climate

Question 1

climatic zones

Answer 1

Paks topographical features range from lofty mountains in the north to coastal plains in south. This diversity leads to a variety of climates.
Highland climate
Lowland climate
Coastal climate
Arid climate

Note: climate zones do not experience exactly the same conditions throughout the zone. There are great variations in rainfall, humidity, temperature etc.

Question 2

highland climate

Answer 2

Region includes northern, north western & western highlands
Long, cold and snowy winters
Short and mild summers

In mountainous areas, rainfall is normally associated with altitude
Rainfall in northern mountains is highest in highland zone; western mountains experience less rainfall
Gilgit and Chitral are in rainshadow areas so they experience less rainfall.

Temperature also varies with altitude. Summers are short, mild and wet in northern mountains but dry and warm in western mountains.

Question 3

lowland climate

Answer 3

Region includes all of the Indus plain except for coastal areas
Most parts of Indus plain lie at western end of tropical monsoon zone
Arid and extreme climate, hot summers, cool winters and summer monsoon rainfall
Amount of rainfall differs from north to south
Foothills of northern mountains and potwar plateau are wetter than Indus plain, and also receive rainfall from western depressions
Thunderstorms common in north and northwest of Indus plains
Southern upper indus plains & whole of lower Indus plain = much less rainfall & hot spills

Question 4

coastal climate

Answer 4

Region includes the southern coastal strip comprising the Indus delta, karachi and Makran coast.
Climate dominated by sea breezes all year
Marine influence keeps daily temperature range low
Temperature of sea and land is different owing to unequal heating of land and water by sun. In the summer the land heats up quickly while the water is comparatively cooler. In winters, the land loses its warmth and becomes cold quickly while the water is much warmer and keeps its warmth for a long time.

Humidity level moderately high
Mean monthly temperature = 32oC
May,june,oct = hottest months
Oct: dry winds from south-eastern desert dominate the climate
Rainfall is scarce all year

Question 5

arid climate

Answer 5

South-western balochistan & south-eastern desert = arid climate
Dry and hot
Hot dusty winds prevail almost continuously from mid-may to mid-september
Scarce rain in south-western balochistan falls in winters
South-western deserts = summer monsoons brings little rain
Main features: extreme heat, dryness and dust storms

Question 6

Pakistan: the 4 seasons

Answer 6

Pak has 4 main seasons
Winter
Early summer
Late summer (monsoon)
Post-monsoon

Question 7

temperature

Answer 7

Diversity in temperature in various regions is due to the following factors:
Large spread of latitude from 24oN to 37oN
Diversity of relief from mountains up to 8610 metres in the north, to low lying coastal areas in the south

Upper and lower indus plain heat up in summer, taking daily max temperature to 40o - 45oC which is v hot
Jacobabad, in lower Indus plain is known as the ‘thermal pole’ of the subcontinent, where max temp reaches 53o.C in june.

Question 8

rainfall

Answer 8

Most of Pak is arid or semi-arid
Rainfall decreases from the himalayas towards the south
Sources of rainfall:
Monsoon winds
Western depressions
Convectional currents causing thunderstorms
Relief rainfall
Tropical cyclones

Question 9

monsoon winds

Answer 9

‘Monsoon’ = season
Summer monsoon winds = south-west monsoons
Winter monsoon winds = north-east monsoons
South-east monsoons:
Are giant sea breezes which bring heavy rainfall
Rain begins when summer sun heats tropical continents much faster than the oceans around
Warm air rising over land creates low pressure, attracting cool, moist air from the sea, and rain-bearing winds gradually push further inland, bringing heavy rainfall
North-east monsoons:
Blow from land towards sea
In winter: high pressure are is created over tropic of cancer
Winds blow from land to sea, which is low pressure area
Mostly dry and bring no significant change because they originate in dry area

