AQA A Level Geography Water and Carbon Cycle PDF

AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Where the effects of an action are ampli- positive feedback fied by a knock on or secondary effect...

AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Where the effects of an action are ampli- positive feedback fied by a knock on or secondary effect Where the effects of an action are nul- Negative feedback lified by knock on effects. It returns a system to balance. Hydrosphere, atmosphere, biosphere, 5 major subsystems lithosphere and cryosphere Where matter and energy can be trans- ferred from the system into the surround- open system ing environment. There are stores, flows, inputs and outputs; the drainage basin is an open system. These have transfers of energy into and closed system out of the system but not matter The tendency towards a natural state dynamic equilibrium of balance within a constantly changing system Water on or close to the Earth's surface. 97% of it is oceanic water. Inputs are runoff and precipitation and outputs are Hydrosphere evaporation. Long term events like cli- mate change have the potential to de- crease the storage capacity. The portions of Earth's surface where water is in solid form. Accounts for 1.7% of all water on earth and is contained Cryosphere in ice sheets, ice gaps, sea ice, glaciers and permafrost (68% of all freshwater is stored in ice caps and glaciers). Water held in the solid outer layer of the earths crust and upper mantle. Accounts Lithsophere for 1.7% of all water on earth and stores water for the longest time. Accounts for 0.01% of all water on Earth. atmosphere Most common atmospheric water is wa- 1 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas ter vapour- cold water can't hold as much water vapour as warm air. part of Earth in which life exists including Biosphere land, water, and air or atmosphere In a period of cooling, the cryosphere will grow in size because the water cycle is slowed, as ice restricts the return of water to the sea and ocean. In a period of warming, the cryosphere will add water Crysopheric change to the cycle as the water cycle restarts and more of the ice melts, returning wa- ter to sea and SLR and positive feedback will occur. Also CC includes accumula- tion and ablation. Steep sides means water flows quick- P factors- steepness er and therefore faster overland flow so flashier hydrographs Natural land use= more interception, root uptake and evapotranspiration meaning P factors- vegetation less surface run off and less chance of flooding. Reduces interception rates and rainwa- ter hits surface directly. Lack of vegeta- tion roots means there are reduced infil- tration and evapotranspiration rates. Re- sults in rapid overland flow and flashy H factors- deforestation hydrographs. Also there are greater soil erosion rates so the soil is washed away and may lead to sedimentation of the channel which reduces bankfull and in- crease chance of flooding. Impermeable surfaces means no infiltra- tion and overland flow, most likely sheet flow= flashy hydrographs. Most settle- H factors- Urbanisation ments have drainage systems which transfer water away from the urban areas quickly but can result in flooding in the 2 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas river. Short lag time and higher flood risk. Arable farming means more interception and infiltration as water can be uptaken H factors- agriculture by the roots and so less surface run off. Ploughing also breaks up the top soil and allows for greater infiltration. Planting of trees. Increases rates of inter- ception, root uptake and evapotranspira- H factors- afforestation tion which all reduce the amount of water in the drainage basin. The downward movement of water from the surface into the soil. Coarse soils have larger pores and a higher infiltration Infiltration rate whereas saturated, baked or frozen soil is impermeable and will have a much lower infiltration capacity. Vegetated ar- eas= high infiltration rate. The speed at which the soil can absorb water. Normally declines rapidly during Infiltration rate the early part of a rain storm and then reaches a constant value after several hours of rainfall. the maximum rate at which soil can ab- sorb water- if rainfall intensity is greater than the infiltration rate then the soil has infiltration capacity reached infiltration capacity and the wa- ter will build up on the surface as surface storage. The sum of evaporation and plant tran- Evapotranspiration spiration from the Earth's land and ocean surface to the atmosphere The change of state from a gas to a Condensation liquid. As air cools it's able to hold less water. 3 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas When energy from solar radiation hits the Evaporation surface of water/land and causes liquid water to change state to water vapour. The area that supplies a river with its drainage basin supply of water. Separated by high land called a watershed. The downward movement of water through soil and rock due to gravity. It Percolation then can move vertically and laterally by groundwater flow which can feed rivers through long periods of drought. Water flowing through the top soil layer Throughflow parallel to the surface. This is much slow- er than overland flow. Rainfall that falls straight to the ground, Throughfall without interception taking place. Water being prevented from reaching the Interception surface by trees or grass. It's a store. 