Natural hazards Flashcards

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1
Q

What is the volcanic eruption theory? and what affect does it have on the earth

A

big volcanic eruptions create so much ash and gas that is blankets over the earth. this means solar energy is reflected back and lowers the earths average temperature.

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2
Q

What are the Milankovitch cycles?

A
  • Eccentricity (orbital theory)
  • Axial Tilt/ obliquity
  • Precession (direction of the Earth’s Axis)
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3
Q

What is eccentricity? (orbital theory)

A

Describes the path of the Earth as it orbits the sun. The earths orbit is not fixed- changes from being circular to elliptical, a full cycle takes 100,00 years. This means when the orbit shape is elliptical the Earth is much further away from the sun and so gets much less heat, this cools the earths average temperature.

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4
Q

What is axial precession? (Earth’s wobble)

A
  • Describes a natural ‘wobble’ rather like a spinning top.
  • A complete wobble cycle takes about 26,000 years
  • This wobble accounts for change in season, and why regions such as Norway experience very long days and very long nights at certain times of the year.
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5
Q

What is the axial tilt? (obliquity)

A
  • The earth spins on its axis causing day and night. C
  • Currently the Earths axis is tilted at an angle of 23.5 degrees. However over a period of 41,000 years, the tilt moves back and forth between two extremes- 21.5 degrees and 24.5 degrees.
  • This means that the Earth’s seasons could be shortened or extended
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6
Q

What are the human factors that increase global warming?

A
  • burning fossil fuels
  • deforestation
  • dumping waste in landfill
  • agriculture
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7
Q

How does dumping waste in landfill increase global warming?

A

When the waste is decomposed it produces methane

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8
Q

How does agriculture increase global warming ?

A

Agricultural practices lead to the release a nitrogen oxides into the atmosphere

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9
Q

How does burning fossil fuels increase global warming ?

A

Fossil fuels release carbon dioxide into the atmosphere.

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10
Q

How does deforestation increase global warming?

A

Trees absorb Carbon dioxide during photosynthesis. Is they are cut down, there will be higher amounts of carbon dioxide in the atmosphere

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11
Q

What are the impacts of climate change in the UK ?

A
  • sea levels could rise
  • droughts + floods become more likely as extreme weather increases
  • increased demand for water in hotter summers puts pressure on water supplies
  • industry may be impacted e.g. Scottish ski resorts may have to close due to lack of snow.
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12
Q

Impacts of climate change around the world

A
  • Sea level rise will affect 80 million people
  • tropical storms will increase in magnitude (strength)
  • species affected areas (egartic) may become extinct
  • diseases such as malaria increase, in additional 280 million people may be affected
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13
Q

What are the mitigation strategies of climate change?

A
  • Alternative energy
  • Carbon and capture
  • Planting trees
  • International Agreements
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14
Q

How does alternative energy mitigate climate change?

A

Renewable resources such as solar or wind, reduces amount of carbon dioxide in the atmosphere

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15
Q

How does carbon capture mitigate climate change?

A

Removal of Carbon dioxide from waste gases + storing in old oil or gas fields, this reduces amounts of emissions in the atmosphere

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16
Q

How does planting trees mitigate climate change?

A

Encouraging afforestation, means there will be more trees to absorb the Carbon dioxide in the atmosphere during the process.

17
Q

How do international agreements mitigate change climate?

A

-2005 the Kyoto protocol, countries that signed up, pledged to reduce their emissions.
-2016 the Paris Agreement, aims to limit global warming to well below 2°C. A meeting is held to discuss the actions every country promises to take to reduce emissions

18
Q

What are the adaptation strategies to climate change?

A
  • Agriculture - fames will have to adapt their crops
  • Water supply- water transfer schemes can be used
  • Reducing risk from sea level rise- areas at risk may use sea defences to protect the land
19
Q

What are the case studies for natural hazards? (hint: earthquakes)

A
  • Nepal 2015 vs Chile 2010
20
Q

Nepal earthquake: location (epicentre + plate margins), date and magnitude

A
  • 25th April 2015
  • Epicentre was 80km north- west of Nepal’s capital (Kathmandu) in the foothills of the Himalayas- This is a destructive plate margin where the Indo- Australian plate is colliding with the Eurasian plate- this plate is responsible for the formation of the Himalayas.
  • Magnitude was 7.9 on the Richter Scale
21
Q

Chile Earthquake: location, date and magnitude

A
  • 27th Feburary 2010
  • Chile
  • magnitude: 8.8 on Richter scale
22
Q

What is global atmospheric circulation?

A

Global atmospheric circulation is the transfer of heat from the equator to the poles by the movement of air

23
Q

What causes winds?

A

Differences in air pressure- winds blow from high pressure to low pressure areas

24
Q

What creates a low pressure belt?

A

Warm rising air

25
Q

What creates a high pressure belt?

A

Cool sinking air

26
Q

How many cells does each hemisphere have? + their names

A

3: Hadley, Ferrell, Polar

27
Q

What is the Coriolis effect?

A

When the trade winds curve towards the equator and westerlies curve towards the poles, due to Earth’s rotation

28
Q

What happens at 30°C North and south of the equator?

A

Cool air sinks, creating a high pressure belt

29
Q

What happens at 60°C North and south of the equator?

A

Warmer surface winds meet colder air from the poles. The warm air rises, creating low pressure

30
Q

Where does the UK lie? - global atmospheric circulation

A

Lies close to the low pressure zone at 60° north. Warm air rising brings lots of cloud cover and rainfall

31
Q

How do tropical storms form?

A
  1. An ocean temperature of 27°C or higher is needed
  2. The warm surface water evaporates, rises and condenses into clouds. This releases huge amounts of energy producing, powerful storms. Rising air creates an area of low pressure which increases surface winds
  3. Easterly winds near the equator move tropical storms towards the west.
  4. The storms spin because of the coriolis effect
  5. As the storm moves over the ocean the energy from the very water strengthens the storm.
  6. When the storm reaches land the energy supply is cut off + the storm weakens
32
Q

Typhoon Haiyan primary effects

A
  • 8000 people were killed
  • over 1 million homes were severely damaged on destroyed
  • 1.9 million people were made homeless
  • strong winds damaged electricity lines + water supplies were contaminated by salt water from the storm surge
  • heavy rain + storm surges flooded 600,000 hectares of farmland
  • cost of damage was approximately US $13 million
33
Q

Typhoon Haiyan secondary effects

A
  • Flooding triggered several landslides which blocked roads + delayed the arrival of aid
  • 5.6 million workers lost their jobs after businesses + agricultural land was destroyed
  • lack of clean water caused outbreaks in diseases such as dysentery
34
Q

The Philippines and the wider world’s immediate responses to typhoon Haiyan

A
  • Fisherman were warned to to not go sea
  • Philippines declared a state of emergency, led to charities offering aid in the form of food, shelter and clean water
  • plan International constructed pit latrines for 100,000 people to help prevent the spread of disease
  • warnings that were sent out, led to the evacuation of 800,000 residents before the storm, however, some of these people died when evacuation centres flooded
35
Q

The Philippines and the wider world’s long-term responses to typhoon Haiyan

A
  • UN appealed for over $300 million to help fund rebuilding + relief
  • Charities built new storm-resistant houses for those who lost their homes
  • tourism board encouraged people to visit the country after the storm by emphasising that most areas were unaffected, and the money from tourism would help the rebuilding process
36
Q

Typhoon Haiyan facts

A
  • When? 8th November 2013
  • where? Philippines