2818367
Descrição
Mapa Mental por Beth Coiley, atualizado more than 1 year ago
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Criado por Beth Coiley
mais de 9 anos atrás
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GCSE Geography - Causes of Climate
Change
- Earth's orbit
- Over a long period of time
- Significant climate change
- Glacial periods
- Glacials - temperature has been 5-6℃ cooler
- E.g. Pleistocene epoch
- E.g. Pleistocene epoch
- Interglacials - temperature has been 2-3℃ warmer
- E.g. current Holocene period has persisted since Pleistocene epoch
- E.g. current Holocene period has persisted since Pleistocene epoch
- Glacials - temperature has been 5-6℃ cooler
- Orbit changes over time - sometimes
elliptical, sometimes circular
- This means there are times
when Earth has less heat energy
- It can take longer for solar radiation to reach Earth
- This means there are times
when Earth has less heat energy
- Earth's axis tilts - on average, 23.5º
- Over a long period of time
- Volcanic eruptions
- Earth relies on gases in atmosphere to trap heat
- E.g. SO₂ (sulphur dioxide)
- SO₂ released by erupting volcanoes
- Eruption must be large enough so that
ejected gas reaches upper atmosphere
- Once in atmosphere, gas is spread by winds in stratosphere
- Gas encircles Earth like a blanket,
forming a layer reflecting radiation
- Gas encircles Earth like a blanket,
forming a layer reflecting radiation
- Once in atmosphere, gas is spread by winds in stratosphere
- Eruption must be large enough so that
ejected gas reaches upper atmosphere
- SO₂ released by erupting volcanoes
- E.g. SO₂ (sulphur dioxide)
- Do not affect climate over a long period
- E.g. Tambora, Indonesia, 1816
- 'Year with no summer'
- 200,000 deaths in Europe
- Sunlight reaching Earth 10% lower for next 5 years
- 'Year with no summer'
- Earth relies on gases in atmosphere to trap heat
- Changes in solar activity
- Sun's output is not constant - cycles detected
- Records began over 2000 years ago
- Sunspots - these darker areas can tell us about heat output
- Black sunspots indicate that the sun is working harder and is more active
- Number of sunspots can be linked to periods of time
- Sun's output is not constant - cycles detected
- Reflectivity
- Earth reflects solar radiation (insolation)
- Normally about 30-70% absorbed
- Normally about 30-70% absorbed
- Albedo is affected by surface colour
- Light surfaces reflect more, dark surfaces absorb more
- Light surfaces reflect more, dark surfaces absorb more
- Positive feedback mechanism
- Earth reflects solar radiation (insolation)
- MOST IMPORTANT CAUSES - REFLECTIVITY AND EARTH'S ORBIT
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