82% of the area is woodland or grassland so there's lots of interception, root up- take and evapotranspiration and there- fore less surface run off and reduced chance of flooding. Peaty moorland soils- Natural features of River Exe high infiltration, slow transfer or water. 84.4% of the rock is impermeable, prima- ry Devonian sandstone= low infiltration and rapid overland flow= counteracts the land use. Prior to 1998 a lot of drainage ditches were dug to increase the speed of flow to the Ricer Exe and for agriculture but a Exmoor Mires Project lot of silt was transported and there was high overland flow as less water was able to be stored in the soil. Many of these ditches have now been refilled with peat- 4 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas the project cost £4.5 m and had restored 1000 hectares by 2015! Infiltration capacity has increased as the peats can store more water. This means there is a reduced risk of flooding- there has been a 33% reduction in storm flow leaving the restored areas. The water quality has also increased as Effect of Exmoor Mires Project silt is no longer being transported due to slower water transfer. Biodiversity has increased and jobs have been created regarding the maintenance of the area. There has been a 2.65cm rise in the wa- ter table due to the increased saturation. Construction of this in 1979 regulated Wimbleball Reservoir discharge patterns and made both floods and droughts rarer. Reduced storm flow. area where warm, moist air rises close to Inter tropical convergence zone the equator and this air is at low pressure The large scale movement of air which, together with ocean circulation, means Global atmospheric circulation thermal energy is redistributed on the surface of the earth. The circulation takes place in cells by convection. Winds are created across the planet as air moves from areas of high pressure to areas of low pressure; these winds move at an angle due to the corolis effect. GAC There is high pressure between the Hadley and Ferrel cell. It leads to areas of high rainfall like trop- ical rainforests and areas of dry air like deserts. the bending of currents of air due to Corolis effect Earth's rotation. 5 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Precipitation (P)= discharge (Q) + evapo- Soil water balance transpiration (E) +/- storage changes (S) Where there is more precipitation than evapotranspiration (more inputs than outputs). Positive water balance The soil is refilled with water, during recharge, until saturated and the excess water is stored on land. Where there is more evapotranspiration than precipitation (more outputs than in- puts). i.e. during summer months. negative water balance The soil is used by plants, during utilisa- tion, until there is so limited water that they are forced to adapt to only take it up when available (there is a deficit). recharge: P>E surplus: P>E utilisation: E>P deficit: E>P Water Balance Graph The balance between inputs and outputs to the soil in the drainage basin. Can be Water balance/budget positive or negative. They vary depend- ing on: depth, type, texture and perme- ability of soil. Occurs when water enters the soil faster then the soil can absorb or move it e.g. Infiltration excess overland flow precipitation exceeds infiltration capacity. In the UK, it's more common in summer. Saturation excess overland flow 6 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Occurs when soil spaces are so full of water that no more rain can be absorbed. In the UK, it's more common in the winter. The part of the river's discharge that is Baseflow provided by groundwater seeping into the bed of the river. A very slow process. More circular= water reaches the chan- nel quicker and so lag-time is shorter and P factors- shape of drainage basin peak discharge is higher= flashy hydro- graph. Impermeable (clay soils/ shale rock/ De- vonian sandstone) results in higher over- land flow (particularly saturation excess) P factors- soil/rock type and less through flow and infiltration- flashy hydrograph. Baked or frozen soils will have low infiltration and throughflow rates as water can't percolate Heavy rainfall= soil reaches field capac- ity quicker and so after that point there is little infiltration and high infiltration ex- P factors- rainfall cess overland flow=shorter lt + higher p Or prolonged rainfall=saturation excess overland flow=shorter lag time + higher peak Aquifer can become depleted and con- taminated by inflowing salt water if the water table drops below sea level. This reduces the amount of water in the H factors- water abstraction drainage basin which can be harmful to ecosystems. e.g. irrigation in the Middle East- aquifers are at risk of becoming depleted. e.g. drought: causes reduction in water stores in rivers and lakes and vegeta- tion either dies or is destroyed by fire. The heat and dry