Topic 1: Hazardous Earth

• Explain it hotter at the equator than at the poles

  • The sun is directly overhead at the equator so the heat is concentrated.

  
  

  • The sun is at a lower angle at the poles so the heat is scattered. This makes the poles colder
• Define low air pressure

  • Warm air rises away from the Earth's surface . This air will then cool, condense and form clouds.

  
  

  • An area of low pressure will receive a lot of rainfall.
• Define high air pressure

  • This occurs when cold air sinks towards the earth.

  
  

  • No clouds form

  
  

  • Areas of high pressure receive very little rainfall
• Label the areas of high and low pressure on the diagram

  A) Low pressure

  B) High pressure

  C) Low pressure

  D) High pressure

  
• Explain how ocean currents spread heat energy around the earth

  Ocean currents redistribute heat through convection. Cold water is heavy and has a higher salt content. This causes it to sink deeper whilst warmer water with a lower salt content floats to the surface.

  
  

  As the cold water sinks it pulls the lighter, less dense surface water to replace it. Similar to a perpetual conveyor. It is transferred through the convection current and the distribution of latent heat brings warmth to the poles
• What are the 4 causes of natural climate change?

  Orbital theory, Sunspot theory, eruption theory and asteroid collision
• Explain how sunspot theory helps explain past climate change?

  • Sunspots are large dark spots on the suns surface

  • Sometimes the sun has a lot of spots, other times not as many

  • The amount of dark spots tells you how active the sun is

  • Lots of dark spots means more solar energy is being fired out from the sun to earth - this energy is called a solar flare
• Explain how eruption theory helps explain past climate change

  • Very large, explosive stratovolcanoes produce ash and sulfur dioxide gas

  • These are spread around the earth in the stratosphere and block solar radiation.

  • This makes the climate cooler.
• Explain how asteroid collisions help explain past climate change

  • Big asteroids with 1km diameter hit earth every 500,000 years.

  • This blasts tonnes of ash and dust into the atmosphere and blocks the sunlight

  • This cools the climate for 5-10 years which is relatively short term
• Explain how orbital theory helps explain past climate change

  • The earths orbit changes from circular to more elliptical every 100,000 years.

  • This effects the amount of solar radiation the earth receives as sometimes the earth will be further away from the sun, or closer instead of equidistant.

  • This triggers and ends ice ages.

  • The angle of earths axis tilt and how the earth wobbles on its axis also affects where sunlight hits
• Explain how ice core evidence helps explain past climate change

  •Within ice cores, there are carbon dioxide bubbles trapped within the ice.

  • The more carbon dioxide bubbles means there was more carbon dioxide in the atmosphere resulting in a warmer climate

  • The ice core bubbles can date back thousands of years
• Explain how tree ring evidence helps explain past climate change

  • Trees grow a ring every year.

  • If the conditions of the climate was good for plant growth, the ring would be thicker whilst if the climate was colder it would be thinner

  • This only shows a short time scale
• Explain how historical evidence helps explain past climate change

  • Diaries and books contain accounts of the weather at that time.

  • Charles Dickens' books always reference snow in London meaning Victorian England was colder
• Define greenhouse effect

  • Heat from the sun is trapped within the earth's atmosphere by greenhouse gasses, for example carbon dioxide.
• Describe the greenhouse effect

  1. UV radiation (light) from the sun enters the earths atmosphere

  
  

  2. Energy is absorbed by the earths surface. The Earth warms and emits infra-red radiation (heat)

  
  

  3. Some heat passes through in the atmosphere into space

  
  

  4. Some heat is trapped in the atmosphere by greenhouse gases such as carbon dioxide warming the atmosphere

  
  

  5. The earths temperature is 15°C with this, however without the effect the earth would be -18°C
• What greenhouse gas does rice and cattle farming release?

  Methane
• What greenhouse gas does transport release e.g. driving cars and flying planes?

  Carbon dioxide
• What greenhouse gas does using fridges and aerosols release?

  CFCs
• What greenhouse gas does deforestation release?

  Carbon dioxide
• What greenhouse gas does landfill release?

  Methane
• Define enhanced greenhouse effect


  Anthropogenic impacts has resulted in a large increase in the production of greenhouse gases, leading to the enhanced greenhouse effect and global warming
• What are the 3 consequences of climate change?

