earth life support system - knowledge

Anthropocene

Age of humans ( we are the factor that changed the climate), ice sheets melt as temperatures rise, change the natural balance

Tipping point

A change becomes irreversible, if one point ‘tips’ others will too

System

All systems are connected (links to tipping point)

Melting ice

Increased and happening quicker, when ice melt, globe warms rather than cools

PPM (parts per million)

Amount of carbon in atmosphere, 350-450 is safe, anything above 450 isn’t safe

Amazon

Drying out and less able to generate rain, carbon will release into the atmosphere

Security and stability

Stabilise global temperatures and decrease carbon emitted into world and cut them ½ every year

Goldilocks zone

• Zone from the sun that allows liquid water to exist on planet surface

• Oceans = regulate global temperatures

• Clouds = reflect incoming solar radiation

• Water vapour = absorbs long-ray waves

Close system

• Energy can be received (from the sun) and lost (to space)

• No material crosses the boundary

• E.g earth

Open system

• Energy from the sun can enter the system and be lost to neighbouring systems as heat energy and drives processes like evaporation

• Water can enter and leave the system (evaporation and precipitation)

• E.g. a river drainage basin

Importance of water

• Part of many open systems , water can be stored in every system

• Speed and side of flows vary on short or long term scales

Evaporation

Liquid-vapour (heat is needed), released in condensation

Interception

Vegetation intercepts some water, water then evaporates (interception loss)

Through fall

Intercepted water which falls to the ground

Stemflow

Periods of long rainfall, intercepted water flow onto branches and stems

Ground water flow

When water percolates it then migrates through pores in the rocks as groundwater flow, as temperature decreases groundwater increases

Through flow

Gravity to stream and river channels

Percolation

Soil is underlaid by permeable rocks, water seeps underground

Infiltration

Gravity into soil and lateral movement, infiltration capacity = exceeds lands capacity of water leading to overland flow

Overland flow

Water across the surface as a sheet or as it trickles to streams and river channels, only occurs when the ground is saturated

Run-off

Movement of water across land surface

Transpiration

Evaporation of moisture from pores on the surface of leaves

Sublimation

Change of water (from ice) to vapour

ELR (environmental lapse rate)

Change of temperature with height, average is 6.5 C/km

Convection

Air parcels rise when the temperature is warmer than the atmosphere meaning its in-stable, when temperatures are the same, that’s the top of the cloud

Precipitation

• Way that rainfall can vary, can be water and ice that falls from the clouds (normally as rain, snow adn also hail, sleet and drizzle)

• At high latitudes and mountain catchments, water flows as snow and can take a while to melt=run-of time is delayed

• High intensity = more ground water flow and infiltration capacity is reached

Dew point

Temperature that allows the condensation to occur (water vapour turning into clouds)

Condensation nuclei

Core that water molecule need to attach to create rainfall/ raindrops

Cumuilform clouds

• Flat bases and vertical development

• From when air is heated through contact with the earths surface

• Causes heat to rise freely through the atomosphere, expand and cool.

• As cooling reaches dew point, condensation begins and clouds form

Stratiform clouds

Layers of cloud develop where air moves horizontally across a cooler surface. This process is known as aduection

Cirrus clouds

• Made of ice crystals

• Form at high altitude, consistent of tiny ice crystals

• They don’t produce preciciptaion and have little influence on the water cycle

Why does air cool and condense?

1. Raising air cools by adiabatic expansion

2. Air mass move horizontally across a (relatively) cooler surface

3. Air mass rise when they cross a mountain barrier

4. Warm air masses rise when they collide with cool air masses

Adiabatic expansion

Expansion of a parcel of air due to a decrease in pressure, expansion causes cooling

SALR (saturated adiabatic lapse rate)

• Rate at which saturated parcel of air cools

• Cools as it rises through the atmosphere, because condensation releases latent heat

• 7 C/km

DALR (dry adiabatic lapse rate)

• Rate at which a dry parcel of air cools

• Cooling, caused by adiabatic expansion

• 10 C/km

Carbon cycle

• A closed system (global scale), open (local scale)

• Sedimentary rocks hold 99.9% of carbon

• Carbon stores are known as carbon sinks

• Measure carbon stores and flows in pentagrams and gigatonnes (same thing)

• (Carbon transfer = carbon exchange = carbon flux) = movement of carbon

Fast carbon cycle

• Most carbon moves rapidly between the atomosphere, oceans, soil and biosphere

• 10-1000x faster than the slow cycle

Slow carbon cycle

Some carbon moves slowly bettween geological and ocean systems

Transfers of carbon - vegetation

• Photosynthesis uses sun energy, CO2 and water, plants converge light energy to chemical energy - take CO2 and release CO2

• During respiration the plants absorb oxygen and release CO2 - important as volume of CO2 is 1000x greater than the slow cycle

• Bacteria and fungi decomposes dead organic matter and realises CO2 into the atomosphere

• Regard as part of the fast carbon cycle as they happen daily and are constant (everything else i part of the system is slow)

