water and carbon

open system

systems that have inputs and outputs or energy and matter

eg. drainage basin

closed system

system that has inputs/outputs of energy but not matter

eg. carbon cycle

dynamic equilibrium

when there is a balance of inputs and outputs within the system - all stores stay the same

positive feedback

sequence of events that amplifies or increases change

negative feedback

sequence of events that neutralises/nullifies the effects

+ve feedback in water cycle

• rising se levels means ice shelves become unstable as they are in more contact with warmer ocean water

• leads to increased breaking up of ice shelves

• least to increase in melting

• sea levels further rise

-ve feedback in water cycle

• temperatures rise

• fuel builds up, leading to increased risk of wildfires

• increased wildfires leads to greater combustion of vegetation - releases CO₂

• more CO₂ in atmosphere leads to further increased temperatures

+ve feedback in carbon cycle

• increased temperatures

• leads to increased evaporation from oceans

• leads to more cloud cover

• clouds reflect radiation from the sun

• leads to slight cooling of temperatures

-ve feedback in carbon cycle

• increased atmospheric CO₂

• leads to increased temperatures

• promotes plant growth + rates of photosynthesis

• this removes more CO₂ from the atmosphere

• counteracts rise in temperatures

lithosphere/geosphere

all of the rocks on earth - including mantle and crust

water stored as liquid contained in rocks

hydrosphere

all solid, liquid and gaseous water on the planet

water stored as fresh and saline water, mostly liquid state

biosphere

all microorganisms, plants and animals of earth

atmosphere

body of gases surrounding the planet

water stored as water vapour + condensation of freshwater

cryosphere

water stored in solid state (ice/snow)

pedosphere

water stored as liquid water contained within soil

___% of Earth’s water is in oceans

97

___% of Earth’s water is freshwater

___% of Earth’s water in in oceans

___% of Earth’s freshwater is stored as snow and ice

70

___% of Earth’s freshwater is in groundwater

30

change in water stores - factors affecting evaporation rates

• amount of solar energy

• availability of water

• temperature of air - warmer air holds more water

change in water stores - factors affecting condensation

• decrease in temperature

• higher altitudes - cooler due to less dense air pressure

change in water stores - factors affecting cloud formation

• presence of aerosols or condensation nuclei

• become the core of cloud droplets that water droplets attach to

• humidity needs to increase so that there are enough microscopic water molecules for clouds to form

condensation nuclei

can come from natural sources eg volcanoes or forest fires

can come from human activities such as air pollution or dust

water stores in tropical rain forests

moist areas so have high evaporation rates

water stores in temperate forests

large area occupied by leaves so greater evapotranspiration rates

water stores in deserts

limited rainfall as they receive sinking, dry air from high pressure systems

water stores in polar areas

dry as they receive high pressure systems + cold air that can’t hold as much moisture as warm air

every 1^oC increase in global temps, there’s a __% increase in moisture holding capacity of the atmosphere

7

convectional rainfall

due to heating sun, warm air rises, condenses as higher altitudes and falls as rain

relief rainfall

warm air is forced upward by a barrier such as mountains, causing it to condense at higher altitudes and fall as rain

frontal rainfall

warm air rises over cool air when two bodies of air meet, as the warm air is less dense and therefore lighter

it condense at higher altitudes and falls as rain

infiltration

process of water moving from above ground into the soil

percolation

water moves from the ground or soil into porous rock

throughflow

water moves through the soil and into streams or rivers

surface runoff

water flows above ground as sheet flow or in rills

groundwater flow

water moves through rocks

stemflow

flow of water intercepted by plants or trees

water stores

• soil

• groundwater

• rivers

• plants

• surface

• ocean

water balance formula

precipitation = total runoff + evapotranspiration ± storage

areas near equator receive ___ rainfall because

convectional

constant solar heating produces large-scale evaporation and moist rising air that forms convectional rainfall

mid-latitude areas receive ___rainfall because

frontal

when a warm, moist air mass cools and is forced to slide up over a colder, denser mass of air

mountain ranges receive ___ rainfall because

relief

near water sources can receive high levels of precipitation - because clouds rise to go over mountains, cool and condensate

albedo effect on water stores (+ve feedback)

• melt lakes + meltwater channels on the surface of the ice absorb heat - accelerating melting

