releasing CO2 and heat
how does carbon move through oceanic carbon pumps?
-vertical mixing: warm surface waters cool, sink, and circulate CO2
-biological pump: marine organisms absorb CO2; decaying matter releases it in deep waters
what are the two main components of the oceanic carbon pump?
-biological pump
-physical pump
describe the biological pump
-transfers surface carbon to the seabed via the food web
-carbon is stored long-term in the deep ocean
-dependent on healthy ecosystems; disturbances can destabilize it, re-emitting carbon back into the atmosphere
describe the physical pump
-driven by ocean circulation in Polar Regions where colder temperatures enhance CO2 absorption
-dense, cold water flows toward the deep ocean, carrying dissolved carbon
-this process stores carbon for hundreds of years but is difficult to measure accurately
how do planktonic ecosystems play a key role in the carbon cycle?
when these micro-algae die, they contribute to carbon storage in the deep ocean and may form oil deposits over time
how could ocean acidification be a good thing?
-the more acidic seawater is, the better it dissolves calcium carbonate rocks
-over time this reaction will allow the ocean to soak up excess CO2 because the more acidic water will dissolve more rock, release more carbonate ions and increase the oceans capacity to absorb CO2
why could warmer oceans reduce the effectiveness of a carbon sink?
-would decrease the abundance of phytoplankton, which grow better in cool, nutrient rich waters
-this could limit the oceans ability to take carbon from the atmosphere through the biological carbon pump and lessen the effectiveness of the oceans as a carbon sink
why could ocean warming also be a good thing?
carbon dioxide is essential for plant and phytoplankton growth- an increase in carbon dioxide could increase their growth by fertilisation and they would take carbon dioxide directly from the water
why does melting sea ice amplify the warming effect?
-when ice melts the highly reflective ice is replaced by more heat absorbent water which amplifies the warming that cause it to melt in the first place
-loss of ice bound algae affects marine predators, added to this is the fact that animals like polar bears rely on sea ice to get their main food source
why is ocean salinity decreasing?
-caused by highest levels or precipitation and higher temperatures
-precipitation leads to higher river run offs that eventually reach the sea
-higher temperatures cause ice sheets to melt which leads to more freshwater in the oceans
what are the two reasons why sea level is rising due to changes in the carbon cycle?
-melting of terrestrial ice
-thermal expansion
how is melting of terrestrial ice causing sea level rise?
-high temperatures have led to an increased rate of summer melting as well as a drop in snowfall
-this imbalance results in a significant net gain in water entering the oceans from rivers against evaporation from the ocean
how does thermal expansion cause sea level rise?
when water heats up it expands- warmer oceans have a greater volume so occupy more space and causing sea levels to rise
what effects does the enhanced greenhouse effect have?
-causes coastal flooding through sea level rise
-increases frequency and intensity of storm surges
-causes smog (human form of fog) which can create health problems such as lung cancer
what effects might the disruption of the North Atlantic Drift have on the NW Europe?
It would make the climate cooler as the North Atlantic Drift brings hot air from the equator which heats up Europes climate. North Western Europe would also be wetter.
What are the likely effects of the predicted sea level rise on coastal communities? How might their response depend on their level of development?
Richer coastal cities won’t move even under risk of flooding as it’s too expensive whereas less developed communities can just relocate and rebuild with a relatively low cost.
how much do geographers know about feedback loops and their impact on climate?
-we’re fairly confident how levels of CO2 affects direct radiation in the atmosphere and how it will cause warming
-there’s probably feedback loops that we haven’t discovered so we don’t know their impact but we know the impact is significant
what are the feedback loops we do understand?
-water vapour feedback
-albedo feedback
why is the water vapour feedback loop important?
because water vapour is the most common greenhouse gas
describe the water vapour feedback loop
-release of CO2
-warmer atmosphere
-air expands
-air holds more water vapour
-warmer atmosphere
describe the albedo feedback loop that is positive
-warmer atmosphere
-ice melts
-more water exposed (lower albedo)
-water warms, more ice melts
-process escalates
-warmer atmosphere
describe the albedo feedback loop that is negative
-CO2 released
-warmer atmosphere
-more water vapour
-more clouds form
-reduced albedo
-less heat absorption
-atmosphere cools
describe how the albedo feedback loop that is negative (forming clouds) can actually also be a positive feedback loop
-warmer atmosphere creates more high clouds
-this prevents heat from rising
-this traps heat
-leads to warmer atmosphere
which feedback loops do we know about but aren’t sure of their outcomes?
land carbon cycle
what is the negative feedback loop of the land carbon cycle?
-CO2 emitted
-CO2 absorbed by oceans and land (about half of the CO2 emitted)
-less CO2 in atmosphere
what is the positive feedback loop of land carbon cycle?
-warmer atmosphere
-more active bacteria and soil respires more
-more decomposition and more permafrost melting
-more CO2 released
-warmer atmosphere
what are the feedback loops that we don’t understand at all?
-permafrost and high latitude peatlands
-methane hydrates
-permafrost methane
describe the potential methane hydrates feedback loop
-could be a very positive feedback loop on climate change
-lots of methane locked in methane hydrates deep in the ocean and in the current climate they’re stable but their stability is strongly temperature dependent so there’s potential that as the climate warms they could destabilise and release methane into atmosphere
-we know from the Paleo climate there have been occasions where methane hydrates have been thought to have released large amounts of CO2 (this could cause abrupt climate change which would be particularly bad as we wouldn’t have time to adapt)
describe the potential permafrost methane feedback loop
-positive feedback (melts=releases CO2)
-we know it’s bad but we don’t know how bad as we don’t know how much CO2 it contains/will releasec
could there be other feedback loops we don’t know about at all?
-yes
-a warming climate may start new feedback loops
-alternatively we have a fairly good understanding of todays climate but as you get further along we have less of an understanding
describe the role of carbonation as a link between the carbon and water cycle
-rainwater absorbs carbon
-rainwater becomes acidic
-calcium carbonate becomes calcium bicarbonate as rainwater meets rocks
-dissolved carbon carried to oceans by rivers
-new shell growth or transferred to atmosphere
how does phytoplankton create a negative feedback loop?
-they release dimethyl sulphide that promotes the formation of clouds
-clouds reflect solar radiation
-cools atmosphere
However,
-less sunshine might lead to a reduction in the amount of phytoplankton thereby reducing this cooling effect
describe a mountain thermostat negative feedback
-warmer temperatures
-tree roots grow faster and deeper
-more growth leads to more leaf litter and therefore more acidic water in the soil
-acidic water
-increases rate of weathering
-less carbon in atmosphere
-lower temps
-climate regulated less vegetation growth
why does weathering decrease CO2 in atmosphere?
by sequestrating CO2 from the atmosphere to facilitate weathering there is a subsequent lowering of global temperature
what are some changes to the climate system, potentially caused by climate change?
-changes in the hydrological cycle
-warmer land and air
-warming oceans
-melting ice
-rising sea levels
-ocean acidification
-global greening
-changes in ocean currents
-more extreme weather
what are some potential impacts of changes to the climate system?
-conflict and climate migrants
-localised flooding
-flooding of coastal regions
-damage to marine ecosystems
-fisheries failing
-loss of biodiversity
-change in seasonality
-heat stress
-habitable regions of pests expands
-rise in forest fires
-damage to infrastructure
-food insecurity
-risk to water supplies
why is climate migration potentially a big issue?
because currently about 1 billion people live on marginalised land (it’s on the margin of being able to support them) so all these people would have to migrate to somewhere else if the climate changes