air initially causes high rates of evapotranspiration but this then 7 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas decline as water on the ground dries up Natural influences on the water cycle: and trees transpire less. extreme weather events Soil moisture also reduces= throughflow ceases. drier seasons: reduced discharge and Natural influences on the water cycle: runoff temperature wetter seasons: increases discharge and runoff The variation (seasonal pattern) in river River regime discharge over the course of a year. When warm moist air from the Atlantic ocean arrives at a mountainous area, it is forced to rise and then condense Relief rainfall which forms clouds, bringing rain. Once the air has passed over the mountains, it descends and warms, creating drier conditions, known as a rain shadow. The ground surface is heated by the sun so the air above is warmed up and rises. It then starts to cool and condense to Convectional rainfall form clouds (which can be cumulonim- bus) which produce heavy rainfall and thunderstorms. Occurs when a warm front meets a cold front. The warmer air rises above the Frontal rainfall colder air as it is less dense. When the warm air rises, it cools and condenses to form clouds, which bring heavy rain. It's the largest rainforest on earth and has approx 2300mm of rainfall annually. WWF estimates that 27% of the Amazon will be without trees by 2030 if the current Amazon Rainforest Deforestation rate of deforestation continues. Driven by demand for : logging, agri- culture, road building, mineral extraction etc. 8 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas As the deforestation is so extensive, there is reduced evapotranspiration (as there is less vegetation) and so less wa- ter vapour in the air. This means there will be less precipitation and so there is a Impacts of deforestation in the Amazon risk of drought as less water reaches the channel= reduced discharge. Local flooding can occur as there is in- creased soil erosion and so the soil is unable to retain water and overland flow will occur. A natural environment that absorbs and stores more carbon dioxide from the at- carbon sink mosphere than it releases, which offsets greenhouse gas emissions. A natural system that releases more car- carbon source bon dioxide than it absorbs and stores. A place where carbon is accumulated and stored- the main stores are the carbon store lithosphere, hydrosphere, cryosphere, atmosphere and the biosphere. transfers The movement of carbon between stores Living organisms convert co2 from the atmosphere and water from the soil, into oxygen and glucose using light energy. It occurs when chlorophyll in the leaves Photosynthesis of the plants react with co2 and it then allows for growth. There is more photosynthesis around the equator where there's more wildlife. It can occur in phytoplankton (in oceans). This occurs when plants and animals convert oxygen and glucose into energy which then produces the waste products Respiration of co2 and water. It helps with excretion and movement and it occurs in the soil. 9 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Overall, plants absorb more co2 than they release, so they are net co2 ab- sorbers from the atmosphere. When living organisms die, they're bro- ken down by decomposers (such as bac- teria and detrivores) which respire, re- turning co2 to the atmosphere. Some or- Decomposition ganic matter is also returned to the soil, where it is stored, and this adds carbon to the humus. Hot, wet and dark conditions increase decomposition e.g. rainforests When fossil fuels and organic matter, such as trees, are burnt, they emit co2 into the atmosphere. Can be caused naturally, e.g. wildfires, Combustion but mostly human caused. 85% of human caused co2 emissions are a result of the combustion of fossil fuels for energy. When carbon is released into the ocean, it's dissolved in it. This increases the acidity of the ocean which poses a threat to wildlife and coral reefs as they will start to bleach and die= plants that rely on coral will suffer. dissolution More dissolution is occurring because of increased co2 emission. Cold water is able to absorb more carbon than warm water and so the problems of dissolution are exaggerated near the poles. The capture and storage of carbon from the atmosphere. It's then held in sedi- mentary rocks, soils etc. Sequestration It can be man made, e.g. carbon capture storage from power stations or natural, e.g. carbon taken in by peat in Exmoor. 