Geography- Changing Climate

  • Created by: Em_New99
  • Created on: 23-05-15 10:07

Past Climate Change

Weather- The day to day variations in atmospheric conditions

Climate- The average weather conditions of a location (over 30 years)

Climate Change- The difference in average weather conditions over time

Quaternary Period- A cycle/ pattern of high and low temprature


We know that climate has changed a great deal in the past. This is shown by:

  • Fossils of animals and plants in regions they are not found in today
  • Evidence of glaciation in regions that are now free of ice
  • Evidence from ice cores showing how much oxygen is in the ice
  • Paintings data. The art that people created at the time could tell us what the climate was like
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The Causes of Climate Change

The Sunspot Theory

  • Sunspots are darker areas on the sun's surface- they are a sign of greater solar activity
  • They come and go in cycles of about 11 years
  • However, there are longr periods when very few sunspots were observed, such as 1645-1715


The Eruption Theory

  • Large eruptions emit vast quantities of dust and gases such as sulphur dioxide into the atmosphere.
  • This blocks out or absorbs incoming solar radiation so the earth cools.
  • Examples include Mt Pinatubo in 1997 


Orbital (Milkankovitch Cycle)

  • The shape of the earths orbit changes (becoming more/ less circular)- Known as orbital eccentricity
  • The wobbling of the earth on its axis can xhange the amount of solar energy recieved by the earth
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The Little Ice Age


The little ice age was one of the best-known recent periods of climate change lasting from early 1300 to around 1870


Impacts of the Little Ice Age

  • The Baltic Sea froze in the winter- as well as the River Thames
  • Sea ice reachd as far as Iceland
  • Winters were much colder reducing growing seasons by several weeks
  • Conditions lead to widespread crop failure and famine
  • Remote areas like Greenland were abandoned as survival became impossible
  • Price of grain increases- Lead to social unrest and revolt
  • Glaciers advanced overrunning towns and farms in the process
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How Do We Know The Little Ice Age Existed?

  • Tree Ring Data (Dendrochronology)- Width of a ring shows how much the tree has grown that year. Smaller ring- Less growth. Bigger ring- Bigger growth
  • Coral reef data- Coral needs warm water to grown. If oceans are cold- coral won't grow
  • Paintings data- People painted pictures that indicate the weather at that time
  • Plants/growth yield- Short seasons due to cold weather meaning no growth
  • Written records- Documents of troops who froze to death ect
  • Ice Cores- Shows you conditions the Ice was like 10-100,000 years ago, to do with oxygen isotapes within
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Causes of the Extinction of Giant Megafauna

During the Ice Age, large numbers of megafauna disappeared comletley- as many as 130 species. This includes giant beavers, mammoths and sabre-toothed tigers. This is an example of mass extinction.


Three sets of explanations for their extinction:

  • They could not cope with climate change with changes to their food chain- both plant and animal- dissapearing; so they died out too
  • Human beings hunted them to extinction. We know for sure we hunted them because of their remains
  • A combibation of them both is also possible
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The 'Enhanced' Greenhouse Effect

The Enhanced Greenhouse Effect- The progressive warming of the earths atmosphere from human activties.


Human activities that contribute towards this are:

  • Burning Fossil Fuels
  • Rearing Cattle
  • Putting rubbish on landfil sites- The decomposition of organic waste
  • Deforestation
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Proof of Global Warming Around The World


  • Rising sea levels- Due to ice melting and thermal expansion
  • Shrinking glaciers
  • Melting polar Ice Caps/ Floating sea ice
  • Higher temprature- warmer summers
  • Frequency and strength of hurricanes has increased
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Postive and Negative Impacts of Climate Change


  • More tourism due to warmer conditions
  • New crops- new sale opportunities ie- Champagne
  • More land farmed at higher altiitudes
  • In winter heating & road gritting costs would fall
  • Fewer deaths of older people from the cold



  • In summer, drought and water shortages could be more common
  • Hot surfaces can melt surfaces and buckle railway lines
  • Erosion could occur at higher rates along the coast due to rising sea levels
  • More ilness- heat stroke & skin cancer
  • Farmers may have to change crops to those that need less water and more sunshine
  • Some plants and animals may die if it gets too hot
  • Low lying areas could flood- ie London. Trying to hold back sea could be expensive.
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Global Warming- Sudan


  • Greatest concern is climate change damaging the agriculture.
  • Sudans economy is heavily based on farming and livestock keeping
  • 70% of the population relies on agriculture- making the economy extremely vunerable to any slight weather change
  • Desertification threatens the Sudanease people who live near the dry Sahel Belt- Even small temprature and rainfal could tip the conditions towards desert.
  • Major yield decline is predicted in the 3 main crops- sorghum, millet and gum arabic



  • Unique place makes it ideal to promote ecologically friendly agriculture and natural resource managment
  • Practical Action is working to spread knowledge and build partnerships in these areas as part of global learning network- Prolinnova. 
  • Practical action is also helping people to adapt to climate change
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Global Warming- Bangladesh

Climatic Impacts:

  • Floods/ Flash Floods- (80% of the country is prine to flooding)
  • Cyclones and Storm Surges- (South and South-eastern parts were hit by tropical cyclones during the last few years)
  • Salinity Intrusion- (Almost the whole Costal Belt along Bay of Bengal is experiencing this)
  • Extreme Temp and Drought- (North and North-western regions)


Sectoral Impacts:

  • Agriculture- Countrys economy depends on agriculture- Extreme temp, drought and Salinity Intrusion are also responsible. Temp and rainfall have also affected crop prdocution
  • Fisheries- 260 species of fish, all senesitive to climate change
  • Water Resources and Hydrology- Water will become severe and alarming. Hydrology will impact economy as people depend on surfact water for fishery and irrigation ect.
  • Coastal Areas- 1/4 of the populaiton live in costal areas. Affected by Floods, Tidal Surges, Erosion due to Rising sea levels
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Global Warming- Bangladesh (Continued)

  • Forestry/ Biodiversity- Climate change would negatively impact the ecosystem of the Forest resources.
  • Urban Areas- Cities and Towns along the Coastal belt are at the front line of climate damage- Impacts directly because of sea level rising. Infastructure may be damaged during extreme events. Slum and squatter settlements of the major cities which are highly prone to disaster during flooding further.
  • Vunerable Groups- The urban poor are at risk especially without necessary infrastructure as well as employment opportunites. Women are vunerable due to gender inequalities (socio- economic and Political Institutions) 
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Global Warming- New York

What New York Can Expect:

  • Minimum increase of 5°F in temprature by 2100
  • Damage to coastal habitat, property and infrasturcture due to rising sea levels
  • Declining drinking water quality and quantity
  • Increased costs to dairy and agricultural farming
  • Declining freshwater and satwater fish populations
  • Further degradation in air quality leading to exacerbated unhealthy conditions
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