Download Notes G1 - 1.1-1.6 Climate change Word document

GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.1 - WHAT ARE THE WORLD’S MAJOR CLIMATES AND
HOW DO THEY RELATE TO BIOMES.
PART 1 - THE GENERAL CIRCULATION OF THE ATMOSPHERE
[1] It is impossible to understand the world’s major climates without
having a basic understanding of the General Circulation of the Atmosphere.
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[2] The General Circulation of the Atmosphere is the name that we give
to the general pattern of belts of pressure and wind on the surface of the
Earth. The general circulation results from four factors.The heat of the sun.
The tendency for wind to blow from High Pressure to Low
Pressure. We call this the Pressure Gradient.
The force exerted on the wind by the spin of the earth. We call
this force the Coriolis Force. It deflects the wind to the right of the
pressure gradient in the northern hemisphere and to the left of the
pressure gradient in the southern hemisphere.
Friction between the wind and the surface of the earth.
[3] The sun heats the surface of the earth near the equator by short wave
radiation. The surface of the earth heats the bottom layer of the air by
conduction. The hot air expands and rises leaving a Low Pressure in the
lower troposphere. This low pressure is sometimes called the Doldrums.
The air rises through the Troposphere above the equator. As it rises it cools
until it can rise no further. The level at which it stops rising is called the
Tropopause. The air cannot rise above the tropopause. Therefore it spreads
out laterally, blowing as a wind in the upper troposphere away from the
equator.
[4] It blows away from the equator as far as Latitude 30°N and 30°S,
where it becomes cold enough to sink towards the surface of the earth. For
our example we shall only follow the air that blows to the north of the
equator. Some air from a Jet Stream, which we call the Sub Tropical Jet
Stream, blowing around the world from west to east above 30°N bleeds
into this sinking air, reinforcing it. This sinking air creates a High Pressure
at the surface of the earth around 30°N.
[5] In a high pressure or anticyclone the skies are very clear as the sinking
air does not allow clouds to form. As 30°N is still fairly near the equator, the
cloud free conditions allow the sun’s intense rays to make the ground very
hot. This heats the bottom of the troposphere but the air cannot rise because
of the huge amount of sinking air above it. Therefore hot, dry air is trapped
near the surface of the ground, creating the tropical deserts over land.
(Refraction of light between the dense cold sinking air and the hot light air
that is trying to, but cannot, rise can result in an optical effect known as a
mirage - where objects can appear in the wrong place the wrong size and
even upside down.) This high pressure is called the Horse Latitudes High
Pressure.
[6] The air will now complete the circulation by returning from the high
pressure at 30°N to the equator as a wind. The pressure gradient would make
this a North Wind, but the resultant of the pressure gradient, the Coriolis
force and friction makes it a North East Wind. This wind is called the North
East Trade Wind. The equivalent wind in the southern hemisphere is called
the South East Trade Wind.
[7] The area within the doldrums where the two trade winds meet and rise
is called the Inter Tropical Convergence Zone.
[8] The circulation described above, where air rises at the equator, blows
towards 30°N and S in the upper troposphere, sinks towards the surface at
30°N and S and returns to the equator was first discovered by a man called
Hadley. It is called the Hadley Cell.
[9] Do remember that not all the air that sinks at 30°N returns to the
equator. Some of it will blow polewards as a South West Wind.
[10] The coldest places on a homogenous earth would be the poles.
(Homogenous = all the same, i.e. in the case of the earth flat, not tilting and
not divided into land and sea). At the poles cold air will sink towards the
surface creating a high pressure called the Polar High Pressure.
[11] This sinking only takes place in a shallow layer, so the troposphere is
very shallow near the poles and the polar tropopause is much lower than the
tropical tropopause.
[12] Air spreads out from the polar high pressure. In the northern
hemisphere it will form a Polar North Easterly Wind.
[13] At around 60°N the warm south west wind (see note 8) and the cold
polar north easterly wind will meet. They cannot mix and the warm air will
rise over the cold air. The line where they meet is called the Polar Front.
The area around the polar front is an area of low pressure and is called the
Depression Belt.
[14] The polar north easterly wind rises up to the tropopause underneath
the polar front; probably warmed by friction with the warm air on the other
side of the polar front. It then returns to the pole in the upper troposphere,
thereby completing the circulation. We call this cell, between the polar front
and the pole, The Polar Cell.
[15] The warm south westerly air rises at the polar front, above the cold
air. Some of it may bleed over the top of the front into the polar cell, but
most of it feeds a second jet stream, one which blows around the world from
west to east above the polar front. We call this jet The Polar Front Jet
Stream.
[16] The Hadley Cell (from the equator to 30°N) and the Polar Cell (from
60°N to the pole) are both clear and easy to understand.
[17] However, the third cell (between 30°N and 60°N is rather more
complicated). Ferrel believed that it was a simple cell like the other two,
with air rising at 60°N, returning to 30°N in the upper troposphere, sinking
at 30°N and blowing back to 60°N as the south west wind. We now know
that Ferrel was not correct and that this Ferrel Cell takes a rather
different form.
[18] The warm air does rise at 60°N, but it feeds into the Polar Front Jet
Stream and blows around the world as part of that jet. The two jet streams
blow around the world in waves, called Rossby Waves, so that the two jet
streams sometimes touch. When they do, air is transferred from the polar
front jet into the subtropical jet. The air then blows around the world as part
of the subtropical jet, until in the end it bleeds out into the sinking air of the
Hadley Cell. It then returns to the Polar Front as the warm south west wind.
[19] THE EFFECT OF THE TILT OF THE EARTH’S AXIS ON THE
GENERAL CIRCULATION OF THE ATMOSPHERE.
[20] The Axis is the name given to an imaginary straight line which
extends from the north pole to the south pole through the centre of the earth.
[21] The earth’s axis tilts at an angle of 23.5° from the vertical and at 66.5°
relative to the Plane of the Ecliptic (the plane of the earth’s orbit around the
sun.
[22] Therefore, the sun will only be overhead at the equator at those times
of the year when the earth is sideways on to the sun, so that the axis appears
to be vertical. The two days when this happens are March 21st and
September 23rd. These days are called the Equinoxes and are the days when
day and night are the same length in all places on earth. On these days the
General Circulation of the Atmosphere will fit the pattern described above,
with the inter-tropical convergence zone centred on the equator.
[23] However, by June 21st the earth’s axis is tilting at 23.5° towards the
sun. On this day, the sun is overhead at latitude 23.5°N. This line of latitude
is called The Tropic of Cancer. The north pole is tilting towards the sun, so
that everywhere in the northern hemisphere will have long days and short
nights. Everywhere north of 66.5°N will have 24 hours day. This line of
latitude is called The Arctic Circle. June 21st is called The Summer
Solstice in the northern hemisphere and the Winter Solstice in the southern
hemisphere. During northern hemisphere summer, all the pressure and wind
belts will move towards the north. The inter-tropical convergence zone may
move 5°, or even more, north of the equator.
[24] By December 22nd however, the earth’s axis is tilting at 23.5° away
from the sun. On this day, the sun is overhead at latitude 23.5°S. This line of
latitude is called The Tropic of Capricorn. The north pole is tilting away
from the sun, so that everywhere in the northern hemisphere will have long
nights and short days. Everywhere north of the arctic circle will have 24
hours night while everywhere south of the Antarctic Circle will have 24
hours day. December 22nd is called The Winter Solstice in the northern
hemisphere and the Summer Solstice in the in the southern hemisphere.
During northern hemisphere winter, all the pressure and wind belts will
move towards the south. The inter-tropical convergence zone may move 5°
or even more, south of the equator.
[25] Pressure and wind belts tend to move more over land and less over the
sea.
[26] The tilt of the earth’s axis has an effect on Wales’s weather. During
spring (according to the General Circulation of the Atmosphere model) we
are under the 60°N Depression Belt. This tends to bring us our typical spring
weather of rapid alternations of bright and stormy weather, of wet and dry
weather and of warm and cold air - hence the old Welsh saying - “Haul y
Gwanwyn - gwaeth na gwenwyn”.
[27] In summer the depression belt passes to the north of us. We are now
under the warm south west wind, which brings us stable Tropical maritime
air. This gives Anglesey its warm dry summer days, though the Welsh
mountains may have some rain due to the air being forced to rise over the
mountains.
[28] In Autumn we return to spring conditions with the depression belt
giving us alternations of bright and stormy weather.
[29] In the middle of winter the depression belt shifts to the south of us.
We are now under the cold polar north easterly winds, which bring us polar
continental air. the short journey over the North Sea may make this air
unstable and bring snow to Eastern England and Scotland but, by the time it
reaches Wales this Polar Continental air is stable, dry and bitterly cold. In
the past many old people died of bronchitis during this airmass and the
Welsh referred to it as “Gwynt traed y meirw”. In Victorian times this winter
airmass was very common, with the Thames and Windermere freezing over,
but the slight global warming of recent decades has made it somewhat rarer;
often only occurring for a fortnight or so in January or early February.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.1 - WHAT ARE THE WORLD’S MAJOR CLIMATES AND
HOW DO THEY RELATE TO BIOMES.
