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Geography Mock - Climate Change + Rivers - Coggle Diagram
Geography Mock - Climate Change + Rivers
Climate Change
Natural causes
Milankovitch cycles
Eccentricity (Orbit)
100,000 year time frame
Earth's orbit around the sun changes from circular to elliptical on a cycle
When the orbit is circular there is less difference between summer and winter temperatures which leads to a cooler climate and the opposite is true during elliptical periods
Obliquity (Tilt)
41,000 year time frame
Changes in Earth's tilt from 22 degrees to 24.5 degrees
Decreased obliquity can cause cooler summers and can help push the climate system into ice ages and the opposite is true for increased obliquity
Precession (Wobble)
26,000 year time frame
The axis on which Earth spins wobbles like a spinning top
This wobble can cause a difference in the types of seasons. This can affect the amount if radiation earth recieves.
The more obble there is the more difference between seasons there will be
Volcanoes
When volcanoes erupt, they can release Sulfur dioxide and ash which reflects and block sunlight, reducing global temperatures
Sunspots
When there is more sunspots the overall global temperature will be higher
Natural causes
Enhanced greenhouse effect (EGHE)
1) The burning of fossil fuels, agricultural practices and deforestation result in the production of greenhouse gases such as CO2, CH4, and N2O
2) These gases then trap the long wave solar radiation that would usually bounce back out into the atmosphere
3) This causes more heat to be retained resulting in Earth's atmosphere becoming warmer
CO2 = Burning of fossil fuels / Deforestation
CH4 = Gas escaping from landfill / Animals, especially cows
N2O = Industrial processes / Fertalisers
Anthropogenic - Relating to or resulting from the influence of human beings on nature
Carbon sink - An area that is large enough to absorb large amounts of CO2
Measuring climate change
Ice cores (100,000s of years)
Cores of ice taken out of glaciers
Bubbles of gas are trapped in the ice, they measure the concentration of these and it allows them to make an estimate on the temperature
Sediment cores (10,000s of years)
Samples of mud/sediement are taken from bodies of water
Pollen and remains of fossils etc, allow you to construct an idea of what the climate was like at the time
Tree rings (100s of years)
Tree rings usually grow wider in warm, wet years and are thinner in cold, dry years
Glacial retreat (10s of years)
Comparing photos of glaciers over time
Impacts/Mitigation of Climate change
Social impacts
Increased risk of skin cancers and heat stroke as temperatures increase
Less ice in the Arctic ocean increases shipping and extraction of gas and oil reserves (economic)
Drought reduces food and water supplies
Increased flood risk as the ground is dry and can't absorb the water efficiently
Environmental impacts
Ice melting leads to destruction of habitats for Polar bears, penguins etc.
Coral bleaching
Increase in forest growth in northern Europe
Carbon capture
Natural process through afforestation
Or direct carbon capture using machines allows us to make a fuel with the carbon we pull out of the air, but it is expensive
Renewable energy
There is an infinte amount of renewables
Solar power / Geothermal / Tidal / Hydroelectric / Wind power
International agreements
Examples are the Paris agreement where 195 countries agreed that they want to keep the global temperatures 2 degrees below pre-industrial levels, ideally 1.5 degrees
Agreements aren't legally binding
Rivers
Courses
Upper - Steep, Narrow-channeled, Vertival erosion, V-shaped
Middle - Widening due to lateral erosion
Lower - Widest, Deepest, Fastest, Less lateral erosion, Flat
Fluvial Processes
Erosion
Abrasion - Scraping of a river's bed and banks by rocks being carried by the river
Attrition - Gradual rounding and smoothing of rock particles as they rub/knock against eachother
Solution - Dissolving of soluble chemicals in water, particularly affecting limestone and chalk
Hydraulic action - The power of flowing water erodes the river and banks
Transportation
Traction - Large particles are rolled along the river bed by the force of the water
Saltation - A bouncing or hopping motion by pebbles to heavy to be suspended
Suspension - Particles suspended within the water
Solution - Chemicals dissolved within the water
Estuaries
Where the river meets the sea
Very flat
The river can be tidal, so when the sea retreats there is less water in the estuary
The river deposits lots of silt in the form of mudflats
Management strategies
Dams - Water colelcted can be used for irrigation, but they can lead to a build up of silt leading to worse flooding, and are expensive
Embankments - Deepen the river channel which reduces the risk of flooding, howvere it restricts the access to rivers for fishing, so people can lose their livelihoods
Flood shelters - Are cheap to construct but they don't save properties
Emergency help / After-care - Helps people economically, but the money wont last forever and areas already flooded can't be accessed easily
River straightening - Helps speed up the flow of water, but increased risk of flooding further down the river and expensive
Boscastle - 2006
Impacts - There was no deaths and only one minor injury / 420 people were left temporarily homeless / There was £15 million worth of damage / Boscastle was completely destroyed leading to tourism (which accounts for 90% of the local economy) plummeting
Responses - The riverbed was lowered and widened which allowed for more channel capacity / A flood wall was installed around the river banks in the town to stop water from going over the bank and floodwall and spilling into the town / They relocted a lower bridge, raising the arch reducing the flood risk by reducing the risk of the bridge collapsing due to debris and blocking the river
Beast from the East - 2018
Primary impacts - A man died in London after being puleld from a frozen lake, there was another 3 deaths
Rural areas experienced lows of -12 degrees
There was gusts of up to 60-70 mph in parts of North England and Wales
Up to 50cm of snow in parts of Southwest England and Southeast Wales
Secondary impacts - `Hundreds of motorists on the M80 near Glasgow for up to 13 hours
Hospital operations were cancelled
Thousands of schools were closed across the UK
Major shopping centres and businesses were forced to close
Responses - The Met office issued red warnings for several areas including Central Scotland
Rail passangers were told to avoid travelling to or from Scotland
Army and Royal Air force personnel were called in to transport health workers to blocked areas in Scotland