earth’s life support systems

Question 1

what are the human uses of water?

Answer 1

domestic

industry

agriculture

leisure

energy

Question 2

what are the human uses of water?

Answer 2

domestic
industry
agriculture
leisure
energy

Question 3

what are the flora uses of water?

Answer 3

photosynthesis

habitat

maintain their rigidity

transport nutrients from soil

transpiration

Question 4

what are the fauna uses of water?

Answer 4

drinking

habitat

all chemical reactions in body including circulation of oxygen and nutrients

Question 5

how much of the earth’s surface do oceans occupy?

Answer 5

71%

Question 6

how much does water make up of all living organisms?

Answer 6

up to 65-95% of all living organisms

Question 7

what is meant by carbon-based life?

Answer 7

life as we know it is carbon-based: built on large molecules of carbon atoms such as proteins, carbohydrates and nucleic acids

Question 8

how is carbon significant as an economic resource?

Answer 8

fossil fuels such as coal, oil and natural gas power the global economy

oil is also used as a raw material in the manufacture of products ranging from plastics to paint and synthetic fabrics

agricultural crops and forest trees also store large amounts of carbon available for human use as food, timber, paper, textiles and many other products

Question 9

how do water and carbon flow at a global scale?

Answer 9

they flow in closed systems between the atmosphere, the oceans, land and the biosphere.

the cycling of individual water molecules and carbon atoms occurs on time scales varying from days to millions of years

Question 10

what does the global water cycle consist of at a macro scale?

Answer 10

three main stores: the atmosphere, oceans and land.

oceans are by far the biggest store and the atmosphere is the smallest

water moves between stores through the processes of precipitation, evapotranspiration, run off and groundwater flow

Question 11

what is the residence time of water in the atmosphere?

Answer 11

10 days

Question 12

what is the residence time of water in land?

Answer 12

highly variable

Question 13

residence time of water in oceans?

Answer 13

3000 years

Question 14

what is the global carbon cycle like?

Answer 14

long term storage in sedimentary rocks holds 99.9 per cent of all carbon on earth

most of the carbon in circulation moves rapidly between the atmosphere, the oceans, soil and the biosphere

the main flows include photosynthesis, respiration, oxidation and weathering

Question 15

what is a system?

Answer 15

groups of objects and the relationships that bind the object together

Question 16

what is a closed system?

Answer 16

where only energy cross the boundaries, not matter

like in the water and carbon cycles

Question 17

what is an open system?

Answer 17

materials as well as the Sun’s energy cross system boundaries

Question 18

what is the residence time of carbon in the atmosphere?

Answer 18

6 years

Question 19

what is the residence time of carbon in sedimentary rock?

Answer 19

150 million years

Question 20

what is the residence time of carbon in oceans?

Answer 20

surface 25 years
deep 1250 years

Question 21

what is the residence time of carbon in terrestrial biomass?

Answer 21

18 years

Question 22

what % of global water is in oceans?

Answer 22

97

Question 23

what % of global water is in polar ice and glaciers?

Answer 23

2

Question 24

what % of global water is in groundwater?

Answer 24

0.7

Question 25

what % of global water is in lakes?

Answer 25

0.01

Question 26

what % of global water is in soils?

Answer 26

0.005

Question 27

what % of global water is in atmosphere?

Answer 27

0.001

Question 28

what % of global water is in rivers?

Answer 28

0.0001

Question 29

what % of global water is in biosphere?

Answer 29

0.00004

Question 30

where can you find fresh water?

Answer 30

fresh water comprises only a tiny proportion of water in store and three quarters is frozen in the ice caps of Antarctica and Greenland

meanwhile, water stored below ground in permeable rocks amounts to just one fifth of all fresh water

Question 31

what are the inputs of water to the atmosphere?

Answer 31

water vapour evaporated from the oceans, soils, lakes and rivers

vapour transpired through leaves of plants

aka evapotranspiration

Question 32

how much carbon is in the atmosphere?

Answer 32

600 billion tonnes

Question 33

how much carbon is in the oceans?

Answer 33

38,700 billion tonnes

Question 34

how much carbon is in sedimentary rocks?

Answer 34

60,000-100,000,000 billion tonnes

Question 35

how much carbon is in sea floor sediments?

Answer 35

6000 billion tonnes

Question 36

how much carbon is in fossil fuels?

Answer 36

4130 billion tonnes

Question 37

how much carbon is in land plants?

Answer 37

560 billion tonnes

Question 38

how much carbon is in soils/peat?

Answer 38

2300 billion tonnes

Question 39

what is the slow carbon cycle?

Answer 39

carbon stored in rocks, sea floor sediments and fossil fuels is locked away for millions of years.

the total amount of carbon circulated by this slow cycle is between ten and 100 million tonnes a year

CO2 diffuses from the atmosphere into the oceans where marine organisms, such as clams and corals, make their shells and skeletons by forming CaCO3. When they die the remains of these organisms sink to the ocean floor. There they accumulate and over millions of years, heat and pressure convert them into carbon-rich sedimentary rocks

some carbon rich sedimentary rocks, subducted into the upper mantle at tectonic plate boundaries, are vented to the atmosphere in volcanic eruptions.

Others exposed at or near the surface by erosion and tectonic movements are attacked by chemical weathering. this releases CO2 to atmosphere and, when in dissolved form, to streams, rivers and oceans

on land, partly decomposed organic material may be buried beneath younger sediments to form carbonaceous rocks such as coal, lignite, oil and natural gas. These act as carbon sinks that endure for millions of years

Question 40

what is the fast carbon cycle?

Answer 40

carbon circulates most rapidly between the atmosphere, the oceans, living organisms and soils. these transfers are between ten and 1000 times faster than those in the slow carbon cycle

land plants and phytoplankton in the oceans are the key components. they absorb CO2 from atmosphere via photosynthesis, and release it via respiration

atmospheric CO2 dissolves in ocean surface waters while the oceans ventilate CO2 back to the atmosphere. Through this exchange individual carbon atoms are stored in the oceans for on average around 350 years

Question 41

what is the water balance equation?

Answer 41

summarises the flows of water in a drainage basin over time

it states that precipitation = evaporation + streamflow, plus or minus water entering or leaving storage

Question 42

what is precipitation?

Answer 42

water and ice that falls from clouds towards the ground

forms when vapour in the atmosphere cools to its dew point and condenses into tiny water droplets or ice particles to form clouds. Eventually these droplets or ice particles aggregate, reach a critical size and leave the cloud as precipitation

Question 43

how does precipitation vary?

Answer 43

most rain on reaching the ground flows quickly into streams and rivers, But in high latitudes and mountainous catchments, precipitation often falls as snow and may remain on the ground for several months. Thus there may be a considerable time lag between snowfall and runoff

high intensity precipitation moves rapidly overland into streams and rivers, because it is falling at a rate that exceeds the infiltration capacity of the soil

prolonged events, linked to depressions and frontal systems, may deposit exceptional amounts of precipitation and cause saturation of the soil which leads to overland flow, and possibly river flooding

in some parts of the world eg East Africa and Mediterranean, precipitation is concentrated in a rainy season so river discharge is high and flooding is common, and in the dry season rivers may cease to flow altogether

Question 44

what is transpiration?

Answer 44

the diffusion of water vapour to the atmosphere from the stomata plants.

responsible for around 10% of moisture in the atmosphere.

influenced by temperature and wind speed and water availability to plants

Question 45

why do deciduous trees shed their leaves in climates with either dry or cold seasons?

Answer 45

to reduce moisture loss through transpiration

Question 46

how do cumuliform clouds form?

Answer 46

cumuliform clouds, with flat bases and considerable vertical development, most often from when air is heated locally through contact with the Earth’s surface

this causes heated air parcels to rise freely through the atmosphere (convection), expand and cool. As cooling reaches the dew point, condensation begins and clouds form

Question 47

how do stratiform clouds develop?

Answer 47

stratiform or layer clouds develop when an air mass moves horizontally across a cooler surface (often the ocean).

this process, together with some mixing and turbulence, is known as advection

Question 48

what are cirrus clouds?

