Section A: The Physical Environment
1.1(a, b)
Location of Pakistan:
Coordinates: between latitudes 24 deg 35’ north and 37 deg 05’ north. Longitude 61 deg east to 78
deg east
Total area is 796,096 km stretching over 1600km from north to south and 885 km from east to
west. In the north-east, Pakistan has a common border with China(585km) and the Durand line
border with Afghanistan in the west(2252 km). To the north-west, Wakhan is the narrow strip
separating Pakistan from Tajikistan. South-west border with Iran, Arabian sea at southern border,
and India at east.
Importance of Pakistan’s location:
Pakistan enjoys a key position in South Asia with few land links to the north and north-west due to
the mountain ranges, but, the Khyber Pass provides route to Afghanistan and the Karakoram
Highway to China. The areas in north and north-west are landlocked so served by the seaports of
Karachi and Gwadar. Its coast provides routes for trade with South Asia, Far East, Middle East to
the west. Some air routes pass through Pakistan because of its central position. The Jinnah
Terminal can be of immense importance as an international airport but greatly under-used with
Dubai taking over Karachi’s natural role. After the breaking up of USSR in 1991, it was discovered
that the states possess untapped mineral resources. Pipelines could be constructed which could
bring enormous economic benefits such as transit revenue, power resource for various industrial,
commercial and domestic uses etc. China has emerged as a trading giant recently and Pakistan
being its neighbor has increased trade. The inflow of Chinese goods to Pakistan has increased
competition with our domestic industry.
Climatic zones:
Humid subtropical(Highland climate):
North, North Western, Western highlands. Winters are long and snowy and the summers remain
short. In the mountains, rainfall is associated with altitude. The height of the Northern Mountain
ranges from 2000m to above 8000m while in the Western Mountains it is over 4000m. Rainfall is
highest in Northern mountains while Western experience less rainfall. The temperature conditions
also vary from north to west depending on altitude. Summers are short, mild and wet in the
Northern but dry and warm in the Western.
Mediterranean(Lowland Climate):
The whole Indus plain except the coastal areas. It has arid and extreme climate with hot summers,
cool winters and summer monsoon rainfall. The amount of rainfall differs from north to south. The
foothills of the Northern Mountains and Potwar Plateau are wetter than the Indus plain, and also
receive rainfall from Western depressions. Thunderstorms are also common in north and north-
west of Indus plain. The southern Upper Indus Plain and the whole of the Lower Indus Plain have
much less rainfall and spels of very high temperature.
Temperate(Coastal climate):
Southern coastal strip: Indus Delta, Karachi and Makran coast. The climate is dominated by sea
breezes throughout the year. The maritime influence keeps the daily temperature range low. The
,influence of the sea is mainly felt through the prevailing winds. The land and sea heat up and lose
heat at different rates, the land is much faster at both. The humidity level is moderately high more
than 50% from April to September. Mean temperature is 32 deg C and May, June and October are
the hottest month. During October, dry winds from the south-eastern desert dominate the climate.
Rainfall is scanty, Karachi up to the Ran of Kutch faces most rainfall during monsoon while Makran
coast has its rainfall in winters.
Desert(Arid Climate):
South-western Balochistan and the south-eastern desert. It is markedly dry and hot. Hot dusty
winds prevail continuously from mid-May to mid-September. Scanty rainfall in winter in south-
western Balochistan while in summer monsoon in south-eastern desert. Main features are extreme
heat, dryness and dust storms.
Nature and causes of seasonal variations in temperature:
Large spread of latitude from 24 deg N to 37 deg N and the diversity of relief ranging from high
mountains to low lying coastal areas are the main factors of variations.
The upper and lower Indus plain heat up during summer with max temperature of 40-45 deg C
Jacobabad in the lower Indus plain is know as the ‘thermal pole’ of Pakistan with a max temp of 53
deg C in June and mean monthly temperature of 43 deg C in May and June.
