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Weather hazards and climate change Flashcards

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1
Q

Features of global atmospheric circulation

A
  • Transfer of heat from equator to the poles
  • Three circulation cells - hadley, ferrel & ; polar
  • Jet streams impact on the movement of heat energy
  • The spin of the earth creates the coriolis effect
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2
Q

Hadley cell

A
  • Hadley cells stretch from the equator to 30N and 30S
  • Warm trade winds blow towards the equator
  • At the equator the trade winds from each hemisphere meet. The warm air rises rapidly causing thunderstorms.An area of low pressure is formed where the air from the 2 cells meet over the equator
  • The air at the top of the troposphere moves towards 30N and 30S where the air cools and sinks towards the ground forming the subtropical high-pressure zone.
  • As the air sinks, it becomes warmer and drier. This creates an area of little cloud and low rainfall, where deserts are found.
  • The Hadley cell is then complete. The air completes the cycle and flows back towards the equator as the trade winds.
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3
Q

Ferrel cell

A

The Ferrel cell occurs between 30N and 60N and 30S and 60S

  • Air on the surface is pulled towards the poles, forming the warm south-westerly winds in the northern hemisphere and north-westerly winds in the southern hemisphere.
  • These winds pick up moisture as they travel over the oceans. At around 60 degrees N and 60 degrees S, they meet cold air, which has drifted from the poles.
  • The warmer air from the tropics is lighter than the dense, cold polar air and so it rises as the two air masses meet.
  • This uplift of air causes low pressure at the surface and the unstable weather conditions that are associated with the mid-latitude depressions. Much of our wet and windy weather in the UK is determined by this.
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4
Q

Polar cells

A
  • Polar cell stretch from latitudes 60N and 60S to the nrth and south poles
  • At the poles, air is cooled and sinks towards the ground forming high pressure, this known as the Polar high.
  • It then flows towards the lower latitudes.
  • At about 60N and S, the cold polar air mixes with warmer tropical air and rises upwards, creating a zone of low pressure called the subpolar low.
  • The boundary between the warm and cold air is called the polar front and is what accounts for a great deal of the unstable weather experienced in these latitudes
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5
Q

Ocean currents

A
  • Heat from the tropics can be transferred to the cold polar regions, by large-scale water movement within the oceans.
  • Each ocean has its own circular pattern of currents.
  • Heat is transferred by warm ocean currents, such as the North Atlantic Drift in the Atlantic Ocean, from low latitudes to high latitudes.
  • Ocean currents are set in motion by the prevailing surface winds associated with the general atmospheric circulation.
  • The direction of water movement is also deflected by the Coriolis force.
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6
Q

What have been recent temperature changes?

A

In last 250 years Earth’s temperature has risen significantly compared to before. Average temperatures in middle of last Ice age was about 5 degrees Celsius below today’s average temperature.

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7
Q

Natural causes of climate change
Milankovitch cycles:
What is the Eccentricity cycle:

A

Earth’s orbit changes approximately every 100,000 years.

-Colder months occur when its more circular, warmer months when it is more elliptical

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8
Q

Natural causes of climate change
Milankovitch cycles:
What is axial tilt cycle?

A
  • Roughly every 40,000 years tilt of Earth’s axis varies.

- A greater degree of tilt is associated with the world having a higher average temperature

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9
Q

What are greenhouse gases released by?

A

human activities including industry, transport, energy production and farming.

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10
Q

What is the enhanced greenhouse effect?

A

Human activity releases increasing levels of co2 and other greenhouse gases into atmosphere, increasing greenhouse effect-more warming.

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11
Q

What is the process of solar radiation entering and leaving Earth?

A
  • Heat energy from sun passes through atmosphere and heats up Earth.
  • Much of heat energy is radiated back into space.
  • Greenhouse gases in atmosphere, e.g. co2, trap some of heat.
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12
Q

How does industry help the human cause of climate change?

A

Rising demand for consumer good increases production, burning more fossil fuels, which release greenhouse gases.

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13
Q

How does energy help the human cause of climate change?