• meltwater travels through glaciers

• helps soften them + drains the bed

• lubricates their movement as they flow towards the sea

drainage basin

area of land drained by a river and the smaller tributaries that flow into it

water surplus

excess water available in a system

occurs when precipitation exceeds evapotranspiration

water deficit

reduction of water available within the system

occurs when evapotranspiration exceeds precipitation

flood hydrograph

graph of the discharge of a river leading up to and following a storm/rainfall event

flood hydrograph - peak discharge

maximum level of water in the river

flood hydrograph - rising/falling limb

increasing/decreasing water level in the river

flood hydrograph - lag time

time difference between peak rainfall and peak discharge

shorter lag time = greater risk of flooding

factors affecting flood hydrograph

• permeable/impermeable rock

• clay soils with low infiltration rate

• sleep slopes

• drainage basin already saturated from previous heavy rainfall

• low density vegetation

• urbanisation leading to impermeable surfaces

• deforestation

• ploughing

natural causes changing water cycle

• seasonable change

• storm events

• droughts

• el nino/nina

seasonal change in water cycle - summer

• higher density vegetation = more interception

• higher temperatures = more evaporation

• dry soils encourages runoff

• channel flow low due to water deficit

• groundwater stores reduce

• lower precipitation inputs

seasonal change in water cycle - winter

• lower density of vegetation = less interception

• lower temperatures = reduced evaporation

• soils may become saturated leading to overland flow

• higher channel flow due to water surplus

• groundwater stores replenished

• higher inputs of precipitation

human causes of change in the water cycle

• water abstraction

• deforestation

• soil drainage

• climate change

impact of storm events on water cycle

• air temps rise → increased evaporation + amount of water vapour held in atmosphere

• leads to more intense rainstorms

• less infiltration as the ground is quickly saturated → more surface runoff → more flooding

• also depends on the antecedent conditions

antecedent conditions

previous rainfall/conditions

previously dry → greater rates of runoff as water can’t infiltrate as the groundwater stores may not be replenished

impact of El Niño on water cycle

• rain moves east following the warm ocean current → creates low pressure system

• place like Peru and Ecuador in S. America receive heavy rainfall

• reduced precipitation in Australasia + S.E Asia → may lead to sever droughts and bushfires

• disruption to global atmospheric circulation can bring unusually sever winter weather to the USA

impacts of La Niña on water cycle

• warm waters pool around SE Asia dye to stronger trade winds

• warmer water heats air above → creates low pressure system with more rainfall in SE Asia and Australasia

• rainfall associated with summer monsoon in SE Asia greater than normal

• due to upwelling → cold water forms around S America → creates high pressure system with reduced rainfall

___% of global water is in the hydrosphere

96

albedo effect

lighter surfaces reflect the sun’s energy/light eg. ice or snow

darker surfaces absorb the sun’s energy/light eg. ocean or water

impacts of droughts (+potential fires) on the water cycle

• rivers/lakes storage will be reduced

• vegetation destroyed by fires → interception/transpiration reduced

• groundwater flow becomes more important as its a long term storage unaffected by drought

• heat+dry air causes higher evapotranspiration rates

impacts of soil drainage on water cycle

• artificially increases through flow speed in soil

• heavy machinery can compact the ground → increases overland flow as less water can infiltrate

• more water reachers rivers more quickly → increases flooding chance

• water table in soil is lowered → soil moisture level reduced

impacts of deforestation on water cycle

Localised:

• evapotranspiration reduced as replacement vegetation has smaller leaves/roots + is less dense

• overland flow and through flow increase

Extensive:

• evapotranspiration low as a lot of water leaves the area in the river channel as runoff rather than being recycled

• precipitation levels fall

• long term - less runoff means less water gets to river → flow is reduced

impacts of water abstraction on water cycle

• intrusion of saltwater from the sea degrades the groundwater

• reduces the flow into river/lakes as many freshwater sources rely on springs from groundwater aquifers during the dry season

• if the groundwater recharge rate is less than what is being utilised than the groundwater stores will disappear as the water table falls

impacts of climate change on water cycle

• warmer atmosphere holds more moisture → more intense downpours

• increased risk of flooding

• earlier snowmelt + more precipitation falling as rain instead of snow

• slower jet stream → more persistent weather patterns → record temps

• may lead to snow and ice melt in the arctic

aquifer

body of permeable rock which can contain or transmit groundwater

feedback

the process of a system trying to achieve dynamic equilibrium

oceanic water covers __% of the planets

72

melting sea ice ___sea level

doesn’t rise as it originates from the ocean water

ice shelves

platforms of ice formed when ice sheets and glaciers move out into the oceans

exist mostly in Antarctica, Green + Arctic

icebergs + affect on sea level

chunks of ice that break off glaciers/ice shelves and drift into oceans

raise it at first when they leave land and push into water, but not when they melt in the water

ice sheets

mass of glacial land more than 50,000km²

form in areas where snow falls and doesn’t melt completely over summer

over 1,000 years the layers of snow pile up, grow thicker/denser, ice compresses

constantly in motion, slowing falling downhill

Antarctica ice sheet is ___km²

14 million

Greenland ice sheet is ___km²

1.7 million

Greenland ice sheet contains __% of the total global fresh water

8

greatest width of Greenland ice sheet is ___km in the north

1,100

Greenland ice sheet length __km vertically

2,400

if total Greenland ice sheet melted, global sea levels would rise by __m

7.2