The Greenhouse Effect and Global Climate
Change
Before commencing the activities in this booklet you should watch the video
‘An Inconvenient Truth’, which can be accessed by clicking on the following
link: An Inconvenient Truth
What is the Greenhouse Effect?
The greenhouse effect is the rise in temperature that the Earth experiences
because certain gases in the atmosphere (water vapour, carbon dioxide,
nitrous oxide, and methane, for example) trap energy from the sun. Without
these gases, heat would escape back into space and the Earth’s average
temperature would be about 15°C colder than it is currently. Because of how
they warm our world, these gases are referred to as greenhouse gases, as
they work in very much the same way as a greenhouse.
Have you ever seen a greenhouse? Most greenhouses look like a small glass
house. Greenhouses are used to grow plants, especially in the winter.
Greenhouses work by trapping heat from the sun. The glass panels of the
greenhouse let in light but keep heat from escaping. This causes the
greenhouse to heat up, much like the inside of a car parked in sunlight, and
keeps the plants warm enough to live in the winter.
Activity 1 – You can type in the box, which will expand as you type
Define “The Greenhouse Effect”.
How does the Greenhouse Effect work?
The Earth’s atmosphere is all around us. It is the air that we breathe.
Greenhouse gases in the atmosphere behave much like the glass panes in a
greenhouse. Sunlight enters the Earth's atmosphere, passing through the
blanket of greenhouse gases. As it reaches the Earth's surface, land, water,
and biosphere absorb the sunlight’s energy. Once absorbed, this energy is
sent back into the atmosphere. Some of the energy passes back into space,
but much of it remains trapped in the atmosphere by the greenhouse gases,
causing our world to heat up.
The greenhouse effect is important. Without the greenhouse effect, the Earth
would not be warm enough for humans to live. But if the greenhouse effect
becomes stronger, it could make the Earth warmer than usual. Even a little
extra warming may cause problems for humans, plants, and animals.
Activity 2
Explain how the Greenhouse Effect Works. You may use your textbook and
the video, ‘An Inconvenient Truth to help you’
Activity 3
Describe what would happen to the Earth if the Greenhouse Effect did not
exist
The Greenhouse Gases
Many gases exhibit “greenhouse” properties and are therefore referred
to as greenhouse gases. Some of them occur naturally (water vapor,
carbon dioxide, methane, and nitrous oxide), while others are
exclusively human-made (like Chlorofluorocarbon gases, CFC’s, used
for aerosols).
Levels of several important greenhouse gases have increased by about
25% since large-scale industrialization began around 150 years ago.
During the past 20 years, about three-quarters of anthropogenic
(human-made) carbon dioxide emissions were from burning fossil fuels.
Can humans change climate?
It may seem hard to believe that people can actually change the Earth’s
climate. But scientists think that the things people do that send greenhouse
gases into the air are making our planet warmer.
Once, all climate changes occurred naturally. However, during the Industrial
Revolution, we began altering our climate and environment through
agricultural and industrial practices. The Industrial Revolution was a time
when people began using machines to make life easier. It started more than
200 years ago and changed the way humans live. Before the Industrial
Revolution, human activity released very few gases into the atmosphere, but
now through population growth, fossil fuel burning, and deforestation, we are
affecting the mixture of gases in the atmosphere.
Since the Industrial Revolution, the need for energy to run machines has
steadily increased. Some energy, like the energy you need to do your
homework, comes from the food you eat. But other energy, like the energy
that makes cars run and much of the energy used to light and heat our
homes, comes from fuels like coal and oil – fossil fuels. Burning these fuels
releases greenhouse gases.
Major sources of greenhouse gases
So what is Global Warming?
Global warming is an increase in average temperature of the Earth’s
atmosphere. It is thought that the increase in greenhouse gases owing to
human activity such as the burning of fossil fuels is directly responsible for
increasing the Earth’s average temperature over the last 100 years.
When Do You Send Greenhouse Gases into the Air?
Whenever you ...










Watch TV
Use an air conditioner
Turn on a Light
Use a hair dryer
Ride in a Car
Play a Video Game
Listen to a Stereo
Wash or Dry Clothes
Use a Dish Washer
Microwave a Meal
... you are helping to send greenhouse gas into the air.
To perform many of these functions, you need to use electricity. Electricity
comes from power plants. Most power plants use coal and oil to make
electricity. Burning coal and oil produces greenhouse gases.
