Weather Hazards and Climate Change

Question 1

What are the features of global atmospheric circulation?

Answer 1

-The transfer of heat from the Equator to the poles.
-There are there circulation cells - Hadley, Ferrel and Polar
-Jet streams impact on the movement of heat energy
-The spin of the Earth creates the Coriolis effect.

Question 2

What is global atmospheric circulation?

Answer 2

The worldwide movement of air which transports heat from tropical to polar latitudes.

Question 3

What is a hemisphere?

Answer 3

A half of the earth. The northern hemisphere is above the equator, th southern hemisphere is below it.

Question 4

What is latitude?

Answer 4

The distance, north or south from the equator measured from 0 to 90 degrees North or South.

Question 5

What is the troposphere?

Answer 5

The lowest layer of the atmosphere. It is thicker at the equator (~20km) than at the poles (~10km) in height.

Question 6

What is a depression (in Geographical terms)?

Answer 6

A low pressure system that produces clouds, wind and rain.

Question 7

What is an ocean current?

Answer 7

A continous directed movement of ocean water. The currents are made from forces acting on the water such as the wind, different temperatures and the Earth’s rotation.

Question 8

What is the ITCZ?

Answer 8

The Inter Tropical Convergence Zone, where the two hemispheres’ Hadley cells meet.

Question 9

What are trade winds?

Answer 9

A wind that blows steadily from the tropics towards the equator. In the northern hemisphere it is from the northeast and in the southern hemisphere it is from the southeast.

Question 10

What are the characteristics of Hadley cells?

Answer 10

-They stretch from the equator to 30 degrees north and south.

-Warm trade winds blow towards the equator.

-At the equator, trade winds from each hemisphere meet. The warm air rises rapidly causing thunderstorms. An area of low pressure is formed in the ITCZ.

-The air at the top of the troposphere moves away from the equator where it becomes cooler and sinks. It warms and any moisture is evaporated around 30 degress north and south. This creates high pressure areas, with cloudless skies.

-On returning to the ground some of the air returns to the equatorial areas as trade winds, completing the circle.

Question 11

What are the characteristics of Ferrel cells?

Answer 11

-Ferrel cells stretch from 30 degrees north and south to 60 degrees north and south.

-These winds collect moisture as they blow over oceans on the Earth’s surface.

-At about 60 degrees north and south they meet cold air from the poles.

-The warm air rises over the cold air as it is less dense. This produces low pressure at the surface causing depressions.

-Some of the air returns to the tropics and some is diverted to the poles as part of the polar cells.

-The cell has a motion to the right in the northern hemisphere and to the left in the southern hemisphere due to the spin of the Earth. This is called the Coriolis effect.

Question 12

What are the characteristics of the polar cells?

Answer 12

Polar cells stretch from latitudes 60 degrees north and south to the poles. They:
-Have air that sinks over the poles producing high pressure.
-Have air that flows towards low pressure in the mid-latitudes, meeting air from the Ferrel cells.

Question 13

What are jet streams?

Answer 13

In the upper atmosphere, winds blow around the Earth in a westerly direction. Within these winds there are bands of extremely fast-moving air known as jet streams. These jet streams can be hundreds of kilometres in width, but only 1000-2000 metres high. They are found at altitudes of about 10000 metres. The jet streams can be found in:

-The polar stream, going from 40 degrees to 60 degrees, in a westerly direction.

-The subtropical jet stream between 25 to 35 degrees in a westerly direction.

Question 14

What are Milankovitch cycles?

Answer 14

The amount of heat the Earth receives from the sun is affected by orbit. Three cycles affect this - eccentricity, axial tilt and precession.

Question 15

What is precession?

Answer 15

The Earth’s axis wobbles like a spinning top, taking around 26,000 years to complete a cycle. The motion is caused by the gravitational action of the sun and moon. This cycle can affect seasonality.

Question 16

What is eccentricity?

Answer 16

The path of the Earth around the sun is eliptical. This shape can change to a circle. This is caused by the gravitational pull of other celestial bodies. One complete cycle lasts for about 100,000 years. It appears colder periods are when the orbit is more circular and warmer periods are when it is more eliptical.

Question 17

What is axial tilt?

Answer 17

The earth is spinning on its own axis. The axis is not upright and takes an angle of between 22.1 degrees and 24.5 degrees. A complete cycle for this tilt takes about 41,000 years. A greater degree of tilt is associated with the world having a higher average temperature.

Question 18

What is solar variation?

Answer 18

This is a change in the amount of heat energy coming from the sun. Sunspots on the surface of the sun can have an impact. Between 1645 and 1715 the Little Ice Age occured perhaps due to lower sunspot activity.

Question 19

What is volcanism?

Answer 19

Large volcanic eruptions release ash and sulphur dioxide into the atmosphere, causing less solar rays to enter the Earth’s atmosphere, cooling the Earth. Sulphur dioxide reacts with water to make Sulphuric acid, which causes acid rain, damaging the environment.

Question 20

How do ice cores prove climate change?

Answer 20

The polar regions have ice frozen for millions of years. Cores can be drilled into to measure the amount of CO2 in the atmosphere at the time it was formed. It can show how CO2 levels have changed.