Main monsoon winds blow from Bay of Bengal
Some winds blow from south-east Pakistan from the Arabian sea. They are weak and have little effect but sometimes an overactive monsoon system brings heavy rain to Karachi and the Sindh coast, damaging infrastructure

Monsoon winds are seasonally reversed and driven by temperature differences between land and sea
Blow towards heart of continent (land areas) in summer
Blow towards sea in winter

Question 10

western depression

Answer 10

Western depressions: cyclones which originate in the Mediterranean sea, cross Afghanistan & Iran, & reach western Pakistan. After striking north western areas i.e Peshawar and Northern Pakistan, they move towards the west and south west. By the time they reach south-western Balochistan, they lose their moisture. These winds cause rainfall in these areas from December to March. I.e Quetta receives most of its rainfall in winter.

Question 11

convectional current

Answer 11

Start of summer: hot air (has high moisture content) rises. When it reaches higher layer of atmosphere → condensation → causes rainfall often as thunderstorms. Strong winds accompanying storm may pick up dust as well
Only northern and north-western Pak receive rainfall from convectional currents
Southern Pak deprived of convectional rainfall due to temperature inversion layer.
Rawalpindi and Peshawar are areas that receive rainfall due to convectional currents.
Temperature inversion layer prohibits condensation at the height og 1600m, so warm air descends and no rainfall occurs. (karachi and other adjoining areas)
Criss cross of warm winds does not alloe condensation to take place.

Question 12

relief rainfall

Answer 12

Related to height of land
Occurs where unstable air moves up a mountain or scarp edge, and is chilled
Chilling → heavy condensation & precipitation on windward side. Lee slope receive sinking, warming air and a dry ‘rainshadow’ area may lie leeward of the barrier
Murree and Kakul receive rainfall in almost all seasons due to high altitude and other sources.

Question 13

tropical cyclones

Answer 13

May bring a few hours of very heavy rain and destructive winds to coastal areas.
Originate over arabian sea quite often but only reach coast of Pakistan every few years.
This source of rainfall is unreliable in terms of when and where on the coast it will occur

Question 14

pressure and winds

Answer 14

In summer, hot air rises and forms a low pressure zone. At the same time, ocean and seas have comparatively low temperatures (bec water absorbs and discharges heat slowly compared to land)
In summer, the air pressure over oceans and seas is highers than over the land
This leads to movement of moisture-laden monsoon winds from sea to land. They bring heavy rainfall to upper and lower Indus plain (July & August)
Winter: situation reversed as pressure over land increases
Summer monsoons gradually retreat in autumn and are replaced by land winds blowing out from the high pressure area.
These are called winter monsoons/north-east monsoons
These winds are generally light and dry

Question 15

effectiveness of rainfall

Answer 15

Rainfall in Pak mainly from monsoon winds and western depressions
Monsoon winds bring rain during summer season
Monsoon rainfall is of limited value to agriculture as it varies in amount, timing and distribution
High temperature conditions from june-sept over the Indus plain leads to a great level degree of evapotranspiration, which also limits the usefulness of rainfall.
Monsoon rain falls in heavy showers → not useful for crops bec land does not absorb rainwater
Most of the monsoon rainfall drains away, causing floods in low lying areas. However, reservoirs of the dams on river Indus and its tributaries help to store extra water during rainy season that can later be utilized in dry season.

Crop planning = difficult if amount of timing and rainfall have above normal fluctuations

Only tiny fraction of potwar plateau has canal irrigation
“Barani land’ due to impracticability of lifting irrigation water up to plateau surface and of irrigating heavily eroded badland areas

Winter rainfall = more effective for farmers as it comes in light showers that continue for several days
However, winter rainfall is insufficient and unreliable.
Only occurs in western and northern regions
Coastal and southern Pak have to depend on monsoon rainfall

Rainfall in Pak is neither dependable nor adequate. As a result, farming mainly depends on irrigation .
Northern Punjab and Potwar plateau (wetter than rest of Pak) have a number of ‘rainfed’ and ‘barani’ farms where subsistence farming is practiced.
It is not possible to develop can irrigation in plateau regions.