10 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Acidic rain dissolves rocks due to chem- ical weathering (corrosion). Some rocks are particularly vulnerable to chemical weathering e.g. limestone and Weathering chalk. Weathering transfers carbon from the lithosphere to the hydrosphere and at- mosphere. Burial and compaction is where organ- ic matter is buried by sediment and becomes compacted. Over millions of years, this organic sediments contain- ing carbon may form hydrocarbons such as coal and oil. Shelled organisms and coral absorb carbon dioxide from the burial and compaction water and converts it into calcium car- bonate which builds their shells. When these organisms die they accumulate on the sea bed. CO2 is released as the carbonates dissolve and the remainder becomes compacted, forming limestone which stores carbon for millions of years. marine sediments and sedimentary rock, the ocean, fossil fuel deposits, soil organ- carbon stores ic matter (deforestation, land use change + soil erosion can release this rapidly), the atmosphere and terrestrial plants. The rate of flow of carbon between Earth's stores. If fluxes didn't exist, car- bon would accumulate within rocks for- ever, which would deplete the amount of carbon entering the carbon cycle. Fluxes Fluxes allow equilibrium to be main- tained and are essential for life on earth yet there are increasingly unbalanced fluxes from human activity that are alter- ing other fluxes, threatening ecosystems. 11 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas 1. Erosion takes place in marine areas but weathering is a sub Ariel process Differences between weathering and 2. Erosion involves the transportation of erosion sediment whereas weathering is just the breakdown of it. the theory, put forward by James Love- lock in 1965, that living matter on the earth regulates the conditions necessary Gaia Hypothesis for the continuance of life. The planet is thus likened to a vast self-regulating or- ganism i.e. in a state of dynamic equilib- rium. Most in the biosphere Very little in the cryosphere There is more near the equator, partic- Global distribution of carbon ularly in South America as the Amazon rainforest is a huge carbon sink (due to mass of vegetation) Very little in North Africa (Sahara desert) A measure of how ecologically active an net primary productivity area is 99.9% of carbon is stored in sedimentary rocks and deep marine sediments- this is the longest store of carbon. Carbon is stored in the lithosphere in lithosphere (carbon) both inorganic and organic forms- inor- ganic deposits include fossil fuels like coal and oil and organic deposits include litter and humus in soils. The hydrosphere is the 2nd largest car- bon store. Carbon transfers into and out of the ocean through diffusion. But current trends in climate change lead hydrosphere (carbon) to higher ocean temperatures=reducing the oceans capacity to hold co2=more co2 in atmosphere. Acid rain and polluted runoff from agricul- 12 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas ture + industry have negative effects on coral reefs, reducing oceanic biodiversi- ty. Carbon is stored in the tissues of living organisms and this carbon is transferred to the soil humus when they die and decompose and then dispersed into the soil. Carbon is also stored in peatlands, biosphere (carbon) which cover 3% of the surface of the planet. Animals also play a small role in the stor- age of carbon and are important in the movement of carbon through the carbon cycle. Co2 is expected to exceed 417ppm this atmosphere (carbon) year sere A stage of a succession. The development of vegetation in a Succession previously uncolonised area, involving changes within each sere. succession on bare rock Lithosere Involves: lichen, moss, grass, bushes, willow trees and oak trees. 1. Rock is created and it begins to un- dergo weathering, which slowly releases carbon. 2. Over time, pioneer species such as lichen grow and photosynthesis and res- piration occur. 3. Soil will develop and then get deep- Lithosere succession er (from root action) to support larger plants. 4. When the plants die and decompose, they will add humus to the soil, making it more fertile and able to support larger species. 5. Over time, the plant species will be- 13 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas come more diverse and eventually there will be a dense forest with many habitats formed. The final stage of the sere where en- vironmental equilibrium is achieved- the Climatic climax ecosystem is fully developed and stable. This is held back by the climate. Halosere a succession in a saline environment. Psammosere A succession on sand dunes Hydrosere Succession in a water environment The first species to populate an area dur- pioneer species ing succession. The species in a community that have the Dominant species highest abundance or highest biomass. An area or habitat where the influences of humans have prevented the ecosys- Plaigoclimax community tem from developing further e.g. defor- estation in the Amazon rainforest Where there are many different types of Polyclimax vegetation present in a climatic zone. David Frappe said that deforestation may reduce global warming because of the Deforestation positive albedo effect. A pale light surface is left and so there is a reflection of heat rather than it being trapped. Reached an all time high temperature of 38C in 2020. The circle is believed to be warming Arctic circle twice as fast as the global average due to a combined result of climate change and weather patterns: hot air is transported far northward. 