Paper 1: Hazardous Earth Flashcards
1
Q
What is the lithosphere?
A
Upper most layer of the earth. It is cool and brittle. It includes the very top of the mantle and above this the crust.
2
Q
What is the crust?
A
The crust forms the earths surface. It is a rock layer forming the upper part of the lithosphere. The lithosphere is split into tectonic plates.
These plates move slowly about 2-5cm each year on a layer called the asthenosphere.
3
Q
How do we know about the Earths interior?
A
Direct evidence from the earths surface and indirect evidence such as earthquakes and materials from space.
4
Q
What are the two types of crust?
A
Continental crust: this forms on the land, it’s made of mostly granite, which is a low density igneous rock. Lower density than the mantle basalt and therefore floats on the mantle. It is 30-50km thick.
Oceanic crust: formed under oceans. This is much thinner 6-8km thick. It is made up from igneous rock basalt same as mantle and therefore has a high density.
5
Q
Properties of mantle:
A
It’s rocky 2900 km thick.
It has two parts the upper and lower mantle.
Upper mantle has the region the lithosphere
Lower mantle reaches outer core
It carries the crust,
6
Q
Properties of the crust:
A
Hot rocks broke up the crust making tectonic plates.
Crust ranges between 50-70 km deep
7
Q
Properties of outer core:
A
This is liquid and it’s temperature ranges from 4000 - 5700 degrees.
Liquid layer of of iron and nickel
8
Q
Properties of inner core:
A
70% the size of the moon Same temperature as the surface of the sun It created the magnetic field Solid 1200 km thick.
9
Q
How do we know the inside of the earth is hot?
A
Molten lava spewing from volcanoes
Hot springs and geysers
10
Q
Why is the inside of the earth hot and what creates it?
A
Heat from the earth is called geothermal. The heat is produced by radioactive decay of elements such as uranium and thorium in the core and mantle. 50% the earths heat comes from radioactive decay. Radioactive decay is formed from unstable isotopes and release heat. The crust forms insolation as the earth is cooling.
11
Q
How does the inner core stay solid and why?
A
The inner core is so deep and under huge pressure so it stays solid. The outer core is less hot and under less pressure so it liquid.
12
Q
What are convection currents and how are they formed?
A
Heat rises from the core it creates convection currents in the liquid outer core and mantle.
These mantle conviction currents are strong enough to move the tectonic plates on the earths surface.
13
Q
What are plumes?
A
These are a part of the convection cells where heat moves towards the surface - called plumes.
These are concentrated zones of heat. In a plume the mantle is less dense. Plumes bring magma to the surface of magma breaks through the crust it erupts as magma through volcanoes.
14
Q
What is the magnetic field and what creates it?
A
The earth is surrounded by a huge magnetic field called the magnetosphere. This is a force field you can sometimes see known as the northern lights/Aurora.
These form when radiation from space hits the magnetosphere and lights up the sky. It also protects the earths from harmful radiation from the sun and space.
15
Q
How do scientists know that Pangea once existed?
A
They know that the continents were joined to form Pangea once. This was because identical fossils in west Africa and eastern South America which means they were once joined.
16
Q
How many tectonic plates are there?
A
Today’s the earths lithosphere is split into 15 large tectonic plates and 20 small ones. They move slowly on the asthenosphere
17
Q
What are the three types of plate boundaries?
A
Divergent -formed when two plates move apart
Convergent- formed when two plates collide
Conservative- formed when two plates slide past each other.
18
Q
How old is oceanic and continental crust?
A
Most continental crust if 3-4 billion years old. The oldest oceanic crust is 180 million years old.
19
Q
Why is oceanic crust younger than continental crust?
A
New oceanic crust constantly forms at divergent plate boundaries. Convection currents bring magma up from the mantle and the magma is injected between the plate separating them.
As magma cools it forms a new oceanic crust plates continue to move apart allowing more magma to be injected. Old oceanic crust is destroyed by subduction at convergent plate boundaries. Continental crust is less dense so can’t be subducted and destroyed.
20
Q
What is the volcanic explosively index (VEI)?
A
Measures the destructive power on a scale of 1-8. (Modern humans have never experienced an 8)
21
Q
What are primary and secondary effects?
A
Primary: caused instantly by eruption. Direct link to volcano such as acid rain, lava etc.
Secondary: in hours, days or weeks after eruption caused by volcano. Causes problems such as disease, food and water shortages.
22
Q
Why do volcanoes effect developing countries more than developed countries?
A
- often built in risky areas because there’s no where else affordable to live.
- can’t afford safe, well built houses so building often collapsed
- they don’t have insurance
- their governments don’t have money and resources to provide aid
- communications are poor so warnings and evacuation may not happen.
23
Q
What is an earthquake?
A
This is a sudden release of energy. Underground tectonic plates try to push each other along fractures building up tension which is suddenly released sending out pulses of energy.
24
Q
What are tsunamis?
A
Earthquakes under the sea can be generated by tsunamis. Tsunamis are waves that travel up to 900km/h and wavelengths over 200km.
25
What happens when a tsunami hits?
It causes a very powerful flood, pushing several km inland destroying homes, bridges and infrastructure. Warning systems in the ocean can detect tsunamis and set of sirens and alarms but this is only useful if the epicentre is some distance from the coast.
26
What is the asthenosphere?
It is part of the earths mantle. It is a hot semi molten layer that lies beneath the tectonic plates. It is the top layer of the mantle.
This acts as a lubricating layer under the lithosphere to help move the tectonic plates.
27
What is the mantle?
The middle layer of the earth. It lies beneath the crust and the core and is about 2900km thick. It’s an outer layer is the asthenosphere. Below the asthenosphere is mainly rock.
28
Explain one difference between the lithosphere and the asthenosphere?
The lithosphere is the upmost layer of the earth which is split into tectonic plates, while the asthenosphere underneath it is composed of the uppermost part of the mantle. As we move from the lithosphere to the asthenosphere the temperature increase. This increase in temperature as well as extreme pressure causes the rocks to become plastic. In time these semi-molten rocks will flow. This is caused by convection currents.
29
Explain one difference between oceanic and continental crust.
One difference between oceanic and continental crust is that continental crust is made u of thick granite which is impermeable so therefore it has a low density and can float on the mantle as the mantle is made up of basalt which is a denser rock.
