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Natural hazards Flashcards

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1
Q

What are the greenhouse gases?

A
  • carbon dioxide (CO2)
  • methane (CH4)
  • nitrogen oxides (NOx)
  • water vapour (H2O)
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2
Q

Greenhouse gases allow

A

our atmosphere to trap heat near to the planet

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3
Q

All of the heat on the surface of our planet comes from

A

solar radiation

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4
Q

Infra-red radiation

A

It warms our planet

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5
Q

The natural greenhouse effect

A
  • Infra-red radiation
  • When it gets closer to our planet, some of it goes to space.
  • When infra-red radiation hits a surface of our planet, there is heat.
  • Some of the infra-red radiation can get back out into our atmosphere and off into space but greenhouse gases trap heat near to the surface of our planet - keeps some of our heat in.
  • It is why our planet stays warm
  • It is a natural effect.
  • The greenhouse effect keeps the Earth naturally warm anough to support life. It works like a glass greenhouse by:
  • greenhouse gases (eg: water vapour, carbon dioxide, methane and nitrous oxides) trapping heat that would otherwise escape into space
  • allowing short-wave radiation (light) from the Sun through to the Earth.
  • Trapping some of the longer wavelength radiation (heat) that would otherwise be radiated back into the atmosphere.
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6
Q

Human causes of climate change

A
  • power generation
  • factories
  • transport
    -farming practices/ agriculture (methane)
  • manufacturing
  • domestic reasons
  • We are artificially changing the composition of the earthโ€™s atmosphere.
    To do this, you have to burn fossil fuels- coal, oil or natural gas.
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7
Q

Our climate

A

Our climate is changing quite rapidly because our planet is getting warmer

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8
Q

By how much has the temperature of earth risen?

A

1 degrees Celsius

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9
Q

Climate change

A

Our climate has become more unpredictable.

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10
Q

the enhanced greenhouse effect

A
  • we are adding more greenhouse gases into the atmosphere. The atmosphereโ€™s composition is changing.
  • Atmosphere is better at trapping heat, struggled to let some of the infra-red radiation out. Creates heat for a lot longer. Planetโ€™s temperature will very slowly and gently rise.
  • In recent years the amounts of greenhouse gases in the atmosphere have increased. Scientists believe that this enhanced greenhouse effect is due to human activities.
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11
Q

natural causes of climate change

A
  • solar activity (sunspots)
  • volcanic activity
  • Milankovitch Cycles
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12
Q

Solar activity

A
  • The sun goes through different stages in its lifespan
  • parts of the surface of the sun have sunspots- about 2000 degrees colder than the normal temperature of the sun.3500 degrees. If the earth passes in front of one of these sunspots, there may be a small period in which the earth was colder- lowers solar activity-less energy/ infra-red radiation from sun.
  • The surface of the Sun has dark patches called sunspots which mark short-term regions of reduced surface temperature. They are usually accompanied by explosive, high-energy solar flares increasing heat output. Over a period of around 11 years, sunspots increase from a minimum to a maximum, and back again.
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13
Q

volcanic activity

A
  • volcanic eruptions can cause the earth to get warmer or colder
  • volcanoes release ash. If ash gets up into the atmosphere- blocks infra-red radiation coming towards our planet- cooling effect on overall temperature by 2 or 3 degrees- short-term impact.
  • can release lots of carbon dioxide. Carbon dioxide has a warming effect
  • Sulphur dioxide is also blasted out which converts to droplets of sulphuric acid, and acts like mirrors to reflect solar radiation back into space. This longer-term impact (over many years) also reduces temperatures.
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14
Q

Milankovitch cycles

A
  • 3 ideas about the way the earth goes around the sun. Interesting ways that the earth changes its orbit around the sun.
    1, Eccentricity- the earth doesnโ€™t always orbit the sun in a circular shape.
    2, Precession- the wobble of the tilt around the core
    3, Obliquity/ tilt-
    It is not always the same distance from the sun.
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15
Q

Evidence for climate change

A
  • if glaciers/sea ice are melting back further and further
  • rising sea levels - warmer
  • icicle drilling- drill deep down into ice sheets in antarctica- tiny bubbles to see the composition of the atmosphere thousands of years ago- ice cores
  • paintings/writing from hundreds/ thousands of years ago
  • Tree rings - how well they were growing- to see what the climate was like
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16
Q

definition of climate change

A

It refers to the long-term shifts in temperature and weather patterns, mainly caused by human activities, especially the burning of fossil fuels.