  • Rising sea levels

  • Declining arctic ice

  • Extreme weather events
• What are the consequences of rising sea levels on people?

  • Coastal flooding

  • Infrastructure and housing is destroyed.

  • Displaced population as it is not safe to live in coastal areas
• What are the consequences of declining sea ice on people?

  • This causes rising sea levels, which leads to homelessness and displacement
• What are the consequences of extreme weather events?

  • Damages to infrastructure and properties

  • Causes civilians death or injury
• Why is there uncertainty in future temperature change?

  • So many physical and human impacts on temperature that people are unsure how populations and earths system will react to the changes
• Explain why there are physical uncertainties about future climate change

  • Natural processes that enhance climate change

  E.g. Methane is being released by melting permafrost in the Arctic

  more carbon dioxide is released due to forest fires

  
  

  • Water sources that contribute to rising sea levels are variable so they cannot be projected

  E.g. Water in reservoirs

  
  

  • Uncertainty about how weather phenomena affect climate change

  E.g. El Nino climate cycle
• Explain why there are human uncertainties about future climate change

  • We do not know how the population will be therefore uncertainty over future energy and food demands.

  • Lifestyle changes: People may eat less meat and recycle and governments may implement greenhouse gas reduction policies

  • Uncertainty over how much green energy we may use; may still be predominantly fossil fuel or switch to renewables.
• What is a tropical cyclone?

  A large, rotating low pressure system that develop over tropic or sub-tropic oceans
• Explain how human activities produce greenhouse gases that cause the enhanced greenhouse effect leading to global warming. (Energy)


  The demand for electricity is growing because of increasing population and new technologies. Most of our energy is produced through burning fossil fuels which produce greenhouse gases.
• Explain how human activities produce greenhouse gases that cause the enhanced greenhouse effect leading to global warming. (Industry)


  As levels of disposable income rise, increased demand for the production of consumer goods leads to industrial growth and the need for more energy, resulting in more fossil fuels being burnt.
• Explain how human activities produce greenhouse gases that cause the enhanced greenhouse effect leading to global warming. (Transport)

  
With cars becoming more affordable and more people taking flights over long distances, huge quantities of fuel are used. Almost all transport relies on burning fossil fuels in some way, again increasing the amount of greenhouse gases released.
• Describe a piece of evidence for climate change (Global temperature rise)


  • Temperatures have increased by nearly 1°C since 1880 - Expected to rise up to another 4.8°C between 2005 and 2100.

  • The top 10 warmest years since records began have all been since 2000
• Describe a piece of evidence for climate change (Sea level rise and warming oceans)


  • Sea levels have risen by almost 0.3m since 1901
• Explain the distribution of tropical cyclones

  • Tropical cyclones occur between 5-30 degrees north and south of the equator where ocean surface temperatures are above 26.5 degrees Celsius due to differential heating which causes warm air to rapidly rise creating areas of low pressure

  
  

  • Cyclones do not form on the equator as the Coriolis force is too weak here.

  
  

  • The Coriolis force causes the storm to move towards the land

  They cannot stay too far inland as there is no water to fuel the storm
• Label the diagram

  A) The whole system is rotating

  B) High pressure creates calm cloudless conditions

  C) Warm air rises creating heavy rain and strong winds

  
• Why do tropical storms decay over land?

  Its energy will dissipate over land due to the lack of moisture and evaporation which release latent heat powering the storm.
• Explain when tropical storms form


  They usually form towards the end of summer and in autumn. This is because this is when ocean water is at its warmest.
• How do tropical cyclones form

  1.) Warm surface water in tropical oceans evaporate quickly, the vapours cools and condenses to form large cumulonimbus clouds

  2.) Low air pressure forms below the storm causing more air to rush in increasing wind speed

  3.) The rising air currents and clouds begin to spiral due to the Coriolis force

  4.) Some cold, dense air begins to sink into the centre of the storm creating calm, cloudless conditions called the eye.

  5.) The storm tracks from east to west, strengthened from further evaporation, if winds reach 74mph then it is a tropical cyclone
• What are tropical storms called in their respective geographical origins (Atlantic & East pacific; Indian & South Pacific Ocean; West Pacific)?

  • Atlantic & East Pacific - Hurricanes

  • Indian and South Pacific Ocean - Cyclone

  • West Pacific - Typhoons