Topic 2 - Climate & Change

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Transcript Topic 2 - Climate & Change

Climate and change
Year 11 revision
Key terms
Key term
Climate Change
Long-term changes in temperature and precipitation
The chopping down and removal of trees to clear and area of
A community of plants and animals that interact with each other
and their physical environment
Greenhouse Effect
The increased greenhouse effect resulting from human action
(emission of greenhouse gases) and leading to global warming
Geological Climate
Climate changes that result from major geological events such
as volcanic eruptions
Global Warming
A trend whereby global temperatures rise over time, linked in
modern times with the human production of greenhouse gases
Greenhouse gases
Those gases in the atmosphere that absorb outgoing radiation,
hence increasing the temperature of the atmosphere
Key terms
Key term
Ice Age
A period in the earth’s past when the polar ice caps were much
larger than today
Little ice Age
A period of slight global cooling that lasted from around the mid15th Century to the mid-19th Century
Mega fauna
‘Big animals’ which mostly weighed over 40kg e.g. Woolly mammoth
and sabre-tooth cat
Natural causes
Processes and forces that are not controlled by humans
Orbital Changes
Changes in the pathway of the Earth around the sun and the tilt on
its axis
The most recent geological period of the Earth’s history
Solar Output
The energy emitted from the sun
Layer of air 10-50km about the Earth’s surface
Key terms
Key term
Food Chains
Plants and animals are linked together and dependence on each
other for food
Species of plant or animal dying out completely, so none survive
Gradual change of the land into desert
short term, day to day changes in the atmosphere.
the average weather conditions over 30 years.
warm periods between ice ages
cold periods or ice ages. Ice sheets approx.400-3000m thick
extended across the northern hemisphere.
Air mass
A huge body of air with uniform temperature and humidity.
You must be familiar with
reading climate graphs
Key facts: Climate graphs
Read rainfall scale
from here
Read temperature
scale from here
Plymouth, UK
Rainfall (mm)
Temperature .C
Name months!
Key facts: The UK climate
Key facts: The UK climate
What controls the UK climate?
A lot to do with ‘air masses’.
Air masses are huge blocks of air. They can be damp or
dry, warm or cold, depending on where they came from
and over what type of surface they have travelled.
For example, an air mass that has travelled over the
sea will increase its moisture content and be more likely
to produce rainy weather.
Key facts: Past temperatures have always fluctuated
Climate has changed in the past through natural causes on
timescales ranging from hundreds to millions of years.
Key facts: Recording past climate
How do we know climate was different in
the past?
Fossils of animals and plants that no
longer live in the UK.
Landforms left by glaciers
Samples from ice sheets in Antarctica.
Ice sheets are made up of layers of ice,
a layer for each year. Trapped in the ice
sheets are air bubbles. Climatologists
study the CO2 levels to reconstruct past
How do we know climate has changed in the
more recent past?
Old photos, paintings
Recorded dates of blossom and migration of
Natural causes of climate change
Big volcanic eruptions can change the Earth's climate. Small eruptions have no effect, it has
to be very large and explosive. Volcanic eruptions can produce ash and sulphur dioxide Gas. If
the ash and gas rise high enough they will be spread about the Earth's stratosphere by high
level winds. The blanket of ash and gas that this creates will stop some sunlight reaching the
Earth's surface. Instead, the sunlight is reflected off this blanket back into space. This
cools the planet and lowers the average temperature.
Sunspots (black areas on the sun) were first recorded over 2000 years ago. Sometimes there
are lots of these and at other times they disappear. Even though these spots are dark, they
tell us that the Sun is more active than usual. Lots of spots mean more solar energy is being
fired out from the Sun towards Earth. Cooler periods, such as the Little Ice Age, and warmer
periods, such as the Medieval Warm Period, may have been caused by changes in sunspot
Over very long timescales, there have been big changes in climate. Glacial periods were 5-6
degrees colder than today and interglacial periods were 2-3 degrees warmer than today. Such
big changes need a big cause.
Over long periods of time the Earth's orbit changes:
The Earth's orbit is sometimes circular, and sometimes more of an ellipse (oval).
The Earth's axis tilts. Sometimes it is more upright, and sometimes it is more on its side.
The Earth's axis wobbles, like a spinning top about to fall over.
These changes alter the amount of sunlight the Earth receives and they affect where sunlight
falls on the Earth's surface. Over thousands of years these changes could start or end ice
ages. These changes are called MILANKOVITCH cycles.