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17
Q

Milankovitch cycles are

A

Three distinct cycles which increase (cooling) or decrease (warming) the distance from the sun.

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18
Q

Eccentricity

A

Every 100,000 years or so the orbit changes from almost circular, mildly eliptical (oval and back again). This can lead to changes in the Earthโ€™s temperature.(This causes changes in our season or long-term climate).

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19
Q

Axial tilt/ obliquity

A

Every 41000 years the tilt of the Earthโ€™s axis moves back and forth between 21.5 degrees and 24.5 degrees. The difference in angle (normally 23.5 degrees) affects temperature on the planet.

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20
Q

Glycoscopic precession

A

Over a period of around 26000 years the axis wobbles from one extreme to the other.

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21
Q

Carbon dioxide (enhanced greenhouse effect)

A
  • Carbon dioxide is the most important, contributing approximately 60% to the net warming by greenhouse gases
  • Most carbon dioxide comes from burning fossil fuels in industry and power stations. Transport and farming also contribute
  • Deforestation of tropical rainforests by burning is another major source.
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22
Q

Methane (enhanced greenhouse effect)

A
  • CH4 emissions from ever- increasing numbers of farm livestock, rice farming, sewage treatment, and emissions from landfill sites, coal mines and natural gas pipelines are growing even faster than CO2.
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23
Q

Alternative energy

A
  • eg: Lesotho Highland Water project
  • not really done in LICs
  • HICs it is done
  • The UK aims to produce half of itโ€™s electricity from renewable sources
  • The burning of fossil fuels accounts for 87% of all carbon dioxide emissions.
  • Alternative sources of energy represent sustainable, low carbon alternatives.
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24
Q

Carbon capture

A
  • not yet economically viable
  • It uses technology to capture CO2 that is produced by burning fossil fuels in electricity generation and industrial process. Once captured, the CO2 is compressed, piped and injected underground for long-term storage in suitable geological reservoirs, such as depleted oil and gas wells.
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25
Q

Planting trees

A
  • Trees act as carbon sinks, removing carbon dioxide from the atmosphere by the process of photosynthesis. They also release moisture, producing more cloud and so reducing incoming solar radiation.
  • Tree planting is well established in many parts of the world. In fact, plantations are more efficient at absorbing carbon dioxide than natural forests.
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26
Q

International agreements

A
  • Governments are negotiating towards a more sustainable future.
  • eg: The Paris Agreement in 2015 which was the first legally binding global climate deal.
  • aimed to limit global temperature increases to 1.5 degrees Celsius above pre-industrial.
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27
Q

Global impacts of climate change

A
  • reduced crop yields and water supplies
  • more heat-related illness and disease
  • Low-lying coastal areas threatened by flooding
  • Changing ecosystems and animal habitats
  • more extreme weather events, such as droughts and floods
  • stronger tropical storms
  • desertification
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28
Q

Lesotho Highland Water Project

A
  • LIC
  • Highly mountainous, receiving high rainfall between the months of October and April.
  • All of Lesothoโ€™s energy demand is met from these via hydroelectric power (HEP)
  • No blackouts. They have as much energy as they need for a very long time.
  • A 48.2 kilometre long-tunnel which transfers water from the Katse reservoir to the Muela hydroelectric power station in Norther Lesotho. This generates 110 MW of power.
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29
Q

Great Green Wall - planting trees

A
  • By 2030, the Wall aims to restore 100 million hectares of currently degraded land, sequester 250 million tonnes of carbon.
  • Africaโ€™s Sahel region- southern edge of the Sahara desert- desertification- one of the poorest places on the planet. On the frontline of climate change. Persistent droughts, lack of food, conflicts of dwindling natural resources and there is mass migration to Europe.
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30
Q

Agricultural adaptation/ planting more suitable crops

A
  • eg: Gambia
  • works in HICs and LICs
  • to suit them to the new climate
  • Scientists believe that climate change will have a huge impact on agricultural systems across the world, particularly in low latitudes.
  • To adapt farmers will need to:
    . cope with extreme weather such as floods, heatwaves and drought
    . manage water supply by storing water, use efficient irrigation systems, grow drought-resistant crops, and adapt to seasonal changes
    . plant trees to shade seedlings
    . change crops and livestock to suit the new climatic conditions.
    Management strategies:
  • introducing drought- resistant strains of crops
  • New irrigation systems
  • Educating farmers in water harvesting techniques
  • Shade trees can be planted to protect seedlings from strong sunshine
  • New cropping patterns can be introduced eg: changing planting/sowing dates.
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31
Q