Answer 48

wispy cirrus clouds, which form at high altitude, consist of tiny ice crystals.

unlike cumuliform and stratiform clouds they do not produce precipitation and therefore have little influence on the water cycle

Question 49

what are clouds?

Answer 49

they are visible aggregates of water or ice (or both) that float in the free air

Question 50

when does the cooling of water vapour occur? (4 points)

Answer 50

• when air, warmed by contact with the ground or sea surface, rises freely through the atmosphere. As the air rises and pressure falls it cools by expansion (adiabatic expansion). This vertical movement of air is known as convection
• when air moves horizontally across a relatively cooler surface– a process known as advection
• when air masses rise as they cross a mountain barrier or as turbulence forces their ascent
• when a relatively warm air mass mixes with a cooler one

Question 51

what are lapse rates?

Answer 51

they describe the vertical distribution of temperature in the lower atmosphere, and the temp changes that occur within an air parcel as it rises vertically away from the ground

Question 52

what are the three types of lapse rate?

Answer 52

environmental lapse rate (ELR)

dry adiabatic lapse rate (DALR)

saturated adiabatic lapse rate (SALR)

Question 53

what is environmental lapse rate?

Answer 53

the ELR is the vertical temperature profile of the lower atmosphere at any given time

on average the temperature falls by 6.5 degrees celcius for every km of height gained

Question 54

what is dry adiabatic lapse rate?

Answer 54

the DALR is the rate at which a parcel of dry air (ie less than 100 per cent humidity so that condensation is not taking place) cools. Cooling, caused by adiabatic expansion, is approximately 10 degrees celcius per km

Question 55

what is saturated adiabatic lapse rate (SALR)?

Answer 55

the SALR is the rate at which a saturated parcel of air (ie one in which condensation is occuring) cools as it rises through the atmosphere. Because condensation releases latent heat, the SALR, at around 7 degreesC/km is lower than the DALR

Question 56

what are the causes of precipitation?

Answer 56

precipitation develops when the tiny water droplets formed by condensation in saturated air grow until they are heavy enough to fall to the ground through any rising air currents beneath

this happens either through a complex process of droplets coalescing as they collide with each other in turbulent air or by ice crystals growing within clouds as they rise and fall

Question 57

what are the factors affecting interception loss? (meaning the moisture that evaporates from where it was intercepted by vegetation)?

Answer 57

• interception storage capacity. as vegetation becomes saturated, output of water through stemflow and throughfall increases. Interception therefore depends on the duration and intensity of a rainfall event
• wind speed. evaporation increases with wind speed. turbulence also increases with wind speed causing additional through fall
• vegetation type. interception losses are greater from grasses than from agricultural crops. Trees, which have a large surface area and aerodynamic roughness, have higher interception losses than grasses
• tree species. interception losses are far greater from evergreen conifers than from broad leaved deciduous trees, bc most conifers have leaves all year round and water adheres to spaces between conifer needles, increasing evaporation

Question 58

what is throughfall?

Answer 58

rainwater that is briefly intercepted before dripping to the ground is known as throughfall

Question 59

what is stem flow?

Answer 59

during periods of prolonged or intense rainfall, intercepted rainwater may flow to the ground along branches and stems as stemflow

Question 60

what is saturated overland flow?

Answer 60

the idea that overland flow only occurs when soil becomes saturated and the water table rises to the surface

Question 61

what is groundwater flow?

Answer 61

when soils are underlain by permeable rocks, water seeps or percolates deep underground. This water then migrates slowly through the rock pores and joints as groundwater flow, eventually emerging at the surface as springs or seepages

Question 62

what are the main fluxes of the carbon cycle?

Answer 62

precipitation
photosynthesis
weathering
respiration
decomposition
combustion

Question 63

what role does precipitation have in the carbon cycle?

Answer 63

atmospheric CO2 dissolves in rainwater to form weak carbonic acid

rising concentrations of CO2 in the atmosphere, due to anthropogenic emissions, have increased the acidity of rainfall. This has contributed to increased acidity of ocean surface waters with potentially harmful effects on marine life

Question 64

how big is the flux from the atmosphere to land plants and phytoplankton via photosynthesis?

Answer 64

120GT a year

Question 65

what is carbonation?

Answer 65

rainwater is a weak carbonic acid, which slowly dissolves limestone and chalk in a process known as carbonation

carbonation releases carbon from limestones to streams, rivers, oceans and the atmosphere. The process is most effective beneath a soil cover because the higher concentration of CO2 in the soil makes rainwater highly acidic

Question 66

how is combustion significant to the carbon cycle?

Answer 66

combustion is a natural fuel used in many ecosystems.

wildfires caused by lightning strikes are essential to the health of some ecosystems such as the coniferous forests of the Rocky Mountains. Long, cold winters slow the decomposition of forest litter which builds up on the forest floor. Fire shifts this log jam, freeing carbon and nutrients previously inaccessible to forest trees

currently the burning of fossil fuels transfers nearly 10GT of CO2 a year from geological store to the atmosphere, oceans and biosphere

Question 67

what is the physical (inorganic) pump?

Answer 67

involves the mixing of surface and deep ocean waters by vertical currents, creating a more even distribution of carbon in the oceans

initially, CO2 enters the oceans from the atmosphere by diffusion. Surface ocean currents then transport the water and its dissolved CO2 polewards where it cools, becomes more dense and sinks. this downwelling occurs in only a handful of places in the oceans eg the north atlantic between greenland and iceland

downwelling carries dissolved carbon to the ocean depths where individual carbon molecules may remain for centuries

eventually, deep ocean currents transport the carbon to areas of upwelling. There cold, carbon rich water rises to the surface and CO2 diffuses back into the atmosphere

Question 68

what is the biological (organic) pump?

Answer 68

around 50 GT of carbon is drawn from the atmosphere by the biological pump every year

marine organisms drive the biological pump. phytoplankton floating near the ocean surface produce organic material. Whether consumed by animals or through natural death, carbon locked in the phytoplankton either accumulates in sediments on the ocean floor or is decomposed and released into the ocean as CO2

other marine organisms such as molluscs extract carbonate and calcium ions from sea water to manufacture plates, shells and skeletons of calcium carbonate. most of this carbon rich material eventually ends up in the ocean sediments and is ultimately lithified to form chalk and limestone

Question 69

where is the amazon rainforest?

Answer 69

occupies more than 6 million km2 of land.

70 percent is in Brazil, but parts also extend into Peru, Ecuador, Venezuela, Colombia, Bolivia and Guyana

Question 70

climactic features of the amazon rainforest?

Answer 70

high average annual temperatures between 25 degreesC and 30 degreesC

small seasonal variation in temperature

high average annual rainfall (>2000mm) with no dry season

Question 71

precipitation characteristics of the amazon rainforest?

Answer 71

high average rainfall

rainfall fairly evenly distributed throughout the year though short drier season occurs in some places

high intensity convectional rainfall

interception by forest trees is high (around 10 per cent of precipitation). Intercepted rainfall accounts for 20-25 per cent of all evaporation

Question 72

evapotranspiration characteristics in the amazon rainforest?

Answer 72

high rates due to high temps, abundant moisture and dense vegetation

strong evapotranspiration-precipitation feedback loops sustain high rainfall totals

around a half of incoming rainfall is returned to the atmosphere by evapotranspiration

most evaporation is from intercepted moisture from leaf surface.

moisture lost in transpiration is derived from the soil via tree roots

Question 73

run off characteristics in the amazon rainforerst?

Answer 73

rapid run off related to high rainfall events and well-drained soils

depending on seasonal distribution of rainfall, river discharge may peak in one or two months of the year

Question 74

atmosphere characteristics of the amazon rainforest?

Answer 74

high temperatures allow the atmosphere to store large amounts of moisture, ie absolute humidity is high

relative humidity is also high

Question 75

soil/groundwater characteristics of the amazon rainforest?

Answer 75

abundant rainfall and deep tropical soils lead to significant water storage in soils and aquifers

Question 76

vegetation characteristics of the amazon rainforest?

Answer 76

rainforest trees play a crucial role in the water cycle, absorbing and storing water from the soil and releasing it through transpiration

Question 77

what is the NPP of the amazon rainforest?