Latitudinal affect:
The areas closer to the equator receive relatively direct rays of the sun resulting in high
temperatures like the Southern Pakistan.
Continental effect:
High temperatures in areas unaffected by maritime influence(influence of the sea on temperatures
as along coastal areas ocean currents and prevailing winds usually have a moderating effect on
temperatures). This results in extreme winter and summer temperatures in those areas.
Altitude and temperature:
There is a relationship between altitude, air density and temperature. The water vapors, dust
particles and solar radiation cause the air above the sea to be the densest while it is the least
dense at high altitude with less solar radiation. As there is less air to absorb heat at a higher
altitude the temperature increases by about 6.5 deg C every 1000 meters increase in altitude
Cloud cover and temperature:
Cloud cover reduces the amount of incoming solar radiation during daytime and traps outgoing
heat in night resulting in lower temperature drops during night and lower temperature gain during
daytime.
Latitude and angle of the sun:
Angle of the sun means the position of sun in relation to the Earth. Sun rays do not fall evenly on
every part of the Earth. The areas with a more direct and shorter path to the sun receive more heat
while areas such as the north pole and south receive less heat due to the low angle of the sun.
The nature and causes of seasonal variations in rainfall:
,Monsoon Winds:
Seasonal winds which blow during summer called south-west monsoon and winters ones are called
north-east monsoon. South-west monsoon are giant sea breezes that bring heavy rainfall. The
summer sun heats up the land much quicker than the sea and the over land war air creates low
pressure absorbing moist, cool air from the sea, and rain-bearing winds gradually push farther
inland bringing heavy rainfall.
North-east monsoon are mostly dry land breezes and bring no significant change as they originate
in a dry area.
Southwest monsoon blows from Bay of Bengal, Indian ocean and the Arabian sea. The winds
normally start to blow in June and cause heavy rainfall in Northern Punjab in July from the Bay of
Bengal winds whose tail winds enters northern Pakistan. Karachi and the coastal areas of Sindh
receives heavy rainfall from an occasionally over-active monsoon system from the Arabian Sea.
Western Depressions:
Cyclones originated in the Mediterranean sea, which travel across Afghanistan then Iran and then
reach the western Pakistan. After north-western areas such as Peshawar and northern Pakistan, the
winds move towards western and south-western parts and by the time they reach Balochistan they
are robbed of their moisture. These winds cause rainfall in these areas from December to March.
For e.g. Quetta received most of its rainfall in winter.
Convectional currents:
At the start of summer, hot air rises containing moisture and condenses after reaching high
altitude causing rainfall, often thunderstorms. Only northern and north-western Pakistan receive
rainfall from it. Southern Pakistan doesn’t because of the temperature inversion layer(criss-cross
system of warm winds at height of 1600m preventing condensation to occur) which is why like
Karachi do not receive rainfall from convection currents.
Relief rainfall:
Related to the altitude, as moist air rises up, heavy condensation occurs, on the windward side.
While the lee slopes tend to receive sinking warming air, and a dry rainshadow area may lie
leewards of the barrier.
Areas like Murree and Kakul receive most of its rainfall due to relief.
, Tropical cyclones:
Originate in the Arabian sea, rarely reach the coast of Pakistan, bring heavy rainfall with
destructive winds.
Effectiveness of rainfall:
Pakistan mostly receives its rainfall from monsoon winds and western depressions which are
variable in amount, timings and distribution. High temperature from June to September results in
great evapotranspiration and limits its usefulness. Monsoon rains comes in heavy showers which is
not very useful for the crops as the land doesn’t absorb the rainwater. Most of it drains into rivers
causing floods. However reservoirs may help to store it. The variable nature of monsoon rainfall
makes crop planning difficult. Only a tiny part of Potwar plateau has canal irrigation, rest of it is
barani land because of the impracticability of lifting irrigation water up to the flat plateau and
irrigation heavily eroded badlands. The winter rainfall comes in light showers making it more
effective for farmers that continue for several days. However its amount isn’t enough. Generally,
the rainfall in Pakistan is neither dependable nor enough in quantity which is why most farms
depend on irrigation system. However, a number of rainfed or barani farms exist in northern Punjab
and Potwar plateau where irrigation is difficult.