Question 21

How do pollen records prove climate change?

Answer 21

Pollen analysis shows which plants were dominant at a particular time due to climate. Each species has specific climatic requirements that influence their geographic distribution. Changes in the pollne found in levels of peat bog shows how climate changes over time.

Question 22

How do tree rings prove climate change?

Answer 22

Trees develop rings each year, if the ring is narrow it shows a cooler, drier year, and thicker rings show hotter and more humid years.

Question 23

How do historical sources prove climate change?

Answer 23

Cave paintings, diaires and documentary evidence can be used. For example, the fairs held on the river Thames when it froze. Since 1873, daily weather reports have been held. Parish records are a good source of climate data too.

Question 24

How does the greenhouse effect work?

Answer 24

When fossil fuels are burned, greenhouse gases are released into the atmosphere, thickening it.

Heat energy from the sun beams down onto Earth, some of it passing through a blanket of gases in our atmosphere.

Some of the heat energy escapes back into space.

Greenhouse gases form a blanket around the Earth which traps heat energy in the atmosphere.

The energy which does not escape into space is reflected back into Earth.

The main greenhouse gases are carbon dioxide, methane and nitrous oxide.

Question 25

How is the greenhouse effect caused?

Answer 25

Industry uses fossil fuels as an energy source to manufacture its products, releasing greenhouse gases into the atmosphere.

Most forms of transport uses combusting fossil fuels to power them, this also releases greenhouse gases.

The generation of power accounts for 25% of global carbon dioxide emissions. The main use of coal and natural gas is to generate electricity.

Farming releases greenhouse gases due to animal excrement like methane. Also, lots of water is used in farming, meaning that global water reserves are depleted.

Question 26

How are rising sea levels impacting people?

Answer 26

Due to sea levels consistently rising, by 2100 hundreds of millions of people could be at risk of being underwater, like whole cities such as New York, London and St Petersburg. Properties are also at risk of being submerged.

Question 27

How is climate change impacting glaciers?

Answer 27

Due to increasing temperatures, glaciers are melting and retreating, this increases water level, causing more increasing temperature, causing a feedback loop.

Question 28

How has crop yield changed due to climate change?

Answer 28

Countries closer to the equator are receiving less precipitation and thus drought is more common, causing crop failure and thus causing more famine.

Question 29

How has the UK climate changed over the last 1200 years?

Answer 29

From about 800 to 1300, the UK went through a warm period, but from 1300 to 1900 it went through a cold period, consistently lower than the average temperatures, but due to global warming, since the 1930s, we have experienced a rapid increase in heat, to even higher temperatures than the peak of a warm period.

Question 30

What is the UK climate like today?

Answer 30

It has the characteristics of a maritime climate. The temperature does not have extremes and the annual temperature range is small. Precipiatation varies in the UK, from 550mm in London to 1800mm in Fort William.

Question 31

What is the prevailing wind in the UK?

Answer 31

The prevailing wind is from the Southwest, from the gulf stream in the Atlantic, this is seen as the Southwest of the UK is normally the most windy.

Question 32

How does the UK’s latitude impact it?

Answer 32

Due to its latitude, sun rays hit the UK at an angle, decreasing ground temperatures in relation to the equator. Also, since at certain times it faces towards and certain times faces away from the sun, day length varies a lot more in the UK than at the equator.

Question 33

How do air masses impact the UK?

Answer 33

Due to its proximity to the poles, the UK receives polar air masses from the north, cooling temperatures here and causing rainfall.

Due to its proximity to the arctic, very cold and dry air reached the north, causing very cold temperatures at cetain times.

Polar continental air from Scandinavia and Russia causes cold and dry air reaching the North Sea coast of the UK. Due to seasonality this makes this area cold in winter and very hot in summer.

Tropical continental air from North Africa and the Mediterranean causes the South of England to become hot and dry in the summer.

Tropical maritime air from the Atlantic and gulf stream causes the West Coast of the UK and Ireland to be very windy, wet and warm in summer.

Question 34

How does distance from the sea influence climate?

Answer 34

Settlements close to the sea will have less extreme temperatures since:

-The sea is constantly moving so water is heated or cooled is circulated so it takes a long time to alter water temperature, this means air around the coast heats up and cools much slower.

Question 35

What are tropical cyclones?

Answer 35

Non-frontal intense low pressure weather systems, known by different names around the world.

-They develop over tropical and subtropical oceans.
-They need a water temperature over 27 degrees C.
-They usually form during late summer.
-The average wind speed is 120 kph but 400 kph is the maximum.
-They normally move from east to west due to trade winds.
-They have an eye, the calm centre of the storm.

Question 36

What are typical impacts of cyclones in developing nations?

Answer 36

-Electricity and fresh water supplies are cut short.
-Many people are displaced since houses are destroyed.
-Some people die from the impacts, like starvation or drowning.
-Many people have to evacuate because of storm surge.
-Roads to villages or key infrastructure like airports can become blocked, so people cannot leave the area.
-Many people lose jobs since workplaces are destroyed.
-Tourism decreases due to transport being blocked.
-Overall GDP and GDP per capita decreases.
-Large areas of farmland are destroyed.
-Farmers living near the coast are cut off or their land or cattle are destroyed.