Answer 77

is high

averaging 2500 grams/m2/year

the biomass is between 400 and 700 tonnes/ha

Question 78

how much carbon does the amazon rainforest absorb per year?

Answer 78

2.4 billion tonnes a year

Question 79

what are exchanges of carbon between the atmosphere, biosphere and soils like in the amazon?

Answer 79

rapid compared to other forest ecosystems

warm, humid conditions ensure speedy decomposition of dead organic matter and the quick release of CO2

meanwhile rates of carbon fixation through photosynthesis are high

Question 80

how does geology affect the water cycle in amazonia?

Answer 80

impermeable catchments (eg large of the Amazon Basin are an ancient shield area comprising impermeable, crystalline rocks) have minimal water storage capacity, resulting in rapid run off

permeable and porous rocks such as limestone and sandstone store rainwater and slow run off

Question 81

how does relief affect the water cycle in amazonia?

Answer 81

most of the amazon basin comprises extensive lowlands

in areas of gentle relief, water moves across the surface or horizontally though the soil to streams and rivers

in the west the Andes create steep catchments with rapid run off.

widespread inundation across extensive floodplains (eg the Pantanal) occurs annually, storing water for several months and slowing its movement into rivers

Question 82

how does temp influence water cycle of amazonia?

Answer 82

high temps throughout the year generate high rates of evapotranspiration

convection is strong, leading to high atmospheric humidity, the development of thunderstorm clouds and intense precipitation

water is cycled continually between the land surface, forest trees and the atmosphere by evaporation, transpiration and precipitation

Question 83

how much of rainforest carbon is stored above ground?

Answer 83

60% of rainforest carbon is stored in the above ground biomass of tree stems, branches and leaves

the remainder is below ground, mainly as roots and soil organic matter

Question 84

what are the physical factors influencing the carbon cycle in amazonia?

Answer 84

leaf litter and other dead organic matter accumulates temporarily at the soil surface and within rainforest soils

high temps and humid conditions promote rapid decomposition of organic litter by bacteria, fungi and other soil organisms. decomposition releases nutrients to the soil for immediate take up by tree root systems and emits CO2 which is returned to the atmosphere

carbonates are largely absent from the mineral composition of rocks in the Amazon Basin, but in the western parts, outcrops of limestone do occur, which are significant regional carbon stores in the context of the slow carbon cycle

Question 85

what are the rates of deforestation in amazonia?

Answer 85

deforestation in Amazonia averaged around 17,500km2/year between 1970 and 2013

since 1970, almost one fifth of the primary forest has been destroyed or degraded

since 2009, annual rates have been lower than the average but have started to rise again in recent years

Question 86

what happened in april 2014 on the Madeira River?

Answer 86

devastating floods occurred on the Madeira River, the largest tributary of the Amazon River

At Port Velho the river reached record levels of 19.68m above normal

vast expanses of floodplain were inundated; 60 people died; 68,000 families were evacuated; and there were outbreaks of cholera and leptospirosis

Question 87

how has human activity modified the Upper Madeira drainage basin?

Answer 87

has modified stores and flows in the water cycle

deforestation has reduced water storage in forest trees, soils (which have been eroded), permeable rocks (due to more rapid run off) and in the atmosphere

fewer trees means less evapot and therefore less precip

total run off and run off speeds have increased, raising flood risks throughout the basin

Question 88

what are the impacts of deforestation on the water cycle ?

Answer 88

converting rainforest to grassland increases run off by a factor of 27, and half of all rain falling on grassland goes directly into rivers

deforestation breaks the normal cycle and can lead to permanent climate change

projections of future deforestation in Amazonia predict a 20 per cent decline in regional rainfall as the rainforest dries out and forest trees are gradually replaced by grassland

Question 89

what are the impacts of deforestation on the carbon cycle?

Answer 89

deforestation exhausts the carbon biomass store

croplands and pasture contain only a small amount of carbon compared to forest trees

drastically reduces inputs of organic material to the soil. this means the soil supports fewer decomposer organisms, thus reducing the flow of carbon from the soil to the atmosphere

deforestation destroys the main nutrient store (the forest trees) and removes most nutrients from the ecosystem. Nutrients no longer taken up by the root systems of trees are washed out of soils by rainwater; and soils, without the protective cover of trees, are quickly eroded by run off

Question 90

how do indigenous people help maintain the rainforest?

Answer 90

indigenous people have lived sustainably in the rainforest for thousands of years, maintaining the water balance, carbon cycle and the forest’s biodiversity

these people survived as hunter-gatherers and shifting cultivators

indigenous people pursued a way of life perfectly adapted to the limited resources and fragility of the rainforest

Question 91

what is shifting cultivation?

Answer 91

a traditional method of cultivation in tropical rainforests, which involves rotation of land rather than rotation of crops

Question 92

what three categories do modern strategies to manage the Amazon rainforest sustainably fall into?

Answer 92

• protection through legalisation of large expanses of primary forest so far unaffected by commercial developments
• projects to reforest areas degraded or destroyed by subsistence farming, cattle ranching, logging and mining
• improving agricultural techniques to make permanent cultivation possible

Question 93

what has the brazilian government done to help manage the rainforest?

Answer 93

since 1998, the Brazilian government has established many forest conservation areas

these Amazon Regional Protected Areas now cover an area 20 times the size of Belgium. By 2015, 44% of the Brazilian Amazon comprised national parks, wildlife reserves and indigenous reserves where farming is bad

Question 94

name of project? plan? strengths + weaknesses?

what have NGOs done to help manage the rainforest?

Answer 94

several reforestation projects sponsored by local authorities, NGOs and businesses underway

eg the Parica project in Rondônia in the western Amazon

this sustainable forestry scheme aims to develop a 1000km2 commercial timber plantation on government-owned deforested land. Plan is for 20 million fast-growing tropical hardwood seedlings, planted on 4000 smallholdings, to mature over a period of 25 years

financial assistance given to the smallholders for land preparation, planting and the maintenance of plots. Tree nurseries provide them with seedlings. Timber will be exported along the Amazon and its tributaries through Manaus or Port Velho

STRENGTHS: sustainable, sequesters carbon into trees and soil, reduces CO2 emissions, re-establishes cycles and reduces run off

WEAKNESSES: cannot replicate the biodiversity of the primary rainforest

Question 95

where? what do they do? + how has the UN’s REDD tied in to this?

what have the Surui people done to help manage the rainforest?

Answer 95

in Rondônia, they participate in a scheme that aims to protect primary rainforest on tribal lands from further illegal logging, and reforest areas degraded by deforestation in the past 40 years

they plant seedlings bred in local nurseries in deforested areas around their villages. The native species planted are chosen to provide them with timber for construction, food crops and a sustainable source of income through logging

2009- were the first indigenous group in Amazonia to join UN’s Reducing Emissions from Deforestation and Degradation (REDD) scheme. This scheme provides payment to the tribe for protecting the rainforest and abandoning logging

Question 96

where is the Arctic Tundra?

Answer 96

occupies some 8 million km2 in northern Canada, Alaska and Siberia

extends from the northern edge of the boreal coniferous forest to the Arctic Ocean and its southern limit approximates the 10degreesC July isotherm

Question 97

what are the climatic conditions like in the Alaskan tundra?

Answer 97

mean temps below -15degreesC

for 8 or 9 months a year the tundra has a negative heat balance with avrg monthly temps below freezing

the ground is permanently frozen with only the top metre or so thawing during the Arctic summer

in winter, when for several weeks the sun remains below the horizon, temps can plunge below -40C

mean annual precipitation is low

Question 98

what is vegetation like in the tundra?(+how it varies spatially)

Answer 98

biodiversity low

apart from a few dwarf species, the ecosystem is treeless

in the southern areas – the Low Arctic – conditions are less severe, and vegetation provides a continuous ground cover. Further north in the High Arctic, plant cover is discontinuous with extensive areas of bare ground

Question 99

what are the main features of the water cycle in the Alaskan tundra?