1.1(c)
PAKISTAN’S ECOREGIONS:
(1)Himalayan subtropical pine forest
(a)Starts in Pakistan, enters Nepal and India.
(b)Flora and Fauna: Pine trees, Chir, tigers, leopards.
(c)Part of the Tropical and Subtropical Coniferous Forest Biome.
(d)Eastern parts receive more rainfall from monsoon rains.
(2)Indus Valley Desert Biome
(a)Sindh- Sagar Doab
(b)Desert Climate
(c)Shrubs and Bushes for vegetation
(d)Nomadic lifestyle(e)Camels are found here
( f ) D e fi c i e n c y o f w a t e r
(g)Sand dunes
(h)Indian Leopards, hyenas
AD
(3)Indus River Delta
(a)Defi ned by mangrove trees(mangrove biome)
(b)Located on sindh coast
(c)100-500mm rain annually.
(d)Summer temperatures up to 50℃
(e)Mangrove trees are dominant due to salt water
(f)Extensive irrigation
(g)Pollution
(h)a fan-shaped delta forms an extensive system of swamps, mudflats, creeks, estuaries, marshes
and mangroves forests.
(i)critical habitat for numerous species of fishes and shellfishes, especially as a spawning ground
and nursery for the larvae and juveniles.
(j)Near freezing in winters
(k)Mangrove vegetation, in general, is not as biologically diverse as other terrestrial broadleaf
forests. But they are structurally quite complex, with a dense canopy and an undergrowth of
seedlings and saplings from the canopy trees. Mangrove trees have unique adaptations to grow in
the saline and anoxic soils. They have evolved a root system where some roots, called
pneumatophores, grow upwards and out of the water instead of into the soil, and are able to take
up oxygen from the air. Other roots that grow from higher up along the trunk act as prop roots to
1.1(a, b)
Location of Pakistan:
Coordinates: between latitudes 24 deg 35’ north and 37 deg 05’ north. Longitude 61 deg east to 78
deg east
Total area is 796,096 km stretching over 1600km from north to south and 885 km from east to
west. In the north-east, Pakistan has a common border with China(585km) and the Durand line
border with Afghanistan in the west(2252 km). To the north-west, Wakhan is the narrow strip
separating Pakistan from Tajikistan. South-west border with Iran, Arabian sea at southern border,
and India at east.
Importance of Pakistan’s location:
Pakistan enjoys a key position in South Asia with few land links to the north and north-west due to
the mountain ranges, but, the Khyber Pass provides route to Afghanistan and the Karakoram
Highway to China. The areas in north and north-west are landlocked so served by the seaports of
Karachi and Gwadar. Its coast provides routes for trade with South Asia, Far East, Middle East to
the west. Some air routes pass through Pakistan because of its central position. The Jinnah
Terminal can be of immense importance as an international airport but greatly under-used with
Dubai taking over Karachi’s natural role. After the breaking up of USSR in 1991, it was discovered
that the states possess untapped mineral resources. Pipelines could be constructed which could
bring enormous economic benefits such as transit revenue, power resource for various industrial,
commercial and domestic uses etc. China has emerged as a trading giant recently and Pakistan
being its neighbor has increased trade. The inflow of Chinese goods to Pakistan has increased
competition with our domestic industry.
Climatic zones:
Humid subtropical(Highland climate):
North, North Western, Western highlands. Winters are long and snowy and the summers remain
short. In the mountains, rainfall is associated with altitude. The height of the Northern Mountain
ranges from 2000m to above 8000m while in the Western Mountains it is over 4000m. Rainfall is
highest in Northern mountains while Western experience less rainfall. The temperature conditions
also vary from north to west depending on altitude. Summers are short, mild and wet in the
Northern but dry and warm in the Western.
