Download The importance of the Greenhouse Effect

WHAT DO YOU THINK CAUSES CLIMATE CHANGE?
Causes of
Climate Change
TASK TIME
Complete the spider diagram above in your jotter. We will
add to this at a later date so leave lots of space around it.
CLIMATE CHANGE
STARTER TASK:
Causes of Climate Change – Card Sort
As a group discuss the 10 cards and sort them into
categories that you can justify.
CLIMATE CHANGE
TASK:
Causes of Climate Change – Card Sort
In the exam these reasons will be organised under the
headings:
1. Human Factors; &
2. Physical Factors
CLIMATE CHANGE
TODAY:
1. The Greenhouse Effect
2. Physical and Human Causes of Climate Change
About 50% of the sun's energy is radiated back into space.
But some of the infrared radiation is trapped by greenhouse gases
and warms the atmosphere,
5
THE IMPORTANCE OF THE GREENHOUSE EFFECT
TASK TIME
Make a copy of this diagram into your jotter. Watch the media
clip on the Greenhouse Effect and use the information in your
booklet to write a paragraph explain what it is.
THE GREENHOUSE EFFECT
This is the name give to the process whereby the Earth is
warmed by the trapping of solar energy by gases in the
atmosphere. Without the atmosphere / greenhouse gases the
planet would be much cooler. It is essential to our survival.
Water vapour is the most important greenhouse gas. It accounts
for almost 98% of the naturally occurring effect.
Gases produced by human activity are responsible for a process
known as ‘The Enhanced Greenhouse Effect’. Most scientists
agree that this has led to an increase in natural warming in
recent times.
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
PHYSCIAL AND HUMAN CAUSES OF CLIMATE CHANGE
This is a key exam topic. You should know the range of causes
extremely well.
Know which factors are human and which are physical as the
examiner has been known to focus on one category only in the
exam.
For each factor include an explanation of why it is occurring
and why it contributes to climate change. Students frequently
lose marks as they do not link back to the question.
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
PHYSCIAL AND HUMAN CAUSES OF CLIMATE CHANGE
You will probably be most aware of the human causes of
climate change as they have dominated recent press and the
global warming debate.
We will start by looking at these human causes of climate
change. A good way to structure your thoughts is to focus on
the four main greenhouse gases attributed to human activity.
Remember these contribute to the enhanced greenhouse
effect.
What do you think these gases are? Which is the most
important?
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
THE ENHANCED GREENHOUSE EFFECT
NOTE
These gases are linked to technological developments and an increase in
the World’s population. Some are more powerful than others.
CLIMATE CHANGE - HUMAN ACTIVITY
TASK:
Causes of Climate Change – Card Sort
Take two human cards each.
Working with someone from another group discuss how
this process contributes to climate change. Consider:
a. What gas is released?
b. Why this process occurs? Why gas is emitted?
c. Whether there are viable alternatives?
d. What this gas does?
CLIMATE CHANGE - HUMAN ACTIVITY
TIP:
In the exam you will be credited for referring to named
greenhouse gases.
You will also get credit for explaining the greenhouse effect.
The main gases we will look at are: Carbon Dioxide, Nitrous
Oxide, Chlorofluorocarbons (CFCs) and Methane. It is good
practice to write these out the first time you refer to them in
your answer. If using chemical symbols / names get them
right!
Variety in your answer will be helped by discussing each gas.
Watch these two clips from
The BBC…
TASK TIME
Use the information in your sheets, the media clips and your
discussion from earlier to complete Task 2 in your booklet.
CLIMATE CHANGE - HUMAN ACTIVITY
CASE STUDY – CARBON DIOXIDE
The link between Carbon Dioxide and Global Temperatures.
Work by scientists in this area started the global warming
movement and underpins much of the theory behind it.
LETS EXAMINE THE ROLE OF CARBON
DIOXIDE IN CLIMATE CHANGE…
Since 1958, scientists have measured the
amount of CO2 in the Earth's atmosphere from
a site on the Mauna Loa volcano in Hawaii, a
group of South Pacific islands. This site is one of
the best locations in the world for measuring
CO2 because there are no plants or human
activities nearby to influence the
measurements (any volcanic venting of gas is
excluded from the record). The Mauna Loa
data are considered to be a precise record of
the concentration of CO2 in the region.
