hazardous earth

  • Created by: jojodrew
  • Created on: 20-05-18 20:12

Surface winds

Cool air reaches ground and either moves back to the equator or towards the poles.

towards equator- trade winds

Trade winds blow from SE and NE - these meet and are geated by the sun 

surface winds towards the poles- Westerlies, NW and SW

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ocean currents

Large scale movements of water that transfer heat energy from warm to cool regions

Surface currents- caused by winds and help transfer heat away from the equator E.g. Gulf Stream bring water from the Caribean and keeps westerna europe warmer

Deep ocean currents -differences in water density 

in poles due to frozen water - water around gets saltier so it becomes denser, 

Denser - sinks so warmer water rises

^ Thermohaline circulation

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Natural climate change

Quaternary period- most recent change  spanning from around 2.6 million years ago
Last glacial period - 15 000 years ago

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orbital changes

Variations of the way earth moves away from the sun

every 96 000 years the path changes from a circle to a ellipse 

ever 41 000 years the earths axis tilts 

every 22 000 years the axi of the earth wobbles

these affect the amounts of solar radiation the earth receives

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Volcanic activity

Major volcanic erruptions eject large amount of material into the atmosphere 

some of these particles refelt sun back into space - earth cools

short term changes- Mount Tambora, indonesia, 1815 led to a "year without a summer'

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Solar Output

the suns output of energy is not constant 

it changes in short cycles about every 11 years

periods when the suns output is reduced may cause for the earth to be cooler

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Asteroid collisions

Asteroids hitting the earths surface can throw up hug amounts of dust into the atmosphere

this prevent the suns energy from reaching the earth 

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evidence of natural climate change

Tree rings - one ring each year. Thickness depends the climate.

Ice cores- ice sheets made up of layers. One layer for each year

scientists drill into ice cores and analyse gases trapped in the layers

Historical records- since 1850 the temps have been measured by thermometres

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Anthropogenic factors of climate change

Greenhouse effect 

Incoming energy from the sun is short wave radiation

Outgoing energy is long wave radiation

gases in the atmosphere act as an insulating layer - trap long wave radiation to regulate temp

gases that are trapped- greenhous gases , carbon dioxide , methane, 

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Activities making greenhouse effect stronger

Farming- livestock produces alot of methane

Land is cleared for farming , stops absorbtion of CO2

Industry- uses energy and industrial processes release greenhouse gases

eg. cement is made from limestone which contains co2

Energy- co2 is released from burning fossil fuels

Transport -cars etc.. run on fossil fuels

Car ownership increasinf in develoing countries

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evidence of anthropogenic climate change

Declining Artic Ice- Ice has declined by 3% each decade over 35 years

Global temps rise- have risen by 1'C since 1880

Thermal expansion- water in the ocean expands

Extreme weather events- since 1950 the has been a higher frequency of heat waves

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Uncertain Climate change projections

Emmisions - dont actually know how emmisions will change

- population increase

Complexity - we dont know what each scenario will cause


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Topical cyclones

Intense low pressure weather systems with heavy rain and strong winds that spiral around the centre.

caused when sea temp is at 26.5'C and the difference in windspeed is low

between 5'and 30' of the equator

the earths rotation deflects the path of the wind causing it to spin 

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physical hazards of tropical cyclones

high winds

inense rainfall - trillions of litres 

storm surges - rise in sea level

coastal flooding

landslides-hills unstable

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