What is Global Warming?
What is Global Warming?
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What is Global Warming? Lesson Objectives: • To understand what is meant by ‘global warming’ • To know what we think causes global warming. • To begin to understand how our activities can cause climate change. 2
• The sun sends out energy as heat and light • comes to our earth during the day time.
sun’s rays can: •
get ‘trapped’ in the atmosphere, these heat up the Earth
• get reflected back into space 3
ELECTROMAGNETIC SPECTRUM
4
What is the EMS (electromagnetic spectrum): the range of energies released by the sun Picture
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6
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Wavelength vs Frequency WAVELENGTH
FREQUENCY
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• radiates heat into space, which cools it down • only really notice at night
• the heat going out is trapped inside by the atmosphere • makes our planet warm enough to live on **But if too much heat is trapped, our planet will warm up and the climate will 9 change.
Weather vs Climate
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What is the atmosphere and why does it trap heat? • atmosphere is the air around the surface of the earth (approximately 7 miles) • mixture of gases • Needed for survival: • Oxygen: animals • Carbon Dioxide: plants (photosynthesis) .
(the atmosphere is really much thinner than it looks above) 11
Composition of the Atmosphere
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Natural Greenhouse effect Heat radiates from the earth
Atmosphere has more greenhouse gases
Enhanced Greenhouse effect
Heat radiates from the earth Less heat goes out to space
Some heat goes out to space
Atmosphere traps some heat
Quite a lot of heat is trapped and the earth is warm enough for life.
Atmosphere traps more heat
More heat is trapped and causes global warming 13
Solar Radiation: Where does the energy go?
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So why is global warming happening? • increasing amounts of greenhouse gases (so more heat is trapped)
• ‘Enhanced Greenhouse Effect’: this is causing the earth to heat up, or global warming ****Global warming doesn’t just mean that the Earth gets hotter; it means that the whole climate is changing.
(the atmosphere is really much thinner than it looks above) 15
So what are the Green-House Gases anyway? • ‘greenhouse gases’: act as a blanket
• ‘Natural Greenhouse Effect’: Without it, the earth would be much colder
(CO2-Carbon Dioxide) (NO2 Nitrous Dioxide) 16
Which gases in the atmosphere trap heat? • 78% Nitrogen and 21% Oxygen • These are NOT “greenhouse gases” What % of the atmosphere is left?
The gases which trap heat make up less than 1% of the atmosphere! They are called the ‘greenhouse gases’. The main greenhouse gases are: Carbon dioxide Methane Nitrous oxide Ozone Water vapour Halocarbons
Human activity increases the amount of these gases in the atmosphere 17
How do humans increase carbon dioxide levels in the atmosphere? • Burning fossil fuels releases the CO2 stored millions of years ago. • carbon dioxide comes from fossil fuels
• Deforestation releases the carbon stored in trees. • Fewer trees, less CO2 removed from the atmosphere during photosynthesis
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Comparative CO2 Levels by Ice Cores
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CO2 emissions by Country
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How do humans increase methane levels in the atmosphere? Increased rice growing; Methane is produced when bacteria rot organic matter,(including flatulence in farm animals)
Increased livestock farming
Methane is also released when fossil fuels are extracted
the soil organisms increase and so does the carbon dioxide level
Increased rubbish in landfill
• Levels of methane in the atmosphere has increased by two and a half times since the Industrial Revolution.21
Methane Gas Core Data
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3 major green house gases data:
23
We humans are thought to be the main cause of global warming and climate change…….. but we still have the chance to do something about it.
24
1
What is Global Warming? Lesson Objectives: • To understand what is meant by ‘global warming’ • To know what we think causes global warming. • To begin to understand how our activities can cause climate change. 2
• The sun sends out energy as heat and light • comes to our earth during the day time.
sun’s rays can: •
get ‘trapped’ in the atmosphere, these heat up the Earth
• get reflected back into space 3
ELECTROMAGNETIC SPECTRUM
4
What is the EMS (electromagnetic spectrum): the range of energies released by the sun Picture
5
6
7
Wavelength vs Frequency WAVELENGTH
FREQUENCY
8
• radiates heat into space, which cools it down • only really notice at night
• the heat going out is trapped inside by the atmosphere • makes our planet warm enough to live on **But if too much heat is trapped, our planet will warm up and the climate will 9 change.
Weather vs Climate
10
What is the atmosphere and why does it trap heat? • atmosphere is the air around the surface of the earth (approximately 7 miles) • mixture of gases • Needed for survival: • Oxygen: animals • Carbon Dioxide: plants (photosynthesis) .
(the atmosphere is really much thinner than it looks above) 11
Composition of the Atmosphere
12
Natural Greenhouse effect Heat radiates from the earth
Atmosphere has more greenhouse gases
Enhanced Greenhouse effect
Heat radiates from the earth Less heat goes out to space
Some heat goes out to space
Atmosphere traps some heat
Quite a lot of heat is trapped and the earth is warm enough for life.
Atmosphere traps more heat
More heat is trapped and causes global warming 13
Solar Radiation: Where does the energy go?
14
So why is global warming happening? • increasing amounts of greenhouse gases (so more heat is trapped)
• ‘Enhanced Greenhouse Effect’: this is causing the earth to heat up, or global warming ****Global warming doesn’t just mean that the Earth gets hotter; it means that the whole climate is changing.
(the atmosphere is really much thinner than it looks above) 15
So what are the Green-House Gases anyway? • ‘greenhouse gases’: act as a blanket
• ‘Natural Greenhouse Effect’: Without it, the earth would be much colder
(CO2-Carbon Dioxide) (NO2 Nitrous Dioxide) 16
Which gases in the atmosphere trap heat? • 78% Nitrogen and 21% Oxygen • These are NOT “greenhouse gases” What % of the atmosphere is left?
The gases which trap heat make up less than 1% of the atmosphere! They are called the ‘greenhouse gases’. The main greenhouse gases are: Carbon dioxide Methane Nitrous oxide Ozone Water vapour Halocarbons
Human activity increases the amount of these gases in the atmosphere 17
How do humans increase carbon dioxide levels in the atmosphere? • Burning fossil fuels releases the CO2 stored millions of years ago. • carbon dioxide comes from fossil fuels
• Deforestation releases the carbon stored in trees. • Fewer trees, less CO2 removed from the atmosphere during photosynthesis
18
Comparative CO2 Levels by Ice Cores
19
CO2 emissions by Country
20
How do humans increase methane levels in the atmosphere? Increased rice growing; Methane is produced when bacteria rot organic matter,(including flatulence in farm animals)
Increased livestock farming
Methane is also released when fossil fuels are extracted
the soil organisms increase and so does the carbon dioxide level
Increased rubbish in landfill
• Levels of methane in the atmosphere has increased by two and a half times since the Industrial Revolution.21
Methane Gas Core Data
22
3 major green house gases data:
23
We humans are thought to be the main cause of global warming and climate change…….. but we still have the chance to do something about it.
24