Question 16

highland zone

Answer 16

Severely cold winters and mild-warm summers characterize climate of northern and northwestern areas of the highland zone
Northern areas: temperature falls below freezing point
Growth of trees = retarded
Grass buried under snow
Rivers and torrents freeze at some places
Farming not possible in winters thus people r involved in indoor activities i.e carpet weaving, embroidery etc

Transhumance also practiced i.e moving flock to cooler highlands in summer and back to the plains in winters
Barren hills of kpk sparsely populated

Most pathan tribes still live as nomadic herders of goat and sheep. Due to extremely low temperature in winters, they have to move with their animals to the lowland areas.
Vale of peshawar = greenest part of this region with extensive woodlands, orchards and irrigated fields

Extreme north: many areas inaccessible due to landslides & heavy snowfall hampering transport links
Job opportunities = limited
Economic activities = difficult to carry out

Southwards: temp increases in both summer & winters
Western highlands and barren mountains of Balochistan = sparsely populated due to harsh physical conditions
Annual rainfall: 125-250 mm (occurs mainly during winters)
Lack of water discourages human settlements
Crop cultivation = difficult but apples, mangoes, apricots & grapes are grown in high valleys

Question 17

arid zone

Answer 17

Zone in 2 parts: south-eastern deserts & kharan desert (including chaghai hills)
Climate = one of the extremes w low annual rainfall , cool-mild winters & hot summers.
Summers v hot during daytime

Region deficient in moisture and extreme in temperature = not suitable for habitation or cultivation
Most ppl = nomads, belonging from groups i.e Brahuis, Balochis and Pathans
Due to scanty rainfall and excessive evapotranspiration, a unique system of underground irrigation called ‘karez’’ is practiced.
Karez: narrow subterranean canal which starts from the base of the hills and mountains where subsoil water is present. On reaching the surface, it irrigates the orchards and fields, many of which are sheltered by date palms. This method prevents the water from being evaporated by the heat of the sun or absorbed by the thirsty land.
The highland areas of Balochistan with its cold and dry climate and winter rains due to depressions are suitable for growing fruits i.e grapes, apples, peaches and melons. (other crops include wheat, millet and barley)

Desert covers almost all of Sindh and southern Punjab
Area receives only 100mm of annual rainfall
Average monthly temperature in summer: over 38oC
Such extreme heat and low precipitation make crop cultivation difficult
However, large areas reclaimed for farming by construction perennial canals to irrigate western part of southern Punjab and wide strip on either side of the Indus in Sindh.
Rice, wheat, cotton and oilseeds cultivated in those areas

Rest of thar desert = barren desert
Lifestyle of ppl affected by the climate. They wear thick clothes for protection against the hot winds & turbans
Move place to place in search of water for themselves and their cattle

Question 18

lowland zone

Answer 18

The fertile punjab plain, drained by river Indus and its tributaries has a continental or extreme type of climate due to its northerly position
Daytime: summers = extremely hot
Winters: cool-mild
Economically, the Punjab plain is the most productive agricultural region of Pakistan
Well developed canal irrigation system to raise crops i.e wheat, millet, cotton and sugarcane

Punjab is the most densely populated province due to its alluvial plains, moderate rainfall, tolerable summer and winter temperatures.

Question 19

coastal zone

Answer 19

Delta coastline in Sindh
Hilly Makran coast in balochistan
Thatta and Badin imp centres on the Sindh coast
Gwadar, Ormara and Pasni located on Makran coast

Karachi:
mild climate w low average precipitation
Winters = mild, summers = hot
Proximity to the sea maintains humidity to a high level (60-70%) & cool sea breezes relieve the heat of the summer months
Winter months considered best time to visit Karachi when most social events take place