Answer 99

low annual precipitation (less than 100mm in most places) with most precipitation falling snow

small stores of moisture in the atmosphere owing to low temps which reduce absolute humidity

limited transpiration because of the sparseness of the vegetation cover and the short growing season of 3 months

low rates of evaporation. much of the sun’s energy in summer is expended melting snow so that ground temps remain low and inhibit convection. Also, surface and soil water are frozen for most of the year

limited groundwater and soil moisture stores. permafrost is a barrier to infiltration, percolation, recharge and groundwater flow

accumulation of snow and river/lake ice during winter months. melting causes sharp increase in river flow, eg Yukon River min discharge of 340 cumecs in winter and a max of 24,600 cumecs in summer

extensive wetlands, ponds and lakes on the tundra during summer bc permafrost impedes drainage, eg in Yukon River, Alaska

Question 100

how much carbon does the permafrost store globally?

Answer 100

1600 GT

Question 101

what is the carbon cycle like in the summer in the tundra?

Answer 101

the flux of carbon is concentrated in the summer months when the active layer thaws.

Plants such as sedges, crowberry and moss grow rapidly. Long hours of daylight allow them to flower and fruit within a few weeks. Nonetheless, NPP is less than 200 grams/m2/year

during the growing season tundra plants input carbon-rich litter to the soil. increased activity of microorgamisms + respiration

Question 102

what is the carbon cycle like in the winter in the tundra?

Answer 102

pockets of unfrozen soil and water in the permafrost act as sources of CO2 and CH4

snow cover may insulate microbial organisms and allow some decomposition despite the low temps

Question 103

what are physical factors affecting stores and slows of water in the alaskan tundra?

Answer 103

avrg temps well below freezing for most of the year = permafrost = poor drainage

in winter, subzero temps preventn evapot. in summer, some evapot occurs from standing water, saturated soils and vegetation. humidity is low all year round and precipitation is sparse

permeability is low owing to the permafrost and the Precambrian igneous and metamorphic rocks which dominate the geology of the tundra in Alaska

The ancient rock surface which underlies the tundra has been reduced to a gently undulating plain by hundreds of millions of years of erosion and weathering. minimal relief and chaotic glacial deposits impede drainage and contribute to waterlogging during the summer months

Question 104

what are the physical factors affecting the carbon cycle in the tundra?

Answer 104

carbon is mainly stored as partly decomposed plant remains frozen in the permafrost. Most of this carbon has been locked away for at least the past 500,000 years

low temps, the unavailability of liquid water for most of the year and parent rocks containing few nutrients all limit plant growth. Thus the total carbon store of the biomass is relatively small. Averaged over the year, photosynthesis and NPP are low with the growing season lasting barely 3 months. However there is some compensation for the short growing season in the long hours of daylight in the summer

low temps and waterlogging slow decomposition and respiration and the flow of CO2 to the atmosphere

owing to the impermeability of the permafrost, rock permeability, porosity and the mineral composition of rocks exert little influence on the water and carbon cycle

Question 105

what were the challenges faced by the development of the oil and gas industries on the North Slope of Alaska?

Answer 105

a harsh climate with extreme cold and long periods of darkness in winter

permafrost and the melting of the active layer in summer

remoteness and poor accessibility

fragile wilderness of great ecological validity

Question 106

what is the melting of the permafrost associated with?

Answer 106

construction and operation of oil and gas installations, settlements and infrastructure diffusing heat directly to the environment

dust deposition along roadsides creating darkened snow surfaces, thus increasing absorption of sunlight

removal of the vegetation cover which insulates the permafrost

Question 107

what are the estimated CO2 losses from the permafrost on the North Slope?

Answer 107

vary from 7 to 40 million/tonnes/year

while CH4 losses range from 24,000 to 114,000 tonnes/year

Question 108

what are other changes to the local carbon cycle (aside from permafrost) on the North Slope?

Answer 108

they are linked to industrial development

the destruction and degrading of tundra vegetation reduces photosynthesis and the uptake of CO2 from the atmosphere

the thawing of soil increases microbial activity, decomposition and emissions of CO2

the slow growing nature of tundra vegetation means that regeneration and recovery from damage takes decades

Question 109

how has oil and gas production impacted the water cycle in Alaska?

Answer 109

melting of the permafrost and snow cover increases run off and river discharge, making flooding more likely

strip mining of aggregates for construction creates artificial lakes which disrupt drainage and also exposes the permafrost to further melting

artificial lakes at Goldstream, near Fairbanks, have experienced 15m permafrost thaw in the last 60 years

drainage networks are disrupted by road construction and seismic explosions used to prospect for oil and gas

water abstracted from creeks and rivers for industrial use and for the building of ice roads in winter, such as the one between Fairbanks and Prudhoe Bay, reduce localised run-off. BP extracts most of the water it need from the Kuparuk River and Big Lake

Question 110

how do insulated ice and gravel pads reduce the impact on water and carbon cycles? (give example)

Answer 110

roads and other infrastructural features can be constructed on insulating ice or gravel pads, thus protecting the permafrost from melting. The Spine Road and Prudhoe Bay lies on a 2m deep pad

Question 111

how does elevating buildings and pipelines on piles reduce the impact on water and carbon cycles?

Answer 111

constructing buildings, oil/gas pipelines and other infrastructure on piles allows cold air to circulate beneath these structures. This provides insulation against heat-generating buildings, pipework etc, which would otherwise melt the permafrost

Question 112

how does drilling laterally beyond drilling platforms reduce the impact on water and carbon cycles?

Answer 112

new drilling techniques allow oil and gas to be accessed several km from the drilling site

Shell has developed the ‘snake drill’ which allows directional drilling across a wide area from a single drilling site. With a fewer sites needed for drilling rigs, the impact on vegetation and the permafrost due to construction (access roads, pipelines, production facilities etc) is greatly reduced

Question 113

how do more powerful computers that can detect oil and gas bearing geological structures remotely help to reduce the impact on water and carbon cycles?

Answer 113

fewer exploration wells are needed thus reducing the impact on the environment

about 10% of all supercomputers have been delivered to the oil industry. Its two big computational tasks are seismic data processing (to deduce underground geological structures), and reservoir modelling (to stimulate the flows within a producing field, in order to optimise the amount of oil that can be recovered

Question 114

how do refrigerated supports help reduce the impact on water and carbon cycles?

Answer 114

refrigerated supports are used on the Trans-Alaskan Pipeline to stabilise the temp of the permafrost

similar supports are widely used to conserve the permafrost beneath buildings and other infrastructure

Question 115

what is dynamic equilibrium?

Answer 115

a system, displaying unrepeated average states through time

Question 116

what is a negative feedback loop

Answer 116

negative feedback loops within stores restore balance

Question 117

example of a negative feedback loop in the water cycle?

Answer 117

in a drainage basin, unusually heavy rainfall will increase the amount of water stored in aquifers

this in turn will raise the water table, increasing flow from springs until the water table reverts to normal levels

Question 118

example of a negative feedback loop in the carbon cycle?

Answer 118

burning fossil fuels increases atmospheric CO2 but at the same time stimulates photosynthesis. This negative feedback response should remove excess CO2 from the atmosphere and restore equilibrium

Question 119

how does urbanisation affect the flows of the water cycle?

Answer 119

artificial surfaces are largely impermeable so they allow little to no infiltration and provide minimal water storage capacity to buffer run off

drainage systems = high proportion of water from precipitation flows quickly into streams and rivers, leading to a rapid rise in water level

Question 120

how does urbanisation affect the stores of the water cycle?

Answer 120

development on floodplains reduces water storage capacity in drainage basins, increasing river flow and flood risk

drainage systems = rapid rise in water level of streams

Question 121

how does urbanisation affect the carbon cycle?

Answer 121

the removal of vegetation and its replacement with urban surfaces results in reduced amounts of organic carbon

the development of factories and homes, along with increased vehicle usage, results in the release of carbon dioxide into the atmosphere from the burning of fossil fuels

Question 122

how does farming modify the natural water cycle?