Other things we do send greenhouse gases into the air too;
The trash that we send to landfills produces a greenhouse gas called
methane. Methane is also produced by the animals we raise for dairy and
meat products and when we take coal out of the ground. Whenever we drive
or ride in a car, we are adding greenhouse gases to the atmosphere. And,
when factories make the things that we buy and use everyday, they too are
sending greenhouse gases into the air.
Greenhouse Gas Emissions in Australia
Agriculture; hunting & trapping; forestry &
fishing
Mining
Manufacturing
Electricity and gas
Construction
Transport
Services
Household production
Total
Greenhouse Gas
Emissions (Gigagrams
of CO2 equivalents
(CO2-e).)
7,188
Percentage
Share of Total
Greenhouse Gas
Emissions
15,136
57,166
169,562
4,958
30,939
9,063
9,063
339,597
Activity 4
Complete the above table and draw a pie chart using Microsoft Excel to show
the source of greenhouse gas emissions in Australia.
How do fossil fuels contain carbon?
Coal, oil and gas are the three fossil fuels that we burn, which in turn sends
several tonnes of CO2 into the atmosphere every day. But why do these fuels
contain so much carbon? If you think back to your understanding of the
carbon cycle, CO2 is removed from the atmosphere through plant respiration.
It is this intake of carbon by plants that led to the development of fossil fuels
several thousand years ago. The diagram below, explains it simply:
Activity 5
When humans add more greenhouse gases to the atmosphere it often causes
“The Enhanced Greenhouse Effect”. Describe what is meant by the term “The
Enhanced Greenhouse Effect”.
Activity 6
Make a large copy of the table below and complete it with the details on how
humans contribute to the Greenhouse Effect. Use your textbook to help you.
Greenhouse Source of the
Gas
Greenhouse
Gas
Ways in which humans add this Greenhouse
Gas into the Atmosphere
What is the evidence of global warming?
The graph below shows the variation from the global average temperature
over the past 130 years. It is possible to see from the graph that year
temperatures were below the world average up until about 1960, with the
exception of a small period above average around 1940. Since 1960, on the
whole the yearly global average temperature has risen significantly above the
average temperature for the past 130 years. It has risen to nearly 0.5 °C
above the world average over the last five years, which is concerning.
Similarly, if we look at carbon dioxide concentrations in the atmosphere since
1960 in the graph below, we see a continued rise. This has led scientists to
believe that humans increasing greenhouse gases in the atmosphere,
particularly CO2, is leading to global warming and climate change.
Activity 7
Study the graphs below. Describe the trends in global temperatures and
greenhouse gas emissions since 1960.
The future influence of the Enhanced Greenhouse Effect on
the World’s Climate and Human Lives
What Might Happen? It is important to understand that scientists don't know
for sure what global warming will bring. Some changes brought about by
global warming will be good. If you live in a very cool climate, warmer
temperatures might be welcome. Days and nights could be more comfortable
and people in the area may be able to grow different and better crops than
they could before. But it is also true that changes in some places will not be
very good at all.
Human Health
Climate change may affect people's health both directly and indirectly. For
example, heat stress and other heat related health problems are caused
directly by very warm temperatures and high humidity. Untreated, heat stress
can be a very serious medical problem. Scientists suspect that, in many
places, global warming will increase the number of very hot days that occur
during the year. More hot days increases the possibility of heat related health
problems.
Indirectly, ecological disturbances, air pollution, changes in food and water
supplies, and coastal flooding are all examples of possible impacts that might
affect human health.
How people and nature adapt to climate change will determine how seriously
it impacts human health. Some people and places are likely to be affected
more than others. Generally, poor people and poor countries are less likely to
have the money and resources they need to cope with preventing and treating
health problems. Very young children and the elderly adults will run the
highest risks.
Ecological Systems
Climate change may alter the world's habitats and ecosystems – all living
things are included in and rely on these places. Many of these places depend
on a delicate balance of rainfall, temperature, and soil type. A rapid change in
climate could upset this balance and seriously endanger many living things.
Most past climate changes occurred slowly, allowing plants and animals to
adapt to the new environment or move somewhere else. However, if future
climate changes occur as rapidly as some scientists predict, plants and
animals may not be able to react quickly enough to survive. The ocean's
ecosystems also could be affected for the same reasons.
Sea Level Rise
Global warming may make the sea level become higher. Why? Well, warmer
weather makes glaciers melt. A glacier is a large sheet of ice that moves very,
very slowly. Some melting glaciers add more water to the ocean. Warmer
temperatures also make water expand. When water expands in the ocean, it
takes up more space and the level of the sea rises.
