Climate and Change

Climate and Change

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  • Created by: Sophie
  • Created on: 09-04-13 13:45

Theories

Sunspot Theory

  • Variations in sun's output
  • Dark spots contain large volumes of superheated gas, these are emitted and sometimes can reach the Earth's surface and higher amounts of these spots can lead to an increase in average temperature 

Milankovitch

  • Circular to Elliptical orbit changes closesness to sun which in turn increases/decrease average temperature
  • Varies over 100,000 years
  • Axis tilt varies by 1 degree which changes the amount of solar energy reaching parts of Earth's surface 
  • Varies over 41,000 years
  • Earth wobbles as it spins
  • Closer or further
  • Varies over 23,000 years
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Theories 2.0

Eruption Theory

  • Volcanic eruptions emit ash and sulphur dioxide gas
  • If high enough can spread around Earth in stratosphere by high level winds
  • This creates a blanket effect which stops some sunlight reaching Earth's surface
  • Reflected off the ash and gas
  • Produces cooling effect lowering average temperature


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Greenhouse Effect

  • Carbon Dioxide is a very important gas because it helps to regulate the Earth's temperature
  • Keeps planet comfortably warm
  • Without greenhouse gases, planet would be frozen wasteland
  • 0.1% energy from sun reaches Earth's surface
  • Some reflected most absorbed which warms land and oceans
  • Energy later re-emitted, warms up the atmosphere
  • most trapped by atmospheric (greenhouse) gases
  • Trap energy and reflect back down to Earth
  • Pollution from cities emit gases like CO2 which accumulate in the atmosphere
  • Increases strength in greenhouse effect
  • Increase energy reflected to Earth
  • Increase average temperature

Other Greenhouse Gases
Methane
Nitrous Oxide
Halocarbons 

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Evidence For Climate Change

Photos of the landscape/Diaries and books/Recored dates of regular events
Fossilised plants/animals no longer native to that country 

Glacial Retreat

  • Shrinking, several hundred metres over 30 years
  • Rising air temperatures causes melting
  • Summer melting exceeds winter accumulation

Polar Ice Caps

  • Since 1970's North Pole ice sheet has shrunk by 30%
  • Arctic air temperature has rise by 2 degrees celsius

Sea Level Change

  • Measurements, tidal gauges
  • 20cm rise in sea level over past 200 years
  • Observations such as the Maldives islands being flooded as 2m above sea level
  • Causes by melting of polar ice sheets 
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Effects Of Climate Change For The UK

  • Heating and road gritting costs could fall
  • Tourism industry boost
  • New crops might mean sales opportunities for farmers
  • More land could be farmed at higher altitudes 
     
  • Drought and water shortages could become common
  • There could be more illness like sun cancer
  • Very hot temperatures could melt road surfaces and buckle railway lines
  • Some plants and animal species could die out 

What can we do?
We could reduce our use of fossil fuels and switch to green energy like wind, solar and tidal power
We could recycle more
We could use cars less and public transport 

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Effects Of Climate Change For Egypt

  • Less/more unreliable rainfall
  • Spread of Sahara desert
  • Desertification of farmland
  • Falling crop yields as temperatures rise and water shortages increase
  • Heat-waves bringing more illness and death
  • Spread of diseases like malaria
  • 7 million people may have to find somewhere else to live if the nile (main water supply) floods
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Viking Greenland

Erik the Red was a Norse Viking who was banisehed to Greenland in 982.
He and 500 other Vikings found a land that was largely free of ice.
This was in the start of the Medieval warm period when Greenland was very different

  • Had 200 farms with goats, sheep, cows and hay
  • A population of 4000 Vikings
  • Trade links with Iceland and Norway

Died out shortly after 1410
The Little Ice Age made life impossible for them but they did little to help themselves

  • Deforestation and soil erosion meaing they produced little food
  • Depended too much on trade with Norway and Iceland. When stopped because of sea ice they had no one else to turn to
  • Not very adapted. Tried to live as had done previously.

Should have learnt from the Inuit people because they were acclimatised and adapted and knew how to conserve resources and use their tools so aren't dependent on other countries.

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Why The Vikings Died Out

(http://img201.imageshack.us/img201/3693/vikings.png)

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The Little Ice Age

  • Cold and rain lashed Europe in the spring and summer of 1315
  • Wheat and oats did not ripen and the harvest failed
  • Cool wet weather continued in 1316 and 17
  • The Great Famine lasted from 1316-1325
  • 10-20% of peasant farmers died of hunger in some areas
  • 1349 Europe was struck by the Black Death
  • Many glaciers grew in the cooler climate in the 1820's and 50's they advanced down valleys destroying villages and farmland
  • Farmers stopped growing wheat because it needed warm summers
  • The cold and wet loving potato important from S. America became the crop of choice

However the people did adapt

  • Farmed new crops
  • Abandoned farms on high hillsides
  • Enjoyed Frost Fairs on frozen rivers.
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Effect On Ecosystems

Megafauna
10-15000 years ago
Big animals that weighed over 40kg such as the wooly mammoth, giant elk, ground sloth
As the last ice age ended and the climate warmed up by 6 degrees in only 1000 years, animals had to move

  • They migrated and tried to find new areas to live in, where the climate suited them
  • However, finding right plants to eat would have been difficult
  • Disrupted food chains leaving some animals short of food
  • Climate change stress may also have made the megafauna weaker than normal 

Dinosaurs
65 million years ago dinosaurs became extinct, two causes are:
Strike by massive asteroid in mexico
Huge volcanic eruption in India
Both would have emitted loads of dust, ash & gas into the air blocking out the sun
Plants would have struggled to grow as the climate cooled.
Ecosystems would have broken down as food chains collapsed. 

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