Extreme Weather-Cyclone Nargis
Location:Formed over the Inidan Ocean and hit Burma as a category 4 cyclone on the 2nd May
Violent storms form over warm seas, these are areas on intense low pressure, strong winds over 200km/s and rain rotate over. The winds produce wave surges of 7m high which flood low lying areas. The centre of the storm is a calm 'eye' of sinking air
130,000 people died, 800,000 homes destroyed, spread of disease and food shortages,storm surge, 2008/9 harvests of rice destoryed.
- Slow due to miltary government not wanting foreign help, 6 days after disasters they goverment asked UN for help, UK gave £17 million of aid
- People were rescued, clearing flood derbis, giving people fresh water, tents and food.
- Italian flights brought food supplies on the 7th of May
Processes within the rainforest:
- Water Cycle-the forest acts as a store of water between rainfall events, 80% of rainfall is transferred back to the atmosphere through evaporation and transpiration.
- The Nutrient Cycle-Very delicate, nutrients pass through all the components,plants take up nutrients from the soil, consumers eat the plants absorbing the nutrients, consumers die and nutrients are returned ot the soil by decomposers.
How has the ecosystem been changed? Parts of the rainforest have been cut down to create the largest iron ore mine in the world(Carajas). And a 900km rail links has been built to the coast to export the iron ore.
Gains:Profits to settle foreign debts, long term jobs, encouraged industries to locate in the area
Losses:Native American have lost homeland+culture,loss in speices+plants, medical treatment
Effects on Amazon:Change in biodiversity,hydrology,soils and climate.
How does economic activity change the ecosystem?Deforestation, hydorelectric schemes, slash and burn(farmers clearing and burning forest), cattle ranching for beef.
Sustainable management:Debt for nature swaps, wildlife corridors,sustainable logging,rubber tapping, ecotourism=low density tourism with little effect on ecosystem.
The Sahel Region-Desertification
Location:The Sahel Region stretches along the southern edge of the Sahara desert, passing through countries such as Mali, Niger, Chad and Sudan.
Human causes of desertification: Defroestation,soil is exposed to wind and rain as there is less interception. Over cultivation and poor farming methods,not allowing the nurtrients to return to the soil. Over grazing due to farmers being less nomadic(moving around).Over use of fertillisers, lack of irigation and poverty/civil war(lack of money leads to people over using any available land)
Physical causes:Climate change and drought(climate change means there are more droughts than usual),variation in seasonal rainfall and high evapotranspiration rates(rainfall only occurs in one part of the year leading to pressure on food in other parts of the year),high pressure systems.
Effects on farmers:Farmers removing vegation has led to less water in the atmosphere (less evapotranspiration)=less rainfall, less leaf litter falling into the soil=less nutrients in soil=soil infertility=Crop failure.
Effects on residents: Scarce amount of water, people are using dirty water=diseases, migration due to conditions, crop failure, lack of food and malnutrition.
Effects on environemnt:Animals and plants die, soil erosion.
Solutions: Tree planting schemes,small rock dams,collecting rain water from roof tops, planting grass along contours of gentle slopes.
In 2005,UK gave £3 million to help the food crisis in Niger, Oxfam provided long term aid.
The Holderness Coastline-Coastal Environment
Location: Holderness Coastline lies between the chalk hills of the Wolds and the North Sea.Part of the East Riding of Yorkshire.
Procces acting on the coastline: Rate of erosion=2m per year
The coastline is made up of till(which is very soft), the till becomes saturated with rain water and loses it's strength, the cliff is too steep and and falls as a block or a slurry slide, cliff failure reduces the angle and prevents further erosion, but large waves removes the derbis through longshore drift, cliff over steepens, rain falls cycle begins again. Hydraulic action, solution,attrition and abrasion also take place.
Landforms produced due to erosion:Headlands(Flambrough Head), small cliffs, beaches, splits(Spurn point).
Mappleton-Rock groynes preventing longshore drift, and rock barriers reducing wave energy.
Withersea-Rip-rap, dissipating wave energy.
Spurn Point-Groynes and gabions
Boscastle- River Valency Floods
Location: a village on the North Cornish coast in the South West of England.
Physical casues: 50mm of rain in 1 hour resulted from moist air moving onshore and meeting air moving land causing it to rise rapidly=thunder clouds.
Human causes: Bridges acted as damms and derbis caught on so the water came as a big wave
Other: A very wet August(ground was already saturated so couldn't absorb much water from the flood), impermeable rock, steep slopes, short lag time until peak discharge and the rapid rise in river levels resulted in FLASH FLOODS
Short term effects:
50+ caravans and cars were swept out to sea, 6 buildings were swept away, possesions ruined, bridges swept away, damage to sewers,water and electricity supplies, 60 people evacuated, no deaths,soil erosion, trees uprooted
Long term effects:
90% of economy dependent on tourism, 20 tourist accomadations providers and attractions had to shut down, cost of building and infrastructure repairs, cost to insurance companies, psychological effects.
River Management-Boscastle, River Valency
Location:a village on the North Cornish coast in the South West of England.
Short term management: Emergency services got involved,6 helicopters and 2 lifeboats etc.
150 people airlifted to safety, sandbags and emergency centres opened
Long term managment:
Hard engineering-£4.6 million scheme including raising bridges and carparks, widen+lower river bed, flood defence wall, derbis catching facility
Soft engineering-The river upstream has been given a wider, shallower patterns, this has encouraged more deposition,slows down river flow, trap boulders and derbis.
Community awareness-'At risk' properties are encouraged to use more flood resistant materials and have electricals higher up, flood warning system, encouragement to have an emergency evacuation pack and to take out insurance.
Residents&businesses:Pleased with new schemes as they are more protected
Farmers:The soft engineering may make the river more likely to flood effecting their land,costing them money
Environmentalists..no hard engineering...........Toursists;river looks less natural