Our Natural World


Global Hazards- Global Atmospheric Circulation

Ocean currents and air circulation are why the equator doesn't just get hotter and why the poles don't get colder and colder.

Hadley cell- warm air rises to the equator where both cells meet-> area of low pressure as high insolation causes hot air to rise-> warm with high levels of precipitation.-> 0-30 degrees N and S of equator.

Between the Ferrel and Hadley cell, there is high pressure meaning there are deserts as the cool air sinks becoming warmer and drier.

Ferrel cell- Between the Polar and Hadley cell->  is thermally indirect meaning there is high pressure at the North (30 degrees) of the equator and it sinks to create low pressure-> 30-60 degrees N and S of equator.

Between the Ferrel and Polar cell, there is low pressure as cold air mixes with warm air meaning the UK has a wet, mild climate.

Polar cell- A thermally direct cell meaning when cold air sinks at the North pole, before flowing South it sinks and creates high pressure. Above 60 degrees of the equator.

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Other factors

Albedo effect- NO snow/ice -> More heat absorbed -> Snow/ice-> Surface reflects more heat. Altitude- Air pressure is low higher up-> colder temperatures-> 1 degree for every 100m Ocean currents- e.g. N/Atlantic drift starts in Carribean and keeps UK warm when passes. Winds- air moves from high pressure to low pressure-> large pressure difference creates strong winds. Cloud cover- Equator has more cloud cover-> Reduced insolation...-> Tropics have less cloud cover-> higher insolation Land and sea- Land heats up quickly and cools down quickly-> water is slow to warm up but stays warmer for longer periods of time.

Trade winds- Easterly winds which blow from the tropics towards the equator. From high pressure belts to low pressure belts e.g. Mt Washington 372km/h winds-> forms barrier to westerly trade winds Katabatic winds- a wind flowing downhill (valley sides and floors)-> usually as air cools, condenses and sinks at night. e.g. Antarctica's large ice sheets sloping gently into sea contribute to +320km/h winds Jet streams- Winds high in the atmosphere-> very strong (nothing to slow them down) e.g. Mt Everest recorded 225km/h winds as reaches high up into jet stream.

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Extreme Earth in contrasting countries

Hottest location-  Iran 70.7 degrees -> In the Lut Desert, dark lava in the sands gives a low albedo effect and high insolation -> No cloud cover-> Minimal surface winds -> edge of Hadley cell, high pressure with sinking air.

Coldest location-  Antarctica -89.2 degrees -> further away from equator, low insolation -> 98% covered in ice, high albedo effect -> Altitude, high relief -> Ocean currents keep air cooler for longer -> Katabatic winds

Wettest location-  The Khasi Hills, India -> 9300mm of rain in a month, record (July 1861) -> Clouds blown in from Bay of Bengal travel over flat land of Bangladesh, when they reach Khasi Hills they are forced to rise rapidly -> resulting in relief rainfall

Driest location-  The Atacama, Chile -> Annual average rainfall approx 15mm -> Tropic of Capricorn, rain shadow of Andes mountains -> Cold peruvian ocean current flowing alongside-> no moist, warm air to form clouds. 

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Tropical Storms- Typhoon Haiyan

Conditions: Ocean temperature above 26.5C -> warm, moist air to cause extreme precipitation. Ocean depth more than 60m-> Condensation when warm air rises and cools releses huge amounts of energy, making storms powerful and wind speeds increase -> rising air creates low pressure, which increases surface winds-> Coriolis effect deflects paths of winds, causing storms to spin. Effects- 315km/h winds caused by big pressure difference between low pressure centre and surrounding area 24 hours before hit (super typhoon)-> as warm moist air cools and condences storm surges are formed as high as 20ft bringing big waves with it- Tacloban located in a bay so watere squeezed in causing sea level to rise even more.