14 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas -thawing of permafrost below ground- as this permafrost thaws, co2 and methane will be released, causing further warm- ing and then further thawing of the per- mafrost (positive feedback) -increased rate of ice melt= SLR- loss of Impact of Arctic circle warming highly reflective ice means that the sea absorbs more heat and so more ice melts ( as well as thermal expansion)= positive feedback -wildfires- result of high temps and strong winds The shape of this graph shows temper- ature increase of the Earth's climate in the Anthropocene. In the past 100 years, hockey stick graph there has been a sharp rise in temp- before this, temps fluctuated with glacial and interglacial periods. Temp and Co2 peak every 100,000 years. Changing the function of land from a car- bon sink to a carbon source has a nega- tive impact on the emission balance. Land use change (carbon) Agriculture is often the reason for land use change; amplified recently because of rising population=rising demand. 44% of human induced methane emis- livestock sector is responsible for sions and 5% Co2 1. Enteric fermentation in cattle 2. Rice paddies- are responsible for 12% of global emissions of methane as con- Methane sources stant flooding of the fields creates a bac- teria which produces methane in large quantities. fertilisers (these can also pollute wa- ter and consequently threaten aquatic Nitrous oxide sources ecosystems) , manure, engines burning fossil fuels. 15 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Increasing the land for farming leads to the destruction of natural ecosystems = negative effect on local wildlife and bio- Impact of increased agriculture diversity. Constant exploitation of soils causes ero- sion and compaction= unsustainable as useless for future generations. The period of geological time from about 2.6 million years ago to the present. It includes the Holocene. During the Quarternary, the climate has Quaternary Period alternated between cold glacial and warm interglacial periods- we're current- ly living in the interglacial Holocene peri- od which began 11,700 years ago. about 18,000 years ago, where the last glacial was at its most widespread and Last Glacial Maximum large ice sheets developed in the high middle latitudes of the northern hemi- sphere. Temporary but significant cooling peri- od between 1500 and 1850 that was accompanied by wide temperature fluc- tuations, droughts, and storms, causing Little Ice Age famines and dislocation. Decomposers would also have been less effective, so less carbon would have been transferred to the soil. Anthropecene The period affected by humans. The process of counting tree rings to de- termine the age of a tree. Tree rings are wider in warm, wet years and thinner in years when it's cold and dry. This is be- Dendrochronology cause the tree will grow more in warmer conditions. Darker tree rings represent wood that grew in the late summer/fall and lighter 16 / 29 AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas tree rings represents wood that grew in the spring/early summer. This releases carbon trapped for mil- lions of years within the Earth's crust into the atmosphere. Volcanoes emit 130-380 million tonnes of co2 per year, promoting global warming (but very little compared volcanic activity to human activity). But, when there is a large eruption of ash and dust, the sun's radiation can strug- gle to penetrate and global cooling can occur. A supervolcano in Wyoming, USA. If it erupts, there would be a volcanic win- Yellowstone ter and widespread famine as crops wouldn't be able to grow. Changes in the shape earth's orbit and tilt that cause glacial periods and inter- glacial periods. Orbital changes 19,000 years ago triggered warming in the Arctic which led to ice melt and SLR. The mix- Milankovitch cycles ing of the freshwater with ocean water released co2 into the atmosphere and as the oceans warmed, they were less able to hold co2=more co2 in atmosphere. But human activity has recently been to blame. The orbit goes from circular to elliptical every 100,000 years, changing the dis- tance that the sun's short wave radiation eccentricity must travel to reach Earth. At present, eccentricity is not favourable to glacia- tion. The term describing the angle of tilt of the Earth's axis of rotation. Obliquity (tilt) - today it is about 23.5 degrees - oscillations of the tilt occur on a period 17 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas of 41,000 years from 22 to 24.5 degrees - with less tilt, the sun's solar radiation is more evenly distributed between winter and summer. The Earth's slow wobble as it spins on Precession (wobble) its axis. The cycle of precession spans about 25,000 years Temperature rises first which causes ice and snow melt. This freshwater mixes Does temperature or co2 rise first and into the sea, causing more co2 release why? and varieties in wind and Ocean patterns cause even more mixing. Warmer seas also absorb less co2. -humans are draining peatlands more of- ten to claim and use dry land e.g. Peat- lands in Exmoor - carbon sinks are being turned into car- bon sources -draining peat (which holds huge impact of drainage on carbon cycle amounts of carbon) releases carbon into the atmosphere -this carbon reacts with oxygen in the air to form co2 -this co2 enhances the greenhouse ef- fect=more global warming -pastoral