Answer 122

crop irrigation diverts surface water from rivers and groundwater to cultivated land. Some of this water is extracted by crops from soil storage and released by transpiration, but most is lost to evap and in soil drainage

interception of rainfall by annual crops is less than in the forest and grassland ecosystems, as well as evapot from leaf surfaces

ploughing increases evap and soil moisture loss, and furrows ploughed downslope act as drainage channels, accelerating run off and soil erosion

infiltration due to ploughing is usually greater in farming systems, while artificial underdrainage increases the rate of water transfer to streams and rivers. Surface run off increases where heavy machinery compacts soils, thus peak flows on streams draining farmland are generally higher than in natural ecosystems

Question 123

how does farming impact the carbon cycle?

Answer 123

the clearance of forest for farming reduces carbon storage in both the above and below ground biomass

soil carbon storage reduced by ploughing and the exposure of soil organic matter to oxidation. further losses occur through the harvesting of crops, with only small amounts of organic matter returned to soils.

changes to the carbon cycle are less apparent on pasture land or when farming replaces natural grasslands. Eg in NA, the NPP of annual crops ie wheat on the Great PLains exceeds that of the original Prairie grasslands. However, carbon exchanges through photosynthesis are generally lower than in natural ecosystems, partly bc of a lack of biodiversity in farmed systems, and the growth cycle of crops is often compressed into just four or five months

Question 124

how does forestry impact interception?

Answer 124

higher rates of rainfall interception in plantations in natural forests. In eastern England, interception rates for Sitka spuce are as high as 60%. In upland Britain, where temps and evap are lower, interception is about this figure. In the UK, preferred plantation species are conifers. The needle-like structure of conifer leaves, their evergreen habit and high density of planting all contribute to high rates of interception

Question 125

how does forestry affect evap?

Answer 125

increased evap

a large proportion of intercepted rainfall is stored on leaf surfaces and is evaporated directly into the atmosphere

Question 126

how does forestry affect run-off and stream discharge?

Answer 126

reduced run off and stream discharge

with high interception and evap rates, and the absorption of water by tree roots, drainage basin hydrology is altered. Streams draining plantations typically have relatively long lag times, low peak flows and low total discharge. The effect of conifer plantations in upland catchments is often to reduce water yield for public supply

Question 127

how does forestry affect transpiration?

Answer 127

compared to farmland and moorland, transpiration rates are increased. Typical transpiration rates for Sitka spruce in the Pennines are around 350mm/year of rainfall equivalent

Question 128

what impact does clear felling to harvest timber have on the water cycle?

Answer 128

clear feeling to harvest timber creates sudden but temporary changes to the local water cycle, increasing run off, reducing evapot, and increasing stream discharge

Question 129

‘after 100 years of……..’ + ‘typical plantation in the UK’

how does forestry impact the carbon cycle?

Answer 129

after 100 years after planting, the amount of carbon captured levels off and is balanced by inputs of litter to the soil, the release of CO2 in respiration and by activities of soil decomposers, therefore forestry plantations cycle 80-100 years to remain a carbon sink

forestry increases plant stores, as trees extract CO2 from the atmosphere and sequester it for hundreds of years

in a typical plantation in the UK, mature forest trees contain an average of 170-200 tonnes C/ha, which is 10x higher than grassland

Question 130

what is the River Kennet?

Answer 130

the River Kennet in southern England drains an area of around 1200km2 in Wiltshire and Berkshire.

the upper catchment mainly comprises chalk which is mainly permeable. Thus groundwater contributes most of the Kennet’s flow

As a chalk stream, the river supports a diverse range of habitats and wildlife. Its water. filtered through chalk, has exceptional clarity, high oxygen levels and is fast moving. Among the native fauna are Atlantic salmon, brown trout, water voles, otters and white clawed crayfish

Question 131

who relies on water from the Kennet basin?

Answer 131

within and close to the catchment, several urban areas rely on water from the Kennet basin to meet public supply

Swindon, the largest, has a population of over 220,000.

The Kennet also supplies water for local industries, agriculture and public use.

Thames Water abstracts groundwater from the upper catchment from boreholes. None of this water is returned to the river as waste water

Question 132

what impact does water extraction from the Kennet have on the regional water cycle?

Answer 132

rates of groundwater extraction have exceeded rates of recharge, and the falling water table has reduced flows in the River Kennet by 10-14%

during the 2003 drought, flows fell by 20%, and in the dry conditions of the early 1990s by up to 40%

lower flows have reduced flooding and temporary areas of standing water and wetlands on the Kennet’s floodplain between Marlborough and Hungerford

Lower groundwater levels have caused springs and seepages to dry up and reduced the incidence of saturated overland flow on the chalk hills of the Marlborough Downs

Question 133

what are aquifers?

Answer 133

permeable or porous water-bearing rocks such as chalk and New Red Sandstone

groundwater is abstracted for public supply from aquifers by wells and boreholes

emerging in springs and seepages, groundwater feeds rivers and makes a major contribution to their base flow

within an aquifer the upper surface of saturation is known as the water table. Its heigh fluctuates seasonally and is also affected by periods of exceptional rainfall, drought and abstraction.

In normal years in southern England, the water table falls between March and Sept, as rising temps increase evapot losses. Recharge resumes in late autumn

Question 134

what is an artesian basin?

Answer 134

when sedimentary rocks form a syncline or basin like structure, an aquifer confined between impermeable rock layers may contain groundwater which is under artesian pressure

if groundwater is tapped by a well or borehole, water will flow to the surface under its own pressure. this is known as an artesian aquifer

the level to which the water will rise - the potentiometric surface - is determined by the height of the water table in areas of recharge on the edges of the basin

Question 135

what is the artesian basin of London like?

Answer 135

London is located at the centre of a synclinal structure which forms an artesian basin

groundwater in the chalk aquifer is trapped between impermeable London clay and Gault clay. Rainwater enters the chalk aquifer where it outcrops on the edge of the basin in the North Downs and Chilterns

Groundwater then flows by gravity through the chalk towards the centre of the basin. This under natural conditions the wells and boreholes in the London area are under artesian pressure

Question 136

what are the impacts of groundwater exploitation in London?

Answer 136

groundwater from the chalk is an important source of water for the capital. However, over exploitation in the 19th century and first half of 20th century caused a drastic fall in the water table. In central London it fell by nearly 90m

In the past 50 years declining demand for water by industry in London and reduced rates of abstraction have allowed the water table to recover. By the early 1990s it was rising at a rate of 3m/year and began to threaten buildings and underground tunnels

since 1992 Thames Water has been granted abstraction licences to slow the rise of the water table which is now stable

Question 137

how much CO2 does fossil fuel consumption release into the atmosphere?

Answer 137

releases 10 billion tonnes of CO2 to the atmosphere annually, increasing atmospheric CO2 concentration by over 1ppm.

Question 138

what is carbon capture and storage?

Answer 138

it involves three stages:

first the CO2 is separated from power station emissions. the CO2 is then compressed and transported by pipeline to storage areas. And finally it is injected into porous rocks deep underground where it is stored permanently

Question 139

what is the Drax Project?

Answer 139

the Drax project in North Yorkshire, designed to capture 2 million tonnes of CO2 per year, commenced operation in 2019.

The plan is for the carbon to be transported by pipeline to the North Sea and stored in depleted gas reservoirs

CO2 gas can also be pumped into ‘mature’ oilfields to extract oil that would otherwise be uneconomic to recover

Question 140

how is the effectiveness of CCS limited by economic and geological factors?

Answer 140

it involves big capital costs - the Drax and Peterhead projects will cost at least £1 billion

it uses large amounts of energy - typically 20 per cent of a power plant’s output is needed to separate the CO2 and compress it

requires storage reservoirs with specific geological conditions, ie porous rocks overlain by impermeable strata

Question 141

what is positive feedback?

Answer 141

occurs when an initial change causes further change

Question 142

how do rising temperatures affect the water cycle at a global scale? (positive/negative feedback loops)

Answer 142

in a warmer world, evap increases and the atmosphere holds more vapour, resulting in greater cloud cover and more precipitation. These changes create a positive feedback effect. More vapour in the atmosphere increases absorption of long wave radiation from earth, causing further rises in temperatures

alternatively, more atmospheric vapour can induce negative feedback. More vapour creates greater cloud cover which reflects more solar radiation back into space. And as smaller amounts of solar radiation are absorbed by the atmosphere, oceans and land, average global temps fall

Question 143

example of negative feedback in an individual tree?

