Earth's Life Support Systems Flashcards

Question

What is sublimation?

Answer 1

The change of water state from ice to vapour.

Answer 2

The movement of water across the land surface.

Answer 3

The vertical movement of rainwater through the soil.

Answer 4

The movement of surface and soil water into underlying permable rock.

Answer 5

A permeable rock layer (e.g. chalk or sandstone) that stores and transmits groundwater.

Answer 6

Carbon is neither created nor destroyed, only transformed and transferred.

Answer 7

- Photosynthesis: removes CO2 from the atmosphere. - Respiration: returns CO2 to the atmosphere. - Decomposition: breaks down organic matter, releasing CO2 or CH4. - Combustion: burning of biomass or fossil fuels releases CO2. - Weathering: chemical weathering of rocks absorbs CO2. - Volcanic activity: releases carbon from lithosphere to atmosphere.

Answer 8

- Evaporation: transfer of water from surface to atmosphere as vapour. - Transpiration: water released from plant leaves into the atmosphere. - Evapotranspiration: combined loss of water from evaporation and transpiration. - Condensation: water vapour cools and turns into liquid, forming clouds. - Precipitation: water falls from atmosphere to Earth as rain, snow, etc. - Infiltration: water soaks into soil from the surface. - Percolation: water moves from soil into underlying rock layers. - Surface runoff: water flows over the land into rivers/lakes. - Throughflow: lateral movement of water through soil. - Groundwater flow: slow movement of water through porous rock (aquifers).

Answer 9

Fast carbon cycle: transfers carbon between the atmosphere, oceans, biosphere, and soils over days to decades. - Key processes: photosynthesis, respiration, decomposition, combustion, ocean-atmosphere exchange. Slow carbon cycle: moves carbon through rocks, fossil fuels, and deep oceans over millions of years. - Key processes: weathering, sedimentation, tectonic uplift, volcanic outgassing, fossil fuel formation. The fast cycle dominates short-term carbon fluxes, while the slow cycle regulates long-term climate stability.

Answer 10

- Melting permafrost: rising temperatures cause frozen ground (permafrost) to thaw. - This releases methane (CH₄), a potent greenhouse gas, from decomposing organic matter. - Increased CH₄ enhances the greenhouse effect, causing further warming. - leads to more permafrost melt — reinforcing the cycle (positive feedback loop).

Answer 11

- Increased atmospheric CO₂: higher CO₂ levels can stimulate plant growth (CO₂ fertilisation effect). - More plant growth leads to greater photosynthesis, which removes CO₂ from the atmosphere. - This reduces the rate of warming and helps stabilise the carbon cycle. - The process counteracts the initial change — a negative feedback loo

Answer 12

- Rising temperatures: increase evaporation rates from oceans and surface water. - More water vapour enters the atmosphere — a powerful greenhouse gas. - This enhances the greenhouse effect, leading to further warming. - Warmer temperatures cause even more evaporation — a positive feedback loop.

Answer 13

- Increased evaporation: leads to more cloud formation due to condensation. - Clouds reflect incoming solar radiation (increased albedo). - This can lower surface temperatures, reducing further evaporation. - The system self-regulates — a negative feedback loop.

Answer 14

- The uptake of CO2 from the atmosphere by plants during photosynthesis. - CO2 is released back into the atmosphere during plant and animal respiration and CO2 and methane are released back during the decomposition of dead organic matter. - The cycling of carbon between the soil, vegetation and atmosphere is relatively rapid and is sometimes referred to as the 'fast carbon cycle'.

Answer 15

- The cycling of carbon between rock stores and the atmosphere and oceans through the processes of weathering over millions of years. - Weathering of rocks on continents creates a net carbon sink in the oceans - Chemical weathering of rocks by carbonic acid produces carbonate run-off, which is transferred to the oceans. - Here, organisms use it to create shells; when the organisms die the carbonate sediment produced eventually forms limestone. - This long-term carbon store is released to the atmosphere through volcanic activity.

Answer 16

- Atmospheric carbon occurs as CO2 and methane. - Methane is a more powerful greenhouse gas but is short-lived in the atmosphere. - Carbon dioxide is removed from the atmosphere through interactions with the terrestrial and oceanic carbon cycles, e.g photosynthesis of water absorption.

Answer 17

- Carbon is held in a dissolved form in the waters of the ocean and in the tissues of oceanic organisms. - Inputs & outputs to this cycle take place through gas exchange with the atmosphere and through an input of organic carbon and carbonate ions from continental run-off. - Because of the size of the oceanic carbon store, small changes in carbon cycling have global impacts. - Ocean sediments are an important long-term carbon store.

Answer 18

Evaporation is a process where liquid becomes gas through heat energy provided by the movement of water, or solar energy, as well as air which is not saturated and can therefore absorb evaporated water molecules. Transpiration is a biological process where water is lost from plants through pores called stomata. Together, these two processes are known as evapotranspiration.

Answer 19

- Temperature - Wind - Humidity - Climatic factors e.g hours of sunshine

Answer 20

A physical process where gas (water vapour) becomes liquid. It happens when air cools and is less able to hold water vapour (reaching the dew point). In the cooling process, the water molecules condense onto nuclei (dust, smoke) or surfaces (grass) to form water deposits or frost. Precipitation (rain, sleet, snow etc) occurs when the air can no longer hold the condensed water.

Answer 21

When air can no longer hold condensed water.

Answer 22

Visible masses of water droplets or ice crystals held in the atmosphere.