Question 37

What are typical impacts of a cyclone on a developed nation?

Answer 37

-Power cuts near the coasts are common,
-Many homes are destroyed near to the coast.
-Streets are flooded.
-Storm surge means sea water enters fresh water habitats, impacting wildlife here.
-Lots of oil is spilled.
-Insurance claims mean the council has to repay those affected.
-Financial damage normally totals a lot more than developing nations.

Question 38

What are typical responses to cyclones by developing nations?

Answer 38

-Many people move in with relatives or friends.
-Basic materials provided by the government are used by people to rebuild homes.
-People typically don’t have home insurance.
-Foreign aid from the UN is provided to help rebuild.
-Specific countries may send in peacemaking forces to maintain stability in the country if it is very corrupt.
-The World Food Programme responds to provide food for people who cannot be helped by the government.
-The government makes building materials avqilabe to residents.
-Military teams are mobilised to prevent warlords from taking over areas since they are cut off from the rest of the nation.
-Electricians are dispatched to restore power.

Question 39

What are typical responses to cyclones by developed nations?

Answer 39

-People move in with relatives until houses are rebuilt.
-People rebuild homes using specialist builders.
-People have home insurance and receive aid from government and other organisations.
-Habitats destroyed that house wildlife are rebuilt using soft engineering like beach nourishment.
-Charity organisations provide shelter, food and first aid.
-Teams are sent to provide aid shipments, funding and providing a mobile health clinic.
-Large amounts of money are given to victims by the government.
-Weather warning system infrastructure is improved.
-Specialist teams are used to reopen beaches to encourage tourism.

Question 40

What are the characteristics of arid environments?

Answer 40

-An average rainfall between 100 and 300 mm
-Variations in rainfall totals between 50 and 100% each year.
-Pastoral farming usually by nomads.
-Natural vegetation is sparse
- A short growing season.

Question 41

What are the causes of drought?

Answer 41

Meteorological -
This concerns the amount of precipitation an area receives compared to its average precipitation, causing drought.

Hydrological - This is how a decrease in precipitation can have an impact on overland flow, reservoirs, lakes and ground. This often is defined on a river basin scale: water reserves in aquifers, lakes and reservoirs fall below a statistical average. This can be related to precipitation or human demand and increased usage.

Agricultural - When not enough water is available to support crop production on farms. It often occurs during a fall in precipitation. This causes farmers to use artificial irrigation methods, draining yet more resources, causing a feedback loop.

Dam building - If a dam is constructed on a large river it produces electricity and water for areas close to the dam.

Deforestation - The cutting down of trees for fuel reduces the soil’s ability to hold water. This can cause land to dry out in the area, decreasing crop yield and causing drought.

Question 42

How does global circulation make some areas more vulnerable to drought?

Answer 42

Movement of air from the equator to the mid latitudes causes air to rise at the equator, causing thunderstorms and a loss of moisture. The drier air moves towards the mid latitudes. The dry air descends and warms causibg arid conditions at around 30 degrees north and south.

Question 43

What were the impacts and responses to drought in Namibia?

Answer 43

-Farmers been forced to sell their livestock.
-People migrated to towns in search of work.
-In one village almost all the people left in search of water and grazing land for cattle.
-President Pohamba declared a state of emergency and requested $1 million USD in international support to avert a crisis.
-£13 million in relief for the worst-hit households.
-The Ministry of Agriculture, Water and Forestry 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 a subsidy for the cost of transporting their animals to emergency grazing areas.
-Severe drought can have a major impact on a savannah ecosystem. It can make the soil impossible to irrigate or sustain livestock.
-Large areas of Namibia are changing from savannah grassland to desert due to a lack of rainfall so people move in large number out of these areas an into the core.

Question 44

What were the impacts and responses to drought in California?

Answer 44

-Farmers use 80% of the human use 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 17100 jobs in farming.
-5% of irrigated land in California won’t be planted.
-The Department of Agriculture predicts that prices of fruit and vegetables will rise by 6%.
-Wildfires are becoming a regular occurence. Fires normally occur in 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 by more than 60cm.
-The dry weather meant a better grape harvest.
-The state is preparing to undertake fish rescues - capturing them in shallow waters and transporting them to deeper waters near the ocean.
-Governor Brown issued a state of emergency.
-In March Governor Brown signed drought-relief legislation worth $687 million USD. It included $25.3 million USS for food and $21 million 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 $500 USD fine.
-The Reclamation and Natural Resources announced that they hope to provide up to $14 million USD of federal funds to help farmers conserve water and improve water management.
-New mandatory laws forbid restaurants to put water on tables without it being requested.
-Hotels must also ask guests if they will reuse linen and towels to save water.
-Advanced forecasting models are being developed new ways to betrer manage and monitor the state’s water resources.
-They are developing new ways to better manage and monitor the state’s water resources.
-Farmers will have to pump more water, which will cost an extra $453 USD.
-People have been asked to use water more sparingly.
-Farmers are planting smaller crops because there is not enough water for them to grow.