In contrast to this the oceanic crust is made up of basalt and is more dense. However this is still slightly less dense than basalt so also floats on the mantle. The oceanic crust is much thinner than the continental crust.
30
How do meteorites help geologists to work out what our inner earth is made up of?
Meteorites are fragments of earth and metal that fall to earth from space. Most come from the asteroid belt between Mars and Jupiter.
These meteorites can be fragments of the lithosphere, mantle and core of a shattered planet. So for example iron meteorites may show that the earths core is made up of iron and nickel.
31
What types of meteorites are there?
- stony meteorites with a similar composition to basalt.
- stony iron meteorites containing a lot of the mineral olivine.
- iron meteorites which are solid lumps of iron and nickel.
32
How is the heat distributed globally?
In two ways:
- by air movements caused by pressure differences
- ocean currents
33
Why is wind important in order to keep temperatures at a safe level?
The angle of the suns rays makes solar energy very intense at the equator but disperse over wider areas at the poles. Wind plays an important part in making the Earth habitable by redistributing heat. Without wind the equator would be unbearably hot while the poles would be even colder.
34
How do areas of low pressure and high pressure form over land masses and the sea in the summer?
When the sun heats the land it also heats the air above it. So the air expands, becomes lighter and rises. This forms low pressure over areas of over landmasses in the summer.
In summer air over the sea remains cooler and denser over the sea as the sun takes longer to heat up the sea. This forms areas of high pressure.
35
How do land and sea heat up differently?
On land, dark surfaces (e.g soil and forest) absorb sunlight, which is converted to heat. Land heats up quickly in the summer but only at the surface so cools quickly in the winter.
The sea behaves differently. Some sunlight is reflected from the surface while some is absorbed to 30m deep. It therefore takes longer to heat so so longer to cool.
36
How is wind formed and how does it move?
Differences in air pressure cause air to move - from high to low pressure, creating wind. It moves in a circular way because of the Earths rotation.
37
What is the Gulf Stream?
This is a warm ocean current that can causes temperature differences in areas.
38
Where does the Gulf Stream begin and end?
It is driven by westerly winds and begins in the Gulf of Mexico, blowing northwest where a branch of it heads towards Europe to become the North Atlantic drift. The Atlantic drift keeps January sea temperatures at a warm 11°c. Around Greenland and Northern Canada the current cools turns south and forms the cold ‘Labrador Current’, which chills Newfoundland.
39
How is the Gulf Stream convection current formed?
- in the North Atlantic Cold, salty water is heavy so sinks.
- this sets up a convention current which drags surface water down.
- the current draws warm salty water over the ocean surface from areas near the equator such as The Gulf of Mexico.
- This cools and sinks in the Labrador and Greenland seas and flows south towards the equator where it is warmed again.
40
What is the global circulation model?
A theory that explains how the atmosphere operates in a series of 3 cells on each side of the equator.
41
What is meant by atmospheric circulation?
The movement of air around the Earth to try and balance the temperature.
42
What is the ITCZ?
Inter-Tropical Convergence Zone. This is an area of low pressure which brings rain. It stretches around the Earth, moving North in June when the sun is over head the Tropic of Cancer. By December the over head sun moves south towards the tropical of Capricorn taking the ITCZ with it.
43
In Mali why does rain normally arrive in May and why does Mali have a short rainy season?
Malis rainy season is in May because this is when ITCZ is over Mali. But by December the overhead sun moves south towards the Tropic of Capricorn taking the ITCZ with it so:
- Mali has a short rain season
- it rains in Kano (Nigeria, near Mali) a few weeks earliest and lasts longer.
- in Lagos, Nigeria the rain stays longer still and rains every month.
44
How does the ITCZ form?
The ITCZ forms within tropics, when two masses of air meet - or converge. It is parts of a movement of the atmosphere known as the global circulation model.
45
What causes the convection cells in the global circulation model?
The cells are cured by heating and cooling, and between them create the worlds high and low pressure systems.
46
What are the three global circulation cells?
Polar cell
Ferrel cell
Hadley cell
The Hadley cells is the biggest.
47
What is a high pressure?
When the Earths atmosphere is pushing really hard in the Earths surface, meaning air cannot rise. This results in very little or no precipitation in areas of high pressure.
48
What is low pressure?
When there is very little pressure pushing down on earths surface. This results in lots of rain.
49
Suggest two ways that Global circulation patterns affect rainfall distribution in West Africa (4 marks):
One way Global circulation patterns can affect rainfall distribution is that in the summer the air heats up, expands becomes lighter so rises. This forms areas of low pressure so much rain will occur here.
Another way global circulation patterns affect rainfall over West Africa is that winds blow from high to low pressure, towards West Africa and Southern Sahara. These are known as trade winds and carry moisture inland. These winds and the moisture they contain, cause a lot of rain over West Africa.
50
What causes Mali’s rainy season in the Northern hemisphere in the summer?
The Hadley cell.
51
What causes trade winds?
The Earth spinning (the Coriolis effect) creates three types of wind:
Westerly trade winds
North east trade winds
South east trade winds
52
After bringing rain to Mali in June the Hadley cell moves south due to the chains position of the sun. By January the latter has reversed how has this happened and what are the effects of this?
- the northern hemisphere winter creates a cool, dense high pressure area over North Africa.
- the sun is now overhead at the Tropic of Capricorn, warming the Southern Hemisphere, and forming a new low pressure area.
- Trade Winds blow from high to low pressure, drawing dry air from the Sahara across Mali and causing its dry season.
- these trade winds meet others from the Southern Hemisphere to create the ITCZ, which has shifted southwards. It brings rain to Southern Africa.
- to complete the Hadley cell, rising air from the ITCZ cools high in the atmosphere and becomes denser. Fed by air below, it spreads out until it subsides as high pressure air.
- the Hadley cells is just one part of the global atmosphere. There are two Hadley cells. The ITCZ forms when trade winds from each one meet.
53
Where can the Hadley, Ferrell and Polar cell be located?
Hadley: 0°-30° N and S
Ferrel: 30°-60° N and S
Polar: 60°-90°N and S
54
Which cell brings a front of rain to the UK?