A

New technologies and population increase demand for electricity production from coal, oil and natural gas, which all produce greenhousse gases,

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14
Q

How does farming help the human cause of climate change?

A
  • Livestock, particularly cattle, produce methane as pat of their digestion - 1/3 of methane emissions in agricultural sector
  • Global population growth increases demand for food.
  • Mechanisation burns more fuel, and demand for meat for western-style diets increase methane levels.
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15
Q

How does transport help the human cause of climate change?

A

Rising affluence increases car ownership and air travel, releasing more greenhouse gases into atmosphere.

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16
Q

Where the UK located from the equator?

A

between 50 degrees North and 60 degrees North.

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17
Q

How does maritime influence impact on the UK’s climate?

A

Most of air reaching UK contains lots of moisture as we are surrounded by sea, leading to rainfall all year.

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18
Q

How does prevailing winds impact on the UK’s climate?

A

-Main or prevailing wind for UK comes from South West. -Air travels long distances over Atlantic Ocean, bringing moisture, leading to more rainfall.

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19
Q

How does Atmospheric circulation impact on the UK’s climate?

A

UK is near ‘boundary’ between northern Ferrel and Polar circulation cells. Where warmer air from south and cooler air from north meet, causing unsettled weather.

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20
Q

How do tropical cyclones form?

A
  • Need source of warm ocean temperatures (27 plus).
  • Rising warm air causes thunderstorms which group together, making a strong flow.
  • An area of very low pressure forms at and up, forming a tropical cyclone.
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21
Q

What are tropical cyclones?

A

A tropical cyclone is a very powerful low-pressure weather system which results in strong winds (over 120 km/h) and heavy rainfall (up to 250 mm in one day).

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22
Q

What are tropical cyclone characteristics?

A
  • They develop over tropical and subtropical oceans, between the tropic of cancer and tropic of Capricorn
  • Average wind speed is 120kmph but speeds of 400kmph have been known
  • Move from east to west with the trade winds
  • They have an ‘eye’ which is the calm centre of the storm
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23
Q

What are the frequency of tropical cyclones?

A
  • Happen June-November in northern tropics,
  • November-April in southern tropics.
  • More likely to happen in cooler years, but numbers are hard to predict.
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24
Q

What is the movement of tropical cyclones?

A
  • Cyclone movement is determined by prevailing winds and ocean currents.
  • Cyclone’s track is influenced by how far it travels over the ocean: it will collect more moisture, increasing its strength.
  • Tropical cyclones can travel 600 km a day at 40 km/h.
  • Cyclone movement can be forecast using satellite images.
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25
Q

How are high winds hazardous?.

A

Tropical cyclones are hazards due to the high winds.

  • The high winds can be as strong as 80mph,can uproot trees and buildings potentially causing injuries and loss of life
  • The high winds due to cyclones can rip of house roofs and in some cases the houses can simply fall over.
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26
Q

How is intense rainfall hazardous?

A

Heavy persistent rainfall can lead to flooding, damaging poverty and leaving people stranded.

  • Intense rainfall is experienced frequently during tropical cyclones.
  • In October 2012, during hurricane sandy there was 250mm of rainfall in many places in a few hours!
  • The heavy rainfall can cause the river banks to explode and crops get destroyed
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27
Q

How are storm surges hazardous?

A

Tropical cyclones can cause a large mass of water to hit land, causing damage to beaches and coastal habitats.

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28
Q

How are landslides hazardous?

A
  • Intense rainfall causes soil to be saturated and become heavy. Saturated soil then slides downhill.
  • It cause land slides in many countries, which have been known to destroy the whole village
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29
Q

How is coastal flooding hazardous?

A

Damage to property and lives is increased due to flooding.

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30
Q

How did hurricane sandy travel?

A
  • Across Caribbean Sea, affecting island nations of Jamaica, Cuba and Haiti, before moving north to reach USA, reached New Jersey on 29th October 2012.
  • By time reached land wind speeds of 129km/h were recorded. Storm surges caused most damage to East coasts states.
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31
Q

How was social media used in sandy?

