A LEVEL
GEOGRAPHY
REVISION GUIDE
Paper 1: Physical
Geography
2020
, THE WATER AND CARBON CYCLES
Water cycles
1.1 The global hydrological cycle is of enormous importance to life on earth.
The global hydrological cycle’s operation as a closed system (inputs, outputs, stores and flows)
driven by solar energy and gravitational potential energy.
The relative importance and size (percentage contribution) of the water stores (oceans,
atmosphere, biosphere, cryosphere, groundwater and surface water) and annual fluxes
between atmosphere, ocean and land.
The global water budget limits water available for human use and water stores have different
residence times; some stores are non-renewable (fossil water or cryosphere losses).
1.2 The drainage basin is an open system within the global hydrological cycle.
The hydrological cycle is a system of linked processes: inputs (precipitation patterns and types:
orographic, frontal, convectional) flows (interception, infiltration, direct runoff, saturated
overland flow, throughflow, percolation, groundwater flow) and outputs (evaporation,
transpiration and channel flow).
Physical factors within drainage basins determine the relative importance of inputs, flows and
outputs (climate, soils, vegetation, geology, relief).
Humans disrupt the drainage basin cycle by accelerating processes (deforestation; changing
land use) and creating new water storage reservoirs or by abstracting water. (Amazonia)
1.3 The hydrological cycle influences water budgets and river systems at a local scale.
Water budgets show the annual balance between inputs (precipitation) and outputs
(evapotranspiration) and their impact on soil water availability and are influenced by climate
type (tropical, temperate, polar examples).
River regimes indicate the annual variation of discharge of a river and result from the impact
of climate, geology and soils as shown in regimes from contrasting river basins. (Yukon,
Amazon, Indus).
Storm hydrographs shape depends on physical features of drainage basins (size, shape,
drainage density, rock type, soil, relief and vegetation) as well as human factors (land use and
urbanisation). (P: the role of planners in managing land use).
2.1 Deficits within the hydrological cycle result from physical processes but can have significant
impacts.
The causes of drought, both meteorological (short-term precipitation deficit, longer trends,
ENSO cycles and hydrological.
The contribution human activity makes to the risk of drought: over-abstraction of surface water
resources and ground water aquifers. (Sahelian drought; Australia).
The impacts of drought on ecosystem functioning (wetlands, forest stress) and the resilience
of these ecosystems.
2.2 Surpluses within the hydrological cycle can lead to flooding, with significant impacts for people.
Meteorological causes of flooding, including intense storms leading to flash flooding, unusually
heavy or prolonged rainfall, extreme monsoonal rainfall and snowmelt.
Human actions that can exacerbate flood risk (changing land use within the river catchment,
mismanagement of rivers using hard engineering systems.)
Damage from flooding has both environmental impacts (soils and ecosystems) and socio-
economic impacts (economic activity, infrastructure and settlement). (UK flood events 2007
or 2012).
2.3 Climate change may have significant impacts on the hydrological cycle globally and locally.
Climate change affects inputs and outputs within the hydrological cycle: trends in
precipitation and evaporation.
Climate change affects stores and flows, size of snow and glacier mass, reservoirs, lakes,
amount of permafrost, soil moisture levels as well as rates of runoff and stream flow.
, Climate change resulting from short-term oscillations (ENSO cycles) and global warming
increase the uncertainty in the system; this causes concerns over the security of water supplies.
(F: projections of future drought and flood risk)
3.1 There are physical causes and human causes of water insecurity.
The growing mismatch between water supply and demand has led to a global pattern of
water stress (below 1,700 m³ per person) and water scarcity (below 1000 m³ per person).
The causes of water insecurity are physical (climate variability, salt water encroachment at
coast) as well as human (over abstraction from rivers, lakes and groundwater aquifers, water
contamination from agriculture, industrial water pollution).
The finite water resource faces pressure from rising demand (increasing population, improving
living standards, industrialisation and agriculture), which is increasingly serious in some
locations and is leading to increasing risk of water insecurity. (F: projections of future water
scarcity).
3.2 There are consequences and risks associated with water insecurity.
The causes of and global pattern of physical water scarcity and economic scarcity and why
the price of water varies globally.
The importance of water supply for economic development (industry, energy supply,
agriculture) and human wellbeing (sanitation, health and food preparation); the
environmental and economic problems resulting from inadequate water.
The potential for conflicts to occur between users within a country, and internationally over
local and trans-boundary water sources (Nile, Mekong). (P: role of different players).
3.3 There are different approaches to managing water supply, some more sustainable than others.
The pros and cons of the techno-fix of hard engineering schemes to include water transfers,
mega dams and desalination plants (Water transfers in China).