Impacts- over 1/2 million families homeless-> over 6300 deaths -> damage to 571 health clinics-> communications down and transport unavailable-> $2.86 Billion damage caused ($8 Billion to reconstruct)->77% farmers and 74% fishermen lostmain source of income-> Crops damaged-> Oil barge punctured & 85,000 litres of oil leak into sea-> Trees uprooted

Responces- UN appealed £190million emergency aid-> WHO managed healthcare workers-> Australia $28million package, doctors, medicines, material for shelters, fertilisers/seeds -> By April 20141500km road rebuilt, 560 schools up and running.

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El Nino and La Nina

El niño- pressure rises in the western Pacific and falls in east-> causing trade winds to weaken or reverse direction-> resulting in surface temperature increase preventing upwelling, causing unusually dry weather in high pressure west (droughts seen in eastern Australia and Indonesia)-> Rising air and low pressure in eastern Pacific leads to unusually wet weather (serious floods seen in places that don't recieve much rain, e.g. Peru) -> event occurs every 3-4 years and lasts from 9-12 months-> causes shortages of food and water, bush fires and poor air quality.

La nina- when the normal conditions become more extreme-> trade winds blow to the west more strongly, and more cold water rises in the eastern Pacific resulting in lower surface temperature-> causes more heavy rainfall and floods in the west, and less rainfall and droughts in the east-> occurs every 2-7 years. 

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UK drought 2012

UK Drought: between April 2010 and May 2012 air circulation brought dry winds from Europe in the east-> only recieved 85% of average rainfall-> Warmer temperatures caused more evaporation of water from reservoirs and soils dried out-> made difficult for any rain to soak into ground and became impermeable.

Social impacts- restrictions in homes- hosepipe ban introduced affecting 20million people (can't water gardens or wash cars- fines up to £1000 if caught)

Economic impacts- farmers crops struggled to grow- wheat yield down by 10%, financial loses-> over £55 million spent fighting wildfires which raged through South Wales, Surrey and Scottish border due to dry soils

Environmental impacts- Wild fires in South Wales destroyed habitats-> river water used for irrigation caused change to river ecosystems and posed threat to aquatic wildlife-> Rail networks and many roads affected by ground shrinkage, impacting transport.

Responces- Hosepipe bans -> campaigns to conserve public water (e.g. shower for only 4 minutes and share bath water)-> permits allowed farmers and companies to irrigate water.

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Tectonic Plates

Continental crust- Thicker and less dense. Oceanic crust- is thinner and more dense Tectonic plates move due to convection currents in the asthenosphere of the mantle when hot material that is less dense slowly rises and cools as it gets nearer the top becomming more dense, then slowly sinks creating circular movements. 

  • Destuctive boundaries- two plates moving towards each other-> a dense oceanic plate meets a continental plate, then subducted beneath into the mantle and melts in the subduction zone-> often creates volcanoes and ocean trenches e.g. Pacific plate and Eurasian plate in Japan.
  • Collision boundaries- both plates continental crust that move towards each other-> neither is subducted into mantle- instead both plates are folded and forced upwards, creating fold mountains e.g. Eurasian and Indian plates colliding to form Himalayas.
  • Constructive boundaries- two plates move away from each other-> magma rises from mantle to fill the gap and cools, creating new crust/volcanic islands/Mid-Atlantic Ridge.
  • Conservative boundaries- two plates move sideways past each other, or same direction but different speeds-> crust isn't created or destroyed e.g. San Andreas fault, west USA
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Caused by tension build up at all four plate boundaries:                                              Destructive-> tension builds when one plate gets stuck as it's subducting into the mantle. Collision-> tension builds as the plates are pushed together. Constructive-> tension builds along cracks within plates as move away from each other. Conservative-> tension when plates that are grinding past each other get stuck.

