P2.3 What is the evidence for global warming, why might it be occurring, and how serious a threat is it?

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  • Created by: sofsdvds
  • Created on: 26-04-16 22:27
What do all objects emit?
Electromagnetic radiation
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What is the relationship between frequency of thermal radiation emitted from an object and temperature?
The frequency of thermal radiation emitted from an object increases with temperature
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What passes through the atmosphere?
Some types of the electromagnetic radiation emitted by the Sun
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What happens when the Earth's surface absorbs EM radiation from the Sun?
Earth's surface warms up
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Explain the greenhouse effect
1. Radiation emitted by Earth (infrared radiation) has a lower frequency than EM radiation emitted by the Sun 2. Radiation emitted by the Earth is absorbed or reflected back by CO2, methane and water vapour in atmosphere which keeps Earth warm.
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What happens when there are more greenhouse gases in the atmosphere?
The more greenhouse gases in the atmosphere, the more radiation (emitted from the Earth) is reflected back by these gases in the atmosphere, so the Earth will become warmer
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What are the greenhouse gases in Earth's atmosphere?
Carbon dioxide and methane (both present in small amounts) and water vapour
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How is carbon dioxide returned to the atmosphere as part of the carbon cycle?
1. Respiration in plants and animals 2. Respiration in decomposers which break down dead plants and animals. 3. Burning trees or coal
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How is carbon dioxide removed from the atmosphere as part of the carbon cycle?
Photosynthesis in green plants
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What has happened to the amount of carbon dioxide in the Earth's atmosphere for thousands of years?
The amount of carbon dioxide was approximately constant because the amount of CO2 removed and added was approximately the same
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What has happened to the amount of carbon dioxide in the Earth's atmosphere in the last 200 years?
Amount of CO2 has been steadily rising
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What is the rise in atmospheric carbon dioxide largely a result of?
1. Burning increased amounts of fossil fuels as an energy source 2. Cutting down or burning forests to clear land
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What provides evidence that human activities are causing global warming?
Computer climate models
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What are the consequences of global warming?
1. Impossible to grow some food crops because of climate change (too dry or too wet) 2. More extreme weather events e.g. hurricanes 3. Increased convection (strong winds) so more water vapour (rain) causing more storms and floods
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What are the consequences of higher temperatures?
Continental ice melts and expansion of water in the oceans this can cause sea levels to rise which can cause flooding of low lying land
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Other cards in this set

Card 2

Front

What is the relationship between frequency of thermal radiation emitted from an object and temperature?

Back

The frequency of thermal radiation emitted from an object increases with temperature

Card 3

Front

What passes through the atmosphere?

Back

Preview of the front of card 3

Card 4

Front

What happens when the Earth's surface absorbs EM radiation from the Sun?

Back

Preview of the front of card 4

Card 5

Front

Explain the greenhouse effect

Back

Preview of the front of card 5
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