Answer 23

1) Conduction causes a mass of air to warm faster than the air around it. This air mass rises by convection because it is less dense than the surrounding air. At this point, the atmosphere is described as unstable. 2) As the air rises, it cools, because it expands. This allows the air particles to have more space between them, cooling them down. At first the air cools at a rate of 10°C for every km into the atmosphere. This is because the air is dry. This is called the Dry Adiabatic Lapse Rate. 3) The air continues to cool until reaching its dew point. At this point the water vapour begins to condense and a cloud begins to form. 4) The condensation releases latent heat and the air becomes saturated with water. The air is still rising but this slows the rate at which the mass of air cools. It now cools at a rate of about 7°C per km. This is called the Saturated Adiabatic Lapse Rate. 5) The air mass continues to rise until it is the same temperature as the surrounding air. When this happens the atmosphere is described as stable and this point is also the top of the cloud.

Answer 24

The DALR is the rate at which unsaturated air cools as it rises — 9.8°C per 1000m. As air rises and cools adiabatically, it approaches its dew point, which may lead to condensation and cloud formation.

Answer 25

Latent heat is energy released or absorbed during a phase change without temperature change. In cloud formation, condensation releases latent heat, warming the air parcel and fuelling further uplift and cloud growth.

Answer 26

The SALR (~6°C/km) is the rate at which saturated air cools as it rises. It's slower than the DALR because latent heat is released during condensation, reducing the cooling rate. This is key once clouds start forming.

Answer 27

Air typically starts unsaturated. As it rises and cools (via DALR), it eventually reaches its dew point, becomes saturated, and condensation begins — this is when the air becomes moist and clouds form.

Answer 28

The dew point is the temperature at which air becomes saturated (100% RH). When rising air cools to this temperature, condensation begins, marking the base of cloud formation.

Answer 29

Convection is the vertical movement of warm air, caused by solar heating of the ground. As warm air rises, it cools, reaches the dew point, and condensation occurs, forming cumulus or convective clouds.

Answer 30

Conduction is the transfer of heat via direct contact. It occurs when the Earth’s surface heats the air above it, causing it to rise through convection, setting the stage for cloud development.

Answer 31

Warm air rises because it is less dense than cooler surrounding air. When the Earth's surface is heated by solar radiation, it warms the air above via conduction. This air becomes buoyant and rises through convection. As it rises, it expands and cools, eventually reaching its dew point where condensation begins, forming clouds.

Answer 32

Condensation and cloud formation can be the result of conduction and convection. Precipitation produced in this way is called convectional rainfall. Air may be forced to rise, cooling to form clouds and precipitation: - Over hills and mountains, producing orographic rainfall. - When air masses of different temperatures and densities meet, the warm air rises over the cool air.

Answer 33

When moist air is forced to rise over high ground, such as mountains. As the air rises, it cools, leading to precipitation on the windward side. The leeward side receives little rainfall due to descending, dry air — this is known as the rain shadow effect.

Answer 34

- Accumulation: inputs to a glacial system from snowfall. - Ablation: output from a glacial system due to melting. - Sublimation: Ice changing directly into water vapur. At a global scale, these processes occur in cycles of glacial and interglacial periods.

Answer 35

The study of how water moves within a drainage basin — from precipitation through interception, infiltration, runoff, throughflow, and groundwater flow, eventually exiting via a river. It examines the inputs, outputs, stores, and transfers in a river catchment system.

Answer 36

A drainage basin is the area of land drained by a river and its tributaries. It is an open system with inputs (precipitation), outputs (evaporation, river discharge), and flows and stores such as interception, infiltration, groundwater, and surface runoff. The watershed marks the basin’s boundary.

Answer 37

- Forms a sub-system of the water cycle - Is an open system with inputs and outputs of both matter and energy - Is composed of inputs (precipitation), flows and transfers (throughfall, stemflow, infiltration, percolation, overland flow and groundwater flow) and outputs to the sea or atmosphere (evapotranspiration).

Answer 38

Water vapour turning to liquid. May form fog.

Answer 39

Vegetation cover intercepts the precipitation and a store may be held on leaves and branches. Density of vegetation affects this. Tropical rainforest can intercept 58% of rainfall - sometimes referred to as an interception store.

Answer 40

This mainly occurs in built environments as puddles. In natural environments, infiltration normally occurs faster than rainfall and there are only rainfall puddles after very long periods of rainfall, or impacted surfaces, or bare rock.

Answer 41

Pore spaces between soil particles fill with air and water. The amount of pore space varies in different soils: clay particles occupy 40-60% of total volume, sand 20-45%.

Answer 42

Water stored underground in permeable and porous rocks.

Answer 43

The volume of water in a river channel.

Answer 44

Water flows down the stems of plants and trees.

Answer 45

Water soaks into the soil. The speed at which this happens ins the infiltration rate. The texture, structure and organic content of soil all influence infiltration rate. The rate normally declines during the early part of a storm.

Answer 46

Infiltration rate is the speed at which water enters the soil from the surface, usually measured in millimetres per hour. It affects runoff and soil moisture storage, and is influenced by soil type, vegetation cover, saturation level, and land use.

Answer 47

Rainfall flowing oer the ground surface either because the soil is saturated or because the rainfall exceeds the soil infiltration capacity.

Answer 48

Water moving from vegetation to the ground.

Answer 49

The lateral movement of water down a slope to a river channel. Slower than overland flow but the rate is increased by root systems of vegetation.