The value of more sustainable schemes of restoration of water supplies and water
conservation (smart irrigation, recycling of water) (Singapore). (A: contrasting attitudes to
water supply).
Integrated drainage basin management for large rivers ( Nile, Colorado) and water sharing
treaties and frameworks (United Nations Economic Commission for Europe (UNECE) Water
Convention, Helsinki and the Water Framework Directive and Hydropower, Berlin). (P: role of
players in reducing water conflict risk).
Carbon Cycles
1.1 Most global carbon is locked in terrestrial stores as part of the long-term geological cycle.
The biogeochemical carbon cycle consists of carbon stores of different sizes (terrestrial,
oceans and atmosphere), with annual fluxes between stores of varying size (measured in
Pg/Gt), rates and on different timescales.
Most of the earth’s carbon is geological, resulting from the formation of sedimentary
carbonate rocks (limestone) in the oceans and biologically derived carbon in shale, coal and
other rocks.
Geological processes release carbon into the atmosphere through volcanic out-gassing at
ocean ridges/subduction zones and chemical weathering of rocks.
1.2 Biological processes sequester carbon on land and in the oceans on shorter timescales.
Phytoplankton sequester atmospheric carbon during photosynthesis in surface ocean waters;
carbonate shells/tests move into the deep ocean water through the carbonate pump and
action of the thermohaline circulation.
Terrestrial primary producers sequester carbon during photosynthesis; some of this carbon is
returned to the atmosphere during respiration by consumer organisms.
Biological carbon can be stored as dead organic matter in soils, or returned to the
atmosphere via biological decomposition over several years.
, 1.3 A balanced carbon cycle is important in sustaining other earth systems but is increasingly altered
by human activities.
The concentration of atmospheric carbon (carbon dioxide and methane) strongly influences
the natural greenhouse effect, which in turn determines the distribution of temperature and
precipitation.
Ocean and terrestrial photosynthesis play an important role in regulating the composition of
the atmosphere. Soil health is influenced by stored carbon, which is important for ecosystem
productivity.
The process of fossil fuel combustion has altered the balance of carbon pathways and stores
with implications for climate, ecosystems and the hydrological cycle.
2.1 Energy security is a key goal for countries, with most relying on fossil fuels.
Consumption (per capita and in terms of units of GDP) and energy mix (domestic and foreign,
primary and secondary energy, renewable versus non-renewable).
Access to and consumption of energy resources depends on physical availability, cost,
technology, public perception, level of economic development and environmental priorities
(national comparisons USA versus France).
Energy players (P: role of TNCs, The Organisation of the Petroleum Exporting Countries (OPEC),
consumers, governments) have different roles in securing pathways and energy supplies.
2.2 Reliance on fossil fuels to drive economic development is still the global norm.
There is a mismatch between locations of conventional fossil fuel supply (oil, gas, coal) and
regions where demand is highest, resulting from physical geography.
Energy pathways (pipelines, transmission lines, shipping routes, road and rail) are a key aspect
of security but can be prone to disruption especially as conventional fossil fuel sources deplete
( Russian gas to Europe).
The development of unconventional fossil fuel energy resources (tar sands, oil shale, shale gas,
deep water oil) has social costs and benefits, implications for the carbon cycle, and
consequences for the resilience of fragile environments. (Canadian tar sands, USA fracking,
Brazilian deep water oil) (P: role of business in developing reserves, versus environmental
groups and affected communities)
2.3 There are alternatives to fossil fuels but each has costs and benefits.
Renewable and recyclable energy (nuclear power, wind power and solar power) could help
decouple fossil fuel from economic growth; these energy sources have costs and benefits
economically, socially, and environmentally and in terms of their contribution they can make
to energy security. (changing UK energy mix).
Biofuels are an alternative energy source that are increasing globally; growth in biofuels
however has implications for food supply as well as uncertainty over how ‘carbon neutral’
they are. (Biofuels in Brazil)
Radical technologies, including carbon capture and storage and alternative energy sources
(hydrogen fuel cells, electric vehicles) could reduce carbon emissions but uncertainty exists
as to how far this is possible.
3.1 Biological carbon cycles and the water cycle are threatened by human activity.
Growing demand for food, fuel and other resources globally has led to contrasting regional
trends in land-use cover (deforestation, afforestation, conversion of grasslands to farming)
affecting terrestrial carbon stores with wider implications for the water cycle and soil health.
Ocean acidification, as a result of its role as a carbon sink, is increasing due to fossil fuel
combustion and risks crossing the critical threshold for the health of coral reefs and other
marine ecosystems that provide vital ecosystem services.
