Case studies Physical

• Amazon Rainforest


  Largest tropical rainforest, covering over 40% of the south american continent, home to 20 million people
• Amazon Rainforest


  • Covers 5.7 million sq kms
  • Acts as an important carbon sink, absorbing more carbon dioxide than it releases
  • Yearly absorbs 2.2 billion tons of carbon
  • Only 182 species out of 16000 are specialised in carbon storage
• The Amazon forests help reduce global warming by lowering the planet's greenhouse gas levels
• Water cycle in Amazon Rainforest


  • Basin is drained by the Amazon river and its tributaries
  • Rainfall is high with approximately 2300 mm annually
  • Water cycle works via rainfall being intercepted by the forest and re-evaporated into atmosphere via evapotranspiration
  • Additional evaporation can occur from ground and river surfaces
  • Moisture then resurfaces in the atmosphere and forms rain clouds which then release water right back onto rainforest
• When forests are cut down


  Less moisture goes into the atmosphere and rainfall declines, sometimes leading to drought
• Forest cuts down


  Less plants, less trees therefore less plants to intercept rainfall, less plants for transpiration, less areas of the forest to evaporate rainfall back into atmosphere. Reduces action of evaporation, evapotranspiration, interception etc
• Causes of deforestation in Amazon Rainforest


  • Agricultural (Cattle farming, brazing)
  • Logging
  • Road building
  • Energy development (Hydroelectric power)
  • Mineral extraction
  • Settlement & population growth
• Deforestation effects on soil


  • Removes portions of forest canopy, causing more extreme temperature swings
  • Causes soil to dry out quicker, leading to soil erosion and degradation
  • Reduces water content and minerals in soil, making it infertile
• Deforestation effects on rivers


  • Increased soil erosion and weathering of rainforest soils
  • Flash floods more likely due to less interception and absorption by forest cover
  • Interruption of normal water cycling leading to more droughts and wildfires
  • More soil and silt washed into rivers, changing waterways and transport
  • Disrupts water supplies to many people in Brazil
• Mt St Helens eruption

  Caused by subduction of oceanic crust plate under continental crust, forming magma that rose to the surface
• Tohoku Earthquake


  Massive 9.0 earthquake caused by subduction of thin oceanic Pacific plate under thick continental Eurasian plate, releasing built-up friction
• Bohol Earthquake


  7.2 magnitude earthquake caused by movement of North Bohol faults, releasing stresses between plates
• Boxing Day Tsunami


  Caused by a shallow focus magnitude 9 earthquake, which displaced a large volume of water
• Mangrove swamps act as a natural defence against tsunamis, but had been removed in many affected areas for economic or tourism reasons
• Hurricane Katrina


  Category 5 tropical storm that approached Florida and devastated Louisiana and Mississippi
• Typhoon Haiyan


  Category 5 super typhoon that hit the Philippines
• 2009 Black Saturday Bushfires


  Series of bushfires across Victoria, Australia, started by fallen power lines and arson
• Black Saturday Bushfire (Forest Fires)

  2009
• Black Saturday Bushfire


  • It was a series of bushfires on Saturday 7 February 2009, across Victoria
  • 173 people died
  • 3,500 buildings were destroyed
  • 700 people displaced
  • 12,000 animals lost
  • Worst wildfire in Australian history
• Black Saturday Bushfire


  1. Occurred for over a month until the 14th of March

  2. Forest fire started when power lines had fallen causing a blaze in farmland

  3. Fire spread very quickly from 11:47 am and crossed the Hume freeway at 1:58 pm
• 400 individual bushfires occurred during the time period with over 1,737 square miles destroyed
• The state of victoria was undergoing a heat wave with temperatures ranging between 40 - 50 degrees
• The high pressure system due to the Tasman sea caused the unusually high heatwave
• Responses to the Black Saturday bushfires included immediate community response, donations, and, later, international aid efforts, Government inquiries (including a Royal Commission), and recommendations and discussions from a wide variety of bodies, organisations, authorities and communities
• Odisha Coastline


  • 480 km long coastline
  • East india coastline
  • Straight coastline containing few inlets and harbours
  • Major deltas from rivers (Formed by 52 rivers and rivulets)
  • Depositional landform which comprise most of the original coastline
  • 1435km2 of mangrove forests
  • Submergent coastline - sections of littoral zone where sea level rise inundated areas that were previously part of terrestrial lands
  • Coastline is very flat and low lying susceptible to sea level rise
• Deposition coast


  When deposited sediment is dropped on the coastline such as sand, pebbles etc. The swash is stronger than the backwash and many major river deltas bring across the sediment
• Mangroves


  • Work by stabilising the coastline reducing erosion from storm surges, currents, waves and tides
  • Mangrove odisha - Offers protection, breeding ground for fish, ecotourism (due to bird species)
• Coastline has huge potential for renewable offshore wind energy, tidal and wave power
• No issue with water stores as there is a constant supply for bay of bengal
• Many energy sectors work across the coastline
• Links to ecotourism potential (allows jobs for locals) (many species of birds)
• Beaches in coastal areas helping increase local economy due tourism
• Delta regions with constant river inputs give fertile and agricultural land
• 35% of the coastline built up sediment with heavy metal deposits with additional of clay and limestone resources
• Risks Odisha coastline


  • 28% of the coastline lost
  • Significant coastal erosion
  • Ports have blocked natural sand flow so beaches further north has been eroded
  • Water becomes too saline - negative effect as crops cant grow in this water
  • Summer time more deposition whilst winter increased storms and erosion
• Risk of development - The coastline naturally changes such as the sediment deposing to make new beaches and landforms. This provides the stretch for the Indian coast. The natural changes in seasons cause the coastline to also vary. For example lots of erosion occurs in the winter due to high energy destructive waves whilst accretion occurs in the summer due to low energy waves. By building man made structures to halt these processes only causes unnecessary damage as it can cause downdrift and the reduction of sediment transport. By this happening many beaches and estuaries would be destroyed and disappear and sand and feed sources eliminated.
• Effect of human intervention - Sediment transfer has been interrupted due to human intervention. This causes energy to be displaced meaning energy patterns are not stable due to the transfer of sediment being interrupted as well. Due to erosion occurring as well this has caused further damage as less sediment would be available so more energy is not getting absorbed causing an unbalance cycle. By sediment being removed it also causes increased rates of coastal erosion and the maintenance of coast would deteriorate as it would be structurally weaker.
• Use of ICZM in odisha


  • Their fisheries and livelihoods were now protected
  • They learnt new skills and had a part in the project through the planting of mangrove trees
  • Community based tourism is being developed bringing in more money for the people
  • Local communities are being trained to get jobs as boatmen, guides, and dolphin spotters
  • About 400,000 people from 235 coastal villages are expected to benefit through these measures
• Kiribati Coastline


  • Located in Pacific ocean
  • Susceptible to rising sea level due to climate change
  • Only 2m above sea level
  • Rate of coastal erosion 1.2m a year
• Impacts of sea level rise in Kiribati - freshwater supply contaminated by sea water, Loss of home/culture, pollution from litter, cannot grow crops on contaminated land, loss of trade/economy