Sea level may rise between several inches and as much as 3 feet during the
next century. This will effect both natural systems and manmade structures
along coastlines. Coastal flooding could cause saltwater to flow into areas
where salt is harmful, threatening plants and animals in those areas. For
example, an increase in the salt content of the Delaware and Chesapeake
bays is thought to have decreased the number of oysters able to live in those
waters.
Oceanfront property would be affected by flooding, and beach erosion could
leave structures even more vulnerable to storm waves. Whether we move
back from the water or build barricades in the face of a rising sea, it could cost
billions of dollars to adapt to such change. Coastal flooding also may reduce
the quality of drinking water in coastal areas.
Crops and Food Supply
Global warming may make the Earth warmer in cold places. People living in
these places may have a chance to grow crops in new areas. But global
warming also might bring droughts to other places where we grow crops. In
some parts of the world, people may not have enough to eat because they
cannot grow the food that they need.
Activity 8
Use the table on the next page to prepare notes to discuss the effects of
global warming for various places around the world. You should clearly show
the possible effects of different climatic scenarios on the environment, the
economy and society. Use the ‘An Inconvenient Truth’ video and your
textbook to support your notes.
Impacts of global warming owing to the effects of the enhanced greenhouse effect
Positive impacts
Environmental impacts
Economic impacts
Social impacts
Negative impacts
Countries and Regions producing the most CO2 Emissions
Region/Country
World Total
Asia & Oceania
North America
United States
Western Europe
China
Eastern Europe &
Former U.S.S.R.
Russia
Japan
Middle East
India
Central & South
America
Africa
Germany
Canada
United Kingdom
Korea, South
Italy
South Africa
France
Mexico
Australia
Iran
Brazil
Ukraine
Spain
Saudi Arabia
Indonesia
Poland
Taiwan
Netherlands
Turkey
CO2 Emissions
25,162.07
8,173.74
6,808.20
5,802.08
3,895.76
3,540.97
Region/Country
United States
Australia
Canada
Netherlands
Brunei
Seychelles
CO2 Emissions Per
Capita (Million Metric
Tonnes)
19.95
19.10
19.05
16.07
14.97
14.55
3,099.33
1,606.42
1,205.54
1,203.21
1,024.83
Estonia
Belgium
Saudi Arabia
Taiwan
Bahamas, The
13.89
13.66
13.52
12.40
11.26
1,023.97
957.85
842.03
600.18
564.56
469.53
465.48
411.25
409.18
404.72
376.83
372.00
351.46
345.87
339.71
327.41
318.35
286.17
280.32
259.58
204.17
Russia
Czech Republic
Denmark
Israel
Iceland
Finland
Cyprus
Ireland
Germany
Norway
New Zealand
Korea, South
Puerto Rico
Kazakhstan
United Kingdom
Greece
Japan
South Africa
Hong Kong
Libya
Austria
11.21
10.94
10.94
10.56
10.41
10.41
10.26
10.26
10.21
9.93
9.91
9.84
9.80
9.72
9.53
9.50
9.44
9.13
9.08
8.96
8.92
.
Activity 9
Using the figures and countries in the table, comment on the relationship
between the population of a country and its total greenhouse gas emissions.
Activity 10
Using the figures and countries in the table, comment on the relationship
between greenhouse gas emissions per capita and the level of development
of a country.
Facing up to the possible problem of global climate change
The problem of Global Warming, which is though to be causing Global
Climate Change was first discussed at the first ever Earth Summit in Rio de
Janeiro in 1992. Discussion centred around a cry from scientists and
environmentalists to cut back on greenhouse gas emissions. There was,
however, much argument surrounding who is responsible for the problem and
whether we can really cut back on our greenhouse gas emissions. Countries
struggle to agree on how much they should cut back on their greenhouse gas
emissions. In 1997 the Kyoto Protocol was formed that has since become a
Treaty that has the commitment of many countries to cut back on their
greenhouse gas emissions.
The Kyoto Protocol - now the Kyoto Treaty
The Kyoto Protocol is an agreement between countries to reduce the amount
of greenhouse gases their countries produce. The wording of this agreement
was written and voted on in Kyoto, Japan on 11th December 1997 and came
into force on February 16th 2005 when Russia joined.
They agreed to reduce greenhouse gases: carbon dioxide (CO2); methane
(CH4); and nitrous dioxide (N2O), by a percentage of the levels produced in
1990, before 2012. They also agreed to reduce hydrofluorocarbons (HFC’s),
perfluorocarbons (PFC’s) and sulphur hexafluoride (SF6). Each country has a
different target based on their industrialisation and economic health (level of
development).