farming releases methane (en- teric fermentation) and human demand for red meat enhances this - to power machinery, fossil fuels are burnt=co2 impact of farming on carbon cycle -fertiliser usage releases co2 and nitrous oxide -rice paddies releases methane -but farming can assist with sequestra- tion of carbon in soil 18 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas -removal of natural land and replacement with impermeable land prevents carbon cycling - building, transport and general industry all release large amounts of co2 impact of urbanisation on carbon cycle -natural processes like photosynthesis and sequestration can't occur=more co2 in atmosphere -globally, urban areas only occupy about 2% of land area but account for 97% of all anthropogenic carbon emissions -large scale clearance of trees for farm- ing, mining etc, turns major carbon sinks into carbon sources -this stops photosynthesis absorbing co2 from atmosphere Impact Deforestation on Carbon Cycle -this also reduces soil fertility and makes it difficult to grow new and diverse vege- tation e.g. particularly in the Amazon rainforest in South America - Cold water is able to dissolve more co2 than warm water= in winter/cold areas, chemical processes are more active - acidification in oceans and coral reefs impact of cold water on carbon cycle will bleach and die, affecting the food chain and biodiversity - As the Antarctic + Arctic are warming, they can hold less co2 - A warmer globe would see higher cov- erage of forests in high latitudes - this would mean higher respiration and photosynthesis=less co2 in atmosphere impact of high temperatures on carbon (negative feedback) cycle -more ice and snow will melt and runoff into oceans - runoff will contain sediment which will get deposited and compacted into deep 19 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas ocean sediments and fossil fuels -permafrost at risk of melting across Northern Russia=release of methane and co2 -decomposers would be less effective as they thrive on heat and moisture impact of colder temps on carbon cycle -reduced decomposition means less car- bon transfer taking place -these can burn for many months e.g. Australia 2019 -they release lots of co2 into the atmos- phere and can turn forests from carbon sinks to carbon sources impact of wildfires on carbon cycle -no trees= no photosynthesis + no respi- ration -but burning releases ash which can be nutritious and it also stimulates species to grow In all time, carbon levels have never been above 300ppm since now, so it is obvi- are the high levels of co2 human or nat- ous that the levels we see today of over ural caused? 400ppm are a result of human activity and not natural. Co2 was just 276ppm at the start of the Industrial Revolution. methane, water vapour, carbon dioxide, 5 greenhouse gases sulfur dioxide and nitrous dioxide. Water vapour is the most potent. 90% according to the IPCC. The remain- How much of anthropogenic carbon re- ing 10% comes from land use change, lease comes from the combustion of fos- land drainage, agricultural practice and sil fuels? urbanisation. 20 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas 1. Short wave solar radiation passes through the atmosphere 2. some of this radiation is absorbed by the atmosphere and Earth's surface and then re- emitted.(long wave) 3. It can also be reflected from pale sur- faces, such as ice sheets, deserts etc. ( this is short wave) 4. The remaining solar radiation is ab- sorbed by the earth's surface and warms the greenhouse effect it. 5. This is then converted to heat, causing the emissions of infrared longwave radi- ation back into the atmosphere 6. Some of this infrared radiation is ab- sorbed and re-emitted by the green- house gas molecules, causing warming of the Earth's surface and troposphere 7. Some of the infrared radiation passes through the atmosphere and is lost in space -Melting of terrestrial ice: higher temps have caused more ice to melt=less white surfaces to reflect heat=more heat is absorbed by the ocean=warmer Causes of SLR ocean=more ice melt=more SLR -Thermal expansion: when water heats up it expands and so there is a rise in sea level. Cement production contributes 8% of global carbon emissions. Overuse (cultivation, irrigation, grazing) on marginal land can lead to desertifi- How does desertification occur due to cation. This is happening more often be- farming? cause population increase results in in- creased demand. Wetlands cover 10% of land but store 35% of terrestrial carbon. Fossil Fuels (Hydrocarbons) 21 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas Formed from the burial and compaction of sediment. 