Global Warming In this presentation you will:  Discover what Global Warming is and investigate some of the causes and effects. ClassAct SRS enabled.

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Transcript Global Warming In this presentation you will:  Discover what Global Warming is and investigate some of the causes and effects. ClassAct SRS enabled.

Slide 1

Global Warming

In this presentation you will:
 Discover what Global Warming is and investigate
some of the causes and effects.

ClassAct SRS enabled.


Slide 2

Global Warming

Elements of weather and
temperature in any region vary
over time, but should remain
within an expected range over a
long period of time. Global
warming is a general long-term
increase in the average
temperature of the Earth's surface
and the oceans.
In this presentation you will find
out about the causes of Global
Warming and what can be done to
help slow it down.

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Slide 3

Global Warming

Scientific Measurements
Scientific measurements indicate
that the average temperature of
the Earth's surface has increased
by around 1.2°F over the past 100
years.

This graph shows how much the
global temperature (of the Earth's
surface) varies from the normal
global temperature.

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Slide 4

Global Warming

Question 1
By approximately how much did the global temperature differ
from the normal temperature in 1990?

A) 1.8°F
B) -0.6°F
C) 0.6°F
D) It didn't differ at all


Slide 5

Global Warming

What Causes Global Warming?
Global warming is thought to be a
result of an "enhanced" greenhouse
effect. The greenhouse effect is a
naturally occurring essential
phenomenon by which an atmosphere
warms a planet.
Gases (greenhouse gases) form a
layer in the atmosphere that allows
short wave radiation from the sun to
reach the earth, and absorbs some of
the long wave radiation that is
reflected back into space.

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Slide 6

Global Warming

Life Without Global Warming?
The result of the long wave radiation
being absorbed is that the earth
retains some of the heat from the
Sun's rays. This produces a net
warming of the surface.
This process is essential to life on
earth because without it the earth
would be approximately 60°F cooler
and therefore uninhabitable.

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Slide 7

Global Warming

Enhanced Greenhouse Effect
It is widely accepted that an
increase in the greenhouse gases
in the atmosphere is enhancing
this warming process.
The concept of an "enhanced"
greenhouse effect really refers to
the increased warming caused by
increasing concentrations of
greenhouse gases introduced by
man. It exceeds the greenhouse
effect caused by naturally
occurring greenhouse gases.

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Slide 8

Global Warming

Question 2
The Greenhouse Effect is essential to support life on Earth.
Is this statement true?

Answer Yes or No.


Slide 9

Global Warming

Question 3
Why does the greenhouse effect occur?
A) Because of the use of glass in
modern building structures.

B) Oceans magnify the intensity of
the radiation from the sun.
C) Gases in the atmosphere increase
the intensity of the radiation from
the sun.
D) Gases in the atmosphere cause
more of the sun's energy to be
absorbed.


Slide 10

Global Warming

Greenhouse Gases
Most greenhouse gases occur naturally in
the atmosphere, while others such as
Chlorofluorocarbons (CFCs) result solely
from human activities.

Naturally occurring greenhouse
gases include water vapor, carbon
dioxide (CO2), methane, nitrous
oxide, and ozone. Certain human
activities add to the levels of most
of these naturally occurring gases.

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Slide 11

Global Warming

Greenhouse Gases
The primary causes of increased
emissions of these gases by man are:

• The combustion of fossil fuels
(oil, natural gas and coal).

• Increased transport usage.
• Deforestation (burning of wood).

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Slide 12

Global Warming

Global Dimming
When fossil fuels are burnt,
particles of sulfur dioxide, soot and
ash are released into the
atmosphere. Water droplets in
clouds form around these particles.
The clouds are then made up of a
greater number of smaller droplets
so they reflect more of the sun's
energy back into space. This
reduction in heat reaching the earth's
surface is known as Global Dimming.
Scientists fear that the effects of global dimming
may have led to an underestimation of the potential
of global warming.

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Slide 13

Global Warming

Question 4
Which of the following greenhouse gases is not naturally occurring?

A) Carbon dioxide
B) CFC's
C) Water vapor
D) Methane


Slide 14

Global Warming

The Effects of Global Warming
Some scientists estimate a rise in sea level
between approximately 4 inches and 35 inches
over the next hundred years. If this happens
many coastal areas all around the world will
flood. There are two reasons for this rise:
• Water expands when it is heated and
oceans absorb more heat than land.
• The increased temperature would cause
the world's ice caps and glaciers to melt.

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Slide 15

Global Warming

The Effects of Global Warming
Global warming could also affect
weather patterns, leading to more
droughts, flooding and extreme
weather, such as hurricanes.

There is a real risk to plants and
animals because of the rapid
changes occurring to their habitat.
Some species may be forced out
of their habitats or become extinct,
while others may flourish.

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Slide 16

Global Warming

Question 5
By how much is it estimated sea level could rise over the next
one hundred years?

A) 4 - 35 feet
B) 4 - 35 inches
C) 36 - 40 inches
D) 41-100 inches


Slide 17

Global Warming

Question 6
Which of the following is a risk associated with Global warming?

A) Extreme weather conditions
B) Rising sea levels
C) Droughts
D) All of these


Slide 18

Global Warming

What can be done?
To reduce the threat of global warming it is important that we lessen the
amount of greenhouse gases being released into the atmosphere. An
important step to achieving this is to replace the use of fossil fuels with
the use of renewable energy sources such as:
• wind
• wave
• solar
• Hydro-electric

These are 'clean' energy options,
as they do not release any byproducts into the atmosphere.

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Slide 19

Global Warming

Nuclear power
Nuclear power is also considered by some
people to be a ‘clean energy’. This is
because it does not involve the burning of
fossil fuels and does not release any byproducts into the atmosphere.
However, nuclear power does produce
nuclear waste which is difficult and
expensive to dispose of safely.
There are also risks involved in running a
nuclear power plant.

Very strict safety measures are needed in order to ensure that the
nuclear materials and waste do not escape and cause contamination.
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Slide 20

Global Warming

Question 7
Which of the following is not a source of renewable energy?

A) Hydro
electric

B) Wind

C) Oil

D) Solar


Slide 21

Global Warming

Summary
Having completed this presentation, you should be able to:
 Identify that one of the main causes of global warming is the
increasing levels of greenhouse gases in the atmosphere
 Describe some of the effects of global warming including rising
sea levels and habitat change
 Recognize how using renewable energy sources is an important
step to reduce global warming

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