The Protocol only came in to effect, and a 'Treaty', when countries accounting
for 55% of greenhouse gas emissions in the world signed up to the Protocol.
In practice this means it wouldn't work without the agreement of one of the
two biggest countries: Russia and USA. The USA have refused to sign, but
Russia have now signed meaning that the Treaty has come into force and the
targets set for reducing greenhouse gas emissions by all the countries signing
are now legally binding on them.
Each country's target is not totally rigid, because there are plans to allow
countries who are well within their target to sell their 'carbon credits' to
countries who were struggling to meet their targets. This is 'emission trading'.
Update
The Kyoto Protocol was further discussed at the Copenhagen Climate
Conference in 2009 where a new treaty was to be signed, the link below
provides you with the main facts as to what happened.
Copenhagen Climate Conference – Quick Facts
Activity 11
Explain why international cooperation is required to address the problem of
global warming.
Activity 12
Explain why countries have found it difficult to reach agreement on cutting
back greenhouse gas emissions.
Activity 13
Suggest why the USA are not taking a lead in cutting back greenhouse gas
emissions. Think back to the philosophy of technocentrism and refer to the
cartoon above.
Activity 15
Explain what is meant by ‘carbon emissions trading’. Use the following link to
this short video to help you: Emissions trading video
Activity 16
Evaluate the impacts of carbon emissions trading for both developed and
developing countries.
Activity 17
To what extent do you think the emissions reduction targets Kyoto Protocol
have been successful? Use the following article to help: Emissions targets
Activity 18
Create a brainstorm diagram using inspiration that outlines several ways that
humans can work locally to cut down their carbon dioxide emissions. Evaluate
how successful each measure could be. Use your textbook to help you.
The Earth’s Changing Climate
Earth's climate has been changing constantly over its 5-billion-year history.
Sometimes, the climate has warmed so that the oceans have risen and
covered much of the Earth. Each of the changes may seem extreme, but they
usually occurred slowly over many thousands of years.
Ancient Climate History
The first people arrived in America between 15,000 and 30,000 years ago.
During that time, much of North America was covered by great ice sheets.
Some 14,000 years ago, the last ice sheet began to melt very quickly. By
7,000 years ago, the ice was gone. This end to the ice ages caused big
changes on the Earth. The changes caused many kinds of plants and animals
to die. For example, mastodons – elephant-like animals – and other large
mammals that preferred cold climates may not have been able to live in the
warmer, drier conditions.
The Little Ice Age
Starting in the 14th century, Europeans lived through what is known as the
"Little Ice Age." The Little Ice Age lasted for several hundred years. During the
Little Ice Age, the advance of glaciers along with hard winters and famines
caused some people to starve and others to leave their homes.
Recent Climate History
The Earth has warmed about 1ºF in the last 100 years. And the four warmest
years of the 20th century all happened in the 1990s. Periods of increased heat
from the sun may have helped make the Earth warmer. But many of the
world's leading climatologists think that the greenhouse gases people produce
are making the Earth warmer, too.
Melting Glaciers: a glacier is a large sheet of ice that moves very, very
slowly. Many glaciers in the world are now melting. For example, glaciers are
melting in Montana's Glacier National Park. Some scientists think the glaciers
are melting partly because the Earth is getting warmer.
Rising Sea Levels
Have you ever built a sandcastle on the beach, close to the ocean on wet
sand? If you have, you probably know that the sandcastle won't last very long.
Chances are the waves will wash away the sandcastle as soon as the tide
comes in. The water goes higher up the beach when the tide comes in. At
most shores throughout the world, two high tides and two low tides occur
every day. But now the level of the sea is rising, so high tides are higher than
they were before. Over the last 100 years, the level of the sea has risen about
6-8 inches worldwide. When the sea level rises, the tide goes farther up the
beach.
Scientists think the sea has risen partly because of melting glaciers and sea
ice. When some glaciers melt, they release water into the sea and make it
higher than it was before. Scientists also think that warmer temperatures in
the sea make it rise even more. Heat makes water expand. When the ocean
expands, it takes up more space.
Activity 19
Describe how the Earth’s climate has changed over time. (you may also use
the graph in your textbook to help you)
Activity 20
Using the graph below, describe the relationship between temperature and
CO2 levels in the atmosphere.