Reducing risk from rising sea levels

A
  • Having already risen 20 cm since 1900, average sea level rises of up to 1m by 2100 are possible.
  • This will:
    . threaten important agricultural land in countries such as Bangladesh, India and Vietnam
    . increase rates of coastal erosion and damage from storm surges
    . contaminate freshwater supplies with saltwater
    The low-lying Indian Ocean islands of the Maldives are already tackling this change by adopting practical management strategies:
  • resotration of coastal mangrove forests- their tangled roots trap sediment and offer protection from storm waves
  • ultimately the entire population could be relocated to Sri Lanka or India
  • construction of sea walls- a 3m sea wall is being constructed outside the capital Male with sandbags used elsewhere.
  • Building houses that are raised off the ground on stilts (more common in LICs)
  • Construction of artificial islands up to 3m high so that people most at risk could be relocated.
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32
Q

Freezing water

A
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33
Q

Factors affecting the impact of an earthquake

A
  • distance from its epicentre- the effects of an earthquake are more severe at its centre
  • The higher on the Richter scale, the more severe the earthquake is
  • Level of Development (MEDC or LEDC) - MEDCs are more likely to have the resources and technology for monitoring, prediction and response.
  • Population density (rural or urban area). The more densely populated an area, the more likely there are to be deaths and casualties.
  • communication- accessibility for rescue teams
  • Time of day influences whether people are in their homes, at work or travelling. A severe earthquake at rush hour in a densely populated area could have devastating effects.
  • The time of year and climate will influence survival rates and the rate at which disease can spread.
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34
Q

Earthquake

A

An earthquake is a sudden, violent period of ground-shaking. Most occur at the margins of slowly-moving tectonic plates. Friction and sticking between plates create enormous pressures and stresses which build to breaking point.

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35
Q

Tectonic plates

A
  • earthโ€™s crust split into 7 major and several minor tectonic plates
  • 2 types of crust - dense, thin oceanic crust and less dense, thicker continental crust
  • Plates move, driven by convection currents within the mantle and under gravity.
  • Plates separate at constructive margins forming new crust, causing volcanic eruptions.
  • Plates collide at destructive plate margins causing subduction, earthquakes, volcanic eruptions and fold mountains.
  • Plates slide by each other at conservative margins, causing earthquakes.
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36
Q

constructive margin

A
  • The two plates move apart and magma forces its way to the surface
  • As it breaks the crust it causes mild earthquakes
  • the magma is very hot and fluid allowing the lava to flow a long way before cooling
  • This results in typically broad and flat shield-volcanoes (eg:Mid-Atlantic Ridge)
  • mild earthquakes and volcanic eruptions
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37
Q

Destructive/convergent margin

A
  • Two plates move towards each other (eg: west coast of South America). Here, the dense oceanic plate is subducted beneath the less dense continental plate.
  • Friction causes strong earthquakes.
  • The sinking oceanic plate creates sticky, gas-rich magma (less fluid than constructive)
  • This results in steep-sided composite volcanoes which erupt violently.
  • Where two continental plates meet there is no subduction, so no magma to form volcanoes. The crust crumples and lifts to form fold mountains (eg: Himalayas). Powerful earthquakes can be triggered.
  • strong earthquakes and violent volcanic eruptions
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38
Q

conservative (transform) margin

A
  • Two plates move past each other at different rates
  • Friction between the plates build stresses and trigger earthquakes when they slip.
  • There are no volcanoes because there is no magma.
  • powerful earthquakes
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39
Q

Where do earthquakes mainly occur?

A

At the margins of tectonic plates where plates are moving and enormous pressures build up and are released.

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40
Q

Why do hazards happen?

A

Because they happen on the edge of tectonic plates.

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41
Q

What is a natural hazard?

A

It is something that has a threat to life and property. It is a natural event that has had a huge social impact.

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42
Q

Atmospheric hazards

A
  • droughts
  • tornadoes
  • lightning
  • heatwaves
  • Bilzzards
  • wildfires
  • ash clouds
  • mudflows
  • snow storms (tropical and thunder)
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43
Q

Geological hazards

A
  • earthquakes
  • volcanic eruptions
  • landslides
  • sink holes
  • avalanches
  • tsunamis
  • ash clouds
  • mudflows
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44
Q

Flooding hazards

A
  • snow storms (tropical and thunder)
  • Mudflows
  • avanlanches
  • tsunamis
  • glacial bursts
  • storm surges
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45
Q

Geological and flooding hazards

A

avalanches
tsunamis
mudflows

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46
Q

geological and atmospheric hazards

A

ash clouds

mudflows

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47
Q

atmospheric and flooding hazards

A

snow storms

mudflows

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48
Q

What is hazard risk?

