Aqa geography paper 1

• Coastal erosion occurs due to a combination of physical, chemical and biological forces acting on the coastline.
• Topic 1: Global Hazards
• Causes of Drought:

  • El Nino effect associated with creating dry conditions
  • In an El Niño year, cooler water off the coast of Australia reverses wind direction leading to dry, sinking air over Australia causing hot weather and lack of rainfall
• Types of precipitation:

  • Convectional Rainfall
  • Frontal Rainfall
  • Relief Rainfall
• Changing pattern of these Hazards:

  • Tropical Storms: global warming impacting frequency and strength, possibly due to increased ocean temperatures
  • Severity of droughts increased since the 1940s, possibly due to changing rainfall and evaporation patterns related to gradual climate change
• Distribution of Tropical Storms:

  • Known by many names: hurricanes (North America), cyclones (India), typhoons (Japan and East Asia)
  • Occur in a band roughly between the tropics of Cancer and Capricorn
• Distribution of Droughts:

  • Can occur worldwide but more frequent between the tropics of Cancer and Capricorn
  • Many countries in Africa suffer from severe drought, such as Ethiopia, but Australia also suffers
• Formation of Tropical Storms:

  • Sun's heat causes warm, moist air to rise over large ocean areas
  • Rising warm moist air leads to low pressure once temperature is 27°, turning into a thunderstorm
  • Trade winds and rotation of earth cause the storm to spin, forming a tropical storm when spinning faster than 74mph
  • Tropical storm loses strength when hitting land, eventually dissipating
• Convection Currents:

  • Lithosphere divided into tectonic plates moving due to convection currents in the asthenosphere
  • Radioactive decay in core and mantle generates heat, creating convection currents
  • Circular movements of semi-molten rock create drag on tectonic plates, causing movement
• Types of volcanoes:

  • Shield: made of basaltic rock, gentle eruptions, found at hot spots and constructive margins
  • Composite: most common type, explosive eruptions, found at destructive margins
  • Hotspots: away from plate boundaries, plume of magma rises to eat into the plate above, e.g. Hawaii
• Types of Plate Margins:

  • Destructive Plate Margin: oceanic plate subducts beneath continental plate, causing volcanic activity and earthquakes
  • Constructive Plate Margin: two plates moving apart, causing new magma to reach the surface, forming volcanoes
  • Conservative Plate Margin: plates slide past each other, causing earthquakes, e.g. San Andreas Fault, USA
  • Collision Zones: two continental plates collide, forcing both plates up to form fold mountains, causing shallow earthquakes, e.g. Himalayas
• Managing Volcanic Eruptions:

  • Warning signs: seismometers detect earthquakes, thermal imaging detects heat, gas samples taken to measure sulphur levels
  • Prediction methods: satellite surveying, laser reflector, radon gas sensor, seismometer
  • Preparation: evacuation plans, trained emergency services, communication systems
• Earthquake Management:

  • Protection methods: building earthquake-resistant buildings, raising public awareness, improving earthquake prediction
• Quaternary geological period:

  • Last 2.6 million years, with fluctuating temperatures and glacial and interglacial periods
  • Global temperatures increased above average in the past 100 years, known as global warming
• Evidence for climate change:

  • Earth's temperature changes over the last 2.6 million years
  • Evidence collected from ocean sediment, ice cores, historical records
• Topic 2: Climate Change
• Enhanced Greenhouse Effect:

  • Increase in burning fossil fuels emitting greenhouse gases, trapping more solar radiation and causing Earth to become warmer
• Greenhouse Gases:

  • Carbon dioxide: 60% of enhanced greenhouse gases, produced by burning fossil fuels
  • Methane: 15% of enhanced greenhouse gases, 25x more efficient than Carbon dioxide, produced from landfills, rice, and farm animals
  • Halocarbons: 6% of enhanced greenhouse gases, 250x more efficient than Carbon dioxide, produced from refrigerants and aerosols
  • Nitrous Oxide: 6% of enhanced greenhouse gases, produced from fertilisers and cars
• Recent Evidence for climate change:

  • Global temperatures increased by more than 0.6°C since 1950
  • Human activities contribute significantly to greenhouse gas emissions
• Evidence from maps and photos have shown many of the world's glaciers and ice sheets are melting
• Arctic sea ice has declined by 10% in 30 years
• Evidence from the IPCC has shown that the average global sea level has risen by 10-20cms in the past 100 years
• Global impacts of climate change include extreme weather, rising sea levels, impacts on food supply, plants and animals, disease and health, water supply, and climate refugees
• Climate change is causing more unpredictable and severe weather events, such as more frequent and powerful tropical storms, more extreme heatwaves, and lasting droughts
• Sea levels have risen by 20 cm since 1901 due to thermal expansion, melting glaciers and ice caps
• Warmer temperatures and changing rainfall will make it harder to produce a reliable source of food to sustain a rising global population
• About a quarter of animals and plants on Earth could become extinct due to climate change
• Warmer temperatures will increase the spread of infectious diseases like malaria and waterborne diseases such as dysentery
• 1 billion people predicted to not have access to enough water by 2025 due to climate change
• Climate refugees are people forced to leave their homes due to the impact of climate change, such as sea level rises or extreme weather conditions
• Paris Agreement 2015 involved 195 countries making a legally binding global climate deal to limit global warming to below 2°C
• China is responsible for the highest amount of carbon emissions, but per person, the USA contributes far more CO₂ emissions
• Countries in Africa emit low levels of carbon dioxide due to not being industrialized or having a population wealthy enough to consume lots of energy
• Countries like China and India are emitting more carbon dioxide due to increasing industrialization and population sizes
• Countries like the USA and UK emit more carbon dioxide due to being industrialized with a wealthier population that consumes a large amount of energy
• Benefits of the rainforest:

  • Raw materials like timber and rubber are found in the rainforest
  • Provides water, food, health, energy, and climate regulation
  • Large scale 'slash and burn' of land for ranches and palm oil
  • Important foods like bananas, pineapples, and coffee are grown in the rainforest
  • 25% of modern medicines are sourced from rainforest ingredients
  • Large dams generate 2/3 of Brazil's energy needs
  • Acts as carbon sinks by storing 15% of carbon emissions
  • Increases carbon emissions
  • River saltation and soil erosion increasing due to large areas of exposed land
• • Increase in palm oil is making the soil infertile
  • Mass tourism leading to building of hotels in vulnerable areas
  • Negative relationship between government and indigenous tribes
  • Tourism affecting wildlife by exposing them to human diseases
• Distribution of Polar Regions:

  • Arctic: region north of latitude 60°N around the North Pole
  • Antarctic: continent south of latitude 60°S around the South Pole
• Climate of Polar Regions:

  • Arctic: very cold with temperatures rarely above 0 °C, winters average below -40 °C, summers maximum of only 10 °C, low rainfall
  • Antarctic: large and thick ice sheets, mountain range crosses the continent
• Human Activity in Polar Regions:

  • Oil & Gas exploration in Arctic
  • Fishing leading to collapse of fish stocks
  • Whaling causing rapid decline in whale populations
  • Tourism increasing emissions and disturbing wildlife