Climate change Sceptics
The evidence that shows variation in temperature over time has prompted a
number of people to be sceptical about global warming. These people claim
that there are other factors at play responsible for temperature changes and
man-made greenhouse gas emissions are not responsible for climate change.
What Might Happen? Using computer models to predict the
future
Scientists are not fortune-tellers. They don't know exactly what will happen in
the future. But they can use special computer programs to find out how the
climate may change in the years ahead. And the computer programs tell us
that the Earth may continue to get warmer.
Together, the melting glaciers, rising seas, and computer models provide
some good clues. They tell us that the Earth's temperature will probably
continue to rise as long as we continue increasing the amount of greenhouse
gases in the atmosphere.
Activity 21
Watch the documentary ‘The Great Global Warming Swindle’, which can be
accessed by clicking on the following link: ‘The Great Global Warming
Swindle’
Activity 22
Use the video and your textbook to explain why some people remain sceptical
about global warming. What reasons do they provide for the change in global
temperatures?
Activity 23
Give your own opinion of the issue of global warming and state what should
be done about it, if anything
Practice Examination Questions
Once you have completed all activities, there are three practice Paper 2
examination paper questions on the topic of Global Warming. You should do
these as revision for your Trial Examination and get your teacher to give you
some feedback. A mark scheme is provided for your reference. Each
question should take 40 minutes to answer.
Global Warming Paper 2 Practice Questions
1.
The graphs below show the top ten countries in terms of total carbon
emissions and emissions per capita.
Graph A: Total carbon emissions from fossil fuel burning for the top ten
emitting countries, in million tonnes (Mt).
Graph B: Total carbon emissions (tonnes) per capita for the top ten
emitting countries.
[Source: Brown, L. R. et al, State of the World, 1996, Earthscan.]
(a)
Comment on the significance of these data.
(8)
(b)
Describe the international agreements that aim to reduce the
amount of carbon emissions.
(4)
(c)
What technologies and what policies might reduce the amount of
carbon emissions?
(5)
Expression of ideas (3)
(Total 20 marks)
2.
(a)
As well as their direct impact on the atmosphere, the effects of
fossil fuel use are widespread.
Discuss the range of effects of fossil fuel use on the environment.
(8)
(b)
What steps could be taken to reduce these effects?
(5)
(c)
The average cost of petrol (gasoline) for automobiles is four times
higher in Europe than in the USA. Discuss the environmental
implications of this difference.
(4)
Expression of ideas (3)
(Total 20 marks)
3.
The diagram below shows the carbon cycle.
(a)
Describe and explain the processes by which carbon is added to,
and lost from, the atmospheric storage. State examples of the
organisms involved in the processes.
(8)
(b)
Human activities have changed the balance of carbon dioxide. How
has this balance changed and what activities have altered it?
(4)
(c)
Suggest the effects these changes might have on the biosphere.
(5)
Expression of ideas (3)
(Total 20 marks)
Global Warming Paper 2 Practice Questions
Mark Scheme
1.
(a)
(b)
C emissions increase carbon dioxide in the atmosphere which is
a Greenhouse gas and leads to global warming [2];
C emissions are from industry, transport and power stations [1];
US has highest emissions by far – nearly double China [1];
size of C emissions not related to size of population but to
development [2];
US also has most emissions per capita [1];
as do other developed countries [1];
Four of top ten are in Europe [1].
Agreements award up to [4 marks] but must have specific
agreements.
The material below is for information. 1990, Geneva: scientists on
Intergovernmental Panel on Climate Change say 60 % reduction in
current carbon dioxide levels required. [1];
1992, Rio de Janeiro Earth Summit: politicians from 150 countries
sign Climate Change Convention. Its purpose is to slow down
climate
change to a level at which people and ecosystems will be able to
adapt.
Politicians cannot agree on any cuts;
instead industrialised countries agree to keep carbon dioxide levels
down to 1990 levels by year 2000. Developing countries make no
commitments. [1];
March 1995, Berlin: politicians hold climate summit. Agree that
measures previously agreed to meet the Convention’s goals are
inadequate, but defer action on cutting emissions. Agree that legally
binding reduction targets for the early 21st century should be ready
for signing by industrialised countries by 1997. There are to be no
commitments for the developing world. [1];
December 1995, Rome: scientists complete Intergovernmental
Panel on Climate Change second report. Agree for the first time
that humans are discernibly altering the climate. Again warn that
50 to 70 % cuts in Greenhouse gases are required. [1];
October 1996, Paris: International Energy Agency says the great
majority of developed countries will fail to keep Rio Earth Summit
promises to stabilise carbon dioxide emissions. [1];
December 1997, signing of Kyoto Protocol: make or break meeting
for Rio’s Climate Change Convention. New agreement needed to
reduce greenhouse gas emissions from year 2000. [1];
2001: Intergovernmental Panel on Climate Change will report
on the latest state of science. By then climate change is expected
to be well established and measurable.