Mediterranean(Lowland Climate):
The whole Indus plain except the coastal areas. It has arid and extreme climate with hot summers,
cool winters and summer monsoon rainfall. The amount of rainfall differs from north to south. The
foothills of the Northern Mountains and Potwar Plateau are wetter than the Indus plain, and also
receive rainfall from Western depressions. Thunderstorms are also common in north and north-
west of Indus plain. The southern Upper Indus Plain and the whole of the Lower Indus Plain have
much less rainfall and spels of very high temperature.
Temperate(Coastal climate):
Southern coastal strip: Indus Delta, Karachi and Makran coast. The climate is dominated by sea
breezes throughout the year. The maritime influence keeps the daily temperature range low. The
,influence of the sea is mainly felt through the prevailing winds. The land and sea heat up and lose
heat at different rates, the land is much faster at both. The humidity level is moderately high more
than 50% from April to September. Mean temperature is 32 deg C and May, June and October are
the hottest month. During October, dry winds from the south-eastern desert dominate the climate.
Rainfall is scanty, Karachi up to the Ran of Kutch faces most rainfall during monsoon while Makran
coast has its rainfall in winters.
Desert(Arid Climate):
South-western Balochistan and the south-eastern desert. It is markedly dry and hot. Hot dusty
winds prevail continuously from mid-May to mid-September. Scanty rainfall in winter in south-
western Balochistan while in summer monsoon in south-eastern desert. Main features are extreme
heat, dryness and dust storms.
Nature and causes of seasonal variations in temperature:
Large spread of latitude from 24 deg N to 37 deg N and the diversity of relief ranging from high
mountains to low lying coastal areas are the main factors of variations.
The upper and lower Indus plain heat up during summer with max temperature of 40-45 deg C
Jacobabad in the lower Indus plain is know as the ‘thermal pole’ of Pakistan with a max temp of 53
deg C in June and mean monthly temperature of 43 deg C in May and June.
Latitudinal affect:
The areas closer to the equator receive relatively direct rays of the sun resulting in high
temperatures like the Southern Pakistan.
Continental effect:
High temperatures in areas unaffected by maritime influence(influence of the sea on temperatures
as along coastal areas ocean currents and prevailing winds usually have a moderating effect on
temperatures). This results in extreme winter and summer temperatures in those areas.
Altitude and temperature:
There is a relationship between altitude, air density and temperature. The water vapors, dust
particles and solar radiation cause the air above the sea to be the densest while it is the least
dense at high altitude with less solar radiation. As there is less air to absorb heat at a higher
altitude the temperature increases by about 6.5 deg C every 1000 meters increase in altitude
Cloud cover and temperature:
Cloud cover reduces the amount of incoming solar radiation during daytime and traps outgoing
heat in night resulting in lower temperature drops during night and lower temperature gain during
daytime.
Latitude and angle of the sun:
Angle of the sun means the position of sun in relation to the Earth. Sun rays do not fall evenly on
every part of the Earth. The areas with a more direct and shorter path to the sun receive more heat
while areas such as the north pole and south receive less heat due to the low angle of the sun.
The nature and causes of seasonal variations in rainfall:
,Monsoon Winds:
Seasonal winds which blow during summer called south-west monsoon and winters ones are called
north-east monsoon. South-west monsoon are giant sea breezes that bring heavy rainfall. The
summer sun heats up the land much quicker than the sea and the over land war air creates low
pressure absorbing moist, cool air from the sea, and rain-bearing winds gradually push farther
inland bringing heavy rainfall.
North-east monsoon are mostly dry land breezes and bring no significant change as they originate
in a dry area.
Southwest monsoon blows from Bay of Bengal, Indian ocean and the Arabian sea. The winds
normally start to blow in June and cause heavy rainfall in Northern Punjab in July from the Bay of
Bengal winds whose tail winds enters northern Pakistan. Karachi and the coastal areas of Sindh
receives heavy rainfall from an occasionally over-active monsoon system from the Arabian Sea.