  • Plates eventually jerk past each other, sending out seismic shock waves and these vibrations are the earthquake-> Shock waves spread out from the focus-> near focus= waves stronger, cause more damage-> the epicentre is the point on the Earth's surface straight above the focus.
  • Earthquakes are measured using the moment magnitude scale/ Richter scale (energy released) or the Mercalli scale (measures effects). 
  • Shallow-focus = commen, caused by tectonic plates moving at or near the surface, focus between 0-70km (1.0 - 5.0)-> waves radiate horizontally, cause damage over a large area.
  • Deep-focus = rare, crust previously subducted into the mantle moving towards centre of the Earth, heating up or decomposing. Focus between 70-700km. Cause less damage at surface as shock waves travel though more rock, reduces power-> waves radiate vertically so fairly small area suffers intense damage (6.0 - 8.0)
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Japan (AC) earthquake/tsunami March 2011

Causes: over 200 years stress between Pacific plate and North American plate (destructive) eventually released forming 9.0 magnitude earthquake-> shock waves travelled mostly 6km/s -> lasting up to 5 minutes.-> Tsunami caused by compression on faultline, upwelling 6km of sea water being displaced-> 800km/h meant little opportunity to escape-> Japan's earthquake proof buildings helped mitigate impacts (cross bracing, deep foundations)-> however 10 metre high tsunami wall did not work in some places (Miyaki) as earthquake caused coastline to drop by 1 metre.

Economic impacts- £181 billion of damage-> 10% of Japan's fishing ports destroyed

Social impacts - 16,000 people died-> over 300,000 buildings destroyed inc. schools and hospitals destroyed-> Sendai and Miyaki hit badly

Responce- Hawaii tsunami warning issued- evacuations saved 1000s lives-> Save the Children- emergency response teams-> Red Cross- medical care, clean water and shelter.

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  • Found at destructive and constructive plate margins-> at destructive, on subduction a pool of magma forms and rises through cracks in crust called vents. Erupts onto surface (as lava) forming a volcano-> at constructive, magma rises up into the gap created by plates moving apart, forming volcano -> on eruption they emit lava and gases e.g. sulphur dioxide (poisonous and silent) also pyroclastic flows, torrents of hot ash, rocks and gases-> can cover land and block sun.
  • Hotspots found away from plate boundaries where areas of the Earth's crust are hotter than normal-> cause magma from mantle to break through the crust and erupt at the surface forming a volcano-> found anywhere and remain stationary over time, but crust moves above them-> creating chains of volcanic islands e.g. Hawaii (Pacific plate)
  • Composite volcanoes: e.g. Mt. Pinatubo, Philippines -> at destructive plate boudaries-> subducted oceanic crust contains lots of water causing it to erupt-> to start ashy explosions deposit a layer of ash, then erupt a layer of thick, viscous lava (can't flow far) can block up vent building up pressure. This forms a steep-sided cone shape. 
  • Shield volcanoes: e.g. Queen Mary's Peak->usually found at constructive boundaries or hotspots-> not very explosive and made up of only lava-> lava is runny and flows quickly, spreading over a wide area-> forming a low, gently sloping shield shape.
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Mitigation is used to reduce the threat of death and destruction caused by tectonic activity.

Early warning systems- can predict earthquakes by 30-60 seconds using networks of seismometers and lasers-> warnings communicated quickly-> lets people get under cover before shaking-> delicate or dangerous jobs can be stopped for safety-> utilities like gas can be shut off, preventing leaks and fires-> tsunamis warning can allow evacuation to occur while sea wall/barriers are closed.                                                                                      Volcanoe eruptions can be predicted using seismographs to show changes in shape of volcano and escaping gas etc. indicating an eruption-> monitoring them allows emergency services to plan and respond by: extending evacuation zones if more violent-> ash clouds can be tracked to divert/cancel flights to prevent passenger risk-> spread of poisonous gases can mean they warn people to put on gas masks.

Building Design: In AC's 'earthquake proof' buildings can be designed to withstand earthquakes-> reducing deaths and injuries from falling masonary and reduces cost of repairs and rebuilding afterwards-> by using strong building materials (reinforced concrete), deep foundations, shock absorbers  and a damper in roof to absorb earthquake's energy-> pipelines can be designed to flex and not break during earthquakes-> prevent floods/fires.