2020: if by this date the whole world is not locked into an
agreement
8
to combat climate change, the Intergovernmental Panel on Climate
Change say a series of catastrophes loom.
(c)
4
Any that reduce burning of fossil fuels [1];
technology: renewable energy sources for transport [1] and
electricity
generation [1]/e.g. solar HEP [1];
policy: laws to clean car engines – catalytic converters/lean burn
[1]/
reduce car use [1]/improve public transport [1]/energy tax [1]
Expression of ideas [3 max]
5
[20]
2.
(a)
Effects due to: increased carbon dioxide levels/sulfur oxides/
nitrogen oxides/unburned hydrocarbons/particulates/lead/
carbon monoxide/mining/pollution of oceans.
Allow up to [2] for more than 3 effects and then up to [2] for each
category.
Candidates are asked to review so there should be an overview of
most effects not emphasis on one or two.
Carbon dioxide increases → global warming → climate change
→ sea levels rise/disruption of ocean currents (e.g. in North
Atlantic)/possible negative feedback effects from increased snow
fall at poles/coral bleaching/ice caps melt/flooding of low-lying
lands/biomes shift/food production changes [2];
sulfur dioxide → acid deposition → Al/cations leaching → tree
death/acidifies lakes/limestone buildings eroding [2];
nitrogen oxides → also acid deposition/photochemical smog/
CFC breakdown/pollution of oceans/effects of transporting
large quantities of oil round the world e.g. oil spillages,
Exxon Valdez (March 1989), oiling of seabirds [2].
Credit up to one specific health effect correctly attributed to fossil
fuel induced pollution e.g. asthma.
(b)
(c)
(Give credit also for review of other impacts.)
8 max
Award marks for up to 5 strategies (e.g. carbon taxes/alternative
sources of energy/energy efficiencies/liming), provided some
relevant detail is given for each example.
5 max
USA uses more [1]/larger and less efficient automobiles [1];
→ more gases released [1]/In North America, petrol is cheaper so
North Americans use more gasoline per capita [1]; ecological
footprint high [1]/new cars – more efficient technology in
newer engines – cleaner emissions [2]/pollution effects lead to
strong campaign for pollution controls [1]/more smog and
other pollution effects (including lead in environment) [1].
4 max
Candidates may approach problem from either European ‘direction’
or North American ‘direction. e.g. expensive petrol in Europe
encourages more use of public transport, leading to less pollution;
cheap petrol in USA makes public transport unattractive and use
of cars more likely, etc. Credit either approach.
Expression of ideas [3 max]
[20]
3.
(a)
(b)
(c)
Lost from atmospheric storage by fixation by photosynthesis [1];
Photosynthesis by green
plants/phytoplankton/producers/autotrophs [1];
Takes carbon dioxide, water, chlorophyll and light energy to make
organic
compounds/glucose and releases oxygen [1];
Light energy is transformed to chemical energy [1];
Release by respiration [1];
By animals/heterotrophs/zooplankton/decomposers [1]; producers
also respire [1];
Breakdown/oxidation of organic matter using oxygen to produce
energy,
carbon dioxide and water [1];
Release by combustion – fast oxidation of organic matter [1];
Release by diffusion of carbon dioxide from the water to the
atmosphere [1]/dissolves in atmosphere (rain) [1]
(Award marks for reasonable points e.g. examples of the above.)
8 max
More C in atmosphere as carbon dioxide [1]/less C in sink as
organic
molecules [1];
Due to: increased burning of fossil fuels [1]/increased use of cars
[1]/
increased industrialisation [1];
deforestation [1];
increased water temperature – gases less soluble [1]
(Accept any reasonable activity)
4 max
Effects: global warming [1];
Sea temperatures rise – plankton killed [1];
Ice caps melting [1]/habitats destroyed [1];
possible rise in sea levels due to thermal expansion [1]/low lying
lands flooded [1]/organisms displaced [1]/ecosystems destroyed
[1];
weather patterns changed [1]/crop growth patterns altered [1];
(Award marks for any reasonable answers that relate changes
to the biosphere.)
Expression of ideas [3 max]
5 max
[20]