Weather Hazards and Climate change - up to drought

Question 1

Why does the sun heat the Earths surface unevenly?

Answer 1

1. Due to the curvature of the Earth.
2. The sun’s energy is more concentrated at the equator compared to the poles, therefore temperatures are higher.

Question 2

How is heat transferred to the poles?

Answer 2

1. Winds blow from the areas of high pressure to the areas of low pressure.
2. This helps to transfer heat energy away from the equator and redistributes it around the Earth.

Question 3

How is heat transferred by ocean currents?

Answer 3

1. Ocean currents are large scale movements of water that transfer heat energy from warmer to cooler regions.
2. Surface currents are caused by winds and help transfer heat away from the equator, e.g. the Gulf Stream brings warm water from the Caribbean and keeps Western Europe warmer than it otherwise would be.
3. There are also deep ocean currents driven by differences in water density.
4. When water freezes at the poles, the surrounding water gets saltier, increasing its density.
5. As it gets denser, it sinks, causing warmer water to flow in at the surface, creating a current.
6. This warmer water is cooled and sinks, continuing the cycle. This cycle of cooling and sinking moves water in a big loop around the earth, known as the thermohaline circulation.

Question 4

What are trade winds?

Answer 4

1. Surface winds blowing towards the equator are called trade winds.
2. Trade winds blow from the SE in the southern hemisphere and from the NE in the northern hemisphere.
3. At the equator, these trade winds meet and heat from the sun causes them to rise and form clouds.

Question 5

What are westerlies?

Answer 5

1. Surface winds blowing toward the poles are called westerlies.
2. They blow from the NW in the southern hemisphere and from the SW in the northern hemisphere.

Question 6

What are winds part of?

Answer 6

1. Winds are part of global atmospheric circulation loops called cells.
2. These loops have warm rising air which creates a low pressure belt, and cool falling air which creates a high pressure belt.

Question 7

What are the three cells in each hemisphere?

Answer 7

1. Polar cell
2. Ferrel cell
3. Hadley cell

Question 8

How are ice cores evidence of natural climate change?

Answer 8

1. Ice sheets are made up of layers of ice - one layer is formed each year.
2. Scientists drill into ice sheets to get long cores of ice.
3. By analysing the gases trapped in the layers of ice, they can tell what the temperature was each year.

Question 9

How do tree rings give evidence of natural climate change?

Answer 9

1. As a tree grows, it forms a new ring each year - the tree rings are thicker in warm, wet conditions.
2. Scientists take cores and count the rings to find the age of a tree. The thickness of each ring shows what the clime was like.

Question 10

How do pollen records give evidence of natural climate change?

Answer 10

1. Pollen from plants gets preserved in sediment, e.g. at the bottom of lakes or in peat bogs.
2. Scientists can identify and date the preserved pollen to show which species were living at that time.

Question 11

How does Milankovitch cycles cause climate change?

Answer 11

1. Eccentricity. The path of the Earth’s orbit around the Sun changes from an almost perfect circle to an ellipse and back again about every 96,000 years.
2. Axial tilt. The earth is tilted at an angle as it orbits the sun, varying between 22.1 and 24.5 degrees. This changes over a cycle of around 41,000 years,
3. Precession. The axis of the Earth wobbles like a spinning top on a cycle of about 22,000 years.

Question 12

How do sunspots cause climate change?

Answer 12

1. The Sun’s output of energy isn’t constant - it changes in short cycles of about 11 years. This is known as solar variation.
2. Solar variaton is caused by sunspots. Sunspots are cooler areas of the Sun’s surface that are visible as dark patches. They increase the Sun’s output of energy.
3. Perioids where solar output is less and there are very few sunspots may cause the earth’s climate to become cooler in some areas.

Question 13

How does volcanic activity cause climate change?

Answer 13

1. Major volcanic erruptions eject large quantities of material into the atmosphere.
2. Some of these particles reflect the su n’s rays back out to space, so the Earth’s surface cools.
3. Volcanic eruptions may cause short-term changes in climate, e.g the cooling that followed the eruption in Mount Pinatubo in 1991.