Answer 143

in most years precipitation is sufficient to satisfy an individual tree’s demand for water

however, in drought years, shallow rooted trees like silver birch become stressed: water lost in transpiration is not replaced by a similar uptake of water from the soil. The tree responds, reducing transpiration losses by shedding some or all of its leaves. This negative feedback loop restores the water balance and ensures the tree’s survival

Question 144

how could negative feedback neutralise rising levels of atmospheric CO2 by stimulating photosynthesis?

Answer 144

process known as carbon fertilisation

in this way, excess CO2 is extracted from the atmosphere and stored in the biosphere. Eventually much of this carbon would find its way into long-term storage in soils and ocean sediments, allowing the system to return to a steady state

however, increased primary production through carbon fertilisation is conditional on the availability of other requirements for photosynthesis such as sunlight, soil nutrients, nitrogen and water. Therefore, it is not possible to say with certainty that primary production as increased due to increased atmospheric CO2 in recent years

For instance, recently significant increases in primary production have been observed in the Amazon rainforest but this could be explained by lower rainfall, with less cloud cover and more sunlight rather than an increase in CO2

Question 145

example of a positive feedback loop in the carbon cycle?

Answer 145

global warming will intensify the carbon cycle, speed up decomposition and release more CO2 to the atmosphere, thus amplifying the greenhouse effect

Question 146

how do we monitor changes in Arctic sea ice?

Answer 146

NASA’s Earth Observing System (EOS) satellites have monitored sea ice growth and retreat since 1978

measures microwave energy radiating from the surface. Comparison of time series images to show changes

Question 147

how can we monitor changes in ice caps/glaciers?

Answer 147

as well as ground-based estimates of mass balance, satellite technology eg ICESat-2

measures surface height of ice sheet and glaciers using laser technology. Shows extent and volume of ice and changes

Question 148

how can we monitor sea surface temperatures (SSTs)?

Answer 148

NOAA satellites

radiometers measure the wave band of radiation emitted from the ocean surface. Changes in global SSTs and areas of upwelling and downwelling

Question 149

how can we monitor changes in water vapour?

Answer 149

NOAA polar orbiters

measures cloud liquid water, total precipitation water etc. Long-term trends in cloud cover and water vapour in the atmosphere

Question 150

how can we monitor changes in deforestation?

Answer 150

ESA albedo (reflectivity) images from various satellites

measurements of reflectivity of Earth’s surface and land use changes

Question 151

how can we monitor changes in atmospheric CO2?

Answer 151

NASA’s Orbiting Carbon Observatory-2 (OCO-2)

Ground-based measurements at Mauna Loa, Hawaii, since 1958

new satellite measurements of global atmospheric CO2 from NASA’s OCO-2. The satellite also measures the effectiveness of absorption of CO2 by plants

Question 152

how can we monitor changes in primary production in oceans?

Answer 152

NASA’s MODIS/AQUA

measures net primary production in oceans and on land

Question 153

what are the diurnal changes to the water cycle?

Answer 153

significant changes occur within a 24-hour period in the water cycle

lower temps at nigh reduce evap and transpiration. Convectional precip, depending on direct heating of the ground surface by the Sun, is a daytime phenomenon often falling in the afternoon when temps reach a max

this is particularly significant in climactic regions in the tropics where the bulk of precipitation is from convectional storms

Question 154

diurnal changes to the carbon cycle?

Answer 154

during the daytime CO2 flows from the atmosphere to vegetation.

At night the flux is reversed. Without sunlight, photosynthesis switches off, and vegetation loses CO2 to the atmosphere. The same diurnal pattern is observed with phytoplankton in the oceans

Question 155

what are seasonal changes to the water cycle?

Answer 155

higher levels of solar input in the summer result in higher evapot.

in the driest parts of lowland England, up to 80% of precip may be lost to evapot. with large losses of precip to evapot and the exhaustion of soil moisture, river flows in England are normally at their lowest in summer

Question 156

what are seasonal variations in the carbon cycle?

Answer 156

shown by month-to-month changes in the NPP of vegetation

in middle and high latitudes, day length of photoperiod, and temperature drive seasonal changes in NPP. Similar seasonal variations also occur in the tropics, though there the main cause is water availability

during the northern hemisphere summer, when trees are in full foliage, there is a net global flow of CO2 from the atmosphere to the biosphere. This causes atmospheric CO2 levels to falll by 2 ppm. At the end of summer, as photosynthesis ends, the flow is reversed with natural decomposition releasing CO2 back to the atmosphere. Seasonal fluctuations in the global CO2 flux are explained by the concentration of continental and masses in the northern hemisphere. During the growing season, ecosystems such as the boreal and temperate forests extract huge amounts of CO2 from the atmosphere, which has a global impact

in the oceans phytoplankton are stimulated into photosynthetic activity by rising water temps, more intense sunlight and the lengthening photoperiod. Every year in the North Atlantic there is an explosion of microscopic oceanic plant life which starts in March and peaks in mid-summer, The resulting algal blooms are so extensive, they are visible from space

Question 157

what are the long term changes to the water cycle?

Answer 157

during glacial periods the water cycle undergoes a number of changes. the most obvious is the net transfer of water from the ocean reservoir to storage in ice sheets, glaciers and permafrost

as a result, in glacials the sea level worldwide falls by 100-130m; and ice sheets and glaciers expand to cover around one-third of the continental land mass. As ice sheets advance Equator-wards they destroy extensive tracts of forest and grassland, The area covered by vegetation and water stored in the biosphere shrinks. Meanwhile, in the tropics, the climate becomes drier and deserts and grasslands displace large areas of rainforest

lower rates of evapot during glacial phases reduce exchanges of water between the atmosphere and the oceans, biosphere and soils. This, together with so much freshwater stored as snow and ice, slows the water cycle appreciably

Question 158

include a statistic!! hint, it’s measured in ppm

what are long term changes to the carbon cycle?

Answer 158

there is a dramatic reduction in CO2 in the atmosphere during glacial periods. At times of glacial maxima, CO2 concentrations fall to around 180 ppm, while in warmer interglacial periods they are 100ppm higher

no clear explanation exists for the drop in atmospheric CO2 during glacial periods. It is, however, possible that excess CO2 finds its way from the atmosphere to the deep ocean. One mechanism is changes in ocean circulation during glacials that bring nutrients to the surface and stimulate phytoplankton growth. Phytoplankton fix large amounts of CO2 by photosynthesis before dying and sinking to the deep ocean where carbon is stored. Lower ocean temps also make CO2 more soluble in surface waters

other changes occur in the terrestrial biosphere. The carbon pool in vegetation shrinks during glacials as ice sheets advance and occupy large areas of the continents. In this process deserts expand, tundra replaces temperate rainforests and grasslands encroach on tropical rainforests. Which much of the land surface buried by ice, carbon stored in soils will no longer be exchanged with the atmosphere. Meanwhile expanses of tundra beyond the ice limit sequester huge amounts of carbon in permafrost. With less vegetation cover, fewer forests, lower temps and lower precip, NPP and the total volume of carbon fixed in photosynthesis will decline. The implications are an overall slowing of the carbon flux and smaller amounts of CO2 returned to the atmosphere through decomposition

Question 159

how are the water and carbon cycles linked through the atmosphere?

Answer 159

atmospheric CO2 has a greenhouse effect

CO2 plays a vital role in photosynthesis by terrestrial plants and phytoplankton. Plants, which are important carbon stores, extract water from the soil and transpire it as part of the water cycle. Water is evaporated from the oceans to the atmosphere, and CO2 is exchanged between the two stores

Question 160

how are the water and carbon cycles linked through the oceans?

Answer 160

ocean acidity increases when exchanges of CO2 are not in balance (ie inputs to the oceans from the atmosphere exceed outputs). The solubility of CO2 in the oceans increases with lower SSTs. Atmospheric Co2 levels influence SSts and the thermal expansion of the oceans; air temps; the melting of ice sheets and glaciers; and sea level

Question 161

how are water and carbon cycles linked through vegetation and soil?

