KQ3. How much change occurs over time in the water and carbon cycle?

Question 1

How does urbanisation lead to a rapid rise in water levels?

Answer 1

Natural surfaces are replaced by artificial surfaces, often impermeable, there is limited infiltration and water storage capacity to buffer run-off. Urban areas have well designed water systems, e.g. sewers to rapidly redirect rainfall into rivers, leading to a rise in water levels

Question 2

what is the impact of construction on floodplains and river flow?

Answer 2

Urbanisation encroaches floodplains, major water storages, urban development on the areas reduces water storage capacity so it’s directed towards rivers, leading to increased flood risk

Question 3

How does urbanisation impact carbon cycle?

Answer 3

Loss of vegetation, leads to reduced organic carbon material. Also increased CO2 emissions from vehicles from combustion of fossil fuels

Question 4

How does farming impact carbon storage?

Answer 4

Farming leads to often a fall in above and below ground biomass, soil storage depletes due to ploughing and oxidation of soil cover. Further harvesting of crops return little to no carbon back into the soil. Soil erosion also accompanies arable farming, by wind and erosion as soil as little protection cover

Question 5

How does crop irrigation impact water flows and stores ?

Answer 5

Redirects water from surface stores and groundwater. Some is extracted by roots from the soil and mostly lost via evaporation and soil drainage

Question 6

Furrows ploughed downslope act as drainage channels to accelerate…

Answer 6

run-off and soil erosion

Question 7

What 3 flows are reduced in areas with crops?

Answer 7

Interception of rainfall, evaporation and transpiration

Question 8

What is the impact of heavy machinery on soils?

Answer 8

Makes soils compact to increase soil erosion

Question 9

How does forestry impact evaporation?

Answer 9

Increases, more rainfall intercepted and eventually diffuses into the atmosphere

Question 10

How does forestry impact run off and stream drainage?

Answer 10

Run-off reduces, evaporation increases due to interception, more water absorbed by trees and drainage hydrology is altered.

Question 11

How does forestry impact stream drainage?

Answer 11

lower lag times, lower peak flows and lower stream discharge

Question 12

How do transpiration rates in forests compare to that of farmlands and moorlands? give example

Answer 12

Higher, in Sitka spruce, Pennines are around 350mm/year rainfall equivalent

Question 13

How does clear felling impact water cycle?

Answer 13

Removal of timber creates sudden but temporary changes, increased run off, stream discharge and reduced evapotranspiration

Question 14

How does carbon storage in forests compare to that of farmlands, heath and moorlands?

Answer 14

Carbon storage increases. Average mature trees in the UK contain about 170-200 tonnes/ha of carbon, 10x higher than grasslands and 20x higher than heath. Whilst soils are large carbon pools, average in the UK is 500tonnes C/ha in forest soil

Question 15

What is the downside of carbon storage in forests?

Answer 15

Forest trees sequester large amounts of carbon and don’t become active carbon sinks until 100 years or so after plantation

Question 16

Where is River Kennet located?

Answer 16

Southern England, covering area of 1200km^2 across Wiltshire and Berkshire

Question 17

What is the upper catchment of the river Kennet comprised of? and who does this supply mostly to?

Answer 17

Chalk, highly permeable and supplies Swindon, over 220,000 people

Question 18

What company is involved in extraction on the upper catchment of River Kennet?

Answer 18

Thames water

Question 19

How has extraction from Kennet has impact on water cycle? Give 3 ways

Answer 19

1. Rates of ground water extraction exceed recharge as a result, level of water table has reduced by 10-14%
2. During 2003 drought, flows fell by 20%
3. Lower groundwater levels have reduced incidence of seepages and springs, causing them to dry up and saturated overland flow on chalk hills of Marlborough have decreased.

Question 20

what are aquafiers?

Answer 20

permeable or porous water-bearing rocks, such as chalk.

Question 21

what is the water table?