Answer 50

Throughflow is slower because it involves water moving through soil, where it is slowed by soil particles, small pore spaces, and friction. Overland flow is faster as water moves directly over the surface, often with minimal resistance, especially when the ground is impermeable or saturated.

Answer 51

Downward movement of water into underground stores.

Answer 52

Downward and lateral movement of water within saturated rock. This is a very slow movement. Water-bearing rocks are called aquifiers.

Answer 53

Leakage is the loss of water from the drainage basin system, usually when water percolates deeply into underlying rock layers and is no longer part of the active hydrological cycle within the basin. It acts as a long-term store or output.

Answer 54

Run-off is the water that flows over the land surface into rivers and streams. It includes overland flow and contributes to river discharge. It occurs when the infiltration capacity is exceeded, often due to heavy rainfall, impermeable surfaces, or saturated soil.

Answer 55

- Precipitation - Photosynthesis - Respiration - Decompostion - Combustion - Natural sequestration in the ocean - Sequestration by plants - Weathering

Answer 56

Atmospheric CO2 dissolves in rainwater to form weak carbonic acid. Rising concentrations of CO2 in the atmosphere resulting from anthropogenic emissions have increased the acidity of rainfall and led to increased surface acidity of surface ocean waters.

Answer 57

Plants use energy from sunlight and combine CO2 from the atmosphere with water from the soil to form carbohydrates. Virtually all organic mater is formed from this process. Carbon is stored (or sequestered) for long periods of time because trees can live for hundreds of thousands of years and resistant structures such as wood take a long time to decompose.

Answer 58

All plants and animals release CO2 back into the atmosphere through respiration. Soil respiration: microscopic organisms living in soil also release CO2 through respiration.

Answer 59

The process of decomposition by fungi and bacteria returns CO2 to the atmosphere. Decomposition also produces soluble organic compounds dissolved in run-off from the land surface. Greenhouse gases are released as a by-product.

Answer 60

A secondary substance produced during a natural process or human activity. By-products often refer to emissions or waste outputs, such as CO₂ from combustion or methane from agriculture, which can affect carbon and water cycles.

Answer 61

Fossil fuels (coal, oil, natural gas) contain carbon captured by living organisms over millions of years and stored in the Earth's crust. Since the Industrial Revolution, these fuels have served as a primary energy source. The main by-product of fossil fuel combustion is CO2.

Answer 62

CO2 moves from the atmosphere to the ocean by the process of diffusion. At low latitudes, warm water absorbs CO2. At high latitudes, where cold water sinks, the carbon is transferred deep into the ocean (downwelling). Where cold water returns to the surface and warms again (upwelling) it loses CO2 to the atmosphere. In this way CO2 is in constant exchange between the oceans and the atmosphere. This vertical circulation is a process called the physical (inorganic) pump. Phytoplankton also fix CO2 through photosynthesis, and the carbon passes through the oceanic food web. Carbonate is removed from the sea by shell-building organisms. When organisms die the shell sinks into deep water. This is called the biological (organic) pump. Some material forms layers of carbon-rich sediments which over millions of years turn to sedimentary rocks.

Answer 63

Vegetation on land sequesters carbon by the process of photosynthesis.

Answer 64

Sequestration is the long-term storage of carbon in oceans, soils, vegetation, and rocks, removing it from the atmosphere. It occurs naturally through processes like photosynthesis, ocean absorption, and sedimentary rock formation, helping to regulate the Earth's climate.

Answer 65

Weathering processes (driven by the atmosphere and groundwater) break down rocks on the Earth's surface. Small particles are carried to the ocean along with plant and soil particles. Large particles are deposited on the shore. The sediment accumulates in layers and eventually, because of surface pressure, shale rock is formed. In the ocean, dissolved sediments mix with seawater and are used by marine organisms to make skeletons and shells containing calcium carbonate. When these organisms die, the carbonate collects at the bottom of the ocean and sedimentary rocks (e.g limestone) form.

Answer 66

Shale is a fine-grained sedimentary rock formed from compressed mud, clay, and organic matter. It often acts as a carbon store, trapping fossil fuels like oil and natural gas, and plays a key role in the long-term carbon cycle through carbon sequestration in rock layers.

Answer 67

Calcium carbonate forms shells/skeletons in marine organisms. When they die, it sinks and forms limestone, storing carbon in sedimentary rocks for millions of years.

Answer 68

- 6 million square kilometres of rainforest - High average temperatures (25°C - 30°C) with no seasonal variation. - High annual precipitation (>2000mm): seasonal variation, no dry season, just reduced 30-50%

Answer 69

Each tree has a vital role in the cycle, absorbing, storing and transpiring water.

Answer 70

High precipitation causes significant water stores iin soils and aquifiers.

Answer 71

High annual average >2000mm; short drier season with 30-50% less rainfall; convectional rainfall daily.

Answer 72

High temperatures = high rates of evapotranspiration; 50-60% of precipitation is recycled as evapotranspiration.

Answer 73

High average temperatures (25°C - 30°C) with no seasonal variation increase evapotranspiration, raising humidity and fuelling convectional rainfall. Warm air holds more moisture, making temperature a key driver of precipitation and atmospheric moisture cycling.

Answer 74

Rapid run-off due to high and intense rainfall.

Answer 75

Holds large stores of water vapour due to high temperatures and intense evapotranspiration. This maintains high humidity, fuels convectional rainfall, and drives continuous recycling of moisture within the rainforest system.

Answer 76

Rapid exchanges to atmosphere; decomposition rapid due to high humidity and temperatures, so quick release of carbon.