Western Depressions:
Cyclones originated in the Mediterranean sea, which travel across Afghanistan then Iran and then
reach the western Pakistan. After north-western areas such as Peshawar and northern Pakistan, the
winds move towards western and south-western parts and by the time they reach Balochistan they
are robbed of their moisture. These winds cause rainfall in these areas from December to March.
For e.g. Quetta received most of its rainfall in winter.
Convectional currents:
At the start of summer, hot air rises containing moisture and condenses after reaching high
altitude causing rainfall, often thunderstorms. Only northern and north-western Pakistan receive
rainfall from it. Southern Pakistan doesn’t because of the temperature inversion layer(criss-cross
system of warm winds at height of 1600m preventing condensation to occur) which is why like
Karachi do not receive rainfall from convection currents.
Relief rainfall:
Related to the altitude, as moist air rises up, heavy condensation occurs, on the windward side.
While the lee slopes tend to receive sinking warming air, and a dry rainshadow area may lie
leewards of the barrier.
Areas like Murree and Kakul receive most of its rainfall due to relief.
, Tropical cyclones:
Originate in the Arabian sea, rarely reach the coast of Pakistan, bring heavy rainfall with
destructive winds.
Effectiveness of rainfall:
Pakistan mostly receives its rainfall from monsoon winds and western depressions which are
variable in amount, timings and distribution. High temperature from June to September results in
great evapotranspiration and limits its usefulness. Monsoon rains comes in heavy showers which is
not very useful for the crops as the land doesn’t absorb the rainwater. Most of it drains into rivers
causing floods. However reservoirs may help to store it. The variable nature of monsoon rainfall
makes crop planning difficult. Only a tiny part of Potwar plateau has canal irrigation, rest of it is
barani land because of the impracticability of lifting irrigation water up to the flat plateau and
irrigation heavily eroded badlands. The winter rainfall comes in light showers making it more
effective for farmers that continue for several days. However its amount isn’t enough. Generally,
the rainfall in Pakistan is neither dependable nor enough in quantity which is why most farms
depend on irrigation system. However, a number of rainfed or barani farms exist in northern Punjab
and Potwar plateau where irrigation is difficult.
1.1(c)
PAKISTAN’S ECOREGIONS:
(1)Himalayan subtropical pine forest
(a)Starts in Pakistan, enters Nepal and India.
(b)Flora and Fauna: Pine trees, Chir, tigers, leopards.
(c)Part of the Tropical and Subtropical Coniferous Forest Biome.
(d)Eastern parts receive more rainfall from monsoon rains.
(2)Indus Valley Desert Biome
(a)Sindh- Sagar Doab
(b)Desert Climate
(c)Shrubs and Bushes for vegetation
(d)Nomadic lifestyle(e)Camels are found here
( f ) D e fi c i e n c y o f w a t e r
(g)Sand dunes
(h)Indian Leopards, hyenas
AD
(3)Indus River Delta
(a)Defi ned by mangrove trees(mangrove biome)
(b)Located on sindh coast
(c)100-500mm rain annually.
(d)Summer temperatures up to 50℃
(e)Mangrove trees are dominant due to salt water
(f)Extensive irrigation
(g)Pollution
(h)a fan-shaped delta forms an extensive system of swamps, mudflats, creeks, estuaries, marshes
and mangroves forests.
(i)critical habitat for numerous species of fishes and shellfishes, especially as a spawning ground
and nursery for the larvae and juveniles.
(j)Near freezing in winters
(k)Mangrove vegetation, in general, is not as biologically diverse as other terrestrial broadleaf
forests. But they are structurally quite complex, with a dense canopy and an undergrowth of
seedlings and saplings from the canopy trees. Mangrove trees have unique adaptations to grow in
the saline and anoxic soils. They have evolved a root system where some roots, called
pneumatophores, grow upwards and out of the water instead of into the soil, and are able to take
up oxygen from the air. Other roots that grow from higher up along the trunk act as prop roots to