Answer 21

upper surface of saturation within an aquafier

Question 22

name 3 factors effecting groundwater flow

Answer 22

Amount of rainfall, drought and abstraction

Question 23

what is an artesian aquifer

Answer 23

when an aquifer is locates between 2 impermeable rock, it’s under artesian pressure. If bores and well holes are dug, water will rise under this pressure and this is known as an artesian aquifer.

Question 24

what is the potentiometric surface? and what determines it?

Answer 24

it’s the height to which water rises, and determined by the height of the water table in areas of recharge as the edges of the basin

Question 25

Why are boreholes in London under artesian pressure?

Answer 25

Aquifer is found between London and gault clay and the chalk, water reaches by gravity from the Chilterns and North Downs towards the centre and so it’s naturally under pressure.

Question 26

How have water table levels changed over time?

Answer 26

In the 19th and early 20th century, abstractions rates caused a drastic change in the water table. Falling by 90m in central London. In the past 50 years, demand has decreased as well as rates of abstraction. By the 1990s, water table was rising at a level of 3m/year and soon began to threaten buildings and underground tunnels. Thames water was granted license to abstract water therefore

Question 27

How much of the world’s economy in 2019 was made up of fossil fuels for energy consumption?

Answer 27

84%

Question 28

How much carbon dioxide is released annually into the atmosphere?

Answer 28

10 billion tonnes

Question 29

What are the present day Carbon dioxide concentrations in the atmosphere?

Answer 29

415ppm, highest In about 800000 years

Question 30

without oceans and the biosphere to sequester carbon present day levels would exceed…

Answer 30

550ppm

Question 31

what are the 2 main drivers of present day global warming?

Answer 31

Combustion of fossil fuels and transfer of carbon from the geological store to atmospheric and oceans

Question 32

descirbe carbon capture and storage process.

Answer 32

1. Carbon dioxide is separated from emissions
2. It’s compressed and transported by pipeline to storage areas
3. Injected into porous rock

Question 33

how much potential does CCS has to reduce the 40% of American emissions by coal and gas fired powered

Answer 33

80-90%

Question 34

describe the Drax project held in North Yorkshire to use CCS

Answer 34

Capture 2 million tonnes of carbon dioxide and transport it by pipeline to the north Sea and store in depleted gas reservoirs

Question 35

What are the 3 limitations of CCS technology?

Answer 35

1. Big capital costs’ Drax project set to cost 1 billion
2. Requires vast amounts of energy- typically 20% of a plants power output
3. Requires storage reservoirs with certain conditions e.g. porous rock overlaid by impermeable strata

Question 36

what is a positive feedback loop?

Answer 36

Initial change causes further change

Question 37

what is a negative feedback loop?

Answer 37

counters the system change and restores equilibrium

Question 38

Give an example of +ve and -ve feedback loop as the world gets warmer

Answer 38

More evaporation and more moisture in the atmosphere, more cloud cover and increased precipitation. more water vapour on the atmosphere, absorbs more long wave radiation causing a further rise in temperature. But -ve, more cloud cover increases albedo and reflects incoming solar radiation

Question 39

How does the drainage basin respond to changes in equilibrium through change in seasons

Answer 39

1. System responds to above average precipitation by increasing river flow and evaporation whilst aquifers are recharged. More water in permeable rock
2. During droughts the system responds to reduced precipitation via reducing run offand evapotranspiration. Whilst seepage and springs dry up to conserve groundwater stores.

Question 40

How does the birch undergo negative feedback in drought?

Answer 40

shallow rooted trees such as the Solver Birch, undergo transpiration but similar uptake of water is not replaced, so it responds to restore water balance by shedding some or all of its leaves.

Question 41

what is carbon fertilisation?

Answer 41

Negative feedback response to rise in co2 concentration by stimulating photosynthesis. Excess carbon dioxide from the atmosphere makes its way to longterm stores of soil and sediment oceans.

Question 42

what is a limit of carbon fertilisation theory?

Answer 42

Photosynthesis is dependent also upon other factors. Although NPP in recent years has risen, its not for xcertain that this is due to rising carbon dioxide concentration. E.g. Recent Rise in NPP has been observed I. the Amazon, this could be due to less cloud cover and more sunlight

Question 43

give 2 examples of positive feedback loop in the carbon cycle.

