Geography GCSE Edexcel B - Topic 1: Hazardous Earth

• Explain how ocean currents distribute heat around the world

  • In the northern hemisphere currents move in a clockwise direction and in the southern hemisphere they move in a anti-clockwise direction• Cold currents move along the western side of continents, warm currents move along the eastern side• Cold currents move towards the equator, warm currents move away from the equator
• Explain how the Gulf Stream affects the UK climate


  The ocean is warmed at the equator. The currents (in this case the Gulf Stream) move away from the equator clockwise in the northern hemisphere, bringing warm water to the UK, creating a milder climate than areas on a similar latitude such as Canada.
• What are jet streams?

  • They are narrow zone of high-speed winds high above the Earth where the circulation cells meet.• They are caused by temperature/pressure differences between conflicting air masses in the upper atmosphere• They move heat horizontally
• Explain why different regions on the earth have different temperatures

  • The equator receives the most concentrated solar insolation because the Sun's rays hit the surface at a right angle.• Nearer to the poles this gets less and less concentrated as the same amount radiation heats a larger surface area.• Near the poles the angle of the sun's rays means they pass through more atmosphere which absorbs more energy than near the equator.
• What happens at the Equator in the global atmospheric circulation system?

  The area near the equator receives the most direct sunlight. This means the Sun's radiation is most intense and high temperatures cause the tropical air to rise rapidly. As this air rises it expands and becomes less dense, causing low pressure. This area is known as the ITCZ, the air rises to the troposphere.
• What is the climate like at the equator because of the global atmospheric circulation system? What biomes form as a result of this?

  Rising moisture-heavy air causes thunderclouds (cumulonimbus clouds) to form, so rainfall in this zone is heavy and regular. In these latitudes there are often rainforest ecosystems because the daily heavy rainfall and warm temperatures are perfect for plant growth
• What happens at the 30° N/S in the global atmospheric circulation system?

  The Hadley Cells and Ferrel Cells meet around 30° north and south of the Equator. Here both cells are becoming cooler and more dense and sinking so there is a zone of high pressure.
• What is the climate like at 30° N/S because of the global atmospheric circulation system? What biomes form as a result of this?

  High pressure stops any moisture from rising and condensing, so no clouds form. As there are no clouds there is no rain. These areas become arid (dry) this is where deserts are found.
• What happens at the 60° N/S in the global atmospheric circulation system?

  Where the Polar Cell and Ferrel Cell meet, warm air from the south meets cooler air from the north. The warm air rises above the cool air resulting in low pressure and rain.
• What happens at the poles in the global atmospheric circulation system? What biomes are formed here as a result?

  The end of the polar cell sinks causing high pressure, forming cold deserts
• What biome is the climate graph on the other side showing (cover the answer)? Why?

  This is a desert because it has high temperatures but very little rainfall.

  
• Describe how high atmospheric pressure areas form

  • When air is cool, it sinks because it is more dense.• When it sinks it causes high pressure on the earths surface.• When air sinks it cannot form clouds which creates clear skies.
• Describe how low atmospheric pressure areas form

  • When air is warm, it rises as it is less dense• When it rises it causes low pressure on the earth's surface• When air rises it condenses forming clouds which create rain
• What are isobars?

  They are like contour lines that show pressure gradient. The closer the lines are, the steeper the pressure gradient.
• How is wind created?


  when air moves from areas of high pressure to areas of low pressure
• What does a steeper pressure gradient cause?


  stronger winds
• What are the differences between how land and water heat up?

  • Land heats up quickly because it is darker but it also cools down faster• Water heats up slowly because it is always moving
• What effect will the differences between how land and water heat up have on air pressure?

  The air above land will be high pressure, above water will be low pressure.
• Explain how the eruption theory helps explain past climate change?

  When there are large volcanic eruptions ash and sulphur dioxide are released. They stop sunlight reaching the Earth's surface, reflecting it back into space.
• Explain how the asteroid collision theory helps explain past climate change?

  ash and dust rise up high enough into the stratosphere, sunlight is reflected of the ash and gas back into space, cooling the Earth's climate.
• Explain how the sunspot theory helps explain past climate change?


  The sun can have dark spots or eject super heated gas, called solar flares. These variations can affect the earth's weather
• Explain how the orbital theory helps explain past climate change?