1. land: carbon used for photosynthesis, creation of fossil fuels 2. Ocean: calcium carbonate helps cre- Global impacts of carbon cycle ate shells, carbon is food for phytoplank- ton 3. Atmosphere: co2 stabilises global temps through the greenhouse effect The amount of carbon stored or trans- carbon budget ferred in the carbon cycle. -soil : carbon in litter introduces important nutrients to the soil which are essential for plant growth and thus the production of food. Carbon in grass also provides Terrestrial impacts of carbon cycle (glob- fodder (food for livestock) al) -energy: carbon provides energy in fossil fuels -permafrost: rising temps threaten the melting of permafrost which holds a large amount of carbon -shells: carbon can be converted into cal- cium carbonate, which is used by some marine organisms to build shells -phytoplankton: this consumes co2 dur- ing photosynthesis, which is then passed marine impacts of carbon cycle (global) along the food chain. Warmer oceans could decrease the abundance of phyto- plankton (as they grow better in cool wa- ters) which could limit the ocean's ability to absorb co2 and lessen its effective- ness as a carbon sink -greenhouse effect: co2 helps to warm the earth through this effect and without atmospheric impacts of carbon cycle it there would be no life on earth. Also, (global) more co2=more plant growth -human activity: deforestation, combus- 22 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas tion of fossil fuels etc have led to the enhanced greenhouse effect because of high carbon emissions. - it's vitally important to the cc because of photosynthesis vegetation impacts of carbon cycle (re- -areas with dense vegetation= high lev- gional) els of photosynthesis and also evapo- transpiration which leads to high rainfall decreasing pH of ocean waters due to absorption of atmospheric CO2, which has had a negative impact on coral reefs. Coral reefs provide food for 500 million ocean acidification people worldwide and the acidification of oceans threatens the survival of coastal communities through reduced food AND reduced capacity of coastlines to buffer the impact of SLR -carbon can diffuse into/out of water -carbon gets absorbed into rainwater and makes it acidic water and carbon cycle links -chemical weathering leads to limestone and chalk dissolving through carbona- tion. This carbon is then carried into the sea and used for shell growth. 1. In recent years, the Arctic ice has been shrinking quickly because of rising temps 2. This means there is less reflection and more absorption of heat Water cycle positive feedback example 3. Therefore the water warms and caus- es further melting, reducing ice coverage effects: availability of freshwater, trading routes 1. As temps rise, evaporation increase 2. This means there is more water vapour Water cycle negative feedback example in the atmosphere so more clouds are formed 3. Therefore more solar radiation will be 23 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas reflected back out into space by these clouds and temps will fall 1. Higher temps have started to melt per- mafrost, particularly in Siberia 2. Organic matter trapped in the ground acts as an important carbon store (it's es- timated that there's more carbon stored in the permafrost than in the atmos- phere) 3. When the permafrost melts, the organ- Carbon cycle positive feedback example ic matter will start to decompose 4. This will release co2 into the atmos- phere, which enhances the greenhouse effect This may become a highly destructive positive feedback if the balance tips and the Arctic turns from a net carbon store to a net carbon source 1. Higher temperatures have increased the growing season for plants because of Carbon cycle negative feedback exam- more light energy ple 2. This means more photosynthesis is occurring and so there's more absorption of carbon from the atmosphere 1. Higher temps increase the abundance of phytoplankton (which release dimethyl sulphide) 2. This increases cloudiness which in- Water/Carbon cycle negative feedback creases global cooling loop 3. As clouds reduce the amount of solar radiation reaching the Earth's surface, this will actually lead to a reduction in the amount of phytoplankton, therefore reducing the cooling effect Extreme weather events ( severe Impacts of climate change droughts, flooding), decrease in agricul- tural productivity, SLR= flooding and ero- 24 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas sion, ecosystems damaged, decrease in plankton. methane is 21x more powerful than co2 The critical point in a system beyond tipping point which an unstoppable effect or change takes place global temps are expected to be 3-6C hotter by the end of the century An agreement to limit warming to 1.5C above pre-industrial levels, as well as halving carbon emissions by 2030 and Paris 2015 Climate Change Agreement having 0 emissions by 2050. As of Nov 2020, 194 states and the EU have signed the agreement. SLR projected to rise 80cm by the end of the century. In the last 100 years, there's been a 20cm SLR. Antarctica is losing 3x as much ice today SLR stats than 25 years ago, due to ice melting and thermal expansion. Over 600million people live in coastal ar- eas that are less than 10m above sea level. 