PART 2 - KEY TO MAP OF WORLD’S MAJOR CLIMATES (MILLER
CLASSIFICATION
A. HOT CLIMATES
(MEAN ANNUAL TEMPERATURE EXCEEDING 21°C)
1
EQUATORIAL - DOUBLE MAXIMUM OF RAIN
1m EQUATORIAL (MONSOON VARIETY)
2
TROPICAL MARINE - NO MARKED DRY SEASON
2m TROPICAL MARINE (MONSOON VARIETY)
3
TROPICAL CONTINENTAL - SUMMER RAIN
3m TROPICAL CONTINENTAL (MONSOON VARIETY)
B. WARM TEMPERATE (OR SUB-TROPICAL) CLIMATES
(NO COLD SEASON, I.E. NO MONTH BELOW 6°C)
1
WESTERN MARGIN (MEDITERRANEAN) - WINTER RAIN
2
EASTERN MARGIN - UNIFORM RAIN
2m EASTERN MARGIN (MONSOON VARIETY) - MARKED
SUMMER MAXIMUM OF RAIN.
C. COOL TEMPERATE CLIMATES
(COLD SEASON OF ONE TO FIVE MONTHS BELOW 6°C)
1
MARINE - UNIFORM RAIN OR WINTER MAXIMUM
2
CONTINENTAL - SUMMER MAXIMUM OF RAIN
2m CONTINENTAL (MONSOON VARIETY) - STRONG
SUMMER MAXIMUM OF RAIN.
D. COLD CLIMATES
( LONG COLD SEASON OF SIX OR MORE MONTHS BELOW 6°C)
1
MARINE - UNIFORM RAIN OR WINTER MAXIMUM
2
CONTINENTAL - SUMMER MAXIMUM OF RAIN
2m CONTINENTAL (MONSOON VARIETY) - STRONG
SUMMER MAXIMUM OF RAIN.
E. ARCTIC CLIMATES
(NO WARM SEASON OF TWELVE MONTHS BELOW 10°C)
F. DESERT CLIMATES
(LESS THAN 250 mm OF RAIN ANNUALLY)
1.
HOT DESERTS - NO COLD SEASON - NO MONTH BELOW 6°C
2.
MID LATITUDE DESERTS - WITH COLD SEASON - ONE OR
MORE MONTHS BELOW 6°C.
G. MOUNTAIN CLIMATES.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.1 - WHAT ARE THE WORLD’S MAJOR CLIMATES AND
HOW DO THEY RELATE TO BIOMES.
PART 3 - KEY TO MAP OF THE VEGETATION REGIONS OF AFRICA
1
TROPICAL EVERGREEN RAIN FOREST
2
MANGROVE SWAMP
3
TROPICAL FOREST (WITH MARKED DRY SEASON)
4
SAVANNA
5
SCRUB AND SEMI-DESERT VEGETATION
6
HOT DESERT - ROCK OR SAND - WITH SCANTY VEGETATION
7
WARM TEMPERATE RAINFOREST
8
MEDITERRANEAN EVERGREEN
9
TEMPERATE GRASSLAND
10
MOUNTAIN FOREST AND GRASSLAND.
ONLY CLIMATIC CLIMAX VEGETATION IS SHOWN - CULTIVATION IS
NOT SHOWN.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.2 - WHAT ARE THE TEMPORAL PATTERNS OF
CLIMATE CHANGE
PART 1 - INTRODUCTION
[1] WE ARE ALL AWARE, e.g. FROM RECENT NEWS ITEMS
ABOUT THE POSSIBLE INTER-RELATIONSHIP BETWEEN GLOBAL
WARMING AND RISING LEVELS OF GREENHOUSE GASES, THAT
CLIMATE CAN CHANGE AND IS CHANGING. INDEED, IN MY
LIFETIME, SINCE 1950, I HAVE OBSERVED SUMMERS BECOMING
HOTTER AND DRIER AND WINTERS BECOMING WETTER,
STORMIER AND LESS COLD AND SNOWY.
[2] AT AS LEVEL, WE MUST BE AWARE THAT CLIMATE CAN
VARY AT A VARIETY OF SCALES, i.e. LONG TERM CLIMATIC
CHANGES OVER HUNDREDS OF THOUSANDS OR EVEN MILLIONS
OF YEAR; MEDIUM TERM CLIMATIC CHANGES OVER HUNDREDS
OF YEARS; SHORT TERM CLIMATIC CHANGES OVER TEN YEARS
OR SO; and VERY SHORT TERM CHANGES OVER ONE OR TWO
YEARS. INDEED IT COULD BE ARGUED THAT THE VERY SHORT
TERM CHANGES ARE NOT CLIMATIC CHANGES AT ALL, BUT
ARE MERELY VARIATIONS IN THE WEATHER.
[3] THEREFORE, WHEN WE ARE DISCUSSING A TOPIC SUCH AS
GLOBAL WARMING IT IS NOT ALWAYS EASY TO DECIDE
WHETHER WE ARE DEALING WITH SOMETHING THAT IS GOING
TO BE A LONG TERM CLIMATIC CHANGE, A MEDIUM TERM
CLIMATIC CHANGE OR A SHORT TERM CLIMATIC CHANGE.
NOTE: WEATHER IS THE STATE OF THE TROPOSPHERE (LOWER
ATMOSPHERE) IN A GIVEN PLACE AND AT A GIVEN TIME, i.e.
WEATHER VARIES FROM PLACE TO PLACE, FROM DAY TO DAY AND
EVEN FROM HOUR TO HOUR. CLIMATE IS AVERAGE WEATHER,
WHERE THE DATA IS AVERAGED OVER A PERIOD OF 30 TO 35 YEARS,
THEREBY EVENING OUT ANY VARIATIONS DUE TO VARIABLE
WEATHER.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.2 - WHAT ARE THE TEMPORAL PATTERNS OF
CLIMATE CHANGE
PART 2 - LONG TERM CLIMATE CHANGE
[1] In 1837, Louis Agassiz, an European naturalist, proposed that earth
had experienced major periods of glaciation, periods known as ice ages,
where large areas of the continents were covered by sheets of ice. He
presented evidence, controversial at the time, that glaciers once had covered
most of Britain, northern Europe and Asia, as well as the foothill regions of
the Alps.
[2] WE now know that for a very long period from 64,000,000 years ago
to 2,400,000 years ago (the Tertiary Period) the earth was, for most of the
time, considerably warmer than at present. However, 2,400,000 years ago
the climate of the world became considerably colder - heralding in the
period of the ice ages.
[3] Until the 1960s, it was widely believed that the earth had experienced
four major glacial advances followed by warmer interglacial periods (glacial
cycles) during the Pleistocene Period (the last 2 million years or so). In the
foothills of the Alps, evidence for four glacial advances was discovered.
These were named (from oldest to most recent) Gunz, Mindel, Riss and
Wurm, after Alpine rivers.
[4] A major problem in studying long-term climatic changes, such as
those that caused the ice ages, is that erosion and weathering destroy
evidence, e.g. on land, each subsequent advance of the glaciers tends to
destroy, bury, or greatly disrupt the sedimentary evidence of previous
glaciers. The evidence for four ice ages came from deposits from older
glaciations lying beyond the terminal moraines of later glaciations. Evidence
of smaller glaciations, overridden by the moraines of later glaciations was
rarely recognised.
[5] Before the advent of radiometric dating techniques following World
War II, the timing of the glacial advances were only crudely known, e.g.
estimates for the timing of the end of the last ice age varied from 8,000 BP
to 30,000 BP.
[6] In Sweden a more accurate estimate was made based on varves, that
are present in the basins of some lakes that only formed at the end of the ice
age. (A varve is a pairing of organic-rich summer sediment and organic-poor
winter sediment, each couplet representing one year of time.) This technique
suggested that the region had been de-glaciated around 13,000 years ago. At
the time, many scientists were sceptical, because they found it difficult to
believe that much of Europe had been covered in several thousand metres of
ice so recently.
[7] Two major advances in scientific knowledge about climate change
occurred in the 1950s. First, radiometric techniques, such as radiocarbon
dating, that measured the absolute ages of landforms produced by the
glaciers began to be widely used. Radiocarbon Dating in the United States
showed that the maximum of the last ice age occurred only 18,000 years
ago.
[8] The second major advance was the discovery that evidence of detailed
climatic changes has been recorded in the sediments on the ocean floors.
Unlike the continental record, the deep-sea sedimentary record has not
been disrupted by subsequent glacial advances. Rather, the slow, continuous
sediment record provides a complete history of climate changes during the
past several million years. The most important discovery of the dep sea
record is that Earth has experienced numerous major glacial advances during
the Pleistocene, not just the four that had been identified previously.
[9] The deep sea sediment contains the microscopic shells of sea animals
called foraminifera. Their shells are made of Calcium Carbonate. Oxygen
in these shells is made of two isotopes - O16 and O18. The proportion of
these two varies with the depth of seawater. Therefore, during periods of
glaciation O18 levels increase, with water being shallower and during
periods of global warming O16 levels increase as sea water is deeper. This
measurement is called oxygen isotope analysis. As can be seen in the
graph, the last glacial advance was only 18,000 years ago and was one of
about 30 such advances in the last 900,000 years.
[10] Today, climatologists are aware that the present climate is but a short
interval of relative stability in a time of major climatic shifts. Moreover, the
modern climatic period, known as the Holocene or Recent, is a time of
extraordinarily stable, warm temperatures, compared to most of the last 2.4
million years.