The winds that drive the Gulf Stream from part of the Hadley cell collect moisture over the oceans and meet cold dense air from the polar cell between 50°-60°N and S. This creates front brining high rainfall which causes much of the UK’s rainfall.
55
What is one impact of how the global circulation model affects climate around the world?
One impact is that it leaves some tropical areas with little rain.
56
Why are deserts dry either little rain all year round?
E.g:
-in June the rains brought by the ITCZ never reach the Sahara, so it remains dry. In January, a high pressure area brings cooler, clear, dry air which means that the Sahara is dry too.
This is the same for tropical deserts north of the equator e.g Arabian and the same process occurs south of the equator, such as in the Great Sandy Desert in Australia.
This is how all the words tropical deserts originate.
57
How is the polar desert of Antarctica and the Arctic formed?
The cooler Ferrel cell (which contains less moisture because it’s cooler) takes mild sun tropical winds as far as 50°-60°N and S, where they meet colder winds from the Polar Cell forms a front which brings a front of rain, which when cold enough turns to snow. The dry dense air at the poles creates the polar desert of Antarctica and the Arctic sheet.
58
What causes low air pressure?
Rising air leads to low pressure at the Earths surface.
- as air rises and cools it forms clouds of precipitation.
- with low pressure, wind circulated rapidly inwards and upwards.
- storms are deep areas of low pressure that bring string winds and heavy rain.
59
What causes high pressure and where is air pressure the highest?
Sinking air leads to high pressure at the Earths surface. Pressure is highest at sea level.
60
Why is pressure important?
Pressure determines our weather.
61
How is wind created?
Air naturally wants to flow from high to pressure. Combined with the rotation of the Earth, areas of different pressure create our flow of wind.
When air rises (in areas of low pressure) air immediately rushes to take its place in the Earths surface (this air is from areas of high pressure) and the movement of this creates wind.
62
What type of weather is caused by high pressure?
With high pressure, descending air suppresses weather development. This leads to calm sunny conditions or often fog.
63
What is a climatologist?
A scientist who is an expert in climate and climate change.
64
What is the stratosphere?
A layer of air 10-50km above the Earths surface. It is above the cloudy layer we live in, the troposphere.
65
What do volcanic eruptions produce?
- ash
| - sulphur dioxide
66
What are some of the causes of natural climate change?
- volcanoes (the eruption theory)
- asteroid collisions
- solar activity (the sunspot theory)
67
How can large volcanic eruptions cause temporary climate change?
If ash and gas rise high enough from a large eruption, they will be spread around the Earth in the stratosphere by high-level winds. The blanket of ash and gas will stop some sunlight reaching the Earths surface. Instead the sunlight is reflected of the ash and gas back into space. This cools the planet and lowers the average temperature.
68
When did Mount Pinatubo in the Philippines erupt and what were the affects of the eruption?
- erupted in 1991
- released 17 million tonnes of sulphur dioxide. This was enough to reduce global sunlight by 10%, cooling the o,a net by 0.5°c for a year.
- this caused colder temperatures, which affected crops as they died meaning a poor harvest.
69
When did the eruption of Tambora in Indonesia take place and what affects did it cause?
- the eruption occurred in 1815.
- it is the biggest eruption in human history
- in 1816 temperatures around the Earth were so cold that it was called ‘year without summer’
- up to 200,000 people dies in Europe as Harvests failed.
- the effect lasted 4-5 years. In general volcanoes only affect the climate for a few years.
70
What is the asteroid collision theory?
Asteroid collisions can alter Earths climate by they need to be big.
1km sized asteroid strike the Earth every 500,000 years. An impact if this size would blast millions of tonnes of ash and dust into the atmosphere. This would cool the climate at the dust and ash blocking incoming sunlight. It would be similar in impact to a large volcanic eruption and its affects could last 5-10 years.
71
Give an example of an asteroid collision that altered Earths climate:
- in 1908 an asteroid with a diameter of 100m exploded in the air 5km above Tunguska, Russia.
- the blast flattened 80 million trees, but was not large enough to alter the climate.
72
What is a sunspot and what is the sunspot theory?
These are black areas on the suns surface. Sometime the sun has many spots, at other times they disappear. They tell us that the sun is more active than usual. Lots of spots mean more solar energy being fired out from the sun towards Earth.
73
Give two examples of how sunspots have affected our atmosphere in the past:
cooler periods such as the ‘Little Ice Age’ and warmer periods such as the ‘Medieval Warm Period’, Amy have been caused by sunspot activity.
However, some people thick there were more volcanic eruptions during the ‘Little Ice Age’ which caused cooler temperatures.
But climate change in timescales of a few hundred years cannot be explained by volcanic eruptions- but it could be explained by the sunspot theory.
74
What is the orbital theory?
Over long time periods there have been big changes in climate. Cold glacial periods and ice ages were 5-6°c colder than today. Some interglacial periods were 2-3°c warmer than today. Big changes like these need a big cause. This could be explained by the way the Earth orbits the sun.
75
How does the Earths orbit change when orbiting the sun over a long period of time?
- the Earths orbit is sometimes circular, and sometimes more of an ellipse.
- the earths axis tilts. Sometimes it is more upright, and sometimes more on its side.
- the earths axis wobbles, like a spinning top.
These three changes alter how much sunlight the Earth receives. They also affect where the sunlight falls on Earths surface. On times Ames if thousands of years these changes would be enough tot start an ice age or end one. These changes as called the Milankovitch cycle.
76
What is the Milankovitch cycle?
The three long term cycles in the Earths orbit around the sun. Milankovitch’s theory is that glaciers happen when the three cycles match up in a certain way.
77
What is the definition of climate?
The changing weather patterns, which can be predicted.
78
How do scientists know about climate in the past?
- fossilised animals, plants and pollen that no longer live in the UK.
- landforms like U-Shaped valleys left by retreating glaciers.
- samples from ice cores taken from Greenland and Antarctica.
79
How can scientists determine the past climate from ice cores?
Ice sheets are like time capsules. They contain layers of ice, oldest
at the bottom, youngest at the top. Each layer is one year of snowfall. Trapped in the ice layer are air bubbles. These preserve air from the time the snow fell. CO2 is locked in the air bubbles. Climatologists can reconstruct past temperatures by drilling a core through the ice and measuring the amount of trapped CO2 in the air bubbles.