Answer 43

1. Increased global warming due to anthropogenic emissions, can enhance decomposition to release more CO2 to atmosphere.
2. global warming has been known to occur faster in the Arctic tundra more than any other location (1.5-2.5°C in the last 30 years), more exposure as ice and glaciers melt, will lead to reduced albedo and absorbance of solar radiation. This has a significant impact on the carbon cycle because the permafrost is known to store around 1600GT of carbon

Question 44

Name one monitoring technique. and identify what it uses to measure and factors being measured

Answer 44

GIS uses techniques to map changes and identify anomalies. Both remote sensing and 🛰 satellites are used to measure surface temperatures, ice thickness and global temperatures.

Question 45

Describe the diurnal changes to a water cycle.

Answer 45

Changes dramatically. Low temperatures at night lower evaporation and transpiration. Whilst opposite in the day. Moreover, precipitation is a daytime phenomenon, with heating of the surface, e.g. Conventional rainfall. Particularly significant in the tropics

Question 46

Explain diurnal changes to the carbon cycle.

Answer 46

Carbon dioxide is absorbed by plants fir photosynthesis during the day, when sunlight is present. This switches at. Night as carbon dioxide is released back again to the atmosphere at night

Question 47

describe changes to solar radiation in southern England, from June to December

Answer 47

800W/m^2 to 150W/m^2

Question 48

When are river flows lowest I. the year? Explain why

Answer 48

In the summer, soil exhaustion and loss of water to evapotranspirtion (up to 80% in driest parts)

Question 49

what drives variations in NPP in middle and high latitudes?

Answer 49

Changes in temperature and photoperiod

Question 50

explain the role played by the northern hemisphere in global CO2 concentrations.

Answer 50

Sequester mass amounts of Carbon dioxide from atmosphere when trees are in full foliage. It can cause global concentrations to drop by 2ppm. Although by winter it’s reversed as natural decomposition occurs. These seasonal fluctuations are explained by of total land mass. During growing season, boreal and temperate forests extract mass amounts of carbon which has a global impact

Question 51

How many major glacial cycles have we had in the last 400000 years?

Answer 51

4

Question 52

when was the last glacial period

Answer 52

20000 years ago

Question 53

what was ice thickness and temperatures like in the last glacial period?

Answer 53

5°C lower with a Britain covered I. 1m thick ice

Question 54

What happens to oceans and land mass during glacial periods?

Answer 54

oceansshrink by up to 130m as water is transferred from ocean reservoir to ice and glaciers, these expand to cover over 1/3 of the earth’s surface, destroying vegetation as advances to the equator. Water stored in biosphere shrinks. In tropics climate becomes drier as they are converted to grasslands

Question 55

Do flows of water increase or decrease during glacial periods?

Answer 55

water cycle slows down, evapotranspiration slows, reducing flows of water between atmosphere, biosphere, oceans and soils decrease

Question 56

What happens to atmospheric carbon storage during glacial periods?

Answer 56

Decreases, temperatures and co2 concentrations are closely linked. In glacial period maxima, this can fall by 180ppm whilst they 100ppm higher in interglacial periods

Question 57

suggest 2 reasons why atmospheric carbon storage decreases during glacial periods

Answer 57

Perhaps changes to ocean circulation brings nutrients to the surface to stimu l ate phytoplankton growth, which fixes large amounts of carbon dioxide before dying and making there way to ocean floor where they act as storage. Oceans also become cooler to increase solubility of carbon dioxide

Question 58

Why does carbon storage International biosphere decrease Glacial periods

Answer 58

1. Vegetation shrinks and ice sheets and glaciers expand. Tundra replaces temperate forests and grasslands replace tropical rainforest. As a Result Carbon exchanges between the soil and atmosphere decrease Carbon exchanges between the soil and atmosphere decrease

Question 59

How do tundra act as carbon stores in glacial periods?

Answer 59

Sequester carbon in permafrost