[11] In recent years many Climatologists have questioned how long this
stable period would last. In the 1960, following a number of particularly
cold winters, some were predicting an early return to glacial conditions. By
today, following a number of hot summers and mild winters accompanied by
an increase in general storminess worldwide, some are predicting vastly
accelerated global warming and a runaway greenhouse effect, caused by
accelerated release of greenhouse gases since the Industrial Revolution.
[12] Indeed, when we look during the next lesson at Medium Term
Climatic Change, you will realise that the Holocene has not been as stable a
period as some would like to suggest.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.2 - WHAT ARE THE TEMPORAL PATTERNS OF
CLIMATE CHANGE
PART 3 - MEDIUM TERM CLIMATE CHANGE
[1] Although the Holocene has been remarkably stable as a long term
climatic period, a detailed study of the Holocene Period shows a wide range
of medium term climatic changes, varying from a few hundred to a couple of
thousand years.
[2] A long interval of climates hotter than today’s occurred during the
interval from 7,000 BP to around 6,000 BP - a period known as the
Altithermal.
[3] This interval was characterized by grasslands in the Sahara and by
severe droughts on the Great Plains of America!
[4] Other warm intervals occurred during the Bronze Age, around 4,000
BP; during the Roman Empire, around 2,000 BP; and during the late
Mediaeval period and the Renaissance.
[5] An unusually cold interval followed the massive volcanic eruption of
Santorini (Thera) in 3458 BP (1450 BC). This cold period saw the
destruction of the Minoan Civilization of Crete, the probable basis of the
Atlantis Myth - the story of a great civilization destroyed by volcanic
activity.
[6] Another cold period occurred during the Dark Ages - possibly due to
an earlier and more massive eruption of Krakatau. This dark age saw
lowland Roman Britain destroyed by plague and the birth of Celtic Wales
and Anglo-Saxon England.
[7] Further cold periods occurred during the thirteenth and fourteenth
centuries - again accompanied by plague; and during Stuart times - a period
sometimes called the Little Ice Age. Glaciers in Switzerland grew
considerably during the Little Ice Age.
[8] The Little Ice Age had major impacts on civilization. Greenland
settlements set up during the Mediaeval warm period were isolated and then
abandoned; American Indians abandoned the Colorado plateau; and much of
Europe was ravaged by religious wars - possibly caused as much by poor
harvests as by religious zeal.
[9] Climatologists are uncertain as to the causes of many of these
medium-term climatic changes. Therefore, they are uncertain as to the next
medium term changes. Much evidence from the past suggests that the next
long term change will be into another Ice Age, somewhere between 3,000
and 7,000 years in the future but, in the medium term, global warming due to
increased levels of greenhouse gases may be more likely.
[10] THESE NOTES SHOULD BE STUDIED ALONG WITH THE GRAPH
SHOWING CLIMATE CHANGES FROM 10,000 BP TO TODAY.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.2 - WHAT ARE THE TEMPORAL PATTERNS OF
CLIMATE CHANGE
PART 4 - SHORT TERM CLIMATE CHANGE
[1] At the moment we are in a long term Interglacial Period between
two ice ages, the last one peaking around 18,000 BP and the next one due in
between 3,000 and 7,000 years from now. We are also in a medium term
period of Global Warming that has continued with some variation since
around 1850 AD.
[2] However, there are also short term variations in world climates,
variations occurring over a period of a year or a couple of years. Many of
these variations are linked to an oceanic feature called El Niño. (As climate
is defined as average weather, the data averaged over thirty-five years, it
can be argued that these short term variations should be studied as variations
of weather, rather than climate. However, they appear to be linked to
medium term climatic variations, e.g. global warming has been accompanied
by an increasing frequency of El Niño.)
[3] Normally, a cold oceanic current, called the Humboldt current, flows
along the eastern side of the Pacific Ocean, down the western coast of Latin
America. At the same time, a warm equatorial current, linked to the easterly
trade winds, crosses the equatorial Pacific, from east to west, bringing warm
water to the coasts of Indonesia.
[4] These currents have a considerable effect on the climate of the area.
The cold current in the Eastern Pacific causes cold air to sink, generating a
high atmospheric pressure and bringing desert conditions to the west coast
of Latin America. At the same time, the warm current in the Western Pacific
causes warm air to rise, generating a low atmospheric pressure and bringing
heavy rain and a tropical rainforest biome to Indonesia. This whole system
is called the southern oscillation.
[5] However, once every few years this southern oscillation is reversed.
For some unknown reason, pressure rises over Indonesia and falls over the
west coast of Latin America. This change in the pressure gradient causes the
trade winds to weaken or, in some cases, to reverse. This causes the warm
water of the Western Pacific to flow eastwards, increasing water
temperatures in the Eastern Pacific and decreasing temperatures in the
Western Pacific. This reversal of the southern oscillation is called El Niño.
[6] Under normal atmospheric and ocean conditions, clouds tend to
develop over the warm waters of the Western Pacific but not over the cold
waters of the Eastern Pacific. However, during an El Niño, clouds develop
over the central and eastern Pacific, but not over the Western Pacific and
Indonesia. This can cause disastrous flooding and landslides in the normally
arid lands of western Latin America and equally disastrous droughts with
widespread forest fires in Indonesia.
[7] Based on the historical record of Spanish monks in Latin America,
Climatologists know that El Niños have occurred as far back as records go.
However, one disturbing feature is that the are occurring more often and
they appear to be getting stronger.
[8] The El Niño, by interfering with the Hadley Cell can have a knock on
effect on climate worldwide. The 1997-98 El Niño brought copious and
damaging rainfall to the Southern United States from California to Florida.
Also, snowstorms in the North Eastern United States were more frequent
and stronger than in most years and the warm El Niño winter fuelled
Hurricane Linda, which devastated the western coast of Mexico.
[9] American scientists have discovered an Atlantic Cycle, which appears
to be linked to El Niño. During an Atlantic Cycle the Subtropical High
Pressure and the Polar Front Low Pressure become more accentuated,
bringing increased precipitation to the SE United States, cold and dry
conditions to the NE United States and more violent depressions to The
United Kingdom and Western Europe.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.3 - WHAT ARE THE CAUSES OF CLIMATE CHANGE?
PART 1 - THE EVIDENCE FOR CLIMATE CHANGE
•
EXTREME HEAT OR DROUGHT
•
Drought in Southern Brazil in 2006 led to a 10% decrease in soybean yield.
•
About 35,000 deaths were related to heat in France, Italy, The Netherlands,
Portugal, Spain and the UK during the heatwave of 2003.
•
In 2005, Spain experienced the driest winter and early spring since records
began in 1947.
•
More than 1,500 fatalities in India and Pakistan in 2003 were caused by
temperatures over 50°C.
•
In 2006 at least 11 million people were affected by food shortages caused by
drought in Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Somalia and
Tanzania.
•
In 2006 severe droughts in Northern China led to 12% of the nation’s
agriculture being affected. Severe drought in Southern China affected 18
million people.
•
In 1998 the Great Barrier Reef and coral reefs elsewhere experienced the
most severe bleaching (death of coral) ever recorded.
•
Abnormally low or absent rainfall in Australia in the decade up to 2007
severely affected cattle farmers, and led to cities imposing water restrictions.
Arable farmers were warned, in April 2007, of the possibility of restrictions
on water for irrigation.
•
LOCAL TEMPERATURE RISE
•
There has been a widespread retreat of mountain glaciers in the Andes
during the 20th century.
•
The average loss of thickness of glaciers in the European Alps in 2003 was
nearly twice that of the previous record year of 1998.
•
In 2002, 1,250 square miles (3,250 sq km) of the Larsen B ice shelf broke
away from the Antarctic Peninsula. This was followed by an unexpectedly
rapid increase in the rate of glacial flow and ice sheet retreat.
•
A temperature increase of 3°C to 4°C since 1950 is having a visible effect in
Alaska. Roads and buildings in some areas are subsiding as the permafrost
melts and, in the absence of summer sea-ice, is leading to coastal erosion,
making some low lying communities unviable.
•
In much of North Western Europe, autumn 2006 was the warmest since
records began. Records for Central England date back to 1659.
•
Average temperatures in the west of Siberia have risen by 3°C since the
1960s, leading to melting of the permafrost.
•
Northwest China has experienced increasing temperatures, increasing
rainfall and increased glacial melt rates in recent years.
•
EXTREME PRECIPITATION AND/OR WIND
•
The 2005 Atlantic hurricane season broke records for the frequency of
storms, and for the number of category 5 hurricanes. Whether these are signs
of climatic change or not is a fiercely debated topic.
•
Heavy rain and flooding in Bolivia early in 2006 affected around 17,500
people.
•
The first hurricane ever observed in the South Atlantic hit Brazil in 2004.
•
Tens of thousands of people were left homeless and over 160 killed in 2004
by mud-slides and floods in Brazil.
•
In 2006 the Horn of Africa experienced the worst floods in 50 years. They
claimed over 600 lives in Ethiopia and affected hundreds of thousands of
people in Somalia.
•
Heavy rain led to severe flooding and landslides in June 2006, affecting 17
million people in Southern China.
•
Heavy rain and flooding in parts of Northern India, Nepal and Bangladesh in
2004 left 1,800 dead and millions homeless.
•
CHANGING ANIMAL AND PLANT BEHAVIOUR
•
Measurements of Arctic Sea Ice in recent decades suggest that the area of ice
is declining by around 8% each decade, reducing polar bears’ hunting season
and resulting in poorer health and reproductive success.