80
What have ice cores told us about past climates so far?
We know about a period called the Quaternary period (the last 2.6 million years) from ice cores.
-there have been warm periods (interglacials) lasting for between 10,000 and 15,000 years. Cold periods (glacials) lasted about 80,000-100,000 years.
During some glacial periods, it became so cold that the Earth plunged into an ice age. Huge sheets of ice extended across the northern hemisphere. This happened in the last ice age 30,000-100,000 years ago.
81
How can tree rings help scientists discover about past climates?
In temperate climates such as in Western Europe, trees grow every summer. Periods of growth can be seen from the number of rings in a tree-each ring is a years growth.
Some years are warmer and wetter, when growth is greater an others are cooler and drier. Scientists therefore examine tree rings to learn about past climate conditions, before there were accurate rainfall and temperature data. We can learn about the climatic conditions the tree experienced.
82
What is the disadvantage of using tree rings to study past climates?
Trees rarely survive more than a few hundred years, but fossils of trees in peat bogs go back thousands of years.
83
What historical sources provide evidence for past climates?
- old photos, drawings and paintings of the climate.
- written records, such as diaries books and newspapers.
- the recorded dates of regular events, such as harvests, the arrival migrating birds and tree blossom.
84
What is the disadvantage of gaining past climate data form historical sources, such as paintings, newspapers, written rocks, books and recorded dates of harvests etc? And what can this type of evidence suggest about climate trends?
The sources are often not very accurate because they were not intended to record climate. However, they still give us some idea about recent climate trends.
The type of evidence suggests climate changes regularly p-every few hundred years. Average temperatures over the last 2000 years have varied by about 1-1.5°c colder or warmer than average temperatures today.
85
What is the atmosphere?
A layer of gases above the Earths surface.
86
What is the green house effect?
The way that gases in the atmosphere trap heat from the sun. The gases act like the glass in a greenhouse. They let heat in but prevent most of it from getting out.
87
What gases make up our atmosphere and in what quantity?
Nitrogen- 78.1%: is an important nutrient for plants to grow.
Carbon dioxide- 0.03%: taken in by plants which exchange it for oxygen.
Oxygen-20.9%: breathed in by animals, which breath out carbon dioxide.
Water vapour- 1%: forms clouds, essential to the water cycle.
88
Why is carbon dioxide vital for life on Earth?
it only makes up a small percent of the atmosphere. However, it is still important because it helps to regulate temperatures on Earth. It is one of the green house gases and without them the Earth would be inhabitable for humans and and life because the Earth would be too cold.
89
Why is the green house effect important?
This is a natural effect. The gases help to retain heat in the atmosphere. They make the planter warmer by 16°c and without them the Earth would be a frozen wasteland.
90
How do humans produce extra green house gases and how is this harmful?
The extra green house gases which pollute the atmosphere are produced by humans. In the UK we use many fossil fuels. Burning these produces CO2, which end up in the atmosphere as pollution. The main source of pollution is power station which produce electricity.
91
Green house gas statistics, %produced, sources warming compared to CO2 and %increase since 1850:
Carbon dioxide- 89%-burning fossil fuels and deforestation-1-+30%
Methane- 7%- Gas pipe leaks, farming rice in paddy fields, cattle ranching-21x more powerful- +25%.
Nitrous oxide- 3%- jet aircraft engines, cars and lorries, fertilisers and sewage farms- 250x more powerful- +16%.
Halocarbons- 1%- used in industry, solvents and cooling equipment- 3000x more powerful- not natural.
92
In a global scale why are their differences in carbon dioxide production?
Most carbon dioxide production is produced by highly industrialised, urbanised countries and less CO2 emissions are produced by poor countries as they cannot afford many power stations etc.
- The EU, USA and Japan emit 33% of all carbon dioxide emissions.
- China alone admits 29%+ with Russia and India emitting 5%+.
93
How many tonnes of carbon dioxide do people in developed countries emit in comparison to people in developing, third world countries?
- most people in developing countries produce 1-3 tonnes of carbon dioxide per person per year.
- people in developed countries produce 10-25 tonnes per person per year.
94
What are scientists trying to do to reduce carbon dioxide emissions?
- reducing emissions in the developed world, where lots of fossil fuels are used.
- persuading developing countries with high populations (e.g China and India) to slow down their growth in carbon dioxide emissions by using eco friendly alternatives.
- protecting vulnerable people from the future impacts of climate change.
95
How does the green house affect work and how is it causing damage?
Green house gases help control global temperatures. The land and sea absorb sunlight and re-emit it as infra red radiation. Some green house gases trap these. Extra green house gases trap more of this heat leading to rising sea levels as well as affecting rain and snow patterns.
96
What is global warming?
The fact that global climate is changing. It means the warming of Earths temperatures and is caused by the enhanced green house effect.
97
How is the green house affect different to the enhanced green house effect?
The enhanced green house effect is the impact on the climate from additional heat being retained due to the increased amounts of carbon dioxide and greenhouse gases that humans have released into the atmosphere.
98
What statistics show that global warming is happening?
- average temperatures rose by 0.85°c from 1880-2012.
- sea levels rose by 210mm from 1870-2010. They are rising because the sea expands as it warms, thermal expansion. In the future if glaciers and ice sheets melt further sea levels could rise significantly.
- by the end of the century they predict temperatures will rise 2-10°F. This would cause a rise in sea levels, affect weather, more rain, hurricanes and drought and kill many species unable to adapt.
99
What evidence shows that since 1980 global warming seems to be happening more quickly?
- the 10 hottest years on record have occurred since 1998, with 2005, 2010 and 2014 being the hottest.
- including 2013, nine of the ten warmest years on record have occurred in the 21st century.
- by 2012, floating sea ice sheets in the arctic had shrunk to less than half the amount in 1979.
- over 90% of the worlds valley glaciers are shrinking.
100
What was the report ‘Climate Change 2014: Impacts, Adaptations and vulnerability’ about.
In 2014 830 scientists from 80 different countries wrote this report. They work for the Intergovernmental Panel on Climate change, part of the UN.