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Changing Climate- evidence

Past climate- Quaternary period (last 2.6 million years)-> global temperature has shifted between warm interglacial periods (10,000-15,000 years) and colder glacial periods (80,000 - 100,000 years)-> global warming is the sharp rise in global temperatures over the last century, type of climate change.


Ice Cores: one layer of ice formed each year on ice sheets-> cores drilled, scientists analyse gases trapped in layers to find the temperature of each year with O2 and CO2 concentration-> very detailed and reliable

Sea Ice positions: forms around poles in winter when ocean temperatures fall below -1.8C-> melts in summer when warmer-> observe max and min extent of sea ice each year to tell how ocean temperatures are changing-> very reliable, but accurate records not very far back.

Diaries and paintings: historical diaries can show past climate by number of rain or snow days and harvests ie. early harvest suggests warm weather-> e.g. Charles Dickins "a white Christmas" book shows frost fairs on frozen River Thames, winters regularly colder 500 years ago than now-> aren't very reliable, as they are subjective and can be exaggerated.

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Natural causes of climate change

Natural causes:  Milankovitch cyclesvariations in Earth's orbit around the sun-> stretch- orbital path changes from almost perfect circle to an ellipse and back every 96 000 years-> tiltat an angle in orbit, axis changes over cycle of 41 000 years-> wobble- axis of Earth wobbles like a spinning top on cycle of 22 000 years-> these cycles effect distance of the Earth from the Sun, and the angle which the Sun's rays hit-> changes amount of insolation, if recieves more energy it gets warmer-> tilt and wobble affect insolation at different latitudes and times of year-> these could cause glacial and interglacial cycles of Quaternary period

Sunspots- cooler areas of the Sun's surface, visible as dark patchesincrease output of energy-> cycles of about 11 years, sometimes longer cycles several hundreds or thousands of years-> periods of less= reduced solar output, makes Earth's climate cooler in areas.

Volcanic activity- major eruptions eject large plumes of ash and sulfer dioxide gas into atmosphere-> can spread in stratosphere and form barrier of ash and gas, reflecting Sun's rays back out to space, lowering surface temperature of Earth on average-> short-term changes caused e.g. cooling from Mt Pinatubo eruption 1991 -> similar to asteroid collisions

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Other causes

Natural greenhouse effect: essential for keeping our planet warm-> gases in atmosphere naturally act as an insulating layer, trapping outoing heat-> greenhouse gases trap heat- carbon dioxide, methane, nitrous oxide (fertilisers, exhausts) halocarbons (air conditioning...)

Enhanced greenhouse effect: Human activities are contributing to the greenhouse effect by making it stronger, causing global warming-> too much greenhouse gas in the atmosphere means too much energy being trapped, which causes the planet to warm up-> this happens by: farming of livestock and rice paddies, producing methane-> making items in factories by combustion of fossil fuels, like coal, oil, petrol producing CO2-> deforestation means trees stop taking in co2 and when they are burnt they release it.

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Impacts of climate change- Case Study

Global impacts: LAKE CHAD- reduced in size to 1/10th of original, from greenhouse gas emmissions-> 30 million rely on lake for fishing, irrigation and fresh water-> increasing poverty for subsistence farmers in Niger and fishermen, malnutrition, increased rural-urban migration, conflicts caused. TUVALU- island uninhabitable by 2050-> high tide mark rising 5mm per year -> more storms mean increase in saltwater intrusion and salinisation of soils so farmers can't grow crops, forced to migrate to Aukland, New Zealand. BANGLADESH- more serious flooding for longer means increase in water-borne diseases like cholera. ARCTIC- polar bears threatened due to loss of sea iceswim further for food, alters ecosystem. EL NINO- effect more frequent and stronger- Peru more dangerous flooding, Australia more droughts.