•
Scientists have detected a genetic adaptation to warmer temperatures in a
type of North American mosquito. It is entering its winter dormancy 9 days
later than it did 30 years ago, prolonging the period during which it can
spread disease.
•
Trees are flowering on average 4.5 days earlier in Washington DC.
•
Of 35 European non-migratory butterfly species studied, 22 shifted their
ranges north by 20-150 miles (35-240 km) during the 20th century. Only one
shifted south.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.3 - WHAT ARE THE CAUSES OF CLIMATE CHANGE?
PART 2 - THE ATMOSPHERIC PROCESSES THAT RESULT IN CLIMATE
CHANGE
•
There are five main families of theories about the causes of climate change.
They are (1) astronomical variations in the earth’s orbit; (2) changes in the
output of solar energy ; (3) changes in atmospheric gases or dust, causing
changes in incoming or outgoing radiation; (4) changes in oceanic
circulation: and (5) changes in landmasses that affect albedo and oceanic
circulation.
•
The AS syllabus requires that we look in detail at (3), i.e. changes in
atmospheric gases or dust, causing changes in incoming or outgoing
radiation. However, we shall, first of all, look very briefly at the other four.
•
(1) ASTRONOMICAL VARIATIONS IN THE EARTH’S ORBIT Climate is affected by three astronomical variables - (a) a 100,000 year cycle
called the eccentricity cycle, where the earth’s orbit varies between being
circular and being elliptical; (b) a 41,000 year variation in the earth’s tilt
from 24.5° to 22.1° called the obliquity cycle: and (c) a 23,000 year
precession cycle which refers to variation in the time of year when the earth
is at its nearest to the sun. A geographer called Milankovitch worked out
the complex mathematics to correlate a combination of these three with
glacial and interglacial periods. The graphs that he drew showed climatic
cycles, called “Milankovitch Cycles”, which correlate extremely well with
the results of deep-sea cores.
•
(2) CHANGES IN THE OUTPUT OF SOLAR ENERGY - The sun is
slightly variable on an eleven year cycle - called the sunspot cycle. Every 11
years magnetic storms on the sun, called sunspots, reach a sharp maximum
and there is room to believe that these affect short term climatic variations.
Some indirect evidence points to this, e.g. dendrochronologists have
identified an eleven year cycle in tree rings, which reflect climatic change.
•
(4) CHANGES IN OCEANIC CIRCULATION - Oceanographers disagree
as to the effects of ocean currents on climate change, e.g. some
oceanographers fear that an increase in the melting of the Greenland glaciers
will reduce the salinity of sea water and will make the Arctic Ocean less
dense, thereby preventing cold water from sinking and slowing down os
stopping the Gulf Stream. Such a change would reduce Britain’s mean
temperatures by 10°C in all seasons. Other oceanographers point out that no
such effect was experienced during the warm period of the Late Middle
Ages, when grapes were grown in Monasteries over much of England and
Wales.
•
(5) CHANGES IN LANDMASSES WHICH AFFECT ALBEDO AND
OCEAN CIRCULATION - There is evidence that past ice ages, long before
the Pleistocene all occurred when there are continents at or near the poles, as
land cools down more rapidly in winter, thereby allowing ice to accumulate.
It is noticeable that during the Pleistocene there has been a large landmass at
the south pole and that the small Arctic Ocean is surrounded by landmasses
near the north pole.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.3 - WHAT ARE THE CAUSES OF CLIMATE CHANGE?
PART 2 (cont) - THE ATMOSPHERIC PROCESSES THAT RESULT IN
CLIMATE CHANGE
•
(3) CHANGES IN ATMOSPHERIC GASES OR DUST CAUSING
CHANGES IN INCOMING OR OUTGOING RADIATION - Many
theories attribute climate change to variations in atmospheric dust levels.
The primary villain is volcanic activity, which pumps enormous quantities
of ash into the stratosphere, where strong winds spread it around the world.
The dust reduces the amount of insolation reaching the earth’s surface for
periods of one to three years.
•
VOLCANIC ACTIVITY - The climatic cooling effect of volcanic activity is
unquestioned: All of the coldest years of record over the past 200 years have
occurred in the year following major eruptions. Following the massive
eruption of Tambora in 1815, the summer of 1816 was known as “the year
without a summer”. Killing frosts in July killed crops in New England and
Europe, resulting in famines. Several decades later, following the massive
eruption of Krakatoa in 1883, temperatures decreased significantly during
1884. Although no twentieth century eruptions have approached the
magnitude of these two, the 1991 eruption of Mt. Pinatubo produced a
substantial respite of cool conditions in an otherwise continuous series of
record warm years.
•
Volcanic activity is an important variable in global temperatures.
Interestingly, volcanic ashes that accumulated about 2.6 million years ago
are ten times thicker than average on the floor of the North Pacific Ocean.
The modern series of global climatic changes began soon thereafter,
suggesting that the massive eruptions could have played a part in setting off
the climatic changes of the Pleistocene.
•
ATMOSPHERIC GASES - Another phenomenon closely correlated with
average global temperature is the composition of atmospheric gases. For
many years scientists have known that Carbon Dioxide acts as a
“greenhouse gas”. Although the analogy to a greenhouse is problematic
(because gases, unlike solids, do not physically restrict air movement) there
is no doubt that Carbon Dioxide transmits incoming short-wave radiation
and absorbs outgoing long wave radiation, similar to the effect of the glass
panes in a greenhouse. Thus, as the atmospheric content of greenhouse
gases rises, so will the amount of heat trapped in the lower atmosphere.
Although the amount of Carbon Dioxide in the atmosphere is only about
.0036%, its effect on climate is considerable. It has been estimated that the
average temperature on earth would be below freezing, rather than a balmy
16°C if Carbon Dioxide was not present in the atmosphere.
•
A consequence of the combustion of fossil fuels is that Carbon Dioxide is
released in huge quantities. Detailed measurements of atmospheric Carbon
Dioxide since 1958 reveal a cyclical and ever increasing atmospheric
Carbon Dioxide level. The cyclicity is related to the dominance of plant
growth in the Northern Hemisphere summer, which temporarily lowers the
global Carbon Dioxide level.
•
Trapped in the glacial ice of Antarctica and Greenland are air bubbles
containing minor samples of the atmosphere that existed at the time the ice
formed. One of the important discoveries of the ice-core projects is that
prehistoric atmospheric Carbon Dioxide levels increased during interglacial
periods and decreased during major glacial advances. It is still not known
why the two are so closely correlated. One explanation involves the oceans,
since they serve as the primary short term storage sites for Carbon Dioxide.
Unlike many gases, the solubility of Carbon Dioxide increases as water
temperature decreases. This means that cold polar water absorbs Carbon
Dioxide from the atmosphere, whilst warm tropical water releases Carbon
Dioxide into the atmosphere. Global cooling leads to colder oceans, which
increases the amount of Carbon Dioxide taken out of the atmosphere.
Decreasing atmospheric Carbon Dioxide levels cause temperatures to drop,
and glaciers to advance, resulting in a positive feedback loop of global
cooling. Operating in the reverse, warming oceans release Carbon
Dioxide into the atmosphere, producing a positive feedback loop of
global warming and enhancing the greenhouse effect.
•
The fact that average global temperatures and Carbon Dioxide levels
are so closely correlated suggests that Earth will experience record
warmth as the atmospheric level of Carbon Dioxide increases. The
present level of approximately 360 parts per million of Carbon Dioxide is
already higher than at any time in the past million years.
•
Carbon Dioxide is not the only greenhouse gas. Molecule for molecule
Methane is more than 20 times more effective than Carbon Dioxide as a
greenhouse gas, but is considered less important because the atmospheric
concentrations and the lengths of time the molecules of gas remain in the
atmosphere (residence times) are much smaller. Widespread publicity about
the need to reduce the increase in Methane levels has led to proposals to
monitor (and perhaps control) dump emissions and termite mounds, both of
which produce substantial quantities of Methane. A much more important
source of atmospheric methane may be from the Tundra regions or the deep
sea, where vast quantities of methyl hydrates could be released if oceanic
temperatures rise. If warming tundra or ocean water indeed release large
amounts of Methane, the resulting positive feedback cycle of warming
could be enormous.
•
Other greenhouse gases are Chlorofluorocarbons (CFCs) and Nitrous
Oxide. The relative greenhouse contribution of common greenhouse gases
and their average residence times in the atmosphere are given in the table
below.
GREENHOUSE GASES
CONTRIBUTION TO
GREENHOUSE
CARBON DIOXIDE
60%
METHANE
15%
NITROUS OXIDE
12.5%
CHLOROFLUOROCARBONS
12.5%
RESIDENCE IN
ATMOSPHERE
100-200 YEARS
10 YEARS
150 YEARS
65-130 YEARS
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.3 - WHAT ARE THE CAUSES OF CLIMATE CHANGE?
PART 3 - THE RELATIVE ROLE OF ENVIRONMENTAL AND HUMAN
FACTORS IN RECENT CLIMATE CHANGE
•
As will be seen below, the argument of these notes is that environmental
factors can account for long-term climatic change, e.g. the ice ages and for
short term variations, e.g. the eleven-year cycle of cloudiness. However,
having read the evidence, I am now increasingly convinced that human
factors are the main contributing factor to the medium term climatic change
of global warming since the Industrial Revolution.