A

It is the chance of being affected by a natural hazard

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49
Q

March 2015- Bujumbura

A

Landslides struck Bujumbura in Western Burundi, Central Africa, killing several people and leaving thousands homeless. Following a period of heavy rain, mud and rocks plunged down hillsides destroying houses and damaging roads.

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50
Q

What are the most deadly natural hazards?

A

Floods, storms, earthquakes and droughts

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51
Q

What factors affect risk of natural hazards?

A
  • urbanisation
  • poverty
  • climate change
  • farming
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52
Q

Natural hazard risk- urbanisation

A
  • over 50% of the worldโ€™s population now live in cities
  • some of the worldโ€™s most densely populated areas are at great risk from natural events like earthquakes (Tokyo, Istanbul,Los Angeles) and tropical cyclones
  • 2010 Haiti Earthquake destroyed much of the capital Port-au-Prince killing around 230000 people
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53
Q

Natural Hazard risk- poverty

A
  • may force some people to live in areas at risk
  • Lima in Peru or Caracas in Venezuela
  • shortage of housing led to many people building on unstable slopes prone to floods and landslides.
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54
Q

Natural Hazard risk- climate change

A
  • warmer world, atmosphere will have more energy leading to more intense storms and hurricanes
  • climate change may cause some parts of the world to become wetter with an increased risk of flooding
  • other parts drier- prone to droughts and famine
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55
Q

Natural Hazard risk-farming

A
  • when river floods, deposits fertile silt on floodplain- excellent
  • In low-lying countries many people live on floodplains, eg: River Ganges in Bangladesh
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56
Q

how many years into the past can ice cores tell us about?

A

800,000

57
Q

how many years into the past can sediment cores tell us about?

A

200,000,000

58
Q

Why can we not stop climate change now?

A

Climate change has already begun. We know the earth has warmed by 1 degree C since the industrial revolution.

59
Q

What does meteorological mean?

A

Involving the weather, atmosphere or climate.

60
Q

What are geological hazards caused by?

A

The earth and its tectonic plate movements.

61
Q

Examples of meteorological hazards

A
  • heatwaves
  • bushfires
  • hurricanes/typhoons
  • extreme weather caused by climate change
62
Q

Examples of geological hazards

A
  • earthquakes
  • volcanoes
  • landslides
  • avalanches
63
Q

Describe the plate tectonics theory

A
  • it was first proposed by Alfred Wegener in 1915 and was initially based on the concept of โ€˜continental driftโ€™
  • Wegener suggested that all of the continents were once joined together, forming a โ€˜supercontinentโ€™ known as Pangaea. Processes beneath the crust (within the mantle) have caused the continents to split up over time.
  • Wegener suggested that the splitting of Pangaea was a result of the โ€˜constant, relative motionโ€™ of the Earthโ€™s crust divided into tectonic plates, and
  • this movement causes the plates to interact: such interactions cause earthquake and volcanic activity.
  • scientists now believe that convection currents in the mantle are one of the primary driving forces behind tectonic movement
  • these continuous currents cause the movement of the Earthโ€™s crust (divided into plates)- the direction of this movement is determined by the direction of the current, and the direction of the movement relative to other plates determines the activity that results from the plate interactions.
64
Q

Convection currents

A

1, the rising and falling magma creates circular currents with the mantle
2, the less dense magma then starts to rise towards the crust
3, The cooling magma becomes denser and begins to sink
4, as the magma warms it expands and becomes less dense
5, It is these currents that create friction with the crust above and causes it to move
6, Magma (semi-molten rock) near the outer core is heated
7, As the magma nears the crust it begins to cool

65
Q

What is an earthquake?

A

It is a sudden, violent period of ground shaking.

66
Q

Where do most earthquakes occur?

A

At the margins of slowly-moving tectonic plates

67
Q

How do earthquakes occur?

A

Friction and sticking between plates creates enormous pressures and stresses which build to breaking point.

68
Q

How many tectonic plates is the earthโ€™s crust split into?

A

seven major and several minor tectonic plates

69
Q

What are the two types of crust?

A

dense, thin oceanic crust and less dense, thick continental crust

70
Q

How do plates move?

A

By convection currents within the mantle and under gravity

71
Q

What do plates do at constructive margins?