UK impacts: (warmer temperatures, more storms, sea level rise, drought) Storm Desmond 2015- 175mm in 36 hoursover £500 million in damage, Carlisle Cumbria worst effected- 3 died-> more grapes growing 2014, 6.4 million bottles sold-> 2003 heat wave, 2000 died-> 2012 drought, wild fires cost over £55 million a year, hosepipe ban affected 20 million people -> 2014 Winter storms, Devon and Dorset coast (railway track at Dawlish damaged), more coastal erosion meant loss of habitats, and cost of sea defences.

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Distinctive landscapes- UK landscape

Uplands: North and West of UK, formed of harder rocks resistant to erosion and impermeable e.g. Granite in Scottish peaks, igneous slow erosion-> created during glacial periods ice carved U-shaped valleys-> steep gradient-> colder temperatures and high precipitation-> more freeze-thaw weathering and chemical weathering due to higher relief in mountains

Lowlands: non-glaciated, found in south and east-> softer rock landscape impacted by periglacial conditions when ground permafrost through year, rivers flow over chalk (normally permeable as sedimentary) and erode to form a valley-> after ice-age ground becomes permeable again, draining out rivers forming a 'dry valley'-> produces alkali soil- quite fertile

Weathering: MECHANICAL- breakdown of rock w/o changing chemical composition-> temp alternates above and below 0 degrees, water gets into cracks in rock and expands when freezes putting pressure on rock-> when water thaws it contracts releasing pressure, causing rock to break up over time. CHEMICAL- rain has dissolved CO2 making weak carbonic acid -> reacts with rock containing calcium carbonate e.g. limestone/chalk and rain dissolves them -> BIOLOGICAL- breakdown of rocks by living things, e.g. plant roots grow into cracks on rock surfaces and can split them by pushing them apart.

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Mass movement is the shifting of rocks and loose materials down a slope e.g. cliff or valley side-> when force of gravity acting on slope is greater than force supporting it-> cause rapid coastal retreat-> more likely when material full of water- acts as a lubricant makes it heavier -> undercutting of slope by erosion will increase chance of mass movement: e.g. vertical slides or rotational slumps.

Erosion processes: Hydraulic actionwaves force compress air in cracks of rocks, puts pressure which widens and breaks up the rock. Abrasioneroded particles scrape and rub against the rock, removing small pieces and wearing away. Attritioneroded particles in water smash into each other and break into smaller fragments wearing them down and rounding edges off. Solutiondissolved CO2 makes river slightly acidic, reacts chemically with some rocks and dissolving them.

Transportation processes: Tractionlarge boulders/rocks pushed along river bed/sea floor by force of the water. Saltation- pebble-sized particles bounced along river bed by water.  Suspensionsmall particles like silt/clay carried along in water Solution- soluble materials dissolve in water and are carried along.

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Geomorphic Processes

Coastal features caused by erosion: wave cut platform-destructive waves attack lines of weakness between high and low tide-> erosion of fault by geomorphic processes such as abrasion and hydraulic action creates wave cut notch-> continued erosion creates an overhang, eventually collapses unable to support itself, cliff retreats, platform seen low tide.

Dorset's Jurrasic coast is renowned for it's limestone arch 'Durdle door' formed from a headland of resistant limestone with weaknesses ie. cracks-> waves crash enlarging cracks through hydraulic action and abrasion (describe how)-> repeated erosion/enlargement of cracks causes a cave to form that eventually deepens until it breaks through forming an arch-> 'Old Harry' is a chalk stack that was formed by the process of an arch becoming too unstable from continued erosion and collapsing forming an isolated stack separate from the headland  -> 'Swanage Bay' is an example of erosion features due to alternating bands of resistant and less resistant rock along the coastline layered as chalk, clay and limestone-> clay being soft and less resistant in the middle was eroded much quicker by abrasion creating a bay which is sheltered by the resistant headland meaning low energy waves form to carry material to bay

