Topic 2: Weather Hazards And Climate Change (PAPER ONE) Flashcards
(37 cards)
What does Global Atmospheric Circulation describe?
How air circulated around the world
What are the global circulation cells? (Ordered from North Pole to South Pole)
Polar, Ferrel, Hadley, Hadley, Ferrel, Polar
What occurs at areas of low pressure? - what are the conditions like at these areas?
Air warms and rises, leading to evaporation which forms clouds and rainfall
What occurs at areas of high pressure? - what are the conditions like at these areas?
Air cools and sinks, preventing water from evaporating which leads to sunny and clear conditions
Where in the world is hottest? - why?
Equator: The sun’s rays hit the surface at a right angle
What are the conditions like at the equator? - why?
Conditions are wet because hot air rises, leading to low pressure
What are the conditions like at the Tropic of Cancer? - why?
Conditions are sunny because the air is sinking, leading to high pressure
Between which cells does the Tropic of Cancer lie?
The Tropic of Cancer is between the Ferrel and Hadley cells
What are the conditions like at the polar front? - why?
There are wet and cloudy conditions because the air is rising which leads to low pressure
How do the circulation cells distribute heat across the Earth?
The differences in pressure between different points on the earth cause winds which redistribute heat from the tropics across the planet
How do ocean currents help keep the UK warm? Use an example.
GULF STREAM:
- Brings warm water from the Caribbean across the Atlantic Ocean to the UK
- Heat rises from the water and warms the winds blowing across the UK
- This keeps the UK 5’C warmer
What’s the greenhouse effect?
A natural process which keeps the Earth warm
Name the natural causes of climate change
Milankovitch Cycles
Solar radiation
Volcanism
Surface impact
Define the Milankovitch cycles
Natural changes to the Earth’s orbit and position that affect the amount of radiation we receive from the sun
Explain the 3 Milankovitch cycles (how they cause climate change)
ECCENTRICITY:
- Earth’s orbit changes over long periods of time
- When the orbit around the sun is more circular, its slightly warmer (INTERGLACIAL PERIOD)
- When the orbit around the sun is more elliptical it’s slightly cooler (GLACIAL PERIOD)
AXIAL TILT:
- Earth is tilted so the pole are 23 degrees from vertical which creates seasons
- Over approx. 40,000 years, the angle of tilt changes meaning when it’s tilted away from the sun we get warmer summers and colder winters
PRECESSION:
- Earth ‘wobbles’ on its axis when it rotates, changing the direction the axis faces
- This creates a greater difference in summer and winter
- Occurs over approx. 24,000 years
Define solar variation and explain how it causes climate change
Solar Variation - Amount of radiation the sun produces over time
Periods of lower solar activity lead to GLACIAL periods, high solar activity leads to INTERGLACIAL periods
Explain how Volcanism causes climate change
Large scale eruptions eject huge volumes of ash and dust into the atmosphere, partially blocking out solar radiation (leading to GLACIAL periods)
Explain how Surface Impact causes climate change
Large cosmic material can impact Earth’s surface, ejecting large volumes of dust into the atmosphere which partially blocks out solar radiation
(leads to GLACIAL period)
What are the human activities that produce greenhouse gases?
Industry
Transport
Energy
Farming
How does Industry produce greenhouse gases?
- As levels of disposable income rise, there is an increased demand for the production of consumer goods (because more people can afford them)
- This leads to industry growth which requires more energy for the factories resulting in more fossil fuels being burnt
How does Transport produce greenhouse gases?
- Cars are becoming more affordable and more people take flights over long distances
- This requires huge quantities of fuel, naturally increasing the fossil fuels burnt (greenhouse gases released)
How does Energy produce greenhouse gases?
- Increasing population and new technology means an increased demand for electricity
- This requires energy made by burning fossil fuels which produce greenhouse gases
How does Farming produce greenhouse gases?
- population growth has led to a higher demand for food production
- mechanisation = more fuel burnt
- Intensive farming of cattle = increased production of methane (which is a greenhouse gas)
What are the negative effects of climate change? (on people and the environment)
Rising sea levels
Retreating glaciers
Lower crop yields