The report confirmed earlier research which stated that most of the global average temperatures since mid twentieth century was likely due to the increase in Green houses gases produced by humans.
101
What future changes have scientists estimated by 2100?
- temperatures will rise between 1.1°c and 6.4°c.
- sea levels will rise by between 30cm and 1 meter.
- its estimated that temperature will rise by 3.5°c and there will be a sea levels rise of 40cm by 2100.
102
What factors make it difficult to determine future climate change by 2100?
- what the world future climate change will be.
- weather fossil fuels will be used or wether there will be a shift to cleaner energies like wind or solar.
- if people will change their life style and recycle more or use public transport.
103
What impacts could future climate change bring by 2100?
- more frequent floods, droughts and heat waves.
- stringer storms and hurricanes.
- changes to farming, as farmers have to adapt to a warmer climate.
- ‘climate refugees’ as people from low lying places evacuate places that are no longer habitable.
104
How do ice sheets add more water to the sea?
If an ice berg me,to it only expands a small amount. When ice sheets melt and float in to the water it is new water being added to the sea.
105
What is a tropical cyclone?
A general term used to describe a rotating system of clouds and storms that form and develop over tropical or subtropical waters. Once it’s winds exceeds over 118km/h a tropical cyclone is known as a hurricane, typhoon, or cyclone depending upon where it originates.
106
How are tropical cyclones defined in different parts of the world?
‘Hurricane’ is used in the North Atlantic and on the Pacific coast of the USA e.g America
‘Cyclone’ is used in the Indian and South Pacific Oceans e.g India.
‘Typhoon’ is used in the western North Pacific e.g Japan.
107
How are hurricanes defined by different categories?
Category 1 = 74-95mph or 119-153km/h
Category 2 = 96-110mph or 154-177km/h
Category 3 = 111-129mph or 178-208km/h
Category 4 = 130-156mph or 209-251km/h
Category 5 = >157mph or 252>km/h
108
What are some of the environmental impacts of climate change that could be experienced?
- loss of biodiversity
- erosion of beaches and bleaching of coral reefs in the Pacific islands.
- a reduction in thickness of sea ice in the polar regions.
- more extreme weather more frequently, e.g heatwaves, droughts, floods, storms and hurricanes.
109
What are some of the economical impacts of climate change that could be experienced?
- European areas will be affected by loss of tourism due to winter snow.
- crop yield could increase in east and south-east Asia.
110
What are some of the social impacts of climate change that could be experienced?
- changes to farming as farmers will have to adapt to a warmer climate.
- ‘climate refugees’ as people from low-lying places are evacuated.
- in southern Europe there will be increased pressure on water resources?
- in Southern and central Europe health risks such as heat stroke and dehydration will be experienced as temperatures rise.
- traditional ways of life will be lost as sea ice melts and temperatures increase in arctic regions.
111
What sorts of hazards do tropical cyclones bring?
Strong winds
Storm surges
Intense rainfall
Landslides
112
How do strong winds caused by a tropical cyclone cause damage?
They whip up garden furniture, lift roofs, vehicles or caravans, bring down trees, power lines and even destroy while buildings.
113
How do storm surges caused by a tropical cyclone cause damage?
They bring flooding caused by unusually high tides. High tides are even high than normal during a cyclone because air pressure is low. Sea level is raised because there is less weight of air holding it down. High tides extend inland, abusing coastal flooding.
114
How does intense rainfall caused by a tropical cyclone cause damage?
With thick dense clouds, it’s not unusual for 1000mm of rain to fall in a single storm. China holds the mainland record- in 1967 Typhoon Carla brought 2700mm in a single storm. That over 4x London annual rainfall. Although the world record is in The Pacific Island of La Reunion dwarfed even that when over 6400mm fell in 1980 during tropical cyclone Hyacinth.
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How do land slides caused by a tropical cyclone cause damage?
Land slides are caused by the movement of rock, debris or Earth down a slope. They occur when the ground is saturated by rainfall.
Example: In 2014 53 people died in a landslide in the Philippines caused by tropical storm Jangmi which saturated, heavy ground causing it to slump.
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What is the tropical cyclone intensity scale?
This is defined by the maximum mean wind speed over open flat land or water. This is sometimes referred to as the maximum sustained wind and will be experienced around the eye of the cyclone. This scale is used in Australia.
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What is fine Saffir-Simpson Hirricane scale?
Distinguished into 5 categories of hurricanes based in their wind speed and strength. It is used in the North Atlantic and North eastern Pacific oceans.
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What is the meteorology scale?
This has 4 categories of typhoons ranging from typhoon-violent typhoon. This is used in the Western Pacific e.g Japan.
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What is meant by track when referring to tropical cyclones?
Tropical cyclones movement. It follows pathways driven by global wind circulation.
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What is used to determine where tropical cyclones originate?
Satellite photography is used to spot where they originate, which I turn helps forecasters to plot where they will go next. It’s important to track them correctly because otherwise people may die and towns and cities could face costly damage.
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What three conditions occurring at the same time does a tropical cyclones formation depend on?
1- a large, still, warm ocean area whose surface temperature exceed 26.5°c over long periods of time. This helped a body of warm air develop. Tropical cyclones form in late summer when oceans have warmed up. Mid July-September in the Northern Hemisphere and Mid January to March in the Southern Hemisphere.
2-Strong winds high in the troposphere, 10-12km above the Earths surface, are needed to draw warm air up rapidly from the oceans surface.
3- a strong force created by the Earths rotation- cakes coriolis force. Tropical cyclones do not form near the equator, where coriolis force minimal, but instead where rotation is stronger, between 5°-30° latitude.
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Why do tropical cyclones not form near the equator?
a strong force created by the Earths rotation- cakes coriolis force. Tropical cyclones do not form near the equator, where coriolis force minimal, but instead where rotation is stronger, between 5°-30° latitude.
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When do tropical cyclone form?
Tropical cyclones form in late summer when oceans have warmed up. Mid July-September in the Northern Hemisphere and Mid January to March in the Southern Hemisphere.
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Why do cyclones need low air pressure to form?
Tropical cyclones depend on a supply of warm moist air. Warm air is lighter than cold. It expands and rises, creating an updraft. As a result air pressure falls. The lowest air pressure of a tropical cyclone is always found in the centre. Typical pressure is as low as 950mb or even less.