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Coastal management- case study

  • In the 1960s Bournemouth beach nearly disappeared as a result of erosion -> SMP (hold the line) now 100 wooden groynes (hard engineering) prevent longshore drift transporting the sand elsewhere by trapping sediment (£200,000 per groyne)-> this created a wider beach which slows waves, greater protection from erosion -> soft engineering to replace material already lost by beach replenishment, waves then erode this nourished sand rather than houses or roads-> sustainable, booming tourist area.
  • However this had a knock on effect down coast at Barton-On-Sea as longshore drift is stopped due to the groynes, leaving the beaches starved and rapidly eroding-> no longer provide protection for cliff face, made of impermeable clay causing increased mass and liquefication leading to collapse-> lots of mass movement (clay and gravel), rotational slumping
  • West Wales, Harlech spit formed due to coastal deposition by longshore drift-> transported sediment along beach with prevailing winds until end of coastline-> secondary wind changes direction, builds up spit can't go further-> water plants able to grow in spit, turns into a saltmarsh past original coastline, build up over time formed new land 6km long
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UK River Basin- Eden

V-Shaped Valleys formed by vertical erosion in the upper course-> fast-flowing water following heavy rain and high turbulence causes loose rough particles/boulders to be transported, scraping the river bed-> downwards erosion of channel by abrasion-> valley sides exposed to freeze-thaw weathering, this material causes further erosion by abrasion-> not enough energy to erode laterally so vertical erosion is dominant, deepens river valley.

Hell Gill Force a waterfall formed by geomorphic processes-> band of resistant limestone over a less resistant sandstone-> softer rock eroded by hydraulic action and abrasion from fast flowing water, forms step in river channel-> eventually hard rock undercut by erosion becomes unsuported and collapses-> collapsed rocks at foot of waterfall erode soft rock by abrasion, creating deep plunge pool-> over time more undercutting causes more collapses, the waterfall retreats upstream leaving behind a steep-sided gorge

Meanders in middle and lower courses form by erosion and deposition-> the current has a higher velocity on the outside of the bend as the channel is deeper (less friction to slow down)-> more erosion and undercutting here forms river cliffs-> current slower on inside as channel shallower = more friction eroded material deposited on inside forming slip-off slope

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More River Eden

Eden basin north-west England between upland mountains of Lake District and Pennines-> source on high limestone fells and mouth at Solway Firth-> Great Asby Scar is a limestone pavement caused by chemical weathering- carbonation-> Cumbria faces south-westerly prevailing winds, wettest part of the UK-> permeable ground becomes saturated, increases likliness of slumps occuring in upper course-> causing flooding, amount of sediment in river.

Carlisle built on River Eden floodplain-> wide valley floor floods and water slows down depositing eroded material which builds up flood plain (higher)-> meanders migrate across floodplain making it wider-> Levees formed as natural embankments when heaviest material deposited closest to river channel, builds up over time

2005 floods: River Eden flooded (175mm rain in 36 hours)-> in Carlisle, Cumbria up to £250 million in damage 3 people died-> management: £38 million spent since 2005 to protect people living alongside River Eden; 10km raised flood defences (hard engineering), 1000 trees planted in Dalston (soft engineering), 7 CCTV cameras etc. NOT effective....  2015 Storm Desmond: North-west England floods caused £500 million in damage-> 45,000 homes lost power-> 5,200 homes flooded-> 50 miles of road diversions caused-> record breaking 341.4mm rainfall in 24 hours-> 3ft deep water

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Sustaining Ecosystems

An ecosystem is a community of plants and animals, together with their environment (biotic- living and abiotic- non living components make up an ecosystem)-> climate determines what type of ecosystem forms 

Different parts of ecosystems are interdependent-> energy from sun is used by plants for photosynthesis-> add oxygen to atmosphere, needed for animals/humans to respire-> animals depend on plants for food and nutrients-> plants depend on animals' waste to fertilise seeds.