TASK TIME
Using the data in the table on the next slide, graph the annual
average CO2 concentrations from 1959 to 2009.
YOUR GRAPH SHOULD START LIKE THIS…
Remember to
include An appropriate
scale
 Labels on both
axis
 A title
AFTER STUDYING YOUR GRAPH DISCUSS THE
FOLLOWING QUESTIONS:
 WHAT pattern do you notice in the graph over 50 years?
 HOW do the last five years of data compare to the first five
years?
 The level of CO2 in the year 1860 was approximately 280 ppm.
HOW does the rise from 1860 to 1958 compare to that from 1958
to 2009?
 WHAT do you think caused the increase in CO2?
 Looking at the graph, WHAT do you predict the CO2 level will
be in the year 2020? In the year 2050? WHAT factors could
influence these predictions?
 HOW might the change in CO2 affect people and other living
things?
TASK TIME
Once you have agreed on the answers write these up in your
jotter. Try to include as much detail as you can and remember to
include exact figures or simple calculations wherever possible.
NOTE
There is a clear correlation between levels of CO₂ and global temperatures.
LONG TERM CLIMATE CHANGE / CO₂
NOTE
There is a strong correlation between levels of CO₂ in the atmosphere and
average global temperatures.
METHANE
Methane comes from many sources:
a. Belching cattle
b. Rice cultivation
c. Decomposing waste / landfill sites
d. Melting permafrost in Arctic areas
Due to an increase in the world's population the pressure to
meet the demand for food and development of GM crops
has seen an exponential rise in cattle ranching and rice
cultivation. Methane is a potent greenhouse gas that is
very powerful in trapping solar energy.
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
CFCS
Chloroflourocarbons:
a. Released when air conditioning units and
refrigerators are not disposed of correctly
b. Still present in atmosphere from aerosol
spray cans (although their use was banned)
CFCs are a powerful greenhouse gas. They are relatively safe and
used due to their ability to heat and cool quickly. However they are
dangerous when disposed of.
CFCs also thin the Ozone layer allowing more UV radiation in.
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
NITROUS OXIDES
Commonly released as a by product of
generating energy.
Nitrous oxides are released from car exhausts. The level of car
ownership continues to rise dramatically particularly in developing
nations such as India and China.
Nitrous oxides are also released from power stations and are a by
product in the farming industry via fertilisers.
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
CARBON DIOXIDE
Released in a number of ways Carbon Dioxide
is the most well known of the greenhouse gases.
It accounts for 55% of greenhouse gas from human activity.
a. Burning fossil fuels in power stations and to run vehicles
b. Deforestation by burning releases stored carbon. Reduced the
ability of trees to convert carbon dioxide to oxygen
Carbon dioxide levels in the atmosphere have increased dramatically.
Peat bog reclamation in Scotland is another cause where land is
being developed for wind farms.
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
ENHANCED GREENHOUSE EFFECT
THE IMPACT OF HUMAN ACTIVITY
Good geographers will make the connection between rising levels of
greenhouse emissions and other major developments in the world:
a. Rapid population growth in the 20th Century
b. Increasing technology linked to the use of natural resources
c. Development across the developing world
You will be learning about
Global climate change
physical and human causes
local and global effects
management strategies and their
limitations
CLIMATE CHANGE – THE PHYSICAL FACTORS
REMEMBER
The planet has been warmer and colder than it is at present in the past.
Scientists note a cyclical pattern in the Earth’s temperature.
CLIMATE CHANGE – THE PHYSICAL FACTORS
THINK
What might be causing this? What do we know causes the planet to warm
and cool? What else might determine the amount of energy received?
ACTIVITY
Pair/group will research one physical factor. Use the resources
you
have been provided. Revision books, textbooks etc.
You must make up a fact sheet on your chosen physical factor
that can be photocopied for the other members.
1. Be no more than 2 pages
2. Include maps and / or graphs explaining how your factor
affects temperature
3. Make reference to named examples / scientists
1. Volcanic Eruptions. 2. Sunspot Variation. 3.
Milankovitch Cycles. 4. Variation in Albedo.