•
It seems likely that long-term climatic change is affected by the three
astronomical variables of the eccentricity cycle, the obliquity cycle, and the
precession cycle. Milankovitch’s work in drawing up his “Milankovitch
Cycles” based on these three correlates so well with evidence of Pleistocene
Ice ages based on the results of deep-sea cores as to leave little doubt that the
main causes of glacial periods and inter-glacial periods within the
Pleistocene is astronomical.
•
However, studies of pre-Pleistocene ice ages suggest a close correspondence
between “several million year long” colder periods, e.g. the Pleistocene, and
the concentration of land near the poles; whilst there is an equally close
correspondence between “several million year long” warmer periods, e.g.
the Tertiary, and oceans around the poles.
•
It must be remembered, however, that our knowledge is limited by an
incomplete rock and fossil record. The beginning of the Pleistocene seems to
have followed a period of intense volcanic activity whilst the beginning of
the Tertiary, 64,000,000 years ago, appears to have closely followed the
eruption of the Deccan Traps in India and an asteroid impact in Yucatan.
•
At the other extreme, very short term climatic changes are more likely to be
due to the sunspot cycle, e.g. in my astronomical work I have observed an
eleven-year cycle in cloudiness; whilst short, sharp cold periods may follow
major volcanic eruptions.
•
However, the evidence that our present period of global warming is caused
by human activity is overwhelming. I began preparing this course of work
highly sceptical. That is no longer the case! The close correspondence
between the graphs for increases in greenhouse gas emissions and the graphs
for temperature increases suggests that a correlation exists and, as noted
below, most greenhouse gas emissions are human in origin.
•
Carbon dioxide accounts for 50% of global warming. It can remain in the
atmosphere for up to 200 years. About half of all current greenhouse gas
emissions are from the energy used in heating and lighting, transportation
and manufacturing. Countries with a long history of industrialization have
contributed the majority of the greenhouse gases in the atmosphere, e.g. the
USA produces 27% of the world’s carbon dioxide and Europe produces
24%.
•
In the future, countries currently undergoing industrialisation will account
for a high percentage of greenhouse gas emissions, e.g. China already
produces 11% of the world’s carbon dioxide. Emissions from China, India
and other rapidly developing nations will inevitably increase. Carbon
Dioxide emissions have already gone up from 285 parts per million to 381
parts per million in 2005.
•
Nearly two thirds of carbon dioxide emissions, along with a significant
amount of nitrous oxide and methane, derive from the burning of fossil fuels
such as oil, natural gas and coal. These are burned primarily for electricity,
transportation, heating and cooling, and industrial processes. China, for
instance, depends on coal for over 75% of its total energy, and the decisions
it takes over future power generation will have a major impact on levels of
atmospheric carbon dioxide.
•
Methane is much more efficient at warming the atmosphere than carbon
dioxide, but it is present in much smaller quantities and has a short
atmospheric lifetime. Methane is produced by rice cultivation, coal mining,
energy production and the rearing of livestock. In the industrial world,
landfill sites are a major contributor. It is also produced in the natural
environment, as bacteria break down organic material in anaerobic
conditions.
•
Passenger cars, trucks and air traffic all contribute to greenhouse gas
emissions. Unfortunately, since the late 1950s and early 1960s many
EMDCs have become more committed to road travel and less committed to
rail travel, which is far more fuel efficient. In Britain, a report by Dr
Beeching in the early 1960s, based on profitability alone, resulted in the
closure of half our rail network. The country then went on an orgy of
motorway building so that, by today, almost all containers in the UK are
transported by dirty, polluting trucks - each truck only pulling one container
on average. A railway engine could pull 30 to 40 containers! The situation in
the USA is worse. Transport in the USA produced 1,794,000,000 tonnes of
carbon dioxide in 2003. China produced 270,000,000 tonnes. No other
country produced more than 200,000,000 tonnes. Obviously, heavy
investment in road infrastructure makes this situation difficult to change.
•
Agriculture accounts for 33% of the emissions of greenhouse gases especially methane. Once again the main culprits are the USA and China,
closely followed by Brazil, India, Argentina, Pakistan, France and Australia.
•
However, LEDCs are not guilt free. Forests play an important part in the
carbon cycle, in taking carbon dioxide out of the atmosphere and storing it in
biomass. Farming practices in much of South America, Africa and Asia have
resulted in rapid deforestation, in the burning of forest and in the release of
large amounts of carbon dioxide.
•
Therefore, one can conclude that long term climatic changes, e.g. ice ages,
and short term climatic changes, e.g individual cold years, are environmental
in origin but that the medium term climatic change of global warming is
caused mainly by human factors. Indeed, unless there is a reduction in
greenhouse gas levels or, at least, a reduction in the rate of increase,
global warming could become a long term climatic change.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.4 - WHAT ARE THE ISSUES RESULTING FROM
CLIMATE CHANGE?
PART 1 - CHANGING CLIMATES AND SHIFTING CLIMATIC BELTS AND
THE EFFECT ON BIOMES
•
If climate change is to take the form of global warming, all the climate belts
will shift polewards, to be followed over a longer time period by biomes.
Theoretically, this should advantage some areas and disadvantage others.
•
The Equatorial Climate should extend into areas that now have a Tropical
Continental (wet summer/dry winter) Climate; making their wet summers
longer and their dry winters shorter and, over time, causing the Rainforest
Biome to expand into the Savanna Biome.
•
On the other hand The Tropical Desert Climate should extend into areas that
now have a Warm Temperate Western Margin (Mediterranean or dry
summer/wet winter) Climate; making their dry summers drier and their wet
winters drier and shorter. Indeed there is evidence that this is happening,
with Spain having its worst drought in generations. Over time, this would
cause the Mediterranean Evergreen Forest to be replaced by a Biome of
Desert Annuals and Xerophytes.
•
The effect on Britain, according to theory, would be a drastic change to our
seasons. Traditionally, Britain has depressions and ridges of high pressure
under the polar front in spring. In summer, the polar front shifts to the north
of us, bringing warm , dry, stable Tropical maritime air. In autumn, we have
a repeat of spring weather, with the polar front over us and in winter the
polar front will shift to the south of us allowing cold, dry Polar Continental
air from the North east to cover the country - bringing freezing conditions.
•
The global warming of recent years has already caused a change. Several
times, the polar front has shifted further north in summer giving us very hot,
very dry summers; whilst, in winter the polar front has lingered over us,
giving us mild, wet and windy weather.
•
This change of climate should also cause a shift in the British Biome of
Broadleaf deciduous Forest. However, as little natural forest is left, the
change is best observed in changes in agriculture. Climate change has
caused our “frost free period” to become longer. Therefore, the growing of
crops that require 150 frost free days, e.g. maize, has become commonplace,
whilst the growing of grapes for wine is becoming increasingly common in
Southern England and in Wales - a reminder of the warm period at the end
of the Middle Ages.
•
The disruption of biomes due to climate change is a worldwide
phenomenon. Unprecedented rates of migration by both plant and animal
species will be needed if species are to keep up with climatic change. While
grasslands and deserts can spread fairly quickly, forests may find themselves
outpaced in the race against time. In mountainous regions, some species may
only have to move a few hundred metres up hill to find new terrain, but a
problem arises when those already at the top of a mountain or on the most
northerly landmasses in the Arctic need to move to cooler climates.
•
There are serious concerns about Wales’s arctic alpine flora, e.g. the
Snowdon lilly, as even our highest mountains become too warm for them.
Similar concerns are expressed about Africa’s arctic alpine flora on Mounts
Kenya and Kilimanjaro, where warmer temperatures are melting the
glaciers, endangering the future of all species which depend on glacial
meltwater.
•
In North America there are concerns that climate change may allow non
native species that are destructive to a biome to invade that biome, e.g. the
red fire ant is threatening to destroy native plants in the South East United
States. (This can be a serious problem regardless of climate change , e.g.
Dutch elm disease, grey squirrels in Britain and rabbits in Australia.)
•
In Central America there are concerns that the climate of mountain regions
is becoming drier and hotter. This is endangering over 17,000 species of
plant in the Wet Mountain Forests of the area.
•
In Europe there are twin concerns that a hotter climate is causing more
species to migrate northwards but that the density of human population is
limiting where they can migrate to. A good example can be seen in the
Scottish Crossbill, which is endemic to Scotland, and which may be faced
with a move to Iceland - a journey it would be unlikely to undertake
successfully. As quoted earlier in the notes, 35 European butterfly species
have shifted their ranges north by 20 to 150 miles over the last 100 years.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.4 - WHAT ARE THE ISSUES RESULTING FROM
CLIMATE CHANGE?
PART 2 - INCREASING LEVELS OF EXTREME WEATHER AND THE
IMPACTS ON HUMAN ACTIVITIES.
•
It is extremely difficult to correlate extreme weather and climatic change.
Indeed, the most violent storm to hit the United Kingdom occurred in 1703,
before “global warming” is assumed to have begun. Professor Lamb, one of
Britain’s most famous climatologists, has done a great deal of research into
written records of the “Great Storm”, including both work written by Daniel
Defoe and ships’ logs. It appears that between the 7th and 8th of December
1703 a small, intense secondary depression crossed Mid Wales, the
Midlands, Lincolnshire and the central North Sea. It brought sustained winds
of 80 to 90 miles per hour with gusts of up to 125 miles per hour. 30 percent
of the British merchant navy was lost. 7,500 seamen lost their lives.