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Define air pressure:
The weight of air breathing down on the Earths surface and is measured in millibars.
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What is Earths average air pressure and how is this different to the air pressure of a cyclone?
1013 is the average air pressure on the Earths surface at sea level. Tropical cyclones have a much lower air pressure than the air surrounding them. The bigger the difference in pressure, the stringer the winds. One of the lowest air pressures recorded was 877mb typhoon Ida in the Philippines in 1958 which reached winds over 300km/h.
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How does a tropical systole form?
Stage 1: Warm air currents rise from the ocean. As the warm air rises more air wishes into replace it; then it too rises drawn by the drought above.
Stage 2: up-draughts of air contain huge volumes of water vapour from the oceans, which condense to produce cumulonimbus clouds. Condensation releases heat energy stored in water vapour, which poses the cyclone further.
Stage 3: coriolis force causes rising currents of air to spiral around the centre of the tropical cyclone, so it resembles a whirling cylinder. It rises and cools and some of it descends to form the clear cloudless syill eye of the storm.
Stage 4: as the tropical cyclone tracks away from its source, it is fed new heat and moisture from the oceans enlarging it as it does so.
Stage 5: once it reaches landmass , it loses its energy source from the ocean. Air pressure rises as temperature falls, winds drop, rainfall decreases, and it decays to become a mere storm.
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Where did cyclone Aila hit and what areas did it affect?
- the continent of Asia.
- affected areas of India and Bangladesh, mainly Bangladesh
- formed over the Bay of Bengal
- surroundings countries include: India and Nepal.
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When did tropical cyclone Aila hit and what were some of the biggest impacts?
- hit on the 25th May 2009.
- 275 people were reportedly dead
- 6 million people displaced
- tens of thousands of homes destroyed and damaged.
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What were the social impacts of cyclone Aila?
- 3.5 million people affected losing their homes and their livelihood.
- 275 people were killed.
- 750,000 made homeless, their homes either destroyed by winds or floods. 90% of those displaced were from Bangladesh’s lowest income groups.
- the storm surge raised sea level at high tide by 3m, which submerged and destroyed several villages. Over half of the Earth embankments in South Bangladesh, built to hold back clouds and protect people were washed away.
- Many schools destroyed meaning this affected children getting a good education.
- sickness and typhoid were problems- flooding meant that fresh water was contaminated by sewage, and moist air brought mosquitos and therefore malaria.
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What were the economic impacts of cyclone Aila?
- 59,000 animals (including cattle and deer) were killed, depriving families of food or income.
- worst affected land was the delta, much of which was flooded with salt water, which killed crops.
- salt from sea got absorbed into land (salinisation). This means crops were unable to grow.
- Bangladesh is flat, only 6-10m above sea level which meant the storm surge hit many eastern areas destroying/affecting towns and cities.
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What were the environmental impacts of cyclone Aila?
- greatest problem was scarcity of drinking water as saline from the sea has spilled into almost all the ponds, rivers and sources of water.
- loss of animals means that dung- a source of cooking fuel- was lost, which placed further pressure on firewood sources so more logging. (A rising population already meant wood land was in decline)
- The sunderbans is an area of mangrove forest that was badly affected. The area is home to the highly endangered Royal Benga-tiger and is a protected reserve. Mud embankments burst drowning at least 30 tigers.
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What were some of the responses to hurricane Aila?
- Red Cross supplied water purifying tablets.
- Bangladesh Navy was sent out to help.
- dry, clean clothes were distributed by NGO’s.
- water was rationed so everyone got fresh water to drink.
- Government camps set up to give people a safe place to stay.
- Government issued health work shops to explain importance of washing hands.
- Oxfam gave out grants to help people rebuild their houses.
- NGOs are teaching people to design cyclone proof houses. Although these houses are low cost, $15,000 it’s still more than local people can afford.
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What steps are Bangladesh taking to ensure these impacts will be less in the future?
- neighbouring countries such as India give Bangladesh regular updates as to air pressure, winds speeds and temperatures.
- they will warn Bangladesh is they pick up a cyclone.
- messages are sent out to people on incoming cyclones.
- however, as Bangladesh has a population 3x that of the UK it means it is impossible to evacuate everyone.
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What 3 factors made cyclones Aila especially severe?
- intensity of the rain. On 26th May the estuary region alone received 120mm of rain in a few hours. -that’s 1/5 of London’s annual total. Overall 200mm of rain fell everywhere.
- wind strength, which at its peak was 360km/hr.
- most seriously, low air pressure 967mb caused sea levels to rise, creating a huge storm surge.
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What is some of the basic Geography about Bangladesh?
- with an area of 144 000 sq km it is 60% of the size of the UK.
- It is home to 156 million people which is over twice the population of the UK.
- it remains among the worlds poorest countries.
- 80% of Bangladesh is less than 10m above sea level and 10% is below 1m.
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Why is Bangladesh vulnerable to a cyclone and what factors can make the impact of the cyclone worse?
Three of the world largest rivers the, Ganges, Brahmaputra, Meghna, join within Bangladesh and form one of the worlds largest flood plains. During the monsoon is one river floods they all do, inundating much of the coastal areas and threatening many people. Combined with a cyclone only makes this much worse.
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What were some of the long term issues of cyclone Aila?
- By mid 200 000 people still had not returned home and were living in temporary shacks.
- Many had migrated to the cities such as Dhaka, in search of work. However, poverty forces them to live in slum areas.
- some found their lack of skills meant they had to take labouring jobs, or pull rickshaws.
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What percentage of cyclones does Bangladesh receive and how does this compare to the damage they cause and why is Bangladesh so badly affected?
It receives 5% of the world cyclones but yet it suffers 85% of the worlds deaths and damage caused by cyclones.
It’s people are poor GDP per capita is $2100 in 2013 and 31% of its population love below the poverty line. This is why the damage is so bad.
The poorest people are the landless Labourers that are women. They are forced to live on cheaper flood-prone land in poorly-built housing, they suffer the most form cyclones.
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What ways have Bangladesh developed technology to protect its population?
- predicting cyclones (using forecasting and satellite technology).
- developing warning systems.
- introducing evacuation strategies and building storm surge defences.