A

They separate, causing volcanic eruptions

72
Q

What do plates do at destructive margins?

A

Plates collide which causes subduction, earthquakes and volcanic eruptions and fold mountains.

73
Q

What do plates do at conservative margins?

A

They slide by each other, causing earthquakes

74
Q

Where do volcanoes occur?

A

They occur in belts like earthquakes along plate margins (eg: the Pacific Ring of Fire and the Mid-Atlantic Ridge). Some occur at hot spots where the crust is thin and magma breaks through the surface (eg: Hawaiian islands).

75
Q

Why do people live at risk from tectonic hazards?

A
  • Poor people have no choice- money, food and family are seen as more important
  • earthquakes and volcanic eruptions are rare, so not seen as a great threat
  • earthquake- resistant building designs reduce risk
  • effective monitoring of volcanoes and tsunami waves allow evacuation warnings to be give
  • Plate margins often coincide with favourable areas for settlement and trade eg: flat, coastal area
  • some people have no experience or knowledge of the risks
  • volcanoes can bring benefits such as fertile soils, rich mineral deposits and hot water
  • earthquake fault lines can allow water to reach the surface- important in arid regions.
76
Q

Living on a plate margin- iceland

A
  • it has volcanic eruptions on average every five years- on Mid-Atlantic ridge
  • geothermal energy generates 25% of Icelandโ€™s electricity (most of the rest is HEP)
  • tourism
77
Q

How are all active volcanoes monitored?

A

Using high-tech scientific equipment including

  • remote sensing: satellites detect heat increases
  • seismicity: seismographs record microquakes
  • ground deformation: laser beams measure changes in the shape of the ground
78
Q

How are earthquakes monitored?

A
  • they generally occur without warning
  • A number of events can occur before an earthquake strikes, but these are never certain enough to issue warnings
  • these include:
    . microquakes before the main tremor
    .bulging of the ground
    .raised groundwater levels
79
Q

Prediction- volcanoes

A
  • the prediction of a volcanic eruption is based on scientific monitoring. In 2010, an increase in earthquake activity beneath the Eyjakfallajokull ice cap in Iceland enabled scientists to make an accurate prediction about the eruptions that took place in March and April that year
80
Q

Prediction- earthquakes

A
  • it is impossible to make accurate predictions about earthquakes due to the lack of clear warning signs
  • scientists study historial record to predict earthquakes at plate margins they have identified to be at the greatest risk.
81
Q

Protection- volcanoes

A

The sheer power of a volcanic eruptions means there is often little that can be done to protect people and property

  • however it is possible to use earth embankments or explosives to divert lava flows away from property
    eg: this has been done on the slopes of Mount Etna in Italy
82
Q

Earthquake protection

A
  • it is the main way to reduce risk
  • it is possible to reconstruct buildings and bridges to resist the ground shaking associated with an earthquake
  • In Chile, new buildings have reinforced concrete columns strengthened by a steel frame. Regular earthquake drills help people keep alert and be prepared. It is possible to construct tsunami walls at the coast to protect people and important buildings like nuclear power stations.
83
Q

Planning - volcanoes

A
  • hazard maps have been produced for many of the worldโ€™s most dangerous volcanoes, showing the likely areas to be affected
  • they can be used in planning to restrict certain land uses or identify areas that need to be evacuated when an eruption is about to happen.
84
Q

Planning- earthquakes

A
  • maps can be produced to show the effects of an earthquake or identify those areas most at risk from damage. High-value land uses like hospitals, reservoirs and office blocks can be protected in these vulnerable areas.
85
Q

Describe the process of global atmospheric circulation?

A
  • sinking air creates high pressure and rising air creates low pressure
  • surface winds move from high to low pressure, transferring heat and moisture from one area to another
  • these winds curve due to the Earthโ€™s rotation and change seasonally as the tilt and rotation of the Earth causes relative changes in the position of the overhead sun.
86
Q

How does global circulation affect the worldโ€™s weather?

A
  • cloudy and wet in the UK because 60 degrees north is close to where cold polar air from the north meets warm subtropical air from the south. These surface winds from the south west usually bring warm and wet weather, because rising air cools and condenses forming clouds and rain
  • hot and dry in the desert because most deserts are found at about 30 degrees N and S where sinking air means high pressure, little rain, hot daytime temp and very cold night
  • hot and sweaty at the equator because low pressure marks where the sun is directly overhead. Hot, humid air rises, cools and condenses. causing heavy rain- hence the tropical rainforests.
87
Q

What is a tropical storm?

