Science and impacts of climate change Satheesh C. Shenoi Indian National Centre for Ocean Information Services (INCOIS) Ministry of Earth Sciences Hyderabad – 500 055 [email_address] Centre for Science and Environment South Asian media briefing workshop on climate change 27-28 August 2009, India Habitat Centre, New Delhi

Satheesh C. Shenoi

Indian National Centre for Ocean Information Services (INCOIS)

Ministry of Earth Sciences

Hyderabad – 500 055

[email_address]

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)

Reconstructed

Sea level (red)

(Church, White)

TG Measured

Since 1950 (blue)

Altimetry (black)

Sea Level Trend Shoreline Change Rate Long Term Sea Level Data from tide gauges Satellite and Secondary data DEM data Return periods (T) Extreme water level (H max ) Future Sea Level after T (A) Future Shoreline after T (B) Contours Multi-hazard Line=A>B>C Contour of H max (C) Methodology for multi-hazard coastal vulnerability Multi-hazard Map

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) 20m 5m 10m Coastline in 1950 Coastline in 2005 Predicted erosion in 100 yrs Predicted 100 year flood level Composite 100 year hazard line

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 5.74 -0.52 5.22 55 Diamond Harbour 1.09 -0.39 0.70 53 Vishakhaptnam 1.75 -0.44 1.31 54 Kochi 1.20 -0.43 0.77 113 Mumbai 1.06 -0.45 0.61 44 Karachi 1.37 -0.16 1.21 58 Aden Net sea level rise (mm/yr) GIA (mm/yr) Trends (mm/yr) No of years Station

Return period of the extreme water levels Gringorten distribution technique p Extreme 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

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

Calculation of Shoreline Change Rate (1972-2000)

Landward Shoreline after 100 year

Multi-hazard Map of Cuddalore Area

Composite Multi-hazard line overlaid on the Google Earth

Zoomed area of the Cuddalore Town

Multi-hazard vulnerability map of Nellore district, Andhra Pradesh * 236 villages are under the multi-hazard line

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 S. No Parameter Length (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

0.8 ° C 0.4 ° C Source- http://worldviewofglobalwarming.org

8 0 ppm of CO2 concentration due to human contributions ! 7.7 ° F 300 ppm 380 ppm Major polluters ?