Science and impacts of climate change

• Satheesh C. Shenoi• Indian National Centre for Ocean Information Services

(INCOIS)• Ministry of Earth Sciences• Hyderabad – 500 055• shenoi@incois.gov.in

Centre for Science and Environment South Asian media briefing workshop on climate change 27-28 August 2009, India Habitat Centre, New Delhi

Sea levels are rising worldwide and along much of the South Asian coast. (IPCC, 2007). Tide gauge measurements and satellite altimetry suggest that sea level has risen worldwide approximately 4.8-8.8 inches (12-22 cm) during the last century (IPCC, 2007). A significant amount of sea level rise has likely resulted from the observed warming of the atmosphere and the oceans.

Annual averages of global mean sea level

• Reconstructed Sea level (red)

• (Church, White)• TG Measured • Since 1950

(blue)• Altimetry (black) Figure 5.13

Sea Level Trend Shoreline Change Rate

Long Term Sea Level Data from tide gauges

Satellite and Secondary data

DEM dataReturn periods (T)Extreme water level (Hmax)

Future Sea Level after T (A) Future Shoreline after T (B) Contours

Multi-hazard Line=A>B>C

Contour of Hmax (C)

Methodology for multi-hazard coastal vulnerability

Multi-hazard Map

20m

5m

10m

Coastline in 1950

Coastline in 2005

Predicted erosion in 100 yrs

Predicted 100 year flood level

Composite 100 year hazard line

Illustration of Methodology

Parameters Considered•Shoreline change (Landsat data 1972-2000)•Probability of extreme water level in a return period (Observed Tide data)•Contours (ALTM & Carto-DTM)

Mean-sea-level-rise trends along the north Indian Ocean coasts from past tide-gauge records

Estimated trends vary from 1.06 to 1.75 mm/year for individual records (an average of 1.30 mm/year) Unnikrishnan and

Shankar (2007)

Net sea-level-rise trends

Station No of years

Trends (mm/yr)

GIA (mm/yr)

Net sea level rise (mm/yr)

Aden 58 1.21 -0.16 1.37

Karachi 44 0.61 -0.45 1.06

Mumbai 113 0.77 -0.43 1.20

Kochi 54 1.31 -0.44 1.75

Vishakhaptnam

53 0.70 -0.39 1.09

Diamond Harbour

55 5.22 -0.52 5.74

Return period of the extreme water levels

Return Period of the extreme water levels for the Nagapatnam

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2

5 15 25 35 45 55 65 75 85 95

Return Periods (Y)

Wat

er L

evel

(m

)

Return Period of the extreme water levels for the Chennai

1.50

1.55

1.60

1.65

1.70

1.75

1.80

1.85

1.90

1.95

2.00

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Return Periods (Y)

Wat

er L

evel

(m

)

Gringorten distribution technique p12.0

44.0

88.01

44.0

N

m

N

m

)

R

1-(1loglogauU eeExtreme value distribution

Calculation of the reduced variate y = - loge (-loge p)

•1.94-1.55 meters of extreme water level for the return period of 100 years•2 meter has been considered for the current study

Ca

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197

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ter

100

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Zoomed area of the Cuddalore Town

Multi-hazard vulnerability map of Nellore district, Andhra Pradesh

Return Period of the Extreme Sea Levels

0.002.004.006.008.00

10.0012.0014.0016.0018.00

Che

nnai

Bha

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gar

Coa

chin

Dia

mon

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Gar

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Hal

dia

Kan

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Kar

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Man

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Mar

mag

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Min

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Mum

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Nag

apat

nam

Okh

a

Par

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Por

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Sag

ar

Trib

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Tut

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Vad

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Ver

aval

Vyz

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Stations

Wat

er L

evel

(m

) y5

y10

y25

y50

y75

y100

Return Period of the extreme water levels for the Chennai

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

5 15 25 35 45 55 65 75 85 95

Return Periods (Y)

Wat

er L

evel

(m

)

* 236 villages are under the multi-hazard line

S. No ParameterLength (km)

Low Medium High

1 Shoreline change rate 231 194 55

2 Significant wave height 0 480 0

3 Sea-level change rate 23 166 292

4 Tidal range 141 302 37

5 Coastal regional elevation

91 182 207

6 Coastal slope 10 41 429

7 Tsunami run-up 31 327 121

8 Coastal geomorphology 39 74 367

9 CVI 76 297 107

Srinivasa Kumar T, Mahendra R S, Shailesh Nayak, Radhakrishnan K R and Sahu K C, “Coastal Vulnerability Assessment for Orissa Coast”, 2009, Journal of Coastal Research, Accepted

Coastal Vulnerability Index for the Orissa Coast

0.8 °C 0.4 °C

Source- http://worldviewofglobalwarming.org

80 ppm of CO2 concentration due to human contributions!

7.7° F300 ppm

380 ppm

Major polluters

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