A

helped with damage assessment.

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32
Q

Environmental impacts of hurricane sandy in Cuba

A
  • Around 2600 hectares of banana crops were destroyed.
  • In Santiago de Cuba trees were uprooted and stripped of their leaves.
  • Coffee plantation in mountainous areas were swept away.
  • Area is close to the coast were flooded, with beaches being swept away, destroying wildlife.
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33
Q

What were the economic impacts of Hurricane Sandy on Cuba?

A

Total losses in the Santiago de Cuba area came to £50 million.

  • Roads to the airport were blocked so no tourist could arrive or leave the island causing a loss in revenue. -Total losses of us$2 billion dollars.
  • A 5% drop in Cuba‘s GDP.
34
Q

Social impacts of Hurricane Sandy on Cuba?

A
  • There was no electricity or freshwater.
  • 11 people were killed.
  • Around 17,000 homes were destroyed and 226,000 homes were damaged
  • More then 55,000 people were evacuated because of the storm surge.
35
Q

Environmental impacts of hurricane sandy in USA

A

-The storm surge meant that seawater got in to freshwater habitats, which had severe impact on wildlife from Delaware bay to Long Island sound

  • Around 90% of beaches in New York and New Jersey were damaged; on average the features were 9 to 12m narrower and after the hurricane
  • 1,500,000 L of oil was spilt into Arthur kill which is a stretch of water between New Jersey, stated island, New York, damaging wildlife habitats and killing fish and birds
36
Q

Social impacts of Hurricane Sandy on USA

A
  • 117 people were killed
  • Roughly 9,000,000 homes had a power cuts
  • 650,000 homes were damaged or destroyed in the USA; 250,500 cars were destroyed by floodwater
  • The streets of New York were flooded as was the subway.
37
Q

Economic impacts of Hurricane Sandy on USA

A
  • Insurance claims in New Jersey totalled us$3.3 billion.
  • US$1.1 million was spent repairing the damage to sewage and water pipes in New Jersey and New York.
  • The damage cost in New York totalled US$19 billion.
38
Q

What were the responses of individuals in USA?

A
  • After the hurricane people moved in with relatives and used shelters
  • People rebuilt their homes but use builders rather than doing it themselves
  • Americans have Home insurance but those affected also received aid from the government and other organisations.
39
Q

What were the responses of organisations in Cuba?

A
  • Venezuela sent 650 tons of aid including non perishable food,potable water and heavy machinery.
  • Venezuela, Russia and Japan sent humatarian aid
  • In seven month following the hurricane the Cuban Red Cross delivered support with the help of the Norwegian, Spanish and German Red Cross and red Crescent societies. The relief aid went to approximately 25,000 families and included roofing materials, mattresses and clean drinking water.
40
Q

What were the responses of organisations in USA?

A
  • Hurricane Sandy caused extensive erosion to the Delaware bay beaches, which had an impact on the breeding grounds of horseshoe crabs. The Canadian rivers Institute worked with a number of other NGOs and public agencies to restore the beaches by clearing rubble and replenishing sand
  • The Red Cross had 17,000 trained workers, 90% of them volunteers, providing over 300 responses vehicles, 74,000 overnight stays and 17 million meals and snacks along with other aid.
41
Q

What were the responses of governments in Cuba?

A
  • The government sent teams of electricians from all over the island to Santiago province within hours of the hurricane hitting
  • The government announced a 50% price cut for construction materials and interest-free loans to repair the damage caused
  • The government made building materials available to residents, including corrugate iron sheets,metalrods and cement
  • Local government officials compiled data from families about the damage they had suffered so the government could send appropriate help
42
Q

What were the responses of governments in USA?

A
  • The US government approved US $60.3 billion in aid to the victims of hurricane sandy
  • The government promised that there would be improved weather forecasting, especially of storm surges.
  • FEMA teams and resources were put in place to help people even before the hurricane had caused problems.
  • FEMA and the army corps of engineers worked with the state and local government to quickly reopen most of beaches in New Jersey.
  • The Department of agriculture promised US $6.2 million for emergency food assistance, infrastructure and economic programs to help repair farmland and food plains
43
Q

What is a drought?