Eddystone Lighthouse was swept away. On land, many homes and over 400
windmills were wrecked. We don’t know how many people died on land.
•
The only comparable storm in recent history is the January 1953 storm
which caused disastrous floods. The storm sank the cross channel ferry
Princess Victoria between Larne and Stranraer and then swept across
Northern England and into the North Sea. Here, a rare combination of events
led to disaster - (1) a very high spring tide, (2) very low air pressure making
sea level two metres higher than normal, (3) a very strong north wind
driving seawater southwards, and (4) the peculiar shape of the North Sea very wide in the north and very narrow in the south. Aa a result of these
four, huge areas of East Anglia, North Kent and the delta of the Rhine in
Holland were flooded. 307 English people and over 1800 Dutch people lost
their lives (leading to the Dutch delta scheme). 32,000 were made homeless.
Were it not for the heroic behaviour of some American airmen stationed in
east Anglia, the English death toll would have been much higher. Insurance
losses following the storm, in present day values, were £20,000,000,000.
•
However, there does appear to have been a tendency since the mid 1980s for
fairly severe storms to become more common. The first of these severe
storms hit South east England in October 1987. It is remembered as
“Michael Fish’s hurricane”! It struck on the night of 15-16 October 1987,
and the worst hit area was south east of a line from Dorset to the Wash.
Weather historians believe that this was the most violent wind storm to hit
southern England since 1703. Eighteen people died. The storm struck during
the night. Had it struck during rush hour, the death toll could have been
much higher. Millions of trees were uprooted and damage to property cost
insurance firms, at present day prices, £2,500,000,000.
•
“Michael Fish’s hurricane” was followed fairly closely by the “Burns’ Day
Storm” of 25th January 1990. Widespread structural damage occurred, 47
people died and many high sided vehicles were blown over on the
motorways.
•
Since then most winters have brought fairly severe depressions, though
nothing as severe as the above four. The physics of a causal link between
global warming and storminess is simple. Depressions are formed on the
polar front, where warm south westerly winds meet cold polar north easterly
winds. The temperature of each wind is controlled strongly by the sea over
which it passes. If global warming in making the Atlantic warmer and
melting of Greenland ice is making the Arctic colder, then, theoretically, this
should increase the temperature difference between the winds on either side
of the polar front. This makes the warm air rise more violently over the cold,
making pressure at the surface lower and making the wind stronger and
more stormy.
•
Making a correlation however is difficult. During the twentieth century, the
two stormiest decades were the 1920s and the 1990s, whereas the least
stormy were the 1960s and the 1970s. There is no clear simple pattern.
•
However, there does appear to be a short term climatic pattern, linking
traditional, cold, snowy winters over Britain with normal La Nina conditions
in the Pacific and milder, windier and stormier winters over Britain with El
Nino conditions in the Pacific. El Nino is also linked to stormier conditions
to the South east United States but, on the other hand, is linked to drier,
more stable conditions in the North East United States. It has been
noticeable that El Nino conditions have become more common in the 1980s
and 1990s, two decades where global warming has been noticeable.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.4 - WHAT ARE THE ISSUES RESULTING FROM
CLIMATE CHANGE?
PART 3 - RISING SEA LEVELS AND THEIR IMPACT ON PEOPLE.
•
Warmer temperatures cause oceans to expand, and melting glaciers add to
the volume of water. Both result in rising sea levels. The mean sea level rose
by around 15 centimetres during the 20th century, and projections indicate a
further rise of between 20 and 90 centimetres between 1990 and 2100. Even
if greenhouse gas emissions are radically reduced over the next decades,
because of the huge thermal mass of the oceans the sea level will continue to
rise for centuries - a long term consequence of emissions already released.
•
A rise in sea level of 1 metre, at the upper range of estimates for the next
hundred years, will have drastic consequences for many coastal
communities. The Maldives Islands in the Indian Ocean will be almost
completely inundated, as will large parts of island groups in the Caribbean
and the Pacific. Around the world, valuable agricultural land will be lost,
and cities will be threatened.
•
With stronger windstorms possible, many low-lying communities will be at
risk from storm surges, which can add 5 metres or more to the mean sea
level.
•
Isostatic coastal movement - sinking (e.g. Eastern England) or rising (e.g.
Wales) - also affects the height of the sea relative to the land.
•
The movement of seawater higher up rivers, and into freshwater aquifers,
will affect drinking water supplies across the world, threatening the viability
of many communities.
•
Far more serious sea-level rise is possible. Were the Greenland ice cap to
melt, it would add an estimated 7 metres to the global sea-level. The ice cap
covering West Antarctica rests on rock that is below sea level. Were it to
melt, the sea level might rise by another 5 metres. At present there is only a
low probability that these ice sheets will collapse in the next few centuries.
However, if global warming exceeds 3°C or so, these scenarios become
increasingly likely, with potentially catastrophic consequences around
the world.
•
SOME OF THE IMPACTS OF RISING SEA LEVELS ON PEOPLE.
•
The 200 inhabitants of the Carteret Islands, Papua New Guinea, have
been forced to move to an adjoining island, after their fruit trees were killed
by an increasingly saline water supply, and their homes were washed away
by high tides and storms.
•
Two uninhabited Kiribati Islands disappeared beneath the sea in 1999. The
remaining 33 islands, home to 103,000 people, are likely to suffer the same
fate.
•
Rising seas forced the 100 inhabitants of Tégua, Vanuatu, to abandon their
islands in December 2005.
•
The leaders of Tuvalu, home to 9,000 people, have started making plans for
the eventual evacuation of their island, which is only 3 metres above sealevel. An island in the neighbouring Fiji group is the most likely destination
for the evacuees.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.4 - WHAT ARE THE ISSUES RESULTING FROM
CLIMATE CHANGE?
PART 4 - THE VARIATIONS OF THESE IMPACTS IN DIFFERENT
REGIONS.
•
YOU SHOULD READ THE NOTES BELOW, TAKING INTO
ACCOUNT WHERE THE EFFECTS OF CLIMATE CHANGE ARE
TAKING PLACE, ESPECIALLY THE DIFFERENCE BETWEEN THE
EFFECTS ON LEDCs and MEDCs.
•
Many of the impacts of climate change have already been covered in earlier
notes.(a) Key Question 1.3 - Part 1 - The evidence for climate change.
(b) Key Question 1.4 - Part 1 - Effects on biomes
(c) Key Question 1.4 - Part 3 - The impacts of rising sea-levels on people.
These should be revised as part of Key Question 1.4 - Part 4, together with
the notes below.
•
THREATENED WATER SUPPLIES - Water is a vital resource and is often
taken for granted. With populations increasing in some regions, and a rising
demand for water to irrigate crops throughout the world, water supplies are
already a cause for concern in many countries. It is now apparent that
climate change might make the situation worse, with some areas, e.g. the
American Prairies, probably facing a large decrease in precipitation. Even
some areas that should theoretically face an increase in precipitation, e.g. the
Sahel, may not gain from it, because their precipitation falls in the hot
season and global warming will increase losses by evaporation. Northern
India, with over 500,000,000 people will suffer due to decreased glaciation
in the Himalayas, as many of their irrigation schemes are dependent on
glacial meltwater.
•
FOOD SECURITY - The effects of climate change on agriculture are
complex. Higher temperatures can stress plants, but can also prolong
growing seasons and allow a greater choice of crops to be grown. Higher
concentrations of carbon dioxide speed growth and increase resilience to
water stress. However, pests and diseases may also increase in response to
the more benign climatic conditions. Agriculture is highly adaptable. Crop
calendars can be adjusted to avoid extreme hot periods, new varieties of
plants can tolerate a range of conditions, and good soil management can
overcome water stress. With economic initiatives, world food production
should not be adversely affected by climate change over the next 50 years or
so. Agriculture in temperate climates may actually benefit from longer
growing seasons and warmer temperatures. In parts of the tropical and sub
tropical regions however, reductions in rainfall and increasing risk of
drought, or more intense rainfall and soil erosion, will severely affect
agriculture. The capacity of LEDCs to sustain agricultural production and
food security is already challenged. Most predictions show that the part of
the world likely to suffer worst in its capacity for food production is India,
and India has 20% of the world’s people!
•
HEALTH IMPACT OF CLIMATE CHANGE - Where people are already
vulnerable to disease as a result of poverty and malnutrition, even small
changes in climate may have an effect on health. Warmer temperatures, the
absence of pest-killing sub zero temperatures and increased rainfall all
extend the habitat ranges for diseases and for the insects, rodents and other
organisms that carry them. Climate change will favour the spread of diseases
into previously unaffected areas. More anticyclonic and warmer weather
may increase heat stress and lead to an increase in levels of pollution trapped
in inversions leading to more respiratory disease. However, the worst
problems, and the ones that will hit LEDCs disproportionately hard, are the
increased risk of waterborne diseases following flooding, e.g. cholera,
typhoid and dysentery; and of mosquito borne diseases, e.g. malaria and
yellow fever. The United Nations measure the effect of disease in DALYs
(disability adjusted life years, i.e the number of years of potential
productive life lost due to premature death or premature disability). A survey
in the year 2000 of the health impact of climate change showed Southeast
Asia with 2.5 million DALYs and Africa with 1.9 million, whereas the
MEDCs had only 0.008 million DALYs.