A

Tropical storms are huge storms called hurricanes,cyclones and typhoons in different parts of the world.

88
Q

Where do tropical storms from?

A

5-15 degrees N and S of the Equator, in summer and autumn, where

  • ocean temperature are the highest (above 27 degrees C)
  • the spinning (Coriolis) effect of the Earthโ€™s rotation is very high
  • intense heat and humidity makes the air unstable.
89
Q

How do tropical storms form?

A
  • rising air draws evaporated water vapour up from the ocean surface which cools and condenses to form towering thunderstorm clouds
  • the condensing releases heat which powers the storm and draws up more water vapour
  • multiple thunderstorms join to form a giant rotating storm
  • Coriolis forces spin the storm at over 120 km/h, creating a vast cloud spiral with a central, calm eye of rapidly descending air
  • Prevailing winds drift the storm over the ocean surface like a spinning top, gathering strength as it picks up more and more heat energy
  • on reaching land the energy supply is cut off and the storm will weaken
90
Q

What are tropical storms also called?

A
  • hurricane
  • typhoon
  • cyclone
91
Q

What type of hazard is a tropical storm?

A

An atmospheric/ climatic hazard

92
Q

What are tropical storms called in the USA and Caribbean?

A

hurricanes

93
Q

What are tropical storms called in SE Asia and Australia?

A

cyclones

94
Q

What are tropical storms called in Japan and the Phillipines?

A

typhoons

95
Q

Do we get tropical storms in the UK?

A

No

96
Q

In which direction do tropical storms get pushed and why?

A

West, because of the trade winds

97
Q

What three hazards do you get with a tropical storm?

A
  • rain
  • wind
  • storm surge
98
Q

Why do tropical storms have a seasonal pattern?

A

They occur when sea temperatures are highest (27 degrees C)

99
Q

Where are the strongest wind speeds of a tropical storm?

A

In the eye wall

100
Q

In the northern hemisphere, which way does a tropical storm rotate?

A

anticlockwise direction

101
Q

In the southern hemisphere, which way does a tropical storm rotate?

A

clockwise direction

102
Q

Where do Hadley Cells form?

A

Between 30 and 40 degrees N and S

103
Q

Where do Ferrel cells form?

A

between 60 and 70 degrees N and S

104
Q

Where are the polar cells located?

A

They extend from between 60 and 70 degrees N and S, to the poles

105
Q

How can monitoring reduce the effect of tropical storms?

A

MONITORING:
- โ€˜Preparednessโ€™ is all about planning
- developments in technology, including satellite tracking, allow prediction maps to be prepared and warnings issued.
eg:
. the government of the Phillipines sending out Tropical Cyclone Warning Signals graded on the severity of winds and time frame expected
- the National Hurricane Center in Miami, Florida, USA, using a simpler two-scale warning system of Hurricane Watch (advised- is possible) and Hurricane Warning (expected).

106
Q

How can protection reduce the effects of a tropical storm?

A
  • can be anything from reinforced walls, roofs, and window shutters to storm drains and sea walls.
  • cyclone shelters in Bangladesh are used as community centres, schools or medical centres for most of the time.
107
Q

How can planning reduce the effects of a tropical storm?

A
  • it is unrealistic to stop tens of millions of people living in coastal areas at risk from tropical storms, but they can be made safer
  • it mostly means education and media campaigns raising individual and community awareness in order that people understand the dangers, and are able to respond.
108
Q

What is there evidence of a link between?

A

warmer oceans and intensity (destructive power) of tropical storms

109
Q

How much more intense are tropical storms expected to become more intense by?

A

2-11% by 2100

110
Q

What is the frequency of hurricanes?

A

the number of most severe category 4 or 5 tropical storms has increased since the 1970โ€™s
- predictions suggest that even 1 degree Celsius increase in tropical sea surface temperatures will mean a 3-5% increase in wind speed.

111
Q

What is the frequency of tropical storms like?

A
  • the overall frequency of tropical storms occurring is expected to either remain the same or decrease as a result of climate change
  • However, the number of more severe tropical storms (categories 4 and 5) is expected to increase
  • Category 1-3 storms will decrease
  • The regions where tropical storms are experienced is not expected to change significantly as a result of climate change.
112
Q

uncertainty

A
  • wind speed monitoring has become more accurate in recent decades
  • The use of previous data- which is less accurate- to decide how tropical storms are affected by climate change is questionable
  • Predicting the impact of climate change is unreliable, as the rate of and the impact of climate change in the future is uncertain
  • Potential risk to life and property has already increased due to population growth and building in coastal locations,even without factoring in climate change.
113
Q

How long can surges be up to?