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How does Bangladesh use weather for casting to protect its population from cyclones? And what are the problems with this?
Bangladesh’s Meteorological Department issues weather forecasts on the TV and radio. The problem is that outside Dhaka, the capital city, few people have access to TV and radio. In 2009 it was proven that households with radios had lower death rates, but this is developing very slowly outside the city. However, mobile ownership looks promising. In 2014 mobile ownership reached 50 phones per 100 people.
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How does Bangladesh show use satellite technology to predict cyclones?
Weather forecasting is expensive because it uses digital images from space bought from US, Chinese and Japanese satellites, costing US$12 million a year. In 2012 Bangladesh announced it was going to spend US$150 million on developing its own space satellites.
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How does Bangladesh show use warning systems to protects its people from cyclones?
Since cyclone Bhola killed 300,000 people in 1970 the government has developed an early warning system, enabling coastal communities to be evacuated. It also runs awareness campaigns, using a mix of village meetings, leaflets and posters, film shows and demonstrations to spread information about cyclone warning signals and helping people to prepare for the cyclone. There are now 450,000 cyclone warning volunteers, who live and work in the threatened areas.
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What evacuation strategies does Bangladesh have in place to protect its people?
- The construction of cyclone shelters and coastal embankments by the government has reduced deaths from cyclones.
- for those who are evacuated there are 3500 cyclone shelters in coastal districts, some taking up to 5000 people.
- they are all built from concrete or brick and people who use them usually survive; death rates are double where there are no shelters. More are needed.
- embankments are built to protect against storm surges. Bangladesh has a 400km coastline and thousands of km of low lying rivers, which flood often during storms. Impossible to protect entire country.
145
Has Bangladesh been successful in preventing further damage from cyclones?
-it has reduced death toll and damage caused by cyclones through its warning systems, evacuation plans and shelters.
However, illiteracy means that some do not understand or follow warnings. Others believe in ‘wait and see’ many fear losing their property as that’s all they own and false warnings limit those willing to evacuate.
146
What was the location of Hurricane Katrina?
Hurricane Katrina hit the country if USA. The hurricane hit the states of Mississippi, Alabama and Louisiana and badly affected New Orleans.
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What were some of the social impacts caused by hurricane Katrina?
- flooded 80% of the New Orleans by August 31st with water over 6.1 m deep in some areas.
- 1883 people died.
- people had no electricity. Homes and cars were destroyed.
- 80% (1.3 million) people were evacuated but some chose to stay.
- many people took refuge in the city dome but it had little sanitation, was over crowded and over heated.
- caused extensive damage over many km of land.
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What were some of the economic impacts caused by hurricane Katrina?
- destroyed many buildings and caused extensive damage.
- costliest Atlantic hurricane in history
- over $1 billion lost to fraud that was meant to go to victims.
- caused $108 billion worth of damage.
- 100,000 temporary homes were needed across the region.
- 6 months after there were still no functioning sewage systems, gas and electrical supplies available in some parts.
- timber industry lost $5 million.
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What were some of the environmental impacts caused by hurricane Katrina?
- hurricane winds recorded over a 200km coastline.
- winds exceeded over 282 km/h.
- destroyed many trees and animal habitats.
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Key facts about Hurricane Katrina:
- 6th strongest hurricane in history.
- winds over 200mph.
- made land form in 29th August
- it was a hurricane 5 category when it hit New Orleans.
- caused a storm surge of over 10m.
- has low air pressure of 902mb
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Why was New Orleans so badly affected?
Levees in New Orleans were breached. The city is also low lying so the flood/sea walls did nothing. Once flooded the water had no where to retreat to because the levees retained the water when the storm surge subsided so it couldn’t retreat back out.
The flooding affected poor people more which caused looting, fires and riots.
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What were the responses of hurricane Katrina?
- there was criticism for response of government and president.
- cities levees had been repaired to previous standard.
- retained water was pumped out of levees.
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Why do Hurricanes have less of an impact on the USA compared to Bangladesh?
The US has over 20 satellites operating every day. Weather forecasts are frequent and issued in TVs and radios. Almost everyone has access to media and mobile phone ownership is high 103 phones per 100 people. There is also a National Hurricane centre in Miami whose job is to:
- issue warnings and forecasts of Hazardous weather.
- educate people about tropical cyclones.
154
What problems are faced by the USA when using forecasting and satellite technology?
Satellites are ageing and in October 2012 one failed to to work when hurricane sandy first developed. A back up satellite took over bits its software was out of date, so it only gave broad predictions about eh hurricanes likely track. A correct prediction of its track was actually made by a forecasting centre in the UK. It was these warnings that were used to prepare people and as it tuned out with was the second costliest storm in US history.
155
What risk and evacuation system as the USA got in place for hurricanes?
The USA has a cyclone warning and evacuation system. In Florida towns and cities are classified into risk zones. Areas are for risks from high winds or storm surges using scale between Extreme and low. Only people who need to leave are evacuated so emergency services can work on getting people out without being over whelmed.
156
How do Earthquakes tell us about the Earth?
Seismic waves from Earthquakes tell us about the physical state of the Earth. They speed up, change direction or stop when they meet a new layer in the Earth. It is due to this that we know about the core.
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How can fragments meteorites from rocks tell us about our core?
Most meteorites come from the asteroid belt between Mars and Jupiter. They come in several types:
- stony meteorites, with a similar composition to basalt.
- stony iron meteorites containing a lot of mineral olivine.
- iron meteorites, which are solid lumps of iron and nickel.
These meteorites may be fragments of the lithosphere, mantle and core of shattered planets. Iron meteorites may show the Earths core is made up from iron and nickel.
157
What is radioactive decay?
Some elements are naturally unstable and radioactive Atoms of these elements release particles from their nuclei and give off heat. This is radioactive decay.
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What is meant by geothermal and what creates it?
This is heat from inside the earth. The heat is produced by radioactive decay of elements such as uranium and thorium in the core and mantle. This raises the cores temperature to over 5000°c.
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What is the engine for the movement of plate tectonics?
Radioactivity in the core and mantle is the engine for the movement of plants tectonic.
160
What goes of plumes form what types of plant boundaries?
- some plumes rise as long sheets of heat. These form divergent plant boundaries.