Answer 77

With a high Net Primary Productivity (NPP) of ~2500 g/m²/yr, rainforest trees absorb large amounts of CO₂ via photosynthesis. Trees store up to 180 tonnes of carbon per hectare in above-ground biomass and 40 tonnes in roots, making the forest a major carbon sink in the global carbon cycle.

Answer 78

Hold limited carbon stores because warm, humid conditions cause rapid decomposition of organic matter. Carbon is quickly broken down and recycled into the ecosystem, leaving low long-term soil carbon storage compared to biomass.

Answer 79

The key process for carbon sequestration in the Amazon. Dense vegetation with high NPP (~2500 g/m²/yr) absorbs large amounts of CO₂ from the atmosphere, storing it as biomass in trees and plants. This makes the Amazon one of the world's most important terrestrial carbon sinks.

Answer 80

The continuous movement and reuse of water and carbon through biotic and abiotic components of ecosystems. For example, carbon is recycled through photosynthesis, respiration, decomposition, and combustion; water is recycled via evaporation, condensation, and precipitation.

Answer 81

- Deforestation significantly reduces carbon storage by removing biomass and limiting carbon input to soils. - Replacing trees with crops or pasture leads to a much smaller carbon sink. - Fewer trees also mean less leaf litter, reducing decomposer activity and slowing the return of carbon to the atmosphere through respiration.

Answer 82

- Reforestation & Carbon Markets: Companies like Mombak have planted 5 million native trees and aim for 8 million by June 2025, generating carbon credits purchased by firms such as Microsoft and Amazon. - Amazon Fund Revitalisation: International donors (e.g., Norway, Germany, USA) have resumed contributions to Brazil’s Amazon Fund, supporting forest protection and sustainable land use. - Indigenous Stewardship: Indigenous groups like the Siekopai have regained land rights, enhancing conservation through traditional land management practices. - Corporate Carbon Offsets: Tech giants are investing in large-scale carbon credit purchases (e.g., Microsoft’s $200 million deal with Re.green) to fund reforestation and offset emissions. - Policy & Enforcement: Brazil’s deforestation rate dropped by 49.5% in 2023, aided by stronger environmental policies and international support

Answer 83

- Deforestation reduces evapotranspiration, leading to less atmospheric moisture and a decline in regional rainfall. - Without the forest canopy, infiltration rates fall and surface runoff increases, raising the risk of soil erosion and flooding. - Conversion to pasture or agriculture creates impermeable surfaces, disrupting groundwater recharge and altering river discharge patterns.

Answer 84

- 500,000 km2 of Arctic Tundra in Alaska, northern Canada and Siberia. - Low average temperatures of between 0°C and -30°C for 8-9 months of the year. During the remaining months, average temperatures are above 0°C and in some places can reach 10°C. - The ground is permanently frozen but it thaws to a depth about a metre during the summer months. This is the active layer.

Answer 85

Low (typically <350 mm/year), mostly falling as snow. It contributes to seasonal melting, which leads to surface runoff and the formation of bogs, ponds, and saturated soils in summer. The limited input slows the hydrological cycle, and permafrost prevents infiltration, increasing surface water storage.

Answer 86

Limited role due to sparse plant cover and a short growing season. This results in low rates of transpiration and interception, contributing to reduced atmospheric moisture and slower water cycling. The lack of deep roots also limits soil water uptake, increasing surface water retention.

Answer 87

Low temperatures result in minimal evapotranspiration, as the sun’s energy is mostly used to melt snow, not evaporate water. Much of the water remains frozen in soils and permafrost, limiting moisture transfer to the atmosphere and slowing the overall water cycle.

Answer 88

Small stores of water vapour due to low temperatures, which limit evaporation and moisture capacity. This leads to low humidity and minimal precipitation, contributing to a slow and limited water cycle.

Answer 89

Usually low due to frozen ground, but in summer, the melting of the active layer leads to a rapid increase in surface run-off and river flow. Permafrost prevents infiltration, causing water to accumulate and flow overland, especially after snowmelt.

Answer 90

The ground stores very little water because permafrost prevents infiltration and percolation. In summer, the active layer melts, creating temporary surface water stores as water cannot drain through the frozen subsoil. This leads to saturated soils, surface pooling, and increased run-off.

Answer 91

Limited role due to low Net Primary Productivity (~200 g/m²/yr) and low biomass. Sparse, slow-growing plants absorb small amounts of CO₂ via photosynthesis, contributing modestly to carbon sequestration compared to tropical rainforest.

Answer 92

Sequestration is low due to limited biomass and a short growing season. Although there is rapid plant growth in summer, the overall capacity for CO₂ absorption remains small compared to more tropical rainforest.

Answer 93

Acts as both a source and sink of carbon. CO₂ is released year-round, mainly through plant and microbial respiration, with the highest fluxes during the short summer growing season. Rising temperatures and permafrost thaw may increase atmospheric CO₂ and CH₄ emissions

Answer 94

Permafrost stores vast amounts of carbon, with up to 5 times more below ground than in vegetation. Although carbon accumulation is slow, it has built up over millennia due to low decomposition rates. However, rising temperatures may thaw permafrost, releasing CO₂ and CH₄, turning it from a carbon sink into a carbon source.

Answer 95

Geology; - Hard crystalline rocks add to the low permeability already present due to permafrost. Temperature; - Low temperatures keep water as permafrost - Short summer melt causes some water to flow on the surface (active layer). - Little evapotranspiration, although some in summer from surface water. Relief; - Gently, undulating relief helps store water during the summer months, waterlogging soils.