•
CITIES AT RISK - Many world cities, in both LEDCs and MEDCs, are
built dangerously close to sea level. EXAMPLES; (1) New York:- Without
extensive adaptation efforts, a sea level rise of 1 metre would not only
inundate coastal areas but, coupled with storm surges, would have a
devastating impact on the subway system, sanitation facilities, power plants
and factories. (2) New Orleans:- The effect of a powerful hurricane on a
low lying city was demonstrated by Hurricane Katrina in August 2005. The
storm surge it created flooded large areas of New Orleans and caused
damage valued at over $50,000,000,000. Such hurricanes are expected to
become more common with global warming. (3) London:- London is
protected from particularly high tides and storm surges by the Thames
Barrier, but more frequent storms and the pressure of rising sea-level
increases the risk to the city. (4) Lagos:- Lagos is built on low-lying marshy
ground. Subsidence, coastal erosion, flooding and salinization are already a
problem. These will all be made worse by global warming and a rise in sea
level. (5) Mumbai (Bombay):- A 1 metre rise in sea level would drown
60% of the city of Mumbai - home to 22,600,000 people and India’s most
populous city.
•
THREATENED HERITAGE - Climate change is threatening parts of the
world’s cultural and historical heritage, but the possible loss or damage to
these irreplacable sites is rarely represented in economic estimates of the
cost of climate change. In the Arctic indigenous peoples, e.g the Inuit, will
find it increasingly difficult to maintain traditional hunting and fishing skills
if the sea-ice melts, affecting seal and polar bear populations. A northward
shift in vegetation zones will also take with it their other traditional food
source, the tundra grazing caribou and reindeer. On the Great Barrier Reef
of Australia, as already mentioned, the reef has suffered “bleaching” due to
high water temperatures, and will suffer further if ocean temperatures rise as
predicted. In Boston, USA the combintion of sea-level rise and coastal
storms could increase the height of flooding on the Charles River and
inundate some famous historical sites of Boston. In Scotland, UK a survey
found 600 sites of exceptional archaeological importance at risk from coastal
erosion due to sea-level rise. In the Czech Republic flooding in 2002
damaged concert halls, theatres, museums and libraries. An estimated half a
million books were damaged. Climate change is likely to bring more such
flooding. The monuments of Alexandria, Egypt,including the 15th century
Qait Bey Citadel, are threatened by coastal erosion and the inundation of the
Nile Delta region, caused by sea-level rise. The structural integrity of many
buildings in Venice, Italy is being damaged by frequent flooding. St Mark’s
Square floods about 50 times more frequently than it did in the early 1900s.
This is caused by a combination of land subsidence and sea-level rise.
Severe flooding currently threatens historical sites in Northeastern
Thailand. Floods have already damaged the 600 year old ruins of Sukothai,
the country’s first capital. Finally, Mount Everest is threatened. When Sir
Edmund Hillary returned to Everest in 2003, he remarked that, whereas in
1953 snow and ice had reached all the way to base camp, it now ended five
miles away. Local people are worried that if Everest loses its natural beauty,
tourists will stay away, destroying local livelihoods.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTION 1.4 - WHAT ARE THE ISSUES RESULTING FROM
CLIMATE CHANGE?
PART 5 - THE IMPACTS OF CLIMATE CHANGE ON SOCIETY.
•
AN INVESTIGATION INTO THE EFFECTS OF CLIMATE CHANGE
UPON ANY HUMAN SOCIETY OF YOUR CHOICE. (The syllabus
suggests The Inuit (Eskimoes) as an example, but you may choose your own
example.)
•
1. Choose a society that you wish to investigate - it could be anything from
The Inuit of Northern Canada to the modern western society of Australia.
•
2. Formulate an hypothesis, e.g. “The Lapps of Northern Finland will see
their way of life changed due to climate change.”
•
3. Decide what data you need to collect and where you will get it from. The
internet is normally a very good source. You only need secondary data. You
do not need to collect primary data. (You must do your own research. The
teacher is not to do it for you).
•
4. Collect your data and tabulate it neatly. Data may be numerical or written.
•
5. Analyse the data using a variety of the graphical, mapping and statistical
methods listed in the introductory notes to the syllabus. Marks will be
allocated for skill, relevance and variety. Graphs, maps and statistics should
be annotated with detailed analysis, linking them to your hypothesis. (The
teacher is allowed to help if a student asks for guidance with a particular
graphical, mapping or statistical method.)
•
•
6. You are now ready to write up your investigation.
(a) Introduction - Justify why you chose your society and your hypothesis.
State the hypothsis.
(b) Method - The story of the investigation. May include maps, photos etc.
(c) Tabulated data (see 4 above)
(d) Analysis (see 5 above)
(e) Interpretation and Conclusion.
(f) Evaluation
(g) Acknowledgements and bibliography
•
•
•
•
•
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 1 - INTRODUCTION
•
The challenges of mitigating and adapting to climate change are
unprecedented, but not insurmountable. For mitigation and adaptation to be
sustainable, they must meet two targets - (a) international co-operation to
reduce greenhouse gas emissions to safer levels, and, (b) to facilitate
adaptation among those least able to protect themselves from the impact of
climate change.
•
Negotiations over climate change responses recognised a complex pattern of
causes, relative contributions to the problem, ability to contribute to
solutions, potential for benefits and losses, and irreversible changes. This
complexity, combined with political differences between countries, meant
that dialogue to develop and ratify the Kyoto Protocol did not move
quickly.
•
What is the Kyoto Potocol? - The Kyoto Protocol is an agreement reached
by the countries that attended the United Nations Framework Convention on
Climate Change, at Kyoto, Japan, in 1997. It contains agreements between a
group of countries (called the Annex 1 Countries) to reduce greenhouse gas
emissions; a smaller sub group (called the Annex B Countries) agreening to
a reduction by at least 5% below 1990 levels between 2008 and 2012. This
would mean a reduction of around 55% for most Annex 1 countries. Most,
but not all, other countries agreed to reduce emissions to 1990 levels by
2000.
•
While most nations have signed such international agreements, they are also
faced with forging agreements at home. Meeting reduction targets requires
the involvement of local government, small businesses, corporations, and
civil organisations; even religious organisations are taking a strong stand to
reduce emissions. In nations that have not committed to the Kyoto Protocol,
such as the USA and Australia, municipalities and companies have
organised to reduce emissions and are challenging their national leaders.
•
The relationship between emissions and economic growth is not inevitable.
The greater diversity of renewable energy technologies in recent years opens
more opportunities for energy consumption with low emissions. For LEDCs,
investing early in a less carbon dependent infrastructure offers the potential
for long term savings.
•
Many companies have demonstrated the cost effectiveness of reducing
energy use, switching fuels and controlling greenhouse gas emissions. Yet,
not all technological adjustments will be easy. Decades of investment in
road transportation and private vehicles has created a path dependence that
will be expensive to alter. Carbon trading and international aid help, but they
do not reduce emissions on their own.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 2 - INTERNATIONAL ACTION
•
The UN Framework Convention on Climate Change (UNFCCC) aims to
stabilise greenhouse gas emissions “at a level that would prevent dangerous
anthropogenic (human-induced) interference with the climate system”.
•
This level should be achieved within a time-frame that allows ecosystems to
adapt to climate change, ensures that food production is not threatened, and
enables economic development to proceed in a “sustainable manner”.
Agreed in Rio in June 2002, the Convention came into force in March 1994.
•
The Convention places the initial onus on the MEDCs and on economies in
transition to reduce their emissions, and to finance LEDCs’ search for
strategies to limit their own emissions in ways that will not hinder their
economic progress.
•
The Convention is a flexible framework, clearly recognising there is a
problem. The first addition to the treaty, the Kyoto Protocol, set targets for
reductions in emissions. Adopted in 1997, it came into force in February
2005. The USA and Australia have signed the Convention but not the
Protocol, creating uncertainty around the next steps.
•
Climate change continues to be high on the international agenda, but there is
still much disagreement as to what to do, when and by whom. Conflict over
relative responsibilities for reducing emissions and funding adaptation
continue to slow down negotiations.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 3 -MEETING KYOTO TARGETS
•
THESE NOTES SHOULD BE READ ALONGSIDE THE COLOURED
DIAGRAM - MEETING KYOTO TARGETS
•
In February 2005, seven years after the Kyoto Protocol was negotiated, the
commitments agreed became legally binding, after countries representing at
least 55% of greenhouse gas emissions by MEDCs had ratified the Protocol.
•
Although the Protocol had been ratified by over 160 countries by April
2006, only the Annex 1 countries - those already industrialised or whose
economies were considered to be in transition by 1997 - had been set targets
under the Protocol. This is because they have been been emitting greenhouse
gases into the atmosphere for a long period of time and are considered able
to afford reductions. These countries are committed to reducing their
greenhouse gas emissions by a combined average of 5.2% below their 1990
levels by a target date between 2008 and 2012.
•
Under the Protocol, the industrialised countries were to have made
“demonstrable progress” by 2005. Some are making progress towards their
goals, while others have actually increased their emissions. The refusal of
the USA and Australia to ratify the Protocol means that more than 40% of
current emissions by Annex 1 countries are not covered under this
agreement.
