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
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
Natural climate change
Quaternary period- most recent change spanning from around 2.6 million years ago
Last glacial period - 15 000 years ago
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
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'
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
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
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
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,
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
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
Uncertain Climate change projections
Emmisions - dont actually know how emmisions will change
- population increase
Complexity - we dont know what each scenario will cause
Management
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
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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