GCSE 9-1 Geography- Weather Hazards and Climate Change

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Oceanic Circulation

  • The oceans are equally as effective at redistributing heat as the air is.
  • Ocean currents on the surface are driven by winds across the top of the ocean.
  • Deep ocean currents are driven by the motion of the as a result of changes in temperature.
  • An example of this is the Gulf Stream which brings warm air across the Atlantic Ocean from the Caribbean to the UK. This means that locations on the same latitude (eg.Canada and Russia) experience a much colder climate than we do.
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Eccentricity

  • Over long periods of time the orbit of the earth changes.
  • This means that sometimes the earth's orbit is more circular leading it to be warmer (interglacial).
  • At other times the orbit is more elliptical leading to it being cooler (glacial). 

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Natural Causes of Climate Change

  • Solar Variation- The amount of radiation the Sun emits changes over time. Periods of time where the solar activity is lower are likely to cause glacial periods. Whilst those periods where the solar output is high is likely to cause interglacial periods.
  • Volcanism- Large volcanic eruptions release huge amounts of ash and dust into the atmosphere.  This can cause solar radiation to blocked out and therefore causing glacial periods.
  • Surface Impact- Large cosmic material, such as asteroids and comets can impact the Earth's surface. This impact can eject ash and dust.  This can cause solar radiation to blocked out and therefore causing glacial periods.Climate change caused by surface impact can have a massive effect on lives. This is thought to have caused the extinction of the dinosaurs.
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Edvidence of Climate Change

  • Tree Rings- Due to the fact that trees can live for hundreds of years they can experience the effects of climate change. This is evident through the tree rings. Growth rings are wider in warmer and wetter climates and thinner in colder, drier climates. Tree rings can also have scars which indicate forest fires.
  • Ice Core Samples- In areas where lots of snow falls the snow is compressed into layers of ice. Between these layers volcanic ash, pollen and air can become trapped. All this can give very important information about climate change.
  • Journals- These can give information about the climate in written history.
  • Pollen- Certain plants can only grow in certain climates. Therefore the pollen can show which plants grew in certain periods thus showing the climates.
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Human Activities that Cause Greenhouse Gases

Industry- With levels of disposable income on the rise the demand for products has also increased. This means that production demands have gone up leading to more fossil fuels being burnt which produce greenhouse gases.

Transport- With cars being more affordable more people have them. Also, more people take flights with huge amounts of fuel used. Almost all transport relies on burning fossil fuels in order to move. This also increases the amount of greenhouse gas created.

Energy- The demand for electricity is growing because of the increasing demand for new technologies. The way the most energy is produced is through the burning of fossil fuels. This gives off greenhouse gases.

Farming- Population growth has led to an increase in demand for food. This means that more cattle are farmed which produce methne and the use of mechanics burn fossil fuels.

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Negative Impacts of Climate Change-Food Production

  • Plants produce their own food through the process of photosynthesis
  • Both herbivores and omnivores eat plants
  • This makes plants a very important part of the food chain
  • Photosynthesis is very complex and easily affected by changes in temperature and a decrease in sunlight
  • This causes a lower crop yield
  • Lower crop yields mean that much of the population will suffer from malnutrition, this will be a bigger issue in developing countries
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Negative Impacts of Climate Change- Sea Level Rise

  • With an increase in temperature, sea levels also rise
  • This is due to the rise in temperature causing ice in the poles to melt
  • This adds to the quantity of water in the seas to increase thus causing a rise in sea levels
  • Another cause of sea level rise is thermal expansion
  • Warmer water takes up more space than colder water. With the climate becoming warmer the water is becoming warmer increasing its volume. This makes the sea levels rise
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Case Study-The Maldives

  • The Maldives are a collection of almost 1200 coral island located in the Indian Ocean. It is the Earth's flattest country with the highest point being 2.4m above sea level.
  • Prediction state that within the next century sea levels expected to rise between 20cm- greater than 1 metre
  • This puts the Maldives at great risk-  as a developing country with tourism being the main industry it would be detrimental if any of this was to be ruined by a rise in sea levels
  • Social- More storms and flooding would occur if sea levels continued to rise
    • in 2007, 1600 people had to be evacuated due to coastal flooding
  • Economic- The key attractions of beaches and coral reefs would become inaccessible
    • This would reduce the number of tourists
    • Due to tourism reducing unemployment rates would increase
    • Evacuation + rehousing costs
  • Enviromental-Groundwater supplies will be contaminated. Bleaching and death of the Coral reefs.
  • Responses- The Maldives are trying to rely more on rain water harvesting instead of groundwater incase of infilltration; raising the level of key infastructure and mass migration is also a discussion 
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Retreating Glaciers and Melting Ice Sheets

  • Glaciers and ice sheets account for a majority of land-based ice as well as 10% of the Earth's total land area
  • Increasing global temperatures mean that glaciers are retreating and ice sheets are thinning
  • Locally melting ice sheets will cause flooding and over a long period of time it may cause water shortages
  • Globally this will cause sea levels to rise
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UK's Location and Climate- Altitude

  • The higher the altitude the lower the temperature
  • 1 degree is lost for every 100m
  • When air is forced over the highlands the air calls and therefore more condenses
  • This falls as precipitation
  • An example of this is Scarfel Pike (978m) which receives precipitation 178 days a year. London (35m), on the other hand, receives just 98 days of rain a year
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Tropical Cyclones

Tropical cyclones are large rotating storms that form over water. Dependant on where they form they are called either: typhoons, hurricanes or cyclones. They can be devastating if they move over land. These normally form in the tropics

  • Features
    • The eye is located in the centre
    • The area surrounding the eye is the eyewall
    • High-density clouds cover the rest of the storm area
  • Formation Conditions
    • 27°C of moist warm air
    • Wind converging at the ocean surface causing the air to rise
    • Formation away from the equator so that the Coriolis effect can cause the storm to rotate
  • Formation
    • Tropical cyclones form in tropical areas. High temperatures cause hot air to rise which causes thunderstorms. Although just a local effect if these storms may just be local effects if these converge under the right condition tropical cyclones will form.
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Case Study-Hurricane Sandy-Effects

  • Effects
    • Social
      • More than 150 people were killed
      • Millions of people were left without electricity for days
      • Infrastructure was left severely disrupted
      • Schools were closed and buildings ruined by flooding and high winds
    • Economic
      • The total damage was estimated at over $65 billion
      • New York stock exchange was forced to close for several days
      • Petrol was in short supply and had to be brought into the affected states at cost to the government
      • The New York marathon had to be cancelled which affected tourism
    • Environmental
      • Coastal nature reserves were damaged by the storm surge
      • The flooding meant that gallons of untreated, raw sewage were released into main water supplies
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Case Study-Hurricane Sandy-Responses

  • Responses
    • Media raised funds for those affected
    • Charities like the American Red Cross were involved in providing relief
    • The US government voted in legislation in order to provide billions of dollars of relief to help: rebuilding and supporting the victims
    • New York set up a local government office to help co-ordinate the rebuilding effort as well as to ensure that all areas were covered and received relief
    • Some of the money was paid directly to others and the rest was paid to businesses, infrastructure and community support schemes
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