Answer 161

water availability influences rates of photosynthesis, NPP, inputs of organic litter to soils and transpiration

the water storage capacity of soils increases with organic content

temps and rainfall affect decomposition rates and the release of CO2 to the atmosphere

Question 162

how are the water and carbon cycles linked through the crysophere?

Answer 162

CO2 levels in the atmosphere determine the intensity of the greenhouse effect and melting of ice sheets, glaciers, sea ice and permafrost. Melting exposes land and sea surfaces which absorb more solar radiation and raise temps further. Permafrost melting exposes organic material to oxidation and decomposition which releases CO2 and CH4. Run off, river flow and evaporation respond to temp change

Question 163

colorado basin, bangladesh, amazonia

what is the human impact on the water cycle?

Answer 163

is most evident in rivers and aquifers

rising demand for water for irrigation, agriculture and public supply, especially in arid and semi-arid environments, has created acute shortages

in the Colorado Basin in the southwest USA, surface supplies have diminished as more water is abstracted from rivers, and huge amounts are evaporated from reservoirs like Lake Mead and Lake Powell. Elsewhere, the quality of fresh water sources has declined. Over pumping of aquifers in the coastal regions of Bangladesh has led to incursions of salt water, often making the water unfit for irrigation and drinking

Compared to natural ecosystems, human activities such as deforestation and urbanisation reduce evapot and therefore precip; increase surface run off; decrease throughflow; and lower water tables. In Amazonia, forest trees are a key componenet of the water cycle, transferring water to the atmosphere by evapot, which is then returned through precip. In places, extensive deforestation has broken thiss cycle, causing climates to dry out and preventing regeneration of the rainforest

Question 164

how do human activities cause changes in carbon stores?

Answer 164

it is depleting carbon stores and increasing others

exploitation of coal, oil and natural gas has removed billions of tonnes of carbon from geological store - a process that has gathered momentum in the past 30 years with the rapid industrialisation of the Chinese and Indian economies

Currently around 8 billion tonnes of carbon a year are transferred to the atmosphere by burning fossil fuels.

In addition, land use change (mainly deforestation) transfers approximately 1 billion tonnes of carbon to the atmosphere annually. The additional carbon is stored primarily as atmospheric CO2, where its concentration increases year-by-year. Around 2.5 million tonnes is absorbed by the biosphere, and a similar amount by the biosphere

deforestation means carbon stored in biosphere has declined steeply.

acidification of oceans threatens phytoplankton, which absorb more than half the CO2 from burning fossil fuels, which is significantly more than tropical rainforests

soil is another important carbon store which is being degraded by erosion caused by deforestation and agricultural mismanagement. Carbon stores in wetlands, drained for cultivation and urban development, have also been depleted as they dry out and are oxidised

Question 165

what is the impact of long-term climate change on the water cycle?

Answer 165

global warming as increased evaporation and therefore the amount of water vapour in the atmosphere. this has feedback effect, helping to raise global temperatures, increase evap and precip. meanwhile, increased precip will result in higher run-off in the water cycle and greater flood risks/

water vapour is also a source of energy in the atmosphere, releasing latent heat on condensation. With more energy in the atmosphere extreme weather events such as hurricanes and mid-latitude storms become more powerful and more frequent

global warming is accelerating the melting of glaciers, ice sheets like Greenland and permafrost in the Arctic tundra. Thus water storage in the cryosphere shrinks, as water is transferred to the oceans and atmosphere

Question 166

what is the impact of long term climate change on the carbon cycle?

Answer 166

global warming = increased decomposition + transfer of carbon from biosphere + soil to atmosphere

global warming = change in biomes = rainforests more arid, boreal forests expand in permafrost

global warming = vast peat stores (tundra) decomposition

acidification of oceans = limit phytoplankton = reduce carbon store

Question 167

what is a wetland? why is the destruction bad? how to restore + why?

how does wetland restoration help to protect the global carbon cycle?

Answer 167

wetlands include freshwater marshes, salt marshes, peatlands, floodplains and mangroves. their common feature is a water table at or near the surface causing the ground to be permanently saturated

in the lower 48 US states the wetland area has halved since 1600. The destruction of wetlands transfers huge amounts of stored CO2 and CH4 to the atmosphere

in the twentieth century, Canada’s prairie provinces lost 70% of their wetlands. Restoration programmes in this area have shown that wetlands can store on average 3.25 C/ha/year. Now 112,000 ha have been targeted for restoration in the Canadian prairies which should eventually sequester 364,000 tonnes C/year

the need for protection of wetlands as wildlife habitats as well as carbon stores is reflected in management initiatives such as the International Convention on Wetlands (Ramsar) and European Union Habitats Directive

restoration focuses on raising local water tables to re-create waterlogged conditions. Eg wetlands on floodplains can be reconnected to rivers by the removal of flood embankments and controlled floods. Coastal areas of reclaimed marshland used for farming can be restored by breaching sea defences

elsewhere water levels can be maintained at artificially high levels by diverting or blocking drainage ditches and installing sluice gates

Question 168

remember example of a scheme! (hint: there’s two you can talk about)

how does afforestation help manage the global carbon cycle?

Answer 168

it involves planting trees in deforested areas or in areas that have never been forested

because trees are carbon sinks, afforestation can help reduce atmospheric Co2 levels in the medium to long term and combat climate change. It also has other benefits such as reducing flood risks and soil erosion, and increasing biodiversity

the UN’s Reducing Emissions from Deforestation and Forest Degradation (REDD) scheme incentivises developing countries to conserve their rainforests by placing a monetary value on forest conservation. Several projects are already well established such as those in Amazonia (Puras, Russas-Valparaiso) and the Lower Mississipi

In China a massive government-sponsored afforestation project began in 1978. It aims to afforest 400,000km2 by 2050. In the decade 2000-09, 30,000km2 were successfully planted with non-native, fast-growing species such as poplar and birch. However, the project has a wider purpose: to combat desertification and land degradation in the vast semi-arid expanses of northern China

Question 169

how does land and crop management help to reduce emissions from agriculture?

Answer 169

zero tillage - growing crops without ploughing the soil. This conserves the soil’s organic content, reducing oxidation and the risk of erosion by wind and water

polyculture - growing annual crops interspersed with trees. Trees provide year-round ground cover and protect soils from erosion

crop residues - leaving crop residues (stems, leaves etc) on fields after the harvest, to provide ground cover and protection against soil erosion and drying out

avoiding the use of heavy farm machinery on wet soils, which leads to compaction and the risk of erosion by surface run-off

contour ploughing and terracing on slopes to reduce run off and erosion

introducing new strains of rice that grow in drier conditions and therefore produce less Ch4. Applying chemicals such as ammonium sulphate which inhibit microbial activities that produce CH4

Question 170

how does livestock management reduce emissions?

Answer 170

improving the quality of animal feed to reduce enteric fermentation so that less feed is converted to CH4, mixing methane inhibitors with livestock feed

Question 171

how does manure management reduce emissions?

Answer 171

controlling the way manure decomposes to reduce CH4 emissions. Storing manure in anaerobic containers and capturing CH4 as a source of renewable energy

Question 172

what are international agreements to reduce carbon emissions?

Answer 172

until recently, the only significant international agreement to tackle climate change has been the Kyoto Protocol (1997). Under this, most rich countries agreed to legally binding reductions in their CO2 emissions, though controversially, developing countries, and some of the biggest polluters (China and India) were exempted. Also, several rich countries, notably the USA and Australia, refused to ratify the treaty. This expired in 2012

Then, the Paris Agreement, with implementation from 2020, aims to reduce global CO2 emissions below 60% of 2010 levels by 2050, and keep global warming below 2C, but ideally by 1.5C. However, countries will set their own voluntary targets. These are not legally binding and a timetable for implementing them has yet to be agreed. Meanwhile, rich countries will transfer significant funds and tech to assist poorer countries to achieve their targets. Major CO2 emitters such as China and India argue that global reductions in CO2 emissions are the responsibility of rich countries bc:

• countries such as China and India are still relatively poor and industrialisation, based on fossil fuels energy, is essential to raise living standards to levels comparable with those in the developed world
• historically, Eu and Na through their own industrialisation and economic development are largely to blame for contemporary warming and climate change

Question 173

what is meant by cap and trade?

