Download Global Warming

Yr 10 Chemistry
Environmental Chemistry: Global
Warming
Exam Question
 "Global warming is not real and no evidence
exists that humans are causing temperature
changes on the planet".
 Include in your answer:
Include chemistry in your answer
What is global warming?
What gases cause global warming and why?
Is global warming natural or man-made?
What can we do to reduce its affect?
(Understanding)
 Neat, organised, using subheadings.
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
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(Understanding)
(Understanding)
(Understanding)
(Skills)
Starter
Which is the odd one out?
Give reasons for your answer
car
volcano
house
Challenge………….
 Why does the inside of a car get
hotter than the outside on a sunny
day?
Is the Earth getting hotter?
If it is what is trapping the
heat inside? (since the earth is
not surrounded by a sheet of
glass)
Global Warming Mind Map
Prevention
Affects of Global
Warming
Animals
Plants
Building
Humans
Definition
Global
Warming
Gases that cause Global
Warming
How
Global
Warming
Works.
Man made sources
Objectives
 TO KNOW what is ‘global warming’
and greenhouse gases.
 TO BE ABLE to find ways to reduce
global warming.
 TO UNDERSTAND how greenhouse
gases cause global warming
Is Global Warming Real?
 As ‘scientists’ we need to answer this question in
a logical way….
1. Is there a link between atmospheric gases and
temperature? If so, what is the relationship?
2. If so, what gases may be causing these
changes.
Once we understand these, the big question is……..
3. What is the impact of humans on this process?
Bias
Lets start with what you think is happening.
Write down your opinion to these questions?
1. Is global warming real? Why?
2. Are humans contributing to this? How?
Evidence 1: Recent rising
temperatures
Over the last few hundred
years, the average
temperature of the Earth’s
oceans has been rising.
This is global warming.
Why is this a problem?
Global warming increases the
energy in the atmosphere, making
it turbulent – more storms, more
droughts, more floods.
Evidence 2
Is this just a natural change in temperature.
We need to examine temperature over a much
longer time.
We need to examine if certain atmospheric gases
maybe affecting it.
Measuring the gases in the tiny bubbles in these ice cores is a difficult
process and determining the average global temperature can be done from
the amount of ice present .
1. What trends do you see over the last 400 000 years?
2. Is there a correlation between CO2 levels and
Temperature?
3. Which comes first CO2 levels or Temperature?
4. Why is #3 an important question to find an answer for?
Long Term Trends:
What has happened to the Earth’s climate over many thousands of years? How do we
know this? These are important questions if we want to know what the future
climate of our Earth will be.
One of the ways that scientists can measure Co2 levels and
temperatures levels in the past is by looking at ice core
samples from very old ice. Snow is laid down over the
winter. The top layer is melted over the summer and then
new snow piled up on top during the following winter. This
causes some of the Earth’s atmospheric gases to dissolve in
the melted ice and the ice to form bands or layers. We need
very old ice to measure very old atmospheric gases.
This is a ice core sample
from Vostok Antarctic Base
showing these bands:
Scientist have also been measuring
the level of CO2 in the atmosphere
for about as long as the
temperature.
Is there a relationship between CO2
levels and global temperature?
Which comes first: Increase in CO2
levels or Increase in temperature?
This is an important question!
No body disputes that the Earth is warming up. Six of the hottest years on record
have been in the last decade. What scientist are still debating is the cause or more
importantly how much of this heating up is due to human activities and how much
is “natural”.
The Kyoto Protocols (of which Canada signed in 1997 and came in force in
2005) has set targets to reduce CO2 gases to 1990 levels. Why would we want
to do this?
This is an expensive proposition (we all are now paying a Carbon tax). What if the
basic idea is incorrect?
The Key Greenhouse Gases
A greenhouse gas is a gas in the atmosphere that reflects
infrared radiation back to Earth.
Do these gases act as greenhouse gases in the atmosphere?
Answer ‘yes’ or ‘no’.
gas
carbon dioxide
greenhouse gas?
yes
methane
CFCs
ozone
nitrogen oxide
yes
yes
yes
yes
One of these gases in particular is on the rise, causing the
‘enhanced greenhouse effect’. Which gas?
What processes produce this gas?
What about the greenhouse effect?
The greenhouse effect is a theory to explain why
Light reaches usis
from
the
global warming
happening.
Sun. Some of it is absorbed by
the Earth and warms it. Some
is reflected back into space.
With more greenhouse
gases, more infrared is
reflected back to the Earth,
and it gets warmer still.
The Earth gives off infrared
radiation because it has been
warmed by the Sun.
In the atmosphere is
a layer of
greenhouse
gases.
Some infrared radiation is
reflected back by the
greenhouse gases. This
makes the Earth warmer
than it would be without
the greenhouse gases.
Thedoes
world
the greenhouse
effect.
Without
it the
How
theneeds
greenhouse
effect explain
global
warming?
Earth would be too cold for most organisms to live.
Consequences for Climate Change:
1)Temperature Change
2)Erratic precipitation
3)Sea level Rise
4)Erratic and more intense
Weather
1) Temperature Change:
China 2010 :
Over 700 killed and millions displaced from their
homes
The Earth’s climate is driven by solar radiation, the Earth’s spin, and the average
global temperature. Any changes in these factors will cause significant changes in
the weather patterns.
- imagine what would happen to all the farmers in Africa if the yearly rains
stopped coming?
- Or if the yearly rains in India came in twice the amount for twice as long?
- What would happen to our river and streams if all of our glaciers melted?
- What would happened to our forests if the rains decresed by a significant
portion?
2) Erratic Precipitation:
In many places in the world farming is a marginal proposition. The
farmers depend on rains that may come only once a year. What
happens when those rains fail to appear?
In the 1930’s the rains for the Mid-West in
North America failed to come. Many
farmers had their farms dry up. This
created the infamous “Dust-bowls of the
1930’s”.
3) Sea Level Rise:
The ocean warming up and is rising!
Why is this a problem?
This used to be an island!
Do Worksheet on Ocean Rise.
4. Erratic and more intense Weather
Hurrican
Katrina
(2005)
China Flood 2010)
The big questions still remains:
How much of the Earth’s climate change is
anthropologic?
If a significant amount of climate is due to the
increasing use of fossil fuels (and other human
activities), can we alter human activities to lower the
human effect?
If the human factor is an insignificant effect
then what can we do?
This what scientist are trying
to find out!
Activity: Write a sentence for each term as
it relates to Global Warming
Carbon dioxide
Greenhouse gases
Methane
Infrared radiation
Fossil fuels
Coal
Oil
Atmosphere
Rainforest destruction
Temperature
Activity: Write a sentence for each term as
it relates to Global Warming
Carbon dioxide
Greenhouse gases
Methane
Temperature
Infrared radiation
Core samples
Fossil fuels
Coal
Oil
Atmosphere
Rainforest destruction
Temperature
Using what you have
written, construct a quick
mind map.
Informed Response
Write down your opinion to these questions?
1. Is global warming real? Why?
2. Are humans contributing to this? How?
Has your opinion changed?
How has your answer changed?