Makran coast = dry and hot
Max temp in June 31oC - 40oC
January: 18-19oC
Oceanic influence keeps the temperature lower than the inland areas in summer and higher in winter
Humidity prevails all along the coast
Average annual rainfall below 250 mm
extent of precipitation affects supply of drinking water in Gwadar district as most of it is provided from reservoirs which are rain-dependent.
Moderate climate = one of the imp factors in development of Gadar port as it would make it operational throughout the year for trade activities

Due to mild climate of Sindh Coast:
Economic activities carried on throughout the year
Farming possible all year (depending on availability of water from irrigation channels)
Sea ports open all year round to carry out international trade
Road and rail transport links to inland areas are never closed for business and economic activities
Air flights rarely canceled due to bad weather
All industries (small scale to large scale manufacturing) operational in all seasons
However, during summer months, tropical cyclones sometimes cause coastal flooding in low-lying areas, damaging infrastructure, homes and farmland in Indus delta
Fishing nearly impossible in rough seas thus fishing communities suffer economic losses due to tropical cyclones

Question 20

river floods

Answer 20

River Indus and its tributaries swell and overflow their banks almost every year
Every 7-8 years, there are severe floods
1955: flood inundated 2420 villages. 400 ppl & 70,000 cattle lost their lives. Ravi Syphon (a canal to release water to the fields) was destroyed. Total damage caused by the flood amounted Rs 83 million
1973: floods inundated 3.6 million hectares, demolished 3 million homes and killed 1600 ppl.
1978, 1980s &1990s: floods caused large scale devastation

Summer 2010, monsoon rains fell on pak and caused floods that were described as the ‘worst in 80 years’. Almost 2000 ppl died & 2 million people affected by losing their homes, crops, livestock or livelihood

Question 21

reasons of flooding

Answer 21

Natural:
Melting of snow during summer
Heavy monsoon rainfall
Human:
Deforestation (on foothills which increases surface run-off)
Failure to strengthen or heighten embankments alongside rivers
Dam failure to store extra water due to less capacity

Question 22

what can be done to reduce the flood risk

Answer 22

preventative and creative measures:
Planting trees on foothills to check flow of running water
Enlarging river channel so it can hold more water
Building embankments on either side of the channel to prevent spread of floorwater
Building extra channels to take floorwater away from towns
Building reservoirs on the river to store water and control peak discharge
Prevent building in areas where flooding is most likely
Publicising flood warning
Evacuation of flooded areas and providing necessary facilities for rehabilitation

Question 23

negative effects of flood

Answer 23

For farmers:
Farmers not able to use the land until the water has drained away
Destruction of crops
Loss of food supplies
Precaution: during monsoon season, livestock an precious belongings could be moved to higher places
For local residents:
Houses will be cut off from shops and services
Mud houses and huts could be severely damaged
Spread of water-borne diseases
Precaution: residents be moved to higher areas along w precious belongings, alternative arrangement or basic necessities of life
For transport authorities:
Roads and railway tracks could be damaged
Old routes difficult to follow if damaged by flood water
Precaution: transport authorities could prepare a plan to introduce diversion and warning signs as quickly as possible.
Repair of road and railway tracks should be done on emergency basis

Question 24

benefits of floods

Answer 24

Return nutrients to the land and contribute to the health of wetlands. Wetlands allow floods to spread over a large area, causing little to no damage
Distribute rich sediment and refresh streams
Spread a layer of alluvium which increases fertility of the land
Flooded field can be used for rice cultivation
Allowing rivers and streams to overflow their banks naturally can prevent more serious flooding downstream
Relatively high level of fish production in arabian sea is attributed to the nutrient-rich delta of the Indus river system
Reproduction, breeding and multiplication of inland freshwater fish and prawn species is firmly tuned and adjusted to monsoon flooding
Floods also recharge ground water supplies