Answer 96

Geology; - Little impact on the flows of the carbon cycle due to the impermeability of the permafrost overlying hard crystalline rock. - Most carbon is stored in the permafrost Temperature; - Low temperatures slow photosynthesis and respiration, so limited flow of CO2 to the atmosphere. - Slow decomposition. Biomass; - Total store small due to limited water and sunlight

Answer 97

- Oil and gas exploration have increased snow cover and permafrost melting, so flooding is more likely. - This creates extensive wetlands in summer, increasing evaporation and disrupting drainage networks. - In addition, artificial lakes created by strip mining store water and water from creeks is extracted and used locally in industry.

Answer 98

Oil and gas exploration melts permafrost, releasing stored carbon. Melting is caused by: - building for the oil & gas industry. - depostion of dust along roads, so ice and snow absorb more sunlight (albedo). - removal of vegetation - which previously insulated the permafrost. Removal of vegetation also reduces photosynthesis and CO2 uptake. Increased microbial activity in warmer soil causes more decomposition and greater carbon emissions. Gas flaring and oil spills put CO2 directly into the atmosphere.

Answer 99

- Infrastructure built on gravel pads protects permafrost from melting. - Buildings and pipelines built on piles allow cold air to circulate, stopping permafrost from melting. - Drilling for oil with newer techniques. Allows access to oil kilometres away from drilling sites, reducing impact on vegetation and permafrost. - Improved technology in oil detection reduces need for exploration wells, and therefore, impact. - Refrigerated supports on Trans-Alaskan pipeline, buildings and infrastructure stabilise permafrost temperature.

Answer 100

Exploration wells are drilled to detect and assess underground oil and gas reserves. They can cause land surface disruption, permafrost degradation, and pollution risks in sensitive areas like the Alaskan tundra. However, advances in remote sensing, seismic imaging, and satellite data have reduced the need for physical drilling, making oil detection less invasive and more precise

Answer 101

- The inputs, throughputs, outputs and stores in the water and carbon cycles are in a constantly changing state called "dynamic equilibrium". - There will be short-term fluctuations, but in the long-term, a balance is maintained. - The balance of the system is restored by negative feedback loops. Positive feedback occurs when initial change causes further ongoing change.

Answer 102

- Natural surfaces (vegetation and soil) replaced by impermeable concrete, brick, and tarmac, reducing infiltration. - Urban drainage systems (e.g gutters) remove surface water rapidly. - Water levels in rivers rise rapidly owing to quick transfer of surface water. - Urban development on floodplains reduces water storage capacity and increases river flow and flooding.

Answer 103

- Urban growth reduces the amount of surface vegetation. - CO2 emissions from energy consumption, transport, and industry increase. - Increase in CO2 emissions from cement manufacturing.

Answer 104

- Forested areas (e.g. dense evergreen plantations) significantly increase interception, reducing the amount of rainfall reaching the ground. - Evaporation rises as intercepted water is stored on leaves and evaporates directly back to the atmosphere. - Transpiration is also higher than in moorland or farmland, contributing to greater atmospheric moisture. - These processes lead to reduced run-off, lower stream discharge, longer lag times, and lower peak flows. - In contrast, deforestation reduces evapotranspiration due to sparse vegetation, less interception, and minimal root systems, leading to increased overland flow, higher throughflow, and greater flood risk.

Answer 105

Trees that retain their needle-like leaves year-round and reproduce using cones. Adapted to cold, nutrient-poor environments, such as boreal forests, they perform photosynthesis whenever conditions allow, contributing to carbon sequestration even in short growing seasons.

Answer 106

- Converting land to forestry increases carbon storage, especially in biomass and soils. - Trees remove CO₂ from the atmosphere via photosynthesis and sequester it, mainly in the woody stems. - Forests act as a carbon sink, but this is most effective during the first 80–100 years of growth. - After this, the rate of sequestration slows, so plantation forests are managed on a rotation to maintain active carbon uptake.

Answer 107

- Irrigation diverts water form rivers and groundwater supplies to cultivated land. Some of this water is used by plants from soil storage and released by transpiration. - Interception, evaporation, and transpiration are all less in agro-ecosystems than in forest and grassland ecosystems. - Ploughing increases soil moisture loss and furrows can act as drainage channels increasing run-off and leading to soil erosion. - Underground drainage channels in farmland increase water transfers to rivers. - Use of heavy machinery can compact the soil and increase run-off.

Answer 108

Furrows are shallow, narrow trenches ploughed into soil, typically in agricultural fields, to channel water, plant seeds, or assist with drainage and irrigation. They can affect run-off, infiltration rates, and soil erosion, depending on their orientation and maintenance.

Answer 109

- Clearance of forest for farming reduces above and below-ground carbon stores. - Ploughing reduces soil carbon storage and exposes organic matter to oxidation. - Harvesting means that only small amounts of organic matter are returned to the soil, further reducing carbon stores. - Rice paddies generate methane. - Livestock release methane gas as a by-product of digestion. - Emissions from tractors increase the level of CO2 in the atmosphere.

Answer 110

Irrigation is the artificial application of water to land to support crop growth, especially in regions with insufficient rainfall. It alters the natural water cycle by increasing evapotranspiration, reducing river flow, and potentially causing waterlogging, salinisation, or aquifer depletion if mismanaged.