Question 14

What are greenhouse gases?

Answer 14

1. Greenhouse gases are the gases that trap heat.

Question 15

How does farming cause global warming?

Answer 15

1. Agricultural land contributes to 12% of GHG emissions.
2. Use of pesticides releases greenhouse gases such as nitrous oxide which contributes to the enhanced greenhouse effect.
3. Cattle ranching is the biggest cause of deforestation in Brazil - 80% of deforerrested areas being used for pasture.
4. Less trees exrtracting CO2 from the atmosphere.
5. Cows release between 10kg and 120kg of methane per year, methane has a 23x stronger effect on the enhancred greenhouse effect than CO2.
6. Rice paddy fields are one of the largest sources of Methane in the world. As populations increase, rice producton will increase as it is a staple food.

Question 16

How does industry cause global warming?

Answer 16

1. Total GHG emissions from industry almost doubled between 1970 and 2010.
2. Most industry uses a lot of energy.
3. Some industrial processes also release greenhouse gases, e.g. cement is made from limestone, which contains carbon. When cement is produced, lots of CO2 is released into the atmosphere.
4. Industrial waste may end up in landfill sites where it decays, releasing methane.

Question 17

Why are there regional changes in rainfall in the UK?

Answer 17

1. Prevailing wind from the south west bring moist air from the atlantic which means that the west of the UK tends to have higher rainfall than the east

Question 18

How does continentality affect UK weather?

Answer 18

1. The UK is made up of islands so it is susrrounded by the sea
2. Areas near the sea are warmer than inland areas in winter because the sea stores up heat and warms land
3. Areas near the sea -> cooler in summer because sea takes a long time to heat up so it cools downt the land
4. This means that the UK is milder in winter and cooler in summer than countries on the continent

Question 19

How does the north atlantic drift affect UK weather?

Answer 19

1. The North Atlantic Drift is an ocean current that brings warm water from the Caribbean across the Atlantic to the west coast of the UK
2. This keeps the west coast of the UK warmer than other countries in similar latitudes

Question 20

What are air masses?

Answer 20

They are large volumes of air with roughly the same temperature and water content

Question 21

What five air masses affect the UK and what weather to the bring?

Answer 21

1. Arctic maritime - cold and wet
2. Polar continental - cold and dry
3. Tropical continental - warm and dry
4. Tropical maritime - warm and wet
5. Polar maritime - cold and wet

Question 22

What are tropical cyclones?

Answer 22

Tropical cyclones are intense low pressure weather systems with heavy rain and strong winds that spiral around the centre

Question 23

Where do tropical cyclones form?

Answer 23

1. Most tropical cyclones occur in a band of low pressure and warm temperatures between 5° and 30° N and S of the equator
2. These conditions are created by global atmospheric circulation
3. They develop when the sea temperature is 27°C or higher and when the wind shear between higher and lower parts of the atmosphere is low
4. Warm, moist air rises and condensation occurs -> this releases huge amounts of energy which makes the storms powerful
5. The rising air creates an area of low pressure, increasing surface winds
6. They move west due to easterly winds near the equator. The earths rotation deflects the winds, making the storm spin
7. The cyclone gets stronger due to energy from the warm water, so wind speeds increase

Question 24

Where do most tropical cyclones occur?

Answer 24

Northern hemisphere in late summer and autumn -> sea temperatures are highest

Question 25

What is the centre of the cyclone?

Answer 25

1. It is called the eye 2. It is up to 50km across and caused by descending air 3. There is very low pressure, light winds, no clouds, no rain and a high temperature in the eye

Question 26

What is the eye wall?

Answer 26

The eye is surrounded by the eye wall, where there is spiralling rising air, very strong winds, storm clouds, torrential rain and a low temperature

Question 27

What is the greenhouse effect?

Answer 27

1. Gases in the atmosphere naturally act like insulating layer - they trap long-wave radiation helping to keep earth at right temperature