Impact of past climate change
‘Little Ice Age’
A period of significant cooling
300 years ago
It had a negative impact on
agriculture (farming), people &
Impact of the ‘Little Ice Age’: On people and the environment
English fisherman
found herring
normally located
in the waters off
Increasing grain
prices and lower
wine production
Cool, wet summers
led to outbreaks
of St. Anthony's
Fire illness
Beech trees, were
replaced first by
oak and then by
Wheat and oats
did not ripen so
the harvests
Increase in deepsea fishing helped
to build the
Many farmsteads
were destroyed,
resulting in less
Malaria in several
parts of England
Cold and rain
occurred in the
spring and
summer of 1315
Farms high on
hillsides were
Cod fishing
decreased, as the
cod moved
farther south.
Great Famine
lasted 8 years
In the Alps, valley
glaciers grew in
the colder climate
They had to
change their
crops from wheat
to potatoes
Advancing glaciers 10-20% of
closed the gold
farmers died
from hunger
Impact of past climate change
.....Focus on agriculture.
• Western Europe experienced a general cooling of the
climate between 1150-1460 and a very cold climate
between 1560-1850.
• During the coldest times, England's growing season was shortened
by 1-2 months compared to today.
• Unlike seeds today, back then the seeds could not survive the
extreme cold or warmth, wetness or dryness.
• Price of wheat went up dramatically as it became more difficult to
grow and get hold of.
changes had a
much greater
impact on
output in the
One of the worst famines in the seventeenth century
occurred in France due to the failed harvest of 1693.
Millions of people in France and surrounding countries
were killed.
In Norway, many farms located at higher latitudes were
abandoned for better land in the valleys.
How were ecosystems affected by climate change
in the past?
1. The dinosaur extinction was possibly caused by a massive
asteroid hitting Mexico and a huge volcano in India combining:
 dust, ash, gas go up into the stratosphere
 which blocks the sun out
 which cools the climate
 so plants don’t grow
 so dinosaurs have no food…
…which has a knock on effect through the food chain.
2. Megafauna extinction – big animals like the
woolly mammoth and sabre-toothed tiger.
The climate was warming so they had to find
new areas to live where the climate suited
them. This disrupted food chains. Humans
also hunted them to extinction.
Mega fauna extinction
The ice age
(Pleistocene) period
finished around
10,000 years ago.
The lack of herbivores
meant carnivorous
animals began to die as
they had less prey.
The overall change in
climate caused a big
change in the food chain,
which meant many animals
became extinct.
This caused temperatures
to rise, ice to melt and
glaciers to retreat.
The lack of plants meant
herbivores (vegetarian)
animals began to die.
Other theories suggest
some animals became
extinct because they
were hunted by humans.
The retreating glaciers
meant there was less
water available for the
plants & animals.
The lack of water & rise
in temperature meant
lots of plants died as they
could not adapt.
Climate change and humans
The main
greenhouse gasses
Greenhouse gasses and temperature
“Describe the graph”
Global temperature = -0.4oF
Carbon Dioxide = 300ppm
Fluctuating, but general
increase of both global
temperature and CO2
between 1880-1940. Then a
much faster rate of growth
for both factors, until:
Global temperature = 1oF
Carbon Dioxide = 380ppm
There is a direct link between the amount of carbon
dioxide in the atmosphere and temperature.
How Does the Greenhouse Effect Work?
How Does the Greenhouse Effect Work?
• Greenhouse gases
(CO2 from the burning of fossil fuels,
trap heat from
leaving the atmosphere and re-radiate that heat
back down to earth.
deforestation, Methane from paddy fields etc....)
• The greater the concentration of greenhouse
gases, the more heat is trapped and the warmer
earth becomes.
• We need the NATURAL greenhouse effect – it
makes the planet 16 degrees warmer. Without it
the earth would be too cold for us to survive.
• The extra greenhouse gases produces by humans
burning fossil fuels  power stations,
transport, industry, homes.
Greenhouse gases: Change over time
• Since pre-industrial times, atmospheric concentrations
of greenhouse gases have grown significantly:
– countries become more industrialised
– people become consumers of energy and goods
– Become bigger producers of air pollution (through the
burning of fossil fuels)
Most greenhouse gases are produced by
developed countries – the EU, USA, Japan.
Greenhouse gases: Change over time
• The USA produce the largest amounts of CO2 each year.
• The world’s current level of CO2 is increasing at a rate of
200x faster than at any time in the past million years.
• Rates of methane have also doubled since the 1800s due
to the growing world’s population demanding an increasing
amount of cows for meat.
• Emerging powers such as China and India are now in line
with older polluters such as USA and Europe due to the
take off of their development.
• China is now the world’s largest single polluter.
An atlas of pollution:
C02 emissions:
World C02 emissions:
Highest C02 emissions = North America, Europe, Japan, UAE,
China (predominantly MEDCs and NICs)
Lowest C02 emissions = South America, Africa, Russia
(predominantly LEDCs)
World C02 emissions:
China emits more CO2 than the US and Canada
put together - up by 171% since the year 2000.