Answer 111

Water extraction — the removal of water from surface or groundwater sources for irrigation, industry, or domestic use — can significantly alter the water cycle: - Reduces river discharge, especially during dry periods, leading to lower base flow and altered flow regimes. - Lowers groundwater levels, particularly in areas of heavy aquifer use, which may cause aquifer depletion, subsidence, and reduced spring flow. - Disrupts natural recharge rates, especially where impermeable surfaces or overuse prevent infiltration. - Can lead to drying of wetlands and loss of riparian habitats, reducing biodiversity and ecosystem services. - Over time, extraction can shift a system from dynamic equilibrium to one of deficit, particularly in arid and semi-arid regions or where recharge is slower than withdrawal. Long-term impacts include reduced resilience to drought, salinisation in coastal aquifers due to saltwater intrusion, and increased conflict over water use.

Answer 112

35 billion tonnes

Answer 113

Combustion of fossil fuels and the resulting transfer of carbon from geographical stores to the atmosphere and oceans.

Answer 114

Carbon Capture and Storage

Answer 115

- High capital costs - The process uses lots of energy - Requires storage reservoirs with specific geological conditions

Answer 116

In 2021, Iceland opened the Orca Plant, which takes CO2 directly from the atmosphere and injects it into the ground.

Answer 117

Where CO2 is separated from fossil-fuelled power station emissions. It is compressed and transported, then injected into porous rock underground and stored.

Answer 118

A set of key environmental indicators used to monitor and understand the Earth's climate system.

Answer 119

- Global air temperatures - Sea ice thickness - Sea surface temperatures - Rates of deforestation

Answer 120

Significant changes can occur over 24 hours in the water cycle. Evaporation and transpiration are both much lower at night as temperatures drop. Downpours in the afternoon because of intensive convectional heating are a feature of some global climates. Carbon flows from the atmosphere to vegetation during the day; the flux is reversed at night. Low levels of sunlight reduce photosynthesis in vegetation on land and in phytoplankton in oceans.

Answer 121

Seasons are controlled by variations in the intensity of solar radiation: - This has an impact on rates of evapotranspiration and precipitation which impact the water cycle. - Seasonal variations in the carbon cycle are show in month-month variations in net primary productivity (NPP). - For example, in the Northern Hemisphere, during the summer months there is a net flow of CO2 from the atmosphere to the biosphere as vegetation is in full foilage and photosynthesis is rapid. - A shorter photoperiod during winter months reduces photosynthesis.

Answer 122

- Diurnal change - Seasonal change

Answer 123

Over the last 1 million years, the global climate has been unstable, with large temperature fluctuations occurring at regular intervals. - In the past 400,000 years, there have been four major glacial cycles, with cold glaciers followed by warmer interglacials.

Answer 124

- Sea levels fall. - Ice sheets and glaciers expand. - Ice sheet advance destroys forest and grassland. - Water stored in the biosphere shrinks. - Evapotranspiration declines. - Water cycle slows due to reduction in evapotranspiration and water storage.

Answer 125

- Less CO2 in the atmosphere. - Changes in oceanic circulation bring nutrients to the surface; phytoplankton grows rapidly and fixes carbon dioxide in photosynthesis; when phytoplankton die the carbon is stored in the deep ocean. - Less exchange of carbon between the soil and the atmosphere due to ice coverage. - Because of the increase in ice coverage there s less vegetation and a reduction in the carbon fixed by photosynthesis.

Answer 126

- Cycling of carbon and water are central to supporting life on Earth, and an understanding of these cycles and how they are changing is central to managing global challenges such as the impacts of climate change and consequences for future food, water and energy supply. - Changes in the water and carbon cycles are central to analysis of environmental change and the global challenges it presents. - Understanding the regional variations in the sources and sinks of Co2 helps indentify sequestration and emission management options.

Answer 127

Carbon is transported in running water as dissolved CO₂, organic matter, or weathered minerals. Rivers carry carbon from continents to oceans, making water fluxes a key mechanism in the global carbon cycle.

Answer 128

Rising atmospheric CO₂ alters global temperatures, impacting evaporation rates and shifting precipitation patterns. These changes influence both terrestrial and oceanic water cycling.

Answer 129

Moisture availability controls plant distribution, and vegetation is crucial for carbon sequestration via photosynthesis. Thus, ecosystems mediate both cycles through their role in water retention and carbon uptake.

Answer 130

Climate change and land-use change (e.g. deforestation) disrupt terrestrial ecosystems, altering evapotranspiration, infiltration, and carbon storage. This leads to systemic shifts in both cycles.

Answer 131

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 transport it as part of the water cycle. Water is evaporated from the oceans to the atmosphere, and CO2 is exchanged between the two stores.

Answer 132

Ocean acidity increases when the exchange of CO₂ between the atmosphere and oceans becomes unbalanced — specifically when more CO₂ enters the oceans than leaves. Colder sea-surface temperatures (SSTs) increase the solubility of CO₂, allowing oceans to absorb more. Rising atmospheric CO₂ levels influence SSTs, thermal expansion, global air temperatures, ice sheet and glacier melt, and ultimately sea level rise.

Answer 133

When CO₂ dissolves in seawater, it reacts to form carbonic acid (H₂CO₃). This weak acid dissociates into hydrogen ions (H⁺) and bicarbonate (HCO₃⁻). The increase in H⁺ ions lowers the pH of seawater, making it more acidic. This process is called ocean acidification and reduces the availability of carbonate ions (CO₃²⁻), which marine organisms need to build shells and skeletons.