Climate change, resulting from the enhanced greenhouse effect, may increase the
frequency of drought due to shifting climate belts, which may impact on the health of forests
as carbon stores. (Amazonian drought events)
GEOGRAPHY
REVISION GUIDE
Paper 1: Physical
Geography
2020
, THE WATER AND CARBON CYCLES
Water cycles
1.1 The global hydrological cycle is of enormous importance to life on earth.
The global hydrological cycle’s operation as a closed system (inputs, outputs, stores and flows)
driven by solar energy and gravitational potential energy.
The relative importance and size (percentage contribution) of the water stores (oceans,
atmosphere, biosphere, cryosphere, groundwater and surface water) and annual fluxes
between atmosphere, ocean and land.
The global water budget limits water available for human use and water stores have different
residence times; some stores are non-renewable (fossil water or cryosphere losses).
1.2 The drainage basin is an open system within the global hydrological cycle.
The hydrological cycle is a system of linked processes: inputs (precipitation patterns and types:
orographic, frontal, convectional) flows (interception, infiltration, direct runoff, saturated
overland flow, throughflow, percolation, groundwater flow) and outputs (evaporation,
transpiration and channel flow).
Physical factors within drainage basins determine the relative importance of inputs, flows and
outputs (climate, soils, vegetation, geology, relief).
Humans disrupt the drainage basin cycle by accelerating processes (deforestation; changing
land use) and creating new water storage reservoirs or by abstracting water. (Amazonia)
1.3 The hydrological cycle influences water budgets and river systems at a local scale.
Water budgets show the annual balance between inputs (precipitation) and outputs
(evapotranspiration) and their impact on soil water availability and are influenced by climate
type (tropical, temperate, polar examples).
River regimes indicate the annual variation of discharge of a river and result from the impact
of climate, geology and soils as shown in regimes from contrasting river basins. (Yukon,
Amazon, Indus).
Storm hydrographs shape depends on physical features of drainage basins (size, shape,
drainage density, rock type, soil, relief and vegetation) as well as human factors (land use and
urbanisation). (P: the role of planners in managing land use).
2.1 Deficits within the hydrological cycle result from physical processes but can have significant
impacts.
The causes of drought, both meteorological (short-term precipitation deficit, longer trends,
ENSO cycles and hydrological.
The contribution human activity makes to the risk of drought: over-abstraction of surface water
resources and ground water aquifers. (Sahelian drought; Australia).
The impacts of drought on ecosystem functioning (wetlands, forest stress) and the resilience
of these ecosystems.
2.2 Surpluses within the hydrological cycle can lead to flooding, with significant impacts for people.
Meteorological causes of flooding, including intense storms leading to flash flooding, unusually
heavy or prolonged rainfall, extreme monsoonal rainfall and snowmelt.
Human actions that can exacerbate flood risk (changing land use within the river catchment,
mismanagement of rivers using hard engineering systems.)
Damage from flooding has both environmental impacts (soils and ecosystems) and socio-
economic impacts (economic activity, infrastructure and settlement). (UK flood events 2007
or 2012).
2.3 Climate change may have significant impacts on the hydrological cycle globally and locally.
Climate change affects inputs and outputs within the hydrological cycle: trends in
precipitation and evaporation.
Climate change affects stores and flows, size of snow and glacier mass, reservoirs, lakes,
amount of permafrost, soil moisture levels as well as rates of runoff and stream flow.
, Climate change resulting from short-term oscillations (ENSO cycles) and global warming
increase the uncertainty in the system; this causes concerns over the security of water supplies.
(F: projections of future drought and flood risk)
3.1 There are physical causes and human causes of water insecurity.
The growing mismatch between water supply and demand has led to a global pattern of
water stress (below 1,700 m³ per person) and water scarcity (below 1000 m³ per person).
The causes of water insecurity are physical (climate variability, salt water encroachment at
coast) as well as human (over abstraction from rivers, lakes and groundwater aquifers, water
contamination from agriculture, industrial water pollution).
The finite water resource faces pressure from rising demand (increasing population, improving
living standards, industrialisation and agriculture), which is increasingly serious in some
locations and is leading to increasing risk of water insecurity. (F: projections of future water
scarcity).
3.2 There are consequences and risks associated with water insecurity.
The causes of and global pattern of physical water scarcity and economic scarcity and why
the price of water varies globally.
The importance of water supply for economic development (industry, energy supply,
agriculture) and human wellbeing (sanitation, health and food preparation); the
environmental and economic problems resulting from inadequate water.
The potential for conflicts to occur between users within a country, and internationally over
local and trans-boundary water sources (Nile, Mekong). (P: role of different players).
3.3 There are different approaches to managing water supply, some more sustainable than others.
The pros and cons of the techno-fix of hard engineering schemes to include water transfers,
mega dams and desalination plants (Water transfers in China).
