-Way earth moves around sun changes.-These changes affect amount of solar radiation (energy) the earth recieves.-More energy recieved=warmer. - May have caused glacial+interglacial cycles of Quaternary period.
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Natural - volcanic activity
-Major volcanic eruptions eject large quantities of material into atmosphere.-Some of the particles reflect Sun's rays back out to space, so Earth's surface cools.-Volcanoes release CO2 but not enough to cause global warming.-Cause short-term changes
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Natural - solar output
-Sun's output of energy isnt constant - it changes in short cycles of about 11yrs, and possibly also in longer cycles of several hundred yrs.-Solar output reduced=Earth's climate becomes cooler in some areas.-No major effect on global climate change.
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What is the greenhouse effect?
-Greenhouse gases (e.g. CO2 and methane), absorb outgoing heat, so less is lost to space.-Essential for keeping planet warm.-Too much greenhouse gas in atmosphere=too much energy is trapped=planet warms up.
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Human activity - burning fossil fuels
- CO2 is released into atmosphere when fossil fuels like coal, oil, natural gas and petrol are burnt, e.g. in thermal power stations or in cars.
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Human activity - farming
- Farming livestock produces a lot of methane. - Rice paddies contribute to global warming, because flooded fields emit methane.
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Human activity - cement production
- Cement is made from limestone, which contains carbon. - When cement is produced, lots of CO2 is released into atmosphere.
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Human activity - deforestation
- Plants remove CO2 from atmosphere and convert it into organic matter using photosynthesis. - When trees and plants are chopped down, they stop taking in CO2. - CO2 is released into atmosphere when trees are burnt as fuel or to make way for farming.
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Other cards in this set
Card 2
Front
Natural - volcanic activity
Back
-Major volcanic eruptions eject large quantities of material into atmosphere.-Some of the particles reflect Sun's rays back out to space, so Earth's surface cools.-Volcanoes release CO2 but not enough to cause global warming.-Cause short-term changes
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