Answer 173

cap and trade offers an alternative, international market-based approach to limit CO2 emissions. Under this scheme businesses are allocated an annual quota for their CO2 emissions

if they emit less than their quota they receive carbon credits which can be traded on international markets. Business that exceed their quotas must purchase additional credits or incur financial penalties

carbon offsets are credits awarded to countries and companies for schemes such as afforestation, renewable energy and wetland restoration. They can be bought to compensate for excessive emissions elsewhere

Question 174

scheme + benefits of that scheme

how can forestry be used to manage the global water cycle?

Answer 174

UN and World Bank, together with other organisations and govs, fund programmes to protect tropical rainforests, eg UN’s REDD programme and World Bank’s FCPF fund over 50 partner countries

brazil has received support from UN, WB, WWF and the German Development Bank to protect its forests. The ARPA programme now covers nearly 128 million acres of the Amazon Basin, with a target of 150 million acres. Areas included in the programme are strictly protected and there was a 75% decrease in deforestation rates between 2000 and 2012

the benefits include stabilising regional water cycle; offsetting 1.4 billion tonnes of carbon a year; supporting indigenous forest communities; promoting ecotourism; and protecting the genetic bank provided by thousands of plant species in the forests

Question 175

how do water allocations protect the global water cycle??

Answer 175

agriculture is by far the biggest consumer of water, globally accounts for 70% of water withdrawals and 90% of consumption.

Wastage of water occurs through the evaporation and seepage through inefficient water management.

Improved management techniques which minimise water losses to evaporation include mulching, zero soil disturbance and drip irrigation. Losses to run off on slopes can be reduced by teracing, contour ploughing and the insertion of vegetative strips

meanwhile, better water harvesting with storage in ponds and reservoirs, provides farmers with extra water resources. Recovery and recycling of waste water from agriculture, industry and urban populations is technically feasible, but is yet little used outside the developed world

in semi-arid regions of water scarcity, eg Lower Indus Valley in Pakistan and US Colorado Basin, water agreements divide resources between downstream states. In Pakistan, the Punjab and Sindh receive 92% of the Indus’ flow, and in the Colorado Basin water resources are allocated to California, Arizona, Nevada, Utah and New Mexico. In both regions, the vast bulk of water is used for irrigation

Question 176

What is the human impact on the water cycle regarding the Colorado Basin?

Answer 176

in the Colorado Basin in the southwest USA, surface supplies have diminished as more water is abstracted from rivers, and huge amounts are evaporated from reservoirs like Lake Mead and Lake Powell

Question 177

What is the human impact on the water cycle regarding Bangladesh?

Answer 177

the quality of fresh water sources has declined. Over pumping of aquifers in the coastal regions of Bangladesh has led to incursions of salt water, often making the water unfit for irrigation and drinking

Question 178

What is the human impact on the water cycle regarding Amazonia?

Answer 178

Compared to natural ecosystems, human activities such as deforestation and urbanisation reduce evapot and therefore precip; increase surface run off; decrease throughflow; and lower water tables.

In Amazonia, forest trees are a key component of the water cycle, transferring water to the atmosphere by evapot, which is then returned through precip. In places, extensive deforestation has broken this cycle, causing climates to dry out and preventing regeneration of the rainforest

Question 179

How do human activities like the EXPLOITATION OF COAL, OIL AND NATURAL GAS cause changes in carbon stores?

Answer 179

exploitation of coal, oil and natural gas has removed billions of tonnes of carbon from geological store - a process that has gathered momentum in the past 30 years with the rapid industrialisation of the Chinese and Indian economies

Currently around 8 billion tonnes of carbon a year are transferred to the atmosphere by burning fossil fuels.

Question 180

How do human activities like LAND USE CHANGE cause changes in carbon stores?

Answer 180

land use change (mainly deforestation) transfers approximately 1 billion tonnes of carbon to the atmosphere annually. The additional carbon is stored primarily as atmospheric CO2, where its concentration increases year-by-year. Around 2.5 million tonnes is absorbed by the biosphere, and a similar amount by the biosphere

Question 181

how do human activities like DEFORESTATION cause changes in carbon stores?

Answer 181

deforestation means carbon stored in biosphere has declined steeply.

Question 182

How do human activities such as AGRICULTURAL MISMANAGEMENT cause changes in carbon stores?

Answer 182

soil is another important carbon store which is being degraded by erosion caused by deforestation and agricultural mismanagement. Carbon stores in wetlands, drained for cultivation and urban development, have also been depleted as they dry out and are oxidised

Question 183

What is a wetland?

Answer 183

wetlands include freshwater marshes, salt marshes, peatlands, floodplains and mangroves. their common feature is a water table at or near the surface causing the ground to be permanently saturated

Question 184

How much has the wetland area been decreased by in the USA, and what is the effect of this?

Answer 184

in the lower 48 US states the wetland area has halved since 1600. The destruction of wetlands transfers huge amounts of stored CO2 and CH4 to the atmosphere

Question 185

What are wetland restoration programmes like in Canada?

Answer 185

in the twentieth century, Canada’s prairie provinces lost 70% of their wetlands. Restoration programmes in this area have shown that wetlands can store on average 3.25 C/ha/year. Now 112,000 ha have been targeted for restoration in the Canadian prairies which should eventually sequester 364,000 tonnes C/year

Question 186

How does wetland restoration work?

Answer 186

the need for protection of wetlands as wildlife habitats as well as carbon stores is reflected in management initiatives such as the International Convention on Wetlands (Ramsar) and European Union Habitats Directive

restoration focuses on raising local water tables to re-create waterlogged conditions. Eg wetlands on floodplains can be reconnected to rivers by the removal of flood embankments and controlled floods. Coastal areas of reclaimed marshland used for farming can be restored by breaching sea defences

elsewhere water levels can be maintained at artificially high levels by diverting or blocking drainage ditches and installing sluice gates

Question 187

What is afforestation and how does it help manage the global carbon cycle?

Answer 187

it involves planting trees in deforested areas or in areas that have never been forested

because trees are carbon sinks, afforestation can help reduce atmospheric Co2 levels in the medium to long term and combat climate change. It also has other benefits such as reducing flood risks and soil erosion, and increasing biodiversity

Question 188

What is the UN’s REDD scheme?

Answer 188

the UN’s Reducing Emissions from Deforestation and Forest Degradation (REDD) scheme incentivises developing countries to conserve their rainforests by placing a monetary value on forest conservation. Several projects are already well established such as those in Amazonia (Puras, Russas-Valparaiso) and the Lower Mississippi

Question 189

What is China’s big afforestation project?

Answer 189

In China a massive government-sponsored afforestation project began in 1978.

It aims to afforest 400,000km2 by 2050. In the decade 2000-09, 30,000km2 were successfully planted with non-native, fast-growing species such as poplar and birch.

However, the project has a wider purpose: to combat desertification and land degradation in the vast semi-arid expanses of northern China

Question 190

What is drainage basin planning and how does it help manage the global water cycle?

Answer 190

the management of water resources is most effective at the drainage basin scale. At this scale it is feasible to adopt an integrated or holistic management approach to accommodate the often conflicting demands of different water users

specific targets for drainage basin planning include run off, surface water storage and groundwater.

Rapid run off is controlled by reforestation programmes in upland catchments, reducing artificial drainage and extending permeable surfaces eg gardens, green roofs

in urban areas
surface water storage is improved by conserving and restoring wetlands, including temporary storage in floodplains.

Groundwater levels are maintained by limiting abstraction and by artificial recharge, where wate is injected into aquifers through boreholes

Question 191

What is an example of drainage basin planning?

Answer 191

in england and wales drainage basin management is well advanced

Under the EU’s Water Directive Framework, ten river basin districts have been defined.

The districts comprise major catchments, such as the Severn, Thames and Humber. Each district has its own River Basin Management Plan published jointly by the Environment Agency and Defra.

The plan sets targets in relation to, for example, water quality, abstraction rates, groundwater levels, flood control, floodplain development and the status of habitats and wildlife