  𝗖𝗵𝗮𝗻𝗴𝗲𝘀 𝘁𝗼 𝘁𝗵𝗲 𝗘𝗮𝗿𝘁𝗵'𝘀 𝗼𝗿��𝗶𝘁 𝗮𝗿𝗼𝘂𝗻𝗱 𝘁𝗵𝗲 𝘀𝘂𝗻The earth's orbit around the sun changes from an almost perfect circle to an ellipse and back again about every 96,000 years. This causes the earth to be able to come closer and further away from the sun leading to a decrease in solar energy reaching the earth𝗖𝗵𝗮𝗻𝗴𝗲𝘀 𝘁𝗼 𝘁𝗵𝗲 𝗲𝗮𝗿𝘁𝗵'𝘀 𝗮𝘅𝗶𝘀The earth is tilted on its axis at 23.5° but this can vary from 22.5° to 24.5°. This changes the amount of solar energy reaching the earth. This varies every 41,000 years.𝗖𝗵𝗮��𝗴𝗲𝘀 𝘁𝗼 𝘁𝗵𝗲 𝗲𝗮𝗿𝘁𝗵'𝘀 𝗿𝗼𝘁𝗮𝘁𝗶𝗼𝗻 𝗮𝗿𝗼𝘂𝗻𝗱 𝗶𝘁𝘀 𝗮𝘅𝗶𝘀The earth wobbles on its axis. This results in the earth being slightly further or closer to the sun changing the amount of solar energy it receives. This varies every 23,000 years.
• Explain how ice core evidence helps to explain past climate change?

  As ice forms, it traps tiny bubbles of air frozen into the ice which contain a sample of the atmosphere from the time. Although humans have only been measuring carbon dioxide in the atmosphere since the 1950s, the ice sheets of Antarctica and Greenland have stored records of carbon dioxide levels in the atmosphere for thousands of years. Climate scientists can then identify which layer in the ice core relates to which year. They can then reconstruct what the climate looked like using information on trapped carbon dioxide and methane.
• Explain how tree ring evidence helps to explain past climate change?

  1) Most trees produce one ring within their trunks every year.2) The thickness depends on the climate when the ring was formed e.g. if it was warmer and wetter then it will be thicker3) Scientists can take cores through the tree trunks then date each ring by counting them back from when the core was taken. The thickness of each ring determines what the climate was like each year. e.g. precipitation and temperature
• Explain how historical evidence helps to explain past climate change?

  Historical documents, such as personal diaries, paintings and religious records, lets us examine more recent historical climates. These documents include descriptions of what the climate was like during the past. We can use these records to cross-check evidence from other sources about climate change.
• Define the greenhouse effect


  greenhouse gases in the atmosphere retain heat, keeping the Earth warm enough to support life.
• Explain the greenhouse effect


  1. The sun emits UV radiation to the Earth's surface.2. This is converted into Infrared radiation (heat) and emitted by the surface.3. Greenhouse gases in the atmosphere, such as carbon dioxide and methane, absorb the infrared radiation which would otherwise have been lost into space and re-emit it in all directions.4. This means some is lost into space and some is emitted back to the surface, warming the earth back up. Without this effect, the Earth would be a frozen wasteland.
• Define enhanced greenhouse effect


  Human activity has resulted in a large increase in the production of greenhouse gases, leading to the enhanced greenhouse effect and global warming
• What are the four ways human activity has led to the enhanced greenhouse effect?


  • industry• transport• energy• farming
• 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 prooduction 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.
• Explain how human activities produce greenhouse gases that cause the enhanced greenhouse effect leading to global warming. (Farming)


  Population growth has led to a higher demand for food production. Mechanisation means more fuel is burnt, and intensive farming of cattle and rice results in increased production of methane, which is a greenhouse gas.
• Explain why people in LICs produce only small amounts of greenhouse gases compared to people in HICs.


  People in LIC's only do one of the four things humans do which contribute to the enhanced greenhouse effect which is farming. People in HICs contribute in 3 ways most of the time.
• Name 4 pieces of evidence for climate change


  • Global temperature rise• Sea level rise and warming oceans• Declining Arctic ice• Increased extreme weather events
• 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 0.2m since 1901
• Describe a piece of evidence for climate change (Declining Arctic ice)


  • The extent of arctic sea ice in winter has decreased by more than 3% each decade over the past 35 years
• Describe a piece of evidence for climate change (Increased extreme weather events)


  • Since 1950 there has been a higher frequency of heatwaves in many areas and fewer cold weather extremes.• 2013 was one of the wettest years on record and December 2015 was the wettest month ever recorded in the UK
• Name possible impacts of climate change

  • Some places could become so hot and dry that they could be impossible to inhabit.• Low-lying coastal areas or islands could be lost to sea or flood so often that they become impossible to inhabit - This could lead to migration and overcrowding in other areas.• More extreme weather means more money has to be spent on predicting them, reducing their impacts and rebuilding after them.𝗙𝗮𝗿𝗺𝗶𝗻𝗴• Globally some crops have suffered from climate change e.g. maize crops have got smaller due to warming - Lower crop yields could lead to malnutrition, ill health and death due to starvation particularly in lower latitudes• Some farmers in higher latitude countries (countries further from the equator) are finding that crops benefit from warmer conditions