1/3 of the world's coral reefs have died repeated heat stress due to The process of capturing waste CO2, transporting it to a storage site, and se- curely storing it where it will not enter the atmosphere, normally underground. carbon capture and storage (CCS) E.g. Boundary Dam in Canada that aims to capture 90% of its co2 output. This cost $800m to build and consumes 21% of the coal plant's power output -can reduce carbon emissions by almost CCS Advantages 1/5 -can reduce the cost of tackling the cli- 25 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas mate crisis by 70% -the building and maintenance of it will employ workers -very expensive -very energy intensive: consumes 25-40% more energy than renewable en- CCS disadvantages ergy -safety concerns: risk of the co2 leaking and contaminating groundwater which affects drinking water Where trees of similar age and type are deliberately planted together, to absorb co2. e.g. in 2015, Sri Lanka became the first Plantation forests nation to protect all of its remaining man- grove forests, after losing 76% of them in the 1900s. Their scheme will protect 21,000 acres and 9600 acres will be re- planted in 2013, the global aviation industry pro- duced 705 million tonnes of co2. Improving aviation practices There are ways in which this can be re- duced e.g. design and technology of the planes: increased use of biofuels for eg -reduced use of cars/more efficient cars Individual way to mitigate climate change -cavity wall insulation -improved public transport use Where one type of crop is replaced by another that can absorb more carbon dioxide from the atmosphere. This will aid the growth of plants while mitigating Carbon farming climate change. e.g. California recently pledged $7.5m towards its 'Healthy Soils' programs and now nearly 1/2 of Californian counties have carbon farms 26 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas a permit that allows a country or orga- nization to produce a certain amount of carbon emissions and that can be traded if the full allowance is not used. Carbon credits When a country buys the credits, it funds projects elsewhere to help mitigate cli- mate change BUT they don't force the buyer to change any of their operations and become more sustainable. all member states had fallen behind on EU officials announced in 2018 that reaching their targets. A sustainable approach to logging in which only selected trees are felled and Malaysia selective management system replacements are then planted after- wards. 2000mm avg annual rainfall 27C avg temp Rainforests stats 25% of world's carbon found there 2200g per msquared of carbon absorbed per year -deforestation: carbon sinks turned to carbon sources how humans affect the carbon cycle e.g. just under 1/2 of Indonesia's rain- forest remains as more than 1 million hectares is cleared every year -deforestation leads to soil erosion: soil will degrade and wash away so sur- face runoff increases and there is an in- creased risk of flooding How humans affect the water cycle -deforestation also means there is little interception and little root uptake so in- creased overland flow. Also, less evap- otranspiration=less water vapour in the air=risk of drought 27 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas -decomposition: this is rapid in tropical climates as it thrives in warm and wet conditions. It releases co2 back to the atmosphere -after combustion, rain can wash the re- How carbon cycle operates in rainforests maining ash into the ground so the soil can get more carboniferous which makes soil more fertile -vegetation: this is dense and productive in rainforests and absorbs huge quanti- ties of co2 -Drip tip leaves: these help trees shed water and the rest trickles down through stemflow How water cycle operates in rainforests - Lack of vegetation=less evapotranspi- ration so less humidity in the air -rainforest canopy: this intercepts 37.5% of rainfall Demand for palm oil, paper etc has led to widespread deforestation. Indonesia deforestation case study impacts: usual deforestation effects, en- dangering species, disrupting lives of in- digenous people and wildfires. Forest fires that began in 1997 and last- ed into 1998 spewed carbon smoke par- ticles, causing haze and air pollution. They burnt 8million hectares of land. 2015: over 10,000 fires rages across the Indonesian islands of Sumatra and Kali- Wildfires in Indonesia mantan, caused mostly by illegal slash and burn practices. A strong El nino event exacerbated the fire risk and the thick smoke affected the health of 1000s. Estimated that the fires pumped carbon equivalent to the UK's total annual emis- sions into the atmosphere. 28 / 29  AQA A Level geography water and carbon cycle Study online at https://quizlet.com/_g2mlas the amount of water held in the soil af- ter excess water has drained away and field capacity the rate of downward movement has de- creased How much of all water is fresh water? 3% Zone of ablation and zone of accumula- What are the 2 zones in a glacier and tion. The zone of ablation is growing as which one is growing? there is increased melting of glaciers due to global warming. In which 3 areas can water be stored for Oceans, groundwater and glaciers. the longest? A soil that prevents infiltration is clay/baked/frozen soil. Why might a soil water surplus never be -if there is very short periods of rainfall reached? -if the soil is very permeable the process in which a solid changes Sublimation directly into a gas e.g. solid ice becoming water vapour excess water in a river above the base storm flow flow is 29 / 29