Answer 134

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. Temperatures and rainfall affect decomposition rates and the release of CO2 to the atmosphere.

Answer 135

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 (albedo) and raise temperatures further. Permafrost melting exposes organic material to oxidation and decomposition which releases CO2 and CH4. Run-off, river flow and evaporation respond to temperature change.

Answer 136

- Rising demand for water for irrigation, industrial and domestic usage has created water shortages in many areas across the globe e.g Bangladesh, India and the Colorado Basin in the USA. - Deforestation reduces the carbon store in the biosphere and the carbon fixed by photosynthesis. - Increased soil erosion (due to deforestation) is leading to a decline in the carbon store of soil. - Acidification of the oceans threatens the biological carbon store of oceans and the carbon fixed by the process of photosynthesis in phytoplankton. - Urbanisation reduces evapotranspiration that would naturally occur from vegetation; as a result precipitation can decline. Urban areas also increase run-off and reduce infiltration which can lower water tables. - Fossil fuels account for 82% of global primary energy consumption. This has removed billions of tonnes of carbon from geological stores.

Answer 137

- Global warming has increased the amount if evaporation and thereby the amount of water vapour in the atmosphere. The positive feedback of water vapour - a greenhouse gas - further increase of global temperatures, evaporation and precipitation. - Increased precipitation in areas where there is urbanisation, building on floodplains and deforestation will increase flood risks. - Water vapour is a source of energy in the atmosphere which can lead to more extreme weather events, e.g storms & tornadoes. - Water stored in the cryosphere will shrink as global warming increases melting of glaciers and will be transferred into oceans.

Answer 138

- Impacts are more complex than water cycle, but in the long-term, there will probably be an increase in carbon stored in the atmosphere, a decrease in carbon stored in the biosphere, and a decrease in the carbon store of oceans. - Higher temperatures increase rates of decompostion, and the rate of carbon transfer from the biosphere and soil to the atmosphere will increase. - Where temperatures are so high that aridity increases, forests will be replaced by grasslands which reduces the carbon stored in woody vegetation. - Global warming may allow boreal forests to spread north. - In permafrost areas, carbon is being released from frozen ground as temperatures rise. - Oceanic acidification (caused by CO2 dissolving in oceans and creating carbonic acid) is limiting the capacity of oceans to store carbon.

Answer 139

Afforestation: - This is the planting of trees in areas where deforestation has taken place or in new areas. - Trees act as an important carbon sink, reducing atmospheric CO2. They also reduce flood risks and soil erosion. - The UN's Reducing Emissions from Deforestation and Forest Degration (REDD) schemes encourage developing countries to preserve their forests. Wetland Restoration: - Wetlands include marshes, peatlands, floodplains and margroves. They are important carbon sinks, accounting for 35% of the terrestrial carbon pool. - Protection schemes include the International Convention of Wetlands and the European Union Habitats Directive. - Restoration at a local level includes raising water tables to create waterlogged conditions. - Water levels can be maintained by diverting or blocking drainage ditches and installing sluice gates. Improved Agricultural Practices: - Mulching adds organic matter and prevents carbon losses from soil. - Rotation of cash crops with cover crops can increase the biomass returned to the soil. - Improved crop varieties can increase productivity and enhance soil organic carbon. Reducing Emissions: Carbon trading: Businesses can be allocated a quota for CO2 emissions. Carbon credits are received for emissions below the quota, and financial penalties or the opportunity to purchase additional credits are the consequences of exceeding the quota. Carbon offsets are credits to countries and businesses for schemes like afforestation or the use of renewable energy. International agreements: International co-operation is key to reducing carbon emissions. However, reaching consensus and action from all countries is complex and frequently affected by the self-interests of different countries, industries and organisations. - The Kyoto Protocol (1997) bound most rich countries to agreed reductions in CO2 emissions. Even so, India & China were exempt and the USA didn't ratify the agreement. - Signatories to the Paris Climate Agreement were to set their own voluntary targets (not legally binding) for emissions reduction. - The Glasgow Climate Pact (2021) agreed to speed up action to meet targets. 90% of the world's forests are now covered by a pledge from 130 countries to end deforestation by 2030. Transport Innovations: - Attempts to reduce greenhouse gas emissions from road transport & aviation form a key element of mitigation. Road transport initiatives include sustainable transport schemes, congestion charges, park and ride, etc. Mitigation in aviation included fuel-efficient routes & cruising at lower speeds.

Answer 140

Afforestation is the process of planting trees in areas that have not previously been forested. It helps increase carbon sequestration, enhances biodiversity, reduces soil erosion, and contributes to climate regulation by expanding terrestrial carbon sinks.

Answer 141

TeamTrees is a reforestation initiative launched in 2019 by the Arbor Day Foundation and YouTubers like MrBeast. For every $1 donated, one tree is planted. The project has planted over 24 million trees globally, helping to sequester atmospheric CO₂, restore terrestrial carbon sinks, improve biodiversity, and combat the effects of deforestation.

Answer 142

Marshes are low-lying wetland areas with shallow, standing water and dominated by grasses, reeds, and herbaceous plants. They act as temporary water stores, support biodiversity, and help filter water and store carbon.

Answer 143

Peatlands are wetlands with waterlogged soils rich in partially decomposed organic matter (peat). They are significant carbon sinks, storing more carbon per hectare than forests, but are vulnerable to drainage and burning.

Answer 144

Floodplains are flat areas adjacent to rivers that experience periodic flooding. They store excess water, reduce flood risk, and support fertile soils for agriculture. They also help in the deposition of sediment and organic material.