Transfers of carbon - precipitation

• Atmospheric CO2 dissolves into rain, forms weak carbonic acid (natural) - high levels of CO2, high levels of acidity of rainfall (rain stays in soil)

• A negative is increased acidity of ocean surface may have harmful effects on marine life

Transfers of carbon - combustion

• Organic matter reacts/burns in the presence of oxygen, releasing CO2

• Burning fossil fuels - transfers around 10 GT of CO2/year from geological stores (atmosphere, biosphere and oceans)

• Land use change - burning Forrest’s and grasslands to clear area for agriculture (cultivation, improve grazing)

• NATURAL wildfires benefit the ecosystem as they clear excess litter (through lighting strikes etc)

Transfers of carbon - geological process

• Chemical weathering - rain with dissolved CO2 (acidic), dissolves limestone and chalk (carbonation)

• Plate tectonics - volcanoes erupting can catch fire and melt (rocks etc) which releases carbon through combustion

• The slow carbon cycle as it can take many years for the process to fully happen

Carbon sequestion

Physical and biological pumps absorb carbon from atmosphere, but transfer to deeper ocean differently

Physical ocean pump (in-organic)

• Deep ocean currents can store carbon for a long time

• Latitude, Tempurature and wind have a strong influence

• CO2 enters through diffusion and surface currents transport water and CO2 to the pole where it cools and sinks (down welling). Eventually water warms up and rises (upwelling), causing CO2 to re-enter the atomosphere

Biological pump (organic)

• Around 50 GT of CO2 drawn from atmosphere/year

• Phytoplankton photosynthesis- CO2 consumed by animals, when the die and decompose the carbon is released into the ocean

Phytoplankton

• Responsible for 20% of photosynthesis

• Microscopic, however produce 50% of oxygen

• Move carbon to the slow carbon cycle, and help lower atmospheric CO2 levels

• Climate change causes the photosynthesis to migrate to older ocean therefore bloom earlier or later which effects the food chain (miss the zooplankton)

How does anthropogenic climate warming afffect populations of phytoplankton?

• Warms the ocean - phytoplankton ‘migrates’ to cooler oceans as they aren’t ‘comfortable’ in warmer ocean

• Make ocean more acidic - effects conditions that phytoplankton need to survive (they die)

• Reduce the amount of oxygen in the ocean - when carbon is added into the ocean, oxygen is reduced therefore oxygen for animals to breath

A POSITIVE FEEDBACK LOOP

Surface water

River, lakes, reservoirs (literally the surface)

Sub-surface water

Groundwater held in aquifers deep Benitez the ground

Water table

Upper surface of the ‘zone of saturation’ in permeable rocks and the soil

Aquifer

A groundwater store in permeable rocks (e.g. chalks)

Artisan aquifer

Confined aquifer containing groundwater (when trapped will rise to the surface under own pressure)

Artesian pressure

Hydrostatic pressure exerted on groundwater in a confined aquifer coupling a sync line structure

Potentiometric surface

Water table - potential height of water table if was on the table

Syncline

A downfolded, basin like geological structure

Urbanisation

• Rural (farm and woodland) to urban (housing roads and factories)

• Drainage systems (removes water rapidly through gutters, sewers) - may cause streams water levels to rise

• Ground is covered with impermeable surface - doesn’t allow infiltration and minimal water storage

• Increased vehicle usage - CO2 in the atomosphere

Agriculture - arable farming

• land cleared for planting/harvesting crops

• Clearing of forest = reduction in carbon storage

• Soil CO2 storage id reduced through polling

• Harvesting crops = low levels of organic matter returned to the ground

Agriculture - pastoral farming

• Land cleared for livestock

• Low interception

• Irrigation diverts surface water form rivers to cultivated land

Fossil fuels

Coal, oils and natural gas have driven GLOBAL industrialisation and urbanisation, global economy is over-dependant on fossil fuels

• 2019 84% of global energy consumption

• Oil 33%, coal 27% and natural gas 24%

Anthropogenic emmisons

Environment change/ influenced by people, either directly or indirectly

Fossil fuel facts

• 10 billion tonnes of CO2 is regaled annually

• Carbon emissions grew faster in this decade (2000-2009) than any previous decade

• CO2 levels (atmosphere) are over 415 PPM (highest in 800,000 year)

• 879 GT of anthropogenic CO2 have remained in the atmosphere

• Anthropogenic emmisons total to 2000 GT - ¾ remain in atmosphere

• Anthropogenic emmisons are less than 10% of natural influx to the atmosphere

• Anthropogenic carbon levels if oceans and biosphere hadn’t done anything would be around 500 PPM

Feedback

Response to changes which disturbs systems equilibrium

Positive feedback

When a initial change causes further change (snowball effect)

Negative feedback

A automatic response to changes which disturbs in system which restores the equilibrium

Dynamic equilibrium

State of balance between continuing process - effected by humans

Positive feedback loop -water cycle

1. Water vapour is a greenhouse gas

2. More vapour in atmosphere

3. Increase of absorption of long wave radiation

4. Causes rising temperatures

Positive feedback loop - carbon cycle

• Global warming

• Seeds decomposition (release more CO2)