A

5m

114
Q

What are secondary effects of storms?

A
  • aid is hampered as roads are flooded
  • Torrential rain can also trigger landslides, causing further devastation
  • Water supplies can be contaminated with seawater, sewage, and industrial waste - increasing the risk of waterborne diseases, such as cholera
115
Q

How are tropical storms measured?

A

Using the Saffir-Simpson hurricane wind scale. The higher the category scale, the higher the intensity of the tropical storm.

116
Q

What is the Saffir-Simpson hurricane scale based on?

A

windspeed

117
Q

Describe the location of tropical storms

A

Hurricanes form between 8 to 20 degrees north of the equator. There are cyclones, in the Atlantic there are hurricanes and typhoons in the Pacific. It happens when the Ocean is at least 26.5 degrees.

118
Q

Describe the formation of tropical storms

A

1, At the start of a tropical storm, the temperature and air pressure falls. Air rises and clouds begin to form. It becomes windy.
2, As the tropical storm continues, the air pressure falls more rapidly, wind increases, cumulonimbus clouds form and there is heavy rainfall
3, There is a period of calm with no wind or rain at the eye of the storm. The sun appears, so it gets warmer. Air pressure is very low.
4, Wind and heavy rainfall increase dramatically again, the temperature drops and air pressure begins to rise
5, As the tropical storm ends, the air pressure and temperature rise. Wind and rainfall subside.

119
Q

What is the distribution of tropical storms like?

A
  • over the last few decades, sea surface temperatures in the Tropics have increased by 0.25 to 0.5 degrees Celsius
  • As patterns of sea surface temperatures change, they may affect the distribution of tropical storms
  • In the future, tropical storms may affect areas outside the current hazard zone, such as the South Atlantic and parts of the sub-tropics
  • Hurricanes may also become more powerful
    eg: Hurricane Catrina- category 2 hurricane- first ever recorded- hurricanes do not usually form in the South Atlantic. In March 2004, sea surface temperatures were unusually high. Conditions were right for a hurricane to form. Some events might become more common as sea surface temperatures change.
120
Q

How many kilometres can tropical storms be up to?

A

480 km (300 miles) across

121
Q

Describe the conditions in the eye of a storm

A
  • the central eye is a small area wher relatively cold air sinks towards the ground and warms up
  • there are no clouds here and conditions are warm
122
Q

Describe the conditions of the eye wall

A
  • it is on either side of the eye

- there are strong winds in excess of 120 km/hr, heavy rain, thunder and lightning

123
Q

What is beyond the eye wall?

A
  • there are further banks of clouds with thunderstorms and occasionally tornadoes
  • there will also be strong gusty winds and heavy rain
124
Q

How will climate change affect tropical stoms?

A
  • over the last few decades, sea surface temperatures in the Tropics have increase by 0.25-0.5 degrees Celsius
  • In the future, tropical storms may extend into the South Atlantic and parts of the sub-tropics
  • In the future, tropical storms may become more powerful (as measured on the Saffr-Simpson scale)
  • In the North Atlantic, six of the ten most active years since 1950 have happened since the 1990s.
  • In the North Atlantic, hurricane intensity has risen in the last 20 years
125
Q

What does weather describe?

A

It describes the day-to-day conditions of the atmosphere.

126
Q

What does the climate descibe?

A

The average weather over a 30 day period

127
Q

Why does the UK experience weather hazards?

A
  • the UK roundabout
  • Arctic air can bring heavy snow and bitterly cold conditions
  • Severe winter weather can come from the east
  • Storms from the Atlantic bring heavy rain and strong winds
  • hot and sunny weather from the south can lead to heatwaves and drought.
128
Q

What are the UKโ€™s weather hazards?