A

•It is a period of below average precipitation resulting in proloned shortages in water supply. It happens at 30 degrees north and 30 dergees south

44
Q

What makes an area arid?

A
  • In arid areas normal climate is dry, because normally have high pressure, leading to low precipitation
  • The key factors in whether an area is likely to suffer from drought are how it gets precipitation at any time or in rainy season, when precipitation occurs during winter (when soil can absorb rain more easily)or in summer.
45
Q

How do droughts occur in arid environments?

A

Permanent low precipitation. Sahara is arid; like Kalahari is semi-arid,

  • 10-250 mm precipitation a year
  • high pressure conditions
  • no cloud cover
  • mostly located in tropics (between 23.5 degrees north ans 23.5 degrees south of equator).
46
Q

What are drought conditions?

A

Temporary low precipitation conditions

  • In UK, drought is 15 consecutive days without rainfall, -high pressure conditions
  • no cloud cover located anywhere globally.
47
Q

What is a meteorological cause of drought?

A

Where an area receives less than average precipitation. In UK, high pressure (blocking anticyclone) forces away low pressure systems that bring rain around it. Means no rain falls over all or part of UK for weeks.

48
Q

What are hydrological causes of drought?

A
  • Where the hydrological cycle receives less rainfall than normal.
  • Less precipitation means groundwater supplies and reservoirs aren’t refilled, leading to drought conditions.
49
Q

Why the global circulation makes some locations more

vulnerable to drought?

A

-Global circulation makes some locations more vulnerable to drought.
-Where Hadley and Ferrell circulation cells are, such as African’s Sahel, decreasing dry air means little precipitation.
Rainfall occurs during wet season; if rains don’t come, area has drought conditions.

50
Q

Why are tropical droughts hazardous?

A
  • Wildfires are more common during this period of time as trees become dry. Due to the trees being dry they can catch fire very easily that are
  • The environment can also be destroyed during a drought as when soil becomes dry due to lack of rain, vegetation dies.
  • No top soil is left after a drought therefore crops and plants cannot regrow.
  • Crops fail during droughts and animals die due to the lack of grazing land. This lack of food causes malnutrition and ill health among the population in the area that are experiencing the drought.
51
Q

What are the impacts of Namibia drought on ecosystems?

A
  • Severe drought can have a great impact on a Savannah ecosystem. It can change an area of grassland that could sustain livestock to an area of incredible grasses and plants that live stock cannot live on. This is because grasses cannot cope with drought and are not good for life stock
  • Large areas are changing due to the lack of rainfall in Namibia.Only drought resistant plants can survive in these conditions. Cattle are not able to graze on them.
52
Q

What are the impacts of Namibia drought on people?

A
  • The 2013 drought was the worst drought for 30 years. -One in 3 people were at risk of malnutrition
  • 778,000 Namibians were either severely or moderately food insecure
  • The harvest yielded 42% less than in 2012 which meant severe food shortages
  • People left their homes to search for water as there was none in their villages- the wells have dried up
53
Q

What are the impacts of California drought on people?

A
  • Farmers use 80 percent of the human usage of water. If there are water shortages their crops will die or they will plant fewer crops, resulting in less food for people.
  • Loss of 17,100 jobs in farming
  • 5 percent of the irrigated land in California won’t be planted
  • The Department of Agriculture predicts that prices of fruit and vegetables will rise by 6 percent.
54
Q

What are the impacts of California drought on environment?

A
  • Wildfires are becoming a regular occurrence because of the dry and dead wood. There were more than a dozen fires in may 2014 near san diego. Fires of this nature usually occur in the autumn.
  • Some rivers and streams are closed to fishing. If water levels continue to drop, the water will become warmer and the young salmon will be unable to survive as they require cool running water.
  • The earth is shrinking because of depleted groundwater reserves. Between 2008 and 2011, parts of the central valley subsided more than 60cm.
55
Q

What were the responses of individuals in Namibia?