- other plumes are like columns of heat. These forms hots spots. Hot spots can be in the middle of a tectonic plate, like Hawaii and Yellowstone in the USA.
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What creates the Earths magnetic field?
It’s created by the outer core. As liquid iron flows in the outer core it works like an electric dynamo. This produced the magnetic field.
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What forms at a conservative plate boundary, give an example:
Destructive Earthquakes occur here with magnitudes up to 8.5. There are small earth tremors here almost daily. Nor volcanoes forms here.
E.g San Andreas fault in California, USA, North American and Pacific plates sliding past each other.
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What forms at a divergent plate boundary, give an example:
Small earthquakes up to 5-6 on the Richter scale occur here. The volcanoes that occur here are not very explosive or dangerous. Occur is fissures (cracks in the crust). Erupt basalt lava at 1200°c.
E.g Iceland, on the mid Atlantic ridge. The Eurasian and North American Oceanic plates pulling apart.
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What forms at a convergent plate boundary, give an example:
Very destructive volcanoes occur here up to a magnitude 9.5. Tsunamis can form here. The volcanoes occur here are very explosive, destructive. They are steep sided cone shaped. Lava is 900-1000°c.
165
What forms at collision zones, give an example:
Destructive earthquakes occur here, up to magnitude of 9.0. This triggered landslides. Volcanoes are very rare here.
E.g Himalayas. Formed as the Indian and Eurasian Continental plates push into each other.
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What is a collision zone?
Collapse zones are a type of convergent boundary. They form mountain ranges like the Himalayas. Two continental plates of low density granite collide pushing up mountains. Earthquakes happen on faults (huge cracks in the crust) in Collins zones.
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Define a tectonic hazard:
Natural events caused by movement of the Earths plates that affect people and property.
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Why are earthquakes so violent at convergent boundaries?
Sinking oceanic plates can stick to the continental plate. Pressure builds up against the friction. When the plates finally snap energy is released as a violent earthquake. These earthquakes can be devastating, especially if they are shallow.
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Why are people in a developing world more at risk from tectonic hazards than those developed counties?
- people often build in risky locations, because there is nowhere else affordable to live.
- they can’t afford safe, well-built houses, so buildings often collapse.
- they don’t have insurance
- their governments don’t have the money and resources to provide aid.
- communications are poor, so warning and evacuation may not happen.
Most volcanic eruptions with high death tolls are in the developing world.
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What is relief support?
This is like aid. It is help given by organisation or countries to help those facing an emergency.
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What is the Richter scale?
A scale that measure the magnitude of an earthquake. The scale is logarithmic, a magnitude of 6.0 is 10x more powerful than a magnitude of 5.0.
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What is the epicentre of an earthquake?
The location on the Earths surface above the focus is the epicentre, which experiences the most shaking.
Energy travels outwards from the focus as waves. The shallower the focus, the more destructive the earthquake.
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How can tsunamis be predicted?
Warning systems in the ocean can detect tsunamis and set off sirens and alarms but this is only useful if the epicentre is some distance from the coast.
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The when did the Tsunami hit Japan in 2011 and where?
On 11th of March 2011, an earthquake with a magnitude of 9.0 hit Sendai, Japan and caused a tsunami. The focus was 30km deep on a convergent boundary and the epicentre was 70km from the coast in Sendai Bay.
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What were the primary effects of the tsunami in Japan?
- 1 dam collapsed, 2 nuclear power stations fractured and an oil refinery set on fire by damaged gas pipes.
- Tohoku motorway badly damaged in Northern Japan. Sendai airport closed by the tsunami. One rail link near Sendai badly damaged.
- US$ 235 billion if damage caused by earthquake and tsunami combined. -costliest distaste in history.
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What were the secondary effects of the tsunami in Japan?
(caused by tsunamis)
- 15,900 people died, 2600 missing, 6150 injured, 350,000 people homeless. Most were at work or school when it happened at 2:46pm.
- 93% of deaths were caused by drowning.
- 2 nuclear reactors went into melt down because flooding damaged cooling system. Local people had evacuated and were not returned u TIL 2015.
- businesses disrupted by damaged, clearance and rebuilding.
- homelessness, disrupted schooling, unemployment and increased stress lasted for years as the authorise struggled to cope either damage.
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When did the earthquake in Haiti 2010 occur, where and what was the magnitude of the quake?
Magnitude: 7
Focus: 13km deep on a conservative plate boundary
Epicentre: 25km deep from port-au-Prince (population 2.5 million)
Date: 12th January 2010
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What were the primary effects of the earthquake in Haiti?
- 316,000 people died and a further 300,000 people were injured.
- many houses were poorly built and collapsed instantly.
- 1 million people made homeless.
- the port, communication links and major roads were damaged beyond repair. Rubble from collapsed buildings blocked roads and rail links.
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What were the secondary effects of the earthquakes in Haiti?
- the water supply system was destroyed- a cholera outbreak killed over 8000 people.
- the port was destroyed- making it hard to get aid to the area.
- Haiti’s important clothing factories were damaged. These provided over 60% of Haiti’s imports. 1/5 jobs were lost.
- By 2015 most people displaced by the earthquake had been re-housed.
180
What long term planning have Japan put in place to avoid the impacts of another earthquake like the one in 2011?
Japan is a developed country so can afford to do this. There is a 70% probability of a 7.2 magnitude earthquake hitting Tokyo in the next 30 years. So.....
- every year Japan has earthquake drills. Emergency services practise rescuing people. People keep emergency kits (with water, food, radio, torch and first aid) at home.
- tsunami walls have been designed to protect the coast.
- Many building are Earthquake proof. Gas supplies shut off automatically, reducing fire risk.
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How are earthquake proof building designed to be able to survive earthquakes?
- very deep foundations to prevent building collapsing.
- a damper in the roof acts like a pendulum, reducing sway.
- a string steel frame which is flexible.
- cross bracing stops floods collapsing.
- shock absorbers are built into cross bracers.
- string double glazed windows stop broken glass showering down.
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What is meant by vulnerability?
A measure of extent to which a community or area is likely to be damaged or disrupted by the impact of a hazard.
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What is meant by a risk?
The probability of a hazard event casing harmful consequences (e.g death, injury, loss of property).