•
The reductions under the Kyoto Protocol are considered a first step, as EU
Environment Ministers recommend that reductions of between 60% and
80% by 2050 will be needed to avert some of the more serious consequences
of climate change, e.g. considerable sea level change. As a result of
agreements reached in Montreal at the end of 2005, a working group was
established to start discussing commitments to reductions after 2012.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 4 -CARBON TRADING
•
Under the Kyoto Protocol, countries required to reduce their emissions are
entitled to purchase “carbon credits” from ELDCs or from EMDCs whose
emissions are below the level required. The credits cover emissions of all
greenhouse gases, expressed as “carbon dioxide equivalents”. The trade in
carbon credits is intended to encourage investment in energy efficiency,
renewable energy and other ways of reducing emissions.
•
Many MEDCs have devolved this responsibility on to the commercial
organisations that are creating the greenhouse gases, and much of the trade
therefore takes place at a company level. Carbon markets facilitate the trade
and there are two main types: (a) project based markets, and (b) allowance
based markets.
•
(a) Project-based markets - Buyers invest in projects or companies where
there is a commitment to use the money to reduce greenhouse gas emissions,
compared to what would have happened without the investment. Buyers are
awarded carbon credits in exchange, which they can use to meet targets,
such as those set by the Kyoto Protocol. Examples of such projects - (a) In
Honduras a 12.7 megawatt hydroelectric plant, powered by river run-off, has
been supported by the sale of 310,000 tonnes of Carbon Dioxide emissions,
through the World Bank’s Community Development Carbon Fund. (b) In
Colombia 15 wind turbines have been funded to provide power for the
indigenous Wayuu people. The wind turbines will save more than 1.1
million tonnes of carbon Dioxide over 21 years, compared with emissions
from fossil fuel power stations.
•
(b) Allowance-based exchange - Allowance based markets enable
companies to offset their emissions by purchasing credits from countries that
either have no limit placed on their emissions, or have kept their emissions
below the level required. Trade has grown rapidly since 2003, boosted by
the opening of the EU Emissions Trading Scheme in January 2005. Schemes
are also operating in Australia, Canada and the USA, including the Chicago
Climate Exchange, established by a number of large corporations and by the
World Resources Institute.
•
Carbon markets still account for less than 0.5% of annual global greenhouse
gas emissions. They have also been criticised by environmentalists for
including unsustainable projects such as single-species plantations, large
hydroelectric dams and oil and coal production.
•
Nevertheless, carbon trading is an increasingly important element in
international efforts to slow climate change. An encouraging sign is that
markets have been set up in Australia and the USA to facilitate emissions
reduction, even though these two countries have not adopted the Protocol.
Placing a price on greenhouse gas emissions encourages innovation to
reduce them.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 5 -FINANCING THE RESPONSE
•
LEDCs need money to help them meet the challenges of climate change. Aid
from the MEDCs is distributed through the Global Environment Facility
(GEF). Countries were initially helped to assess their emissions, but the
focus in now on reducing emissions and on adapting to change
•
Aid is also given by the private sector. Companies investing in LEDCs are
taking stock of the risks and are working out how to protect the value of
their investments by minimising the impact of climate change.
•
Examples of Projects Supported by Aid - (a) $13,600,000 has been
donated as part of a rural electrification programme in Argentina; solar cells,
wind farms and small hydroelectric schemes are being used in place of
diesel generators, to supply electricity to 130,000 rural households. (b)
$1,700,000 has been invested in research into the impact of greenhouse gas
levels on natural disasters in China. (c) $7,000,000 has been donated to India
to help them adopt more energy efficient and environmentally friendly
technologies in steel mills.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 6 -LOCAL COMMITMENT
•
Cities around the world, are not waiting for national governments to debate
the implementation of the Climate Change Convention. They have signed
their own commitment to reducing greenhouse gas emissions, as part of the
campaign “Cities for Climate Protection”(CCP).
•
The campaign, established in 1993 by the International Council for Local
Environmental Initiatives, has engaged over 670 local and city governments,
which between them are responsible for an estimated 8% of the world’s
carbon dioxide emissions.
•
In the USA, which has not signed the Kyoto Protocol, concern has led to
local and regional action. Mayors issued a statement in 2003, urging the
national government to slow the rate of global warming. In February 2005,
as the Kyoto Protocol came into effect, the mayor of Seattle issued a Climate
Protection Agreement, pledging to curb greenhouse gas emissions at a local
level. The agreement was endorsed by the US Congress of Mayors and by
May 2006, 230 mayors had signed up.
•
Cities participating in Finland represent almost 50% of the local population.
•
Rome, as a CCP participant, is working to reduce greenhouse gas emissions
by greening the municipal fleet of cars, trucks and other vehicles.
•
At Hyderabad, in India, traffic flow is being improved in order to reduce the
amount of time vehicles spend on the road.
•
At Rayong, in Thailand, a biogas facility has been installed to handle
municipal waste and to provide an alternative fuel source.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 7 -WHAT CAN INDIVIDUALS DO?
•
AN INVESTIGATION INTO WHAT INDIVIDUAL PEOPLE OR
SMALL PRESSURE GROUPS CAN DO TO ADDRESS CLIMATE
CHANGE.
•
1. Formulate an hypothesis, e.g. “I as an individual can affect climate
change” or “Small pressure groups such as “Carbon Neutral Newcastle” can
affect climate change”.
•
2. Decide what data you need to collect and where you will get it from. The
internet is normally a very good source. You only need secondary data. You
do not need to collect primary data. (You must do your own research. The
teacher is not to do it for you).
•
3. Collect your data and tabulate it neatly. Data may be numerical or written.
•
4. Analyse the data using a variety of the graphical, mapping and statistical
methods listed in the introductory notes to the syllabus. Marks will be
allocated for skill, relevance and variety. Graphs, maps and statistics should
be annotated with detailed analysis, linking them to your hypothesis. (The
teacher is allowed to help if a student asks for guidance with a particular
graphical, mapping or statistical method.)
•
•
•
•
•
•
•
•
5. You are now ready to write up your investigation.
(a) Introduction - Justify why you chose your hypothesis. State the
hypothesis.
(b) Method - The story of the investigation. May include maps, photos etc.
(c) Tabulated data (see 3 above)
(d) Analysis (see 4 above)
(e) Interpretation and Conclusion.
(f) Evaluation
(g) Acknowledgements and bibliography.
GEOGRAPHY UNIT G1 - CHANGING PHYSICAL ENVIRONMENTS
THEME 1 - INVESTIGATING CLIMATE CHANGE
KEY QUESTIONS 1.5 & 1.6 - WHAT STRATEGIES CAN BE USED TO
ADDRESS CLIMATE CHANGE? & HOW SUCCESSFUL HAVE
STRATEGIES BEEN IN TACKLING CLIMATE CHANGE?
PART 8 -BRITISH GOVERNMENT ACTION
•
In 1994 the then Conservative government published “Climate Change: The
UK Programme”. This set out proposals to combat climate change. The main
one of these was to set a carbon tax. It was intended to tax energy at 17.5%,
but the government bowed to public pressure and lowered this to 8%. (The
following Labour government lowered it further to 5% in 2005.) It also
emphasised a gradual switch from coal and oil to natural gas in power
stations - gas being more “greenhouse friendly”.
•
The new Labour government, post 1997, published a second “Climate
Change: The UK Programme”.It affirmed Britain’s support for the Kyoto
Protocol and set two goals; (a) to reduce greenhouse gas emissions to 12.5%
below 1990 levels by 2008-12; and (b) to reduce carbon dioxide emissions
by 20% by 2010.
•
Both the above face the problem that Britain is highly dependent on
electricity from coal and oil fired power stations. These, and our nuclear
power stations, are nearing their active life; and there have been serious
delays in deciding how they will be replaced.
•
In 2003 the government produced a white paper on energy recognising the
conflicting themes of: (a) the need to keep energy flowing; and (b) the need
to reduce greenhouse gas emissions. However, it avoided the simple answer
of building more nuclear power stations.
•
In 2005 the UK learned community held a symposium; “Challenges and
Solutions: UK Energy to 2050”. They advised the government of the urgent
need for a new generation of nuclear power stations, (the existing ones, e.g.
Wylfa, coming to the end of their active lives).
•
Within a month, Prime Minister Tony Blair announced an energy review on
whether the UK should embark on a new nuclear programme, and it is likely
that we shall see such a programme, possibly including a Wylfa B.
At around the same time, the government launched a consultation in
December 2005 on “Proposals for Introducing a Code For Sustainable
Homes”. This has resulted in every home sold on the market having to have
an assessment produced of its level of insulation, e.g. double glazing, cavity
wall insulation, lagging in the attic, lagging of immersion heaters etc. It has
also resulted in some local authorities giving generous grants for home
insulation.
•
•
All this has been complicated by the recession of 2008; where a combination
of serious incompetence by senior bankers in the USA and rapid increases in
the prices of food and fuel (e.g. a bag of anthracite coal went up in price
from £12 in August 2008 to £17 in October 2008) have led to a collapse of
the stock exchange, a massive reduction of disposable income, a decrease in
trade and an increase in unemployment. This could have a two edged effect
on the country’s “carbon footprint” On the one hand, increases in the prices
of all fuels may reduce fuel consumption, increase fuel saving measures
such as car pools and the use of public transport and make home insulation
more desirable. On the other hand, unemployment and less disposable
income may make people less likely to spend money insulating their homes
and, the government (worried about its own popularity) may well take the
easy option of keeping electricity flowing by building the (relatively
cheaper) coal fired power stations, rather than the (more expensive) nuclear
or renewable power stations.