A
  • Farmers been forced to sell their livestock
  • People migrated to towns in search of work
  • In one village almost all people, about 350, left in search of water and grazing land for their cattle
56
Q

What were the responses of individuals in California?

A
  • Farmers will have to pump more water, which will cost an extra US$453
  • People have been asked to use water more sparingly
  • Farmers are planting smaller crops because there is not enough water and grazing land for their cattle
57
Q

What were the responses of organisations in Namibia?

A
  • UNICEF appealed for US$7 million to support their efforts to respond to the needs of women and children.
  • The international Red Cross and Red Crescent asked for US$1.5 million.
  • Algeria donated US$1 million in food aid.
58
Q

What were the responses of organisations in California?

A
  • New mandatory laws forbid restaurants to put water on tables without being requested
  • Hotels must also ask guests if they will reuse their linen and towels to save water.
  • Advanced forecasting models are being developed by NASA to help with the water shortage.
59
Q

What were the responses of government in Namibia?

A
  • In May, President Pohamba declared a state of emergency and requested US$1 million in international support to avert a crisis
  • The Ministry of Agriculture, Water and Forestry (MAWF) gave two options to farmers who do not have enough grazing for their animals: either to sell their livestock while they are still in good condition or ab subsidy for the cost of transporting their animals to emergency grazing areas
60
Q

What were the responses of government in California?

A
  • In February President Obama gave US$183 million from federal government funds
  • In March Governor Brown signed drought-relief legislation worth US$ 687 Million. It included US$25.3 million for food and US$21million for housing for people such as farmworkers who are out of work
  • Residents in the Santa Clara Valley have been told to limit watering of lawns to twice a week or face a US$500 fine
  • The Reclamation and Natural Resources Conservation Service announced that they hope to provide up to US$ 14 million federal funds to help farmers to conserve water and improve water management.
61
Q

Natural causes of climate change:

Solar variation

A

Solar output - there can be fluctuations in the amount of radiation from the sun. If there is high amount emitted there will be an increase in Earth’s temperatures.

62
Q

What is evidence for climate change?

Ice cores

A
  • Cores can be drilled into the ice to measure the amount of carbon dioxide trapped in the ice
  • This is a climatic indicator because levels of CO2 tend to be lower during cooler periods and higher when its warmer
63
Q

What is evidence for climate change?

Pollen records

A
  • Pollen analysis shows which plants were dominant at what time due to the climate
  • Each plant species has specific climatic requirements
  • Changes in pollen indicate changes in climate
64
Q

What is evidence for climate change?

Tree rings

A
  • Each year the growth of a tree is shown by a single ring
  • If the ring is narrow, it indicates a cooler drier year
  • If the ring is thicker it indicates a warmer, wetter year
65
Q

What is evidence for climate change?

Historical sources

A

parish records and diaries

66
Q

What are negative impacts of climate change on environment and people?
Rising sea levels

A
  • Global mean sea level has risen by between 10-20cm in last 100yrs
  • Recent studies predict a rise of 0.8 to 2m by 2100 - most of words largest cities (eg new york) would be under water
  • Other studies predict meltdown of Greenland ice sheet- this would mean a sea level rise of 7m (enough to submerge London)
  • Worst case scenario, between 665,000 and 1.7 million people living on pacific island Tuvalu and Kiribati would have to find new homes
67
Q

What are negative impacts of climate change on environment and people?
Changing patterns of crop yields

A
  • Countries the closest to the equator are more likely to suffer as their crop yields will decrease
  • In Africa, countries like Tanzania will have longer periods of droughts and shorter growing seasons
  • In India there will be a 50% decrease in the land available to grow wheat due to hotter and dryer weather
68
Q

What are negative impacts of climate change on environment and people?
Retreating glaciers

A
  • The melting of glaciers at the pole could affect ocean water movement
  • It is believed that melting ice in the arctics could cause the gulf stream to be diverted further south
  • This will lead to colder temperatures in Western Europe
69
Q

How has the earths climate changed in the past 1000 yrs

A
  • During medieval period the UK experienced a warm period with temperatures around 1 degrees warmer than the average
  • Between 1300 and 1900AD there was a period known a the little ice age - temperatures were 1 degrees cooler than present
  • The river Thames froze 20 times between 1564 and 1814 and ice fairs were held
70
Q

What is the UK’s climate like today?