A
  • ๐˜๐—ต๐˜‚๐—ป๐—ฑ๐—ฒ๐—ฟ๐˜€๐˜๐—ผ๐—ฟ๐—บ๐˜€ follow hot weather bringing lightning and torrential rainfall linked with โ€˜flashโ€™ flooding
  • ๐—ฝ๐—ฟ๐—ผ๐—น๐—ผ๐—ป๐—ด๐—ฒ๐—ฑ ๐—ฟ๐—ฎ๐—ถ๐—ป๐—ณ๐—ฎ๐—น๐—น over a long period leads to river floods, such as the very wet winter of 2013/2014 causing flooding across much of southern England
  • ๐—ฑ๐—ฟ๐—ผ๐˜‚๐—ด๐—ต๐˜ ๐—ฎ๐—ป๐—ฑ ๐—ฒ๐˜…๐˜๐—ฟ๐—ฒ๐—บ๐—ฒ ๐—ต๐—ฒ๐—ฎ๐˜ cause rivers to dry up and reservoirs to run dangerously low. The record breaking 2003 heatwave over much of Europe, including the UK, killed over 20000 people- mostly young children, the frail and elderly
  • ๐—ต๐—ฒ๐—ฎ๐˜ƒ๐˜† ๐˜€๐—ป๐—ผ๐˜„ ๐—ฎ๐—ป๐—ฑ ๐—ฒ๐˜…๐˜๐—ฟ๐—ฒ๐—บ๐—ฒ ๐—ฐ๐—ผ๐—น๐—ฑ are less common now, can cause great hardship to people in the north of the UK. December 2010 was the coldest in a century
  • ๐˜€๐˜๐—ฟ๐—ผ๐—ป๐—ด ๐˜„๐—ถ๐—ป๐—ฑ๐˜€, eg: Feb 2014, cause disruption to power supplies, damage from fallen trees and coastal battering from large waves
129
Q

What is the evidence that UK weather is becoming more extreme?

A

2003 heatwave- highest ever temperature recorded in Kent. Over 2000 died, railways buckled and roads melted
2007 floods- several deaths and many left homeless in summer floods
2008 floods- more severe flooding especially in SW and NE England
2009 heavy snow- heavy snow in the south, including 20cm in London
2009 floods- record November rain in Lake District
2010 Heavy Snow- Record low temperatures (-18.7 degrees C) in Northern Ireland
2013/2014 floods- Englandโ€™s wettest winter in 250 years
2015/2016 floods- December 2015 wettest and warmest ever recorded

130
Q

Why might extreme weather events be on the increase?

A
  • recent extreme weather events have also occurred elsewhere in the world: Western USA (2014)
  • No single weather event can be blamed on climate change, but trends over many years could be linked to global warming,
    which:
    . leads to more energy in the atmosphere, which could lead to more intense storms
    . possibly affects atmospheric circulation, bringing floods to normally dry areas and heatwaves to normally cooler areas.
131
Q

Could UK weather patterns be getting stuck?

A
  • UK weather systems, driven by winds from the jet stream, usually cross from west to east
  • the jet stream moves north and south but can โ€˜stickโ€™ in one position resulting in prolonged periods of the same type of weather, such as heatwaves
  • these โ€˜stuckโ€™ periods have become more frequent and could be due to climate change
132
Q

What do marked fluctuations throughout the last 2.6 million years (Quaternary Period) explain?

A
  • they explain glacial periods and warmer inter-glacial periods
133
Q

What is extreme weather?

A

Weather that is unexpected

134
Q

Most tropical storms happen between latitudes of?

A

5 and 30 degrees

135
Q

Why do tropical storms form?

A
  • heat makes the air unstable

- high sea temperatures above 27 degrees C

136
Q

How can you analyse evidence for climate change?

A
  • ice cores
  • oxygen trapped in layers of ocean sediments
  • water molecules in Arctic Snow
  • reliable thermometer records only go back aroung 100 years so these cann be analysed.
  • indicate a clear warming trend, with most of the increase since the mid 1970s
137
Q

What is the recent evidence for climate change?

A
  • some glaciers may disappear by 2035
  • the extent of Arctic sea ice reached an all-time low in 2014
  • rising sea level: glacier and ice cap melting adds more water.
  • thermal expansion: warm ocean waters expand in volume
  • low-lying islands such as the Maldives, and coastal regions in Bangladesh, India and Vietnam are in danger of flooding
  • seasonal changes: tree flowering and bird migration is advancing. Bird nesting is earlier than in the 1970s.
138
Q

Whst is the human impact and the enhanced greenhouse effect?

A
  • in recent years the amont of greenhouse gases in the atmosphere have increased
  • scientists believe this enhanced greenhouse effect is due to human activities
  • CO2 is most important, contributing approximately 60% to the net warming by greenhouse gases
  • most CO2 comes from burning fossil fuels in industry and power stations. Transport and farming also contribute.
  • deforestation of tropical rainforests by burning is another major source
  • CH4 emissions from ever-increasing numbers of farm livestock, rice farming, sewage treatment and emissions from landfill sites, coal mines and natural gas pipelines are growing even faster than CO2

geography (20 decks)

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