Question 25

storms

Answer 25

Common in northern and north-western pak
In summer and post monsoon season, atmospheric pressure falls and conventional currents cause sporadic and localized rainfall in the extreme north and Safed koh mountains
(accompanied by strong winds (60-80km/h)
Stormy rainfall and hail occur as a result of these winds = destruction of apples, pears & other crops
Summer season: dust storms and strong winds experienced due to low atmospheric pressure in southern plains and north western parts of balochistan
Dust storms hit upper Indus plain and damage crops & orchards j like floods
Windstorm of high intensity = roofs of houses badly affected, electricity and communicated system disrupted
Storms less frequent than floods & usually localized

Tropical cyclones from arabian sea can also affect coastal areas of Sindh and Balochistan
May 1999: tropical cyclone ‘2A’ hit coastal areas of Sindh causing widespread damage to ppl and property

Destruction caused by storms increases if relief teams are delayed or don’t arrive
Serious need for coastal areas to have proper arrangements i.e: flood monitoring cells, proper warning systems and relief teams

Question 26

drought in Pak

Answer 26

Hazard of nature and can present v big threat to those who live off land
Lack of rainfall = water shortages = crops destroyed
In worlds poorest countries, droughts bring famine, disease and death on a massive scale

Causes:
Natural:
Unreliability of monsoon winds = seasonal drought in Punjab & Sindh
Hot, dry winds reduce moisture content of soil by lowering level of humidity in the air
Global climate constantly changing
Human:
Deforestation on foothills of mountains increases soil erosion and reduces rainfall
Mismanagement of water resources thru seepage f unlined canals
Disputed an unfair distribution of water between provinces = drought in province deprived of its fair share
Overgrazing of land = soil erosion and reduces fertility of soil
Global warming = climate change

Question 27

types of drought

Answer 27

Permanent drought: exists when crop cultivation is not possible w out irrigation (Thal, cholistan, Chagai (western balochistan))
Seasonal drought: occurs in areas with well defined rainy and dry seasons (Potwar Plateau, southern Punjab)
Invisible drought: is a result of water deficiency that reduces crop yields but is not severe enough to damage them
Unpredictable drought: is a result of abnormally low rainfall, occurs in areas with humid climates

Question 28

effects of drought

Answer 28

on physical environment:
Desertification (process of turning land into desert):
Exposed soil = soil erosion, dust storms, extension of desert areas, rise in temp, los of vegetation & extinction of species
Drying up of rivers, lakes & streams:
Harm to aquatic life, growth of algae in shallow water, unsafe drinking water
Drop in water table:
Less water available for plants & humans from groundwater sources

on human environment:
Widespread famine leading to starvation → malnutrition, health problems → loss of lives
Or
migration from drought affected areas → break up of rural social set up → nomadic lifestyle
Economy
Crop failure, death of livestock → shortage of raw material for industries → reduced exports, increased imports → devastation of the economy

How the 2000-01 drought affected Pakistan
2001: 26 districts of Balochistan suffered from severe famine as a result of drought
22/26 districts = famine reached crisis point
Many people trapped in inaccessible areas
Lives of 20,000 families and over a million cattle were affected

Areas most srsly affected by the drought: provinces of Balochistan and Sindh
Over 3.3 million ppl affected, thousands who are now refugees
Hundreds of people died due to starvation and thirst
30 million livestock affected, 2 million+ dead
Most areas have no rain for 3-8 years
No significant amount of rain is expected

Question 28

drought management

Answer 28

water-shortage schemes
Water can be stored in water-shortage schemes i.e reservoirs of dams and water tanks for irrigating crops and forest areas
This helps to limit losses caused by seasonal drought
Areas that receive monsoon rainfall in heavy showers (jul-Aug) can utilize that extra water throughout the year by a perennial canal system

Uses of technology
Use of sea water through desalination process
Conversion of waste water into clear water through filtration and chemical treatment
Planting drought-resistant crop varieties which consume less water

Lining of canals to avoid wastage and uneconomical use of existing water resources

Planning and management of water resources
Government should ensure that high priority is given to the allocation of water resources for the basic needs of people and economy i.e for agriculture & industrial uses.