The value of more sustainable schemes of restoration of water supplies and water
conservation (smart irrigation, recycling of water) (Singapore). (A: contrasting attitudes to
water supply).
Integrated drainage basin management for large rivers ( Nile, Colorado) and water sharing
treaties and frameworks (United Nations Economic Commission for Europe (UNECE) Water
Convention, Helsinki and the Water Framework Directive and Hydropower, Berlin). (P: role of
players in reducing water conflict risk).
Carbon Cycles
1.1 Most global carbon is locked in terrestrial stores as part of the long-term geological cycle.
The biogeochemical carbon cycle consists of carbon stores of different sizes (terrestrial,
oceans and atmosphere), with annual fluxes between stores of varying size (measured in
Pg/Gt), rates and on different timescales.
Most of the earth’s carbon is geological, resulting from the formation of sedimentary
carbonate rocks (limestone) in the oceans and biologically derived carbon in shale, coal and
other rocks.
Geological processes release carbon into the atmosphere through volcanic out-gassing at
ocean ridges/subduction zones and chemical weathering of rocks.
1.2 Biological processes sequester carbon on land and in the oceans on shorter timescales.
Phytoplankton sequester atmospheric carbon during photosynthesis in surface ocean waters;
carbonate shells/tests move into the deep ocean water through the carbonate pump and
action of the thermohaline circulation.
Terrestrial primary producers sequester carbon during photosynthesis; some of this carbon is
returned to the atmosphere during respiration by consumer organisms.
Biological carbon can be stored as dead organic matter in soils, or returned to the
atmosphere via biological decomposition over several years.
, 1.3 A balanced carbon cycle is important in sustaining other earth systems but is increasingly altered
by human activities.
The concentration of atmospheric carbon (carbon dioxide and methane) strongly influences
the natural greenhouse effect, which in turn determines the distribution of temperature and
precipitation.
Ocean and terrestrial photosynthesis play an important role in regulating the composition of
the atmosphere. Soil health is influenced by stored carbon, which is important for ecosystem
productivity.
The process of fossil fuel combustion has altered the balance of carbon pathways and stores
with implications for climate, ecosystems and the hydrological cycle.
2.1 Energy security is a key goal for countries, with most relying on fossil fuels.
Consumption (per capita and in terms of units of GDP) and energy mix (domestic and foreign,
primary and secondary energy, renewable versus non-renewable).
Access to and consumption of energy resources depends on physical availability, cost,
technology, public perception, level of economic development and environmental priorities
(national comparisons USA versus France).
Energy players (P: role of TNCs, The Organisation of the Petroleum Exporting Countries (OPEC),
consumers, governments) have different roles in securing pathways and energy supplies.
2.2 Reliance on fossil fuels to drive economic development is still the global norm.
There is a mismatch between locations of conventional fossil fuel supply (oil, gas, coal) and
regions where demand is highest, resulting from physical geography.
Energy pathways (pipelines, transmission lines, shipping routes, road and rail) are a key aspect
of security but can be prone to disruption especially as conventional fossil fuel sources deplete
( Russian gas to Europe).
The development of unconventional fossil fuel energy resources (tar sands, oil shale, shale gas,
deep water oil) has social costs and benefits, implications for the carbon cycle, and
consequences for the resilience of fragile environments. (Canadian tar sands, USA fracking,
Brazilian deep water oil) (P: role of business in developing reserves, versus environmental
groups and affected communities)
2.3 There are alternatives to fossil fuels but each has costs and benefits.
Renewable and recyclable energy (nuclear power, wind power and solar power) could help
decouple fossil fuel from economic growth; these energy sources have costs and benefits
economically, socially, and environmentally and in terms of their contribution they can make
to energy security. (changing UK energy mix).
Biofuels are an alternative energy source that are increasing globally; growth in biofuels
however has implications for food supply as well as uncertainty over how ‘carbon neutral’
they are. (Biofuels in Brazil)
Radical technologies, including carbon capture and storage and alternative energy sources
(hydrogen fuel cells, electric vehicles) could reduce carbon emissions but uncertainty exists
as to how far this is possible.
3.1 Biological carbon cycles and the water cycle are threatened by human activity.
Growing demand for food, fuel and other resources globally has led to contrasting regional
trends in land-use cover (deforestation, afforestation, conversion of grasslands to farming)
affecting terrestrial carbon stores with wider implications for the water cycle and soil health.
Ocean acidification, as a result of its role as a carbon sink, is increasing due to fossil fuel
combustion and risks crossing the critical threshold for the health of coral reefs and other
marine ecosystems that provide vital ecosystem services.
Climate change, resulting from the enhanced greenhouse effect, may increase the
frequency of drought due to shifting climate belts, which may impact on the health of forests
as carbon stores. (Amazonian drought events)