Answer 145

Mangroves are coastal wetlands found in tropical and subtropical regions, dominated by salt-tolerant trees and shrubs. They provide storm protection, support biodiversity, and are major carbon sinks, storing large amounts of carbon in their roots and soils.

Answer 146

Sluice gates are mechanical barriers used to control water flow in rivers, canals, and drainage systems. They can be raised or lowered to manage water levels, prevent flooding, enable irrigation, or regulate wetland water balance. Sluice gates are crucial in human modification of the water cycle.

Answer 147

Water Allocations: - Agriculture accounts for 90% of water consumption globally. There is waste by evaporation and seepage due to poor management. Improved management, better storage and recycling of water help, but this is difficult outside developed nations. In countries where water is scarce, water may need to be divided between and then allocated tom separate locations, e.g Colorado Basin, USA. Drainage Basin Planning: - Management can be effective at drainage basin scale. Rapid run-off can be controlled by afforestation. Restoring wetlands can improve water storage. England and Wales have ten river basin catchments, which are well managed by considering water quality, abstraction, flood controls, wildlife and development of the floodplain. Forestry: - Trees impact many processes of the water cycle, e.g interception, infiltration. The important role of trees in the functioning of the global water cycle is recognised by projects such as the UN's Reducing Emissions from Deforestation and Forest Degratation (REDD) scheme, and the World Bank's Forest Carbon Partnership Facility (FCPF) which fund many projects in Africa, Asia and South America.

Answer 148

They are essential for supporting ecosystems, regulating climate, and sustaining biological processes like photosynthesis and respiration

Answer 149

Key stores exist in the lithosphere, hydrosphere, cryosphere, atmosphere, and biosphere. Their size and location vary globally.

Answer 150

Globally they are closed systems (no matter lost or gained), but at the local scale (e.g. drainage basin), they function as open systems.

Answer 151

Water: evaporation, transpiration, precipitation, cryospheric processes. Carbon: photosynthesis, respiration, decomposition, weathering, combustion.

Answer 152

At the global scale and the drainage basin scale, involving inputs, outputs, stores and flows.

Answer 153

Both human and physical factors (e.g. economic, social, environmental) vary in different locations like tropical rainforests and the Arctic tundra.

Answer 154

They alter the functioning of ecosystems, affecting both carbon sequestration and water storage/transfer.

Answer 155

They are connected through the atmosphere, oceans, cryosphere, and biosphere, particularly via vegetation and soil moisture.

Answer 156

To track changes, improve understanding, and support sustainable management.

Answer 157

To demonstrate precision and support arguments (e.g. carbon store sizes, water flux rates).

Answer 158

Consider local to global scales and explain whether processes occur in open or closed systems.

Answer 159

To show higher-level understanding and explain stability or disruption in the system.

Answer 160

Use positive/negative feedback to explain how climate or ecosystem changes affect water or carbon stores.

Answer 161

They help apply theory, strengthen comparisons, and show contextual knowledge (e.g. Amazon vs. Arctic).

Answer 162

Understand the rates of change, influenced by factors like sunlight, temperature, and nutrient availability.

Answer 163

Use SEPE: Social, Economic, Political, Environmental. Split into human and natural causes/effects.

Answer 164

Assess costs, benefits, and sustainability, and compare strategies at different scales (local/global).

Answer 165

- Spend 2–4 minutes - Give direct, concise answers - Apply specific evidence or terminology - No introduction or conclusion needed Example: For 2-mark questions, often 2 short sentences = full marks.

Answer 166

- Spend 10–12 minutes - 1-sentence intro defining key terms - Write 2 developed paragraphs - Each with a clear point, explanation, and example - Use place-specific detail - No need for full conclusion unless time allows

Answer 167

- Spend 20–22 minutes - Brief intro: define terms + outline argument - 3–4 well-developed paragraphs: - Clear points - Detailed examples and processes - Consider scale, feedback, temporal change - Include evaluation where possible - Conclusion: give a final judgement on the extent of agreement

Answer 168

The Amazon has high NPP, fast decomposition, and large above-ground biomass stores. The tundra has low NPP, vast below-ground carbon in permafrost, and slow decomposition. Warming poses risks of turning tundra from a sink to a source.

Answer 169

Amazon has intense evapotranspiration, high rainfall, rapid run-off, and dense vegetation. Tundra has low precipitation, minimal evapotranspiration, permafrost-limited infiltration, and seasonal snowmelt-driven run-off.

Answer 170

Suriname and Guyana have received REDD+ funding to preserve rainforest carbon sinks through sustainable land management and indigenous stewardship.

Answer 171

The biological pump is the process by which phytoplankton fix atmospheric CO2 via photosynthesis. Carbon moves through marine food webs and sinks to the deep ocean as organic matter, helping store carbon long-term.

Answer 172

COP28 (held in Dubai, 2023) was a major UN climate summit where global leaders reaffirmed net-zero targets, agreed to phase down fossil fuels, and strengthened carbon market mechanisms — key for managing carbon cycles.

Answer 173

An international climate treaty signed in 2015, aiming to limit global warming to well below 2°C. Countries submit voluntary targets (NDCs) for emissions reduction, impacting long-term carbon cycle regulation.

Answer 174

The Everglades (USA) is under threat from urbanisation and drainage. It stores significant soil carbon and helps buffer water flow, regulate flooding, and support biodiversity.

Earth's Life Support Systems Flashcards

(198 cards)