Polar ecosystems: surround Earth's geographical poles-> very cold, average temp >10 degrees each month, winters normally below -40 degrees (sometimes -90)-> rainfall/snowfall low no more than 500mm per year-> few different species, polar bears, penguins and marine e.g. whales, seals walruses -> few plants, some lichens and mosses on rocks, some grasses (slow, not tall) near warm coast with dwarf shrubs/trees-> characterized by permafrost 

Hot deserts: between 15 and 30 degree north and south equator high air pressure less than 250mm rainfall per year-> day temp of 50 degrees, night may be sub-zero-> sparse plant growth, cacti/thornbushes have long roots to reach deep water and fleshy stems, thick waxy skin to prevent moisture loss-> animals nocternal (lizards, snakes, scorpians), camels evolved

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More Global Ecosystems

Savannah grasslands: between tropics (Africa, India, Australia etc.)-> low rainfall, 800-900mm per year-> distinct wet/dry seasons, highest temp 35 degrees before wet season, lowest 15 degrees after it-> grass, scrub and small plants, adapted for low rainfall with long roots and small waxy leaves-> lots of insects, lions, elephants, antelope etc. Temperate: mid-latitudes-> hot summers (40 degrees) cold winters (-40 degrees)-> 250-500mm rainfall each year-> grasses and small plants-> fewer animals, more bison, wild horses and rodents.

Coral Reefs: (are living animals) tropical oceans near the equator 30 degrees N and Swarm areas of high insolation-> grow best in shallow, clear, salty water-> few plants other than algae inside the corals tissue (interdependent for nutrients) and sea grasses-> 25% off all marine species live here, flat bodies to hide in small gaps

Temperate forests: between tropical and subtropical regions-> 4 distinct seasons-> high precipitation year round (up to 1500mm)-> deciduous forests broad-leaved, shrubs, undergrowth, forest-floor plants-> Coniferous forests, evergreen trees (pine fir), understory of grasses/low-growing plants make use of available sunlight all year and rich soil-> lots of different mammals, birds, insects, streams and ponds habitat for insects to breed, trout etc.

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Tropical Rainforests

Tropical rainforests: located between tropics, along equator and near coastlines/rivers-> hot temp year round (20-28 degrees) high insolation, high precipitation daily (2000mm a year) ITCZtrade winds blow to equator warming so rise, making low air pressure, condensing then convectional rain-> cover 5% of earth's surface, home to 50% of biodiversity30% worlds birds in canopy-> camouflaged animals e.g. leave-tailed geckos... nocturnal e.g. sloths, sleep day, feed night-> epiphytes ability to climb tall trees reach sunlight e.g. fan palms, buttress roots, lianas and strangler figs-> Nutrient cycle, leaves shed year yound, decaying vegetation  decomposes rapidly, humus nutrients enter soil, dissolve in rainwater, dense vegetation takes up-> deep soils have chemical weatheringnutrient poor, shallow top soil rich in nutrients-> inter-dependent ecosystems with symbiotic relationships between plants/animals Services: help regulate global water cycle by storing water and releasing slowly into atmosphere, reduce risk of drought and floodingdense vegetation intercepts rain-> acts as carbon sink, plants absorb 0.7 billion tonnes of CO2 every year-> provides habitat to high diversity-> Productsmahogany, rubber, periwinkle for medicines-> Human impacts: Logging- soil erosion high, interrupts water cycle, dry wildfires, floods-> Agriculture- slash and burn, increase greenhouse effect, no rain interception, soil fertility reduced-> Minerals- extraction, heavy machinery, toxic chemicals-> trans-amazon highway, 3000 miles long.