A
  • UK climate shows characteristics of a maritime climate
  • Temperature does not have extremes and annual temperature range is small
  • The temperatures change gradually between the months
  • Precipitation falls every month; total amount varies with locations in the UK
71
Q

How does temperatures vary in the UK?

A

North-west: mild winters and cool summers.
south-west: mild winters and warm summers.
Norht-east: cold winters and cool summers.
South-east: cold winters and warm summers

72
Q

How does rainfall vary in the UK?

A

North and West receive most rainfall

73
Q

How does prevailing wind vary in UK?

A

Prevailing wind of UK is from south west, with little variation across the country

74
Q

What is the significance of the UK’s geographic location in relation to its climate:
Latitude

A
  • The latitude of the UK will impact on the amount of heat energy it receives from the sun; places closer to the equator are warmer than the poles
  • Latitudes also influences temperature by influencing the length of days. In winter the day length is short - this means that there are fewer hours of sunlight, resulting n lower temperatures
75
Q

What is the significance of the UK’s geographic location in relation to its climate:
Air masses

A

The origin and journey of the air mass can affect the climate of the UK.

  • For example, the Polar Maritime Air Mass originates in the Poles and travels over the Arctic Sea, therefore it brings cold and wet weather.
  • The Tropical Continental air mass originates in the tropics and travels over land, bringing hot and dry weather to the UK.
76
Q

What is the significance of the UK’s geographic location in relation to its climate:
Ocean current

A
  • The warm North Atlantic Drift significantly impacts the UK’s climate.
  • It carries warm water from the South Atlantic to the western shores of the UK.
  • The prevailing south-westerly winds then spread these warmer conditions, giving the western parts of the country mild winters.
77
Q

Relief rain (latitude)

A

The main upland areas of the British Isles are in the west. When warm moist air is driven onto land by prevailing south-westerly winds, it is forced to rise over the mountains, where it cools, condenses and brings about precipitation. This is called relief rainfall. As a result, there is more rainfall over western upland regions than in lower areas in the east

78
Q

How do tropical cyclones form?

A
  • The air above the warm ocean is heated. -Once the ocean water reaches at least 27°C, the warm air rises quickly, causing an area of very low pressure.
  • As the air continues to rise quickly it draws more warm moist air up from above the ocean leading to strong winds.
  • The rapidly rising warm air spirals upwards, cools, condenses and large cumulonimbus clouds form.
  • These clouds form the eye wall of the cyclone and produce heavy rainfall.
  • In the centre of the cyclone, cold air sinks forming the eye of the cyclone - here, conditions are calm and dry.
79
Q

Human causes of drought

A

Deforestation – removing trees can reduce the amount of water stored in the soil as rain tends to fall and wash off the land as surface run-off. This leaves the ground vulnerable to erosion and desertification which can lead to drought.

Constructing a dam may also cause drought downstream by severely reducing the flow of water.

Agriculture – using large amounts of water to irrigate crops removes water from lakes, rivers and groundwater. Some crops require more water than others, eg cotton.

80
Q

Why are some areas more vulnerable to droughts?

A

Droughts can occur all over the world. However, there is a link between drought and some climate patterns.

A lack of water vapour in the atmosphere means there is less precipitation and more chance of drought. High-pressure systems reduce evaporation and moisture in the atmosphere.

El Niño – as the surface temperature of the Pacific Ocean around the central South American coast increases, storm patterns are disrupted. This phenomenon is thought to create droughts in Indonesia and Australia.

La Niña - as the surface temperature of the Pacific Ocean around the central South American coast decreases, storms are again disrupted and North and South America are prone to droughts

geography (7 decks)

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