• Amplifying greenhouse effect

Negative feedback loop - water

1. More vapour = cloud cover

2. Reflects more radiation in to space

3. Less absorbed means global temperatures to fall

Negative feedback loop - carbon

1. Photosynthesis (carbon fertilisation)

2. Excess CO2 extracted from atmosphere

3. Stored in biosphere

4. Reach long term storage in soils and sediments

Geographic information systems (GIS)

Techniques used for mapping and analysing geographic data to show anomaly’s and trends globally and in specific regions

Remote sensing

• Monsters by satellite, ground based measurements on a global scale are impractical

• Special scale (space) - local, regional, global

• Temporal scale (time) - days, weeks, years

Photoperiod

Length of day from sunrise to sunset

Insulation

Short wave radiation (heat energy) from sun

Net primary productivity (NPP)

Rate at which plants accumulate energy (organic matter), considering energy used in respiration

Why monitor change?

• Max and min - sea level and ice = measure microwaves on earth surfaces and images over time

• Sea surface temperature = radiation emitted from earth, changes in SST and up/down welling

• Deforestation = land use change and reflecting/reflectivity of earth surface

• Atmospheric CO2 = measure levels and the effectiveness of CO2 absorption by plants

Why are remote sensing and GIS vital

• They show change overtime and produce accurate data continuously

• Allow scientists to see effectiveness of there management plans and see what need help and what doesn’t

Spatial scale

Space - local, regional, global

Temporal scale

Time - days, weeks, years

Diurnal

Change from day-night within a 24hr period

Diurnal - water cycle

Lower temperature at night reduce evaporation and transpiration, rainfall is dependant on the heating of the surface in the daytime

Diurnal - carbon cycle

Day CO2 flows from atmosphere - plants, reversed at night due to no sunlight as photosynthesis stops, CO2 flows plants - atmosphere

Diurnal - PSD

• Convectional rainfall can’t happen at night (tropical rainforest)

• In uk, fog, mist and dew can’t form in early morning father a cold night which cools the air Tempurature (dew point)

• In arctic tundra, no diurnal change as often day air night for long periods of time

Seasonal change - water cycle

• Changes in insulation effect the water cycle

• when more intense (June), more evaporation and evapotranspiration - doesn’t reach dew point

• When less intense (December), less evapotranspiration but as dew point is reached therefore more precipitation

Seasonal change - carbon cycle

• In summer a net flow of CO2 from atmosphere - biosphere, CO2 levels reduce by 2ppm, by end of summer the floe is reversed as decomposition releases CO2

• Solar radiation 800 W/m² summer and 150 W/m² winter

Who experiences most seasonal change

• Most land mass in the northern hemisphere

• Latitude has an impact on the level of seasonal change

Glacial

Cold period when glaciers are present, can last up to 100,000 years

Inter-glacial

Periods between glacial periods, much warmer, last around 30,000 years

Long term change - information

• In the last 400,000 years, 4 major glacial cycles

• Each cycle (glacial - inter-glacial) lasts 100,000 years

• Last glacial period was 20,000 years ago

• During the last glacial period uk was 5c cooler and under 1km of ice

• 250 million years ago average global temperatures were 22 c lower ( 7-8 c higher than today)

Effect on water stores during a glacial period (long term change)

Sea levels fall by 100-130 m, ice sheets and glacier cover 1/3 of continental land, net transfer of water in oceans to glaciers, ice sheets and permafrost

Vegetation during glacial period - long term change in water cycle

Glacier destroy areas of forests nad grassland the area covered by vegetation is just the biosphere. The tropics become dryer, deserts and grasslands displace rainforests

Flows of water during a glacial period - long term change

Lower rates of evapotranspiration, reduces exchanges between atmosphere and the oceans, biosphere and soils. Fresh water stored as snow and ice (water cycle slows)

Eustatic change

World wide change in sea level

Isostatic change

• Vertical movements of the earths crust

• Southern England sinking by 1mm/year, northern Scotland rising by 1.5mm/year (isostatic adjustment)

Concentrations of CO2 during glacial periods - long term change

A ‘dramatic’ reduction in CO2 levels, at times of glacial maxima CO2 concentration falls to 180 ppm (average is 415 ppm)

Role of oceans

CO2 transfers from atmosphere to deep ocean, in glacial periods nutrients are brought to the surface (simulates phytoplankton growth).

Phytoplankton take CO2 then die so carbon stored on oceans to floor

low oceans temperature = CO2 more soluble insurance water

Distribution of terrestrial ecosystems in glacial periods - long term change

Ice sheets occupy continents, causes deserts to expand, tundra expands as replaces temperate forest and grasslands ecosystem in glacial periods

Change in carbon fluxes and stores

Carbon stored in soils wont exchange with the atmosphere, tundra sequester high levels of carbon in the permafrost (low levels of vegetation)

Low precipitation, NPP and total volume of carbon fixed in photosynthesis will decline therefore slow of carbon flux

Smaller amounts of CO2 returned to the atomosphere