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Sustainable management- CASE STUDY

Agroforestry: trees and crops grown together, some benefit from shelter of tree canopy-> also prevent soil erosion and crops benefit from nutrients in leaf litter-> Selective logging: trees only felled when a certain height-> young trees mature to ensure canopy height maintained  -> Afforestation: trees planted to replace lost primary forest-> lacks biodiversity, long time for species to re-establish-> Monitoring: satallite technology to ensure no illegal activities

Costa Rica: 1970-1990= 32,000 hectares of rainforest each year-> now try to reserve this-> income from sustainable agriculture/tourism (+2million tourists each year)->Meso-American  wildlife corridor from Mexico to Panama, providing migration routes for rainforest animals-> Ecotourism- Samasati Nature Retreat: doesn't damage natural environment-> no heavy machinary used, doesn't disrupt natural habitats with loud noices, minimal forest needs clearing-> few roads built, use natural springs/rivers, local material timber from afforestation project, buildings fit between trees, only biodegradable soap- use rainwater for showers-> only employs local people, sustainable income without harming rainforest by working for logging companies-> helps them achievegood quality of life-> teaches people about importance of rainforest

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Polar Environments- Human Impacts

Climate: 66 degrees N/S of equator-> winters are long and dark (-20 to -40 Arctic/ -90 Antarctic)-> Angle of sun is low as it is spread over a larger arealess intense-> high albedo effect-> sinking air (high pressure regions)- less rainfall, technically a desert-> Antarctic= no permanent inhabitants-> ice covered continent, main flora is moss/lichen and phytoplankton. 

Arctic impacts: around 5 million people live and work in the region-> large area of land made up of permafrost, thaws in summer months-> at risk of melting (Fairbanks, Canada) causing land to subside, roads and houses fall in on themselves-> Barrow land looks like a sieve, whalers dug cellers to freeze meat in permafrost, floods 20X higher in summer- sea eroded up to 150ft of landhouses lost -> when permafrost melts, trapped dead plants/animals decompose emitting large amounts of methane, greenhouse gas causes global warming-> burning fossil fuels = now 10-15% less sea ice than 1950s, loss of polar bear habitat Nomadic tribes e.g. Swedish Sami impacted by human activity in Kiruna, Norway due to iron ore mining and mineral extraction, largest in world (up to 80,000 tonnes a day), roads/ railways built cross ancient migration paths of reindeer... Sami have to direct into valley to preserve way of life-> mineral exploitation e.g. 1989 Exxon Valdez tanker hit rock & spilled over 11 million gallons oil, hard to clean up in cold oceans impacts still seen on coastlines (arctic oceans contain 13% of worlds untapped oil)->whaling=by 1930s 50,000 killed per year

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Management of Polar environments

Small scale- Arctic: near Clyde River, small settlement of 1000 inuit on Baffin Island in Canada-> in 2008 Marine Wildlife Sanctuary established as an important migration route to conserve 100 endangered bowhead whales from commercial/scientific reseach-> protects 336,000 hectares with restricted access, includes 2 deep ocean troughs (no commercial fishing/mineral exploration)-> however increased hydrocarbons shipping endangers lives of living organisms-> cruise ships waste products-> oil spills could cause catastrophe in route 

Global scale- 1986 International Whaling Convention: banned commercial whaling for meat, oil and bones-> however loopholes allow Norway, Iceland and Japan to catch whales for "scientific research" (over 30,000 whales killed since 1986 still) quotas used-> IWC allows inuit communities to hunt as provides whole community (only one a year- e.g.at Clyde River) Paris Agreement 2015: signed by 195 countries that aim to limit global warming to less than 2 degrees-> help to slow decrease in sea ice (each country aims to reduce carbon dioxide emissions)-> however US are withdrawing from their commitment, this is very damaging->  The Antarctic Treaty: In 1959, 12 countries signed agreement to sustainably manage Antarctic -> In 1998 an environmental protocol had 6 principles for human activity- no mineral exploitation allowed, dumping and burning of waste banned-> all applications for "scientific research" in Antarctic must have Environmental Impact Assessment- can't lie.

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