Climate Change and Environmental Problems

Prof. Dr. S. Shafiqur RehmanDepartment of Environmental

SciencesUniversity of Peshawar

Climate:• Summary of atmospheric environment of a region based on the long-term averages of weather attributes for approx. 35 years;

• Insolation, Temperature, Pressure, Humidity, Cloudiness, types/frequency of Precipitation, Atmospheric turbidity, Wind speed/direction, Albedo etc.

Trends & Variability• Temporal variability is always present in all types of weather data on diurnal, seasonal, annual, decadal & millennial scales

• Short and long-term averages, standard deviation (variability about average) and rise and fall of a particular attribute can be statistically determined

• The Range & Frequency of Extremes indicates the trend

Causes of Climate Change

• External Factors– Changes in the energy outputs from the Sun (Imbrei, 1980)

– Variation in Earth’s orbital parameters (Milankovitch, 1938)

• Internal Factors– Lithospheric Processes– Atmosphere Ocean Interaction– Anthropogenic Interventions

Recent Changes• The current CO2 concentrations, largely attributed to anthropogenic sources, have reached the all times high concentration for the last 800,000 years

• The global average temperatures have increased by 0.7 ◦C during the last 100 years

• Most alarming increase in the heat trapping gases has taken place from 1970 to 2004

Effects of Climate Change (Warming)

• Increased Evapotranspiration• Increased atmospheric humidity & cloudiness

• Geographical & seasonal shift in precipitation patterns

• Increased runoff, floods, siltation, landslides

• Retreat of glacial/snow cover• Rise in sea level

Effect on Glaciers• 5218 glaciers have been identified covering 15,040 km2 area in north Pakistan

• Total ice reserve of 2,738.5 km3

• Shyok, Shigar & Hunza River basisn store 83% of these reserves (Karakoram range)

• There are 2420 glacial lakes in the area covering 126 km2 area of which 52 have been identified as potentially dangerous for GLOFs

Recent Trend in Temperature

Decade Skardu Gilgit

1960-69 17.7 24.7

1970-79 17.9 24.3

1980-89 18.7 23.8

1990-99 19.2 24.1

Effects on Hydrology• Increased discharge & sediment transport

• Frequent river floods• Loss of fertile land & change in land use

• Increased soil erosion• Excessive siltation in reservoirs/canals

• Increased recharge to the aquifer

 

Relationship between mean monthly temperature and discharge of Indus River

201 185 184 260

793

2109

33263148

1490

508

321242

3.0

5.7

11.8

19.1

23.4

28.7

31.7 31.2

27.5

20.7

13.4

6.7

0

500

1000

1500

2000

2500

3000

3500

Jan Feb M ar Apr M ay Jun Jul Aug Sep Oct Nov Dec

Q (m

3 /s)

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

Mean monthly tem

perature (C

)

Time Series of Annual Runoff of Indus River at Kachura

0

50

100

150

200

250

300

350

400

450

Time series 1970-2000

Runoff (m

m)

Dec2%

Nov2%

Jan2%

Apr2%

M ar1%

Feb1%

Jul27%

Jun16%

Aug26%

Sep11%

M ay6%

O ct4%

Monthwise water availability – Indus

at Kachura

1.62.13.4

7.7

16.3

24.823.6

12

4.3

1.51.31.4

0

50

100

150

200

250

300

JAN FEB M AR APR M AY JUN JUL AUG SEP OCT NOV DEC

Mean monthly discharge of Swat River

vs mean Max. Temp at Kalam

5

6

7

8

9

10

11

12

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

Tim e Series (1965-2000)

Runofff (bcm)

Chitral river Time Series

Likely Impacts:• Change in the timing, frequency & intensity of the precipitation

• Land-use changes induced by the earlier• Wildlife habitat• Effects of agricultural practices• Effects on type & extent of forest cover

• Geographic redistribution of plant species

Thank you & God bless you all!