India is now the world's third biggest emitter of CO2 - pushing
Russia into fourth place.
The biggest decrease from 2008-2009 is Ukraine - down 28% in
recent years. The biggest increase is the Cook Islands - up 66.7%
since 2000.
But that is only one way to look at the data - and it doesn't take
account how many people live in each country. If you look at per
capita emissions, a different picture emerges where:
Some of the world's smallest countries and islands emit the most
per person - the highest being Gibraltar with 152 tonnes per
The US is still number one in terms of per capita emissions among
the big economies - with 18 tonnes emitted per person.
China, by contrast, emits under six tonnes per person, India only
For comparison, the whole world emits 4.49 tonnes per person
World C02 emissions:
Reasons for variations in global emissions
Transport – more cars per
capita, bigger cars, more air
Transport – fewer cars, less air
travel, greater use of public
Energy supply – more electrical
goods needing energy i.e.
Televisions, computers,
hairdryers, games consoles
Energy supply – more
traditional fuels used, lower
demand per person, fewer
electrical appliances within
Business and industry – greater Business and industry – more
number of industries, bigger
primary and secondary
outputs, offices.
Homes – larger homes, central
heading/air conditioning, more
energy intensive construction.
Homes – smaller homes, often
traditional building methods
with less environmental impact.
Effects on people
Predicting the future:
Why is it hard
to predict
future levels
of greenhouse
We don’t know
what the
world’s future
population will
We don’t know if
we will continue to
use fossil fuels, or
change to cleaner
energy like wind or
We don’t know if
people will change
their lifestyles
and recycle more,
or use more public
Case studies!
How might a developed country be affected
by climate change?
How might a developed country be affected
by climate change?
Future UK climate
Overall UK summers and winters will be
Temperature on average will rise by 4°C
by 2080.
In the summer heat waves will be
become more common as temperatures
reach 40°C
Rainfall in the summer is
expected to decrease and
as a result we will suffer
from more droughts.
Winters will
bring less snow
and more rain.
We will also
receive more
severe storms.
How might a developing country be affected by
climate change?
A developing country
Low greenhouse gas emissions – 2.6 tonnes per person
per year (world average = 6.8)
Produce less than 1% all green house gases.
99% of Egypt’s people live in 5% land area as so much is desert.
Average rainfall = less than 10mm/yr
The River Nile is an important water supply.
How might a developing country be affected by
climate change?
With Global Warming…
If sea levels rise 50cm, 1/3 of
the city of Alexandria would be
under water.
10% Nile Delta would flood  7
million people would have to leave
their homes  farming would be
hit  there would be less food
 famine.
Less and more unreliable rainfall
 water shortages.
Heat waves  illness and death.
Malaria increase.
Water Wars?
86% of the Nile’s water starts
it’s journey in Ethiopia.
Uganda, Sudan and Ethiopia are
all building huge dams for
Hydro Electric Power (HEP).
This could have a serious
impact on the amount of water
reaching Egypt  This could
lead to conflict and war.
Egypt has a debt of $30 billion.
It may not be able to cope with
the impacts of global warming.
Video revision:
What are air masses?
Antarctic Ice reveals Climate History
Dinosaurs Extinction
Evidence for global warming - polar ice caps
Climate change dangers
Global Warming - None Like It Hot!
BBC climate experiment
Climate Change and the future of weather
Egypt struggles with climate change
Past GCSE questions: A
Outline one reason why sea level is expected to rise in the future
(2 marks)
2. Describe two impact of melting ice sheets on the environment
(2 marks)
3. Describe one impact of a short term past climate change on
a) People b) the environment
(4 marks)
4. Explain how natural events can cause climate change. (4 marks)
5. Describe two natural cause of climate change. (4 marks)
6. Explain how human activity is leading to climate change. (4 marks)
Past GCSE questions: B
7. Describe how two human activities can contribute to climate
change. (2 marks)
8. Give two reasons why developing countries often produce less
carbon dioxide than developed countries (2 marks)
9. Explain the possible economic (money) impacts of climate change
on a named country. (4 marks)
10. Describe one way in which climate change might make people
poorer (2 marks)
11. For a named developing country, explain why climate change is
likely to have a large impact on its people. (6 marks)
Past GCSE questions: C
12. For a named developing country, explain how climate change is
likely to have a large impact on its economy. (6 marks)
13. For a named country, suggest one possible impact of higher global
temperatures. (2 marks)
14. State two possible impacts of climate change in the UK (2 marks)
15. Explain how the future climate of the UK is likely to be affected
by global climate change (6 marks)
16. Describe how climate change in the past, such as the Little Ice
Age, affected people and ecosystems. (4marks).
17. Describe how colder periods, such as the Little Ice Age, affected
farming. (2 marks)
Good luck!