Monday, September 4, 2017

10 lakh lives of Chennaites in peril if sea level rise by one metre, says TN govt study

Chennai:
A total of 10 lakh lives in Chennai will be at peril and 144 square Km area will be lost if the sea level rises by one metre by 2050, according to a study conducted by Tamil Nadu State Land Use Research Board.

The study, which is being done keeping in mind a anticipated sea level rise due to climate change, estimates the loss to the exchequer could be Rs 7,01,790 crore if the sea level rises by one metre.

Sea level rise (SLR) is primarily caused by melting of glaciers and expansion of warm waters. The West Antartic Ice Sheet (WAIS) which lies mainly on bedrock under the sea is showing signs of decreasing mass and glaciologists believe the WAIS holds enough water to raise the sea level by 4.8 metres.

Even the Totten glacier of East Antartica is also melting more rapidly and it holds enough water to raise sea levels by 3.4 metres.

Interestingly, the study, which is part of Tamil Nadu State Action Plan on Climate Change, takes into account the global warming and green house emissions and stresses that coastal cities in the state like Chennai should be prepared for a one metre rise of sea level by 2050.

According to State Action Plan on Climate Change, there is high probability of increase in frequency and intensity of climate related natural disasters. It links sea level rise to coastal erosion, storm surge, coastal flooding and salt water intrusion.

The study has taken into account storm surges and tides and higher mean sea levels before predicting the increase of one metre sea level rise. It predicts the future storm surge which is likely to be more frequent and more intense as a result of climate change will reach between 4.35 metre and 6.85 meter affecting a large area of upto 1,963 square km.

The study taking into account the Gross State Domestic Product for Tamil Nadu in 2016 which is Rs 12.12 lakh crore states that the rise in sea level would result in 50 to 55pc loss of GSDP.

It also highlighted that 2.46 lakh households having a population of nearly 10 lakh will be at risk due to the rise in sea level. Similarly, in Kancheepuram and Thiruvallur it will be more than 5 lakh of population who will face risk, the study stated.

Why the sea level rise is feared:
1. The West Antartic Ice Sheet which rests mainly on bedrock under the sea is showing signs of decreasing mass which can cause sea level to rise by 4.8m
2. The Totten glacier of East Antartica is melting and it can also raise the sea leel by 3.4 metre
3. The Greenland Sheet is melting and it is feared it could result in rise of sea level by six metres
4. The thermohaline circulation a process in which warm waters flow towards north and colder waters sink and flows back south due to melting of glaciers could result in intense storms

How are cities across the globe are preparing:
1. New york is preparing for six metre rise in sea level
2. UK Environment agency has prepared a plan for copig with 2.7 metre and 4 metre sea level rise by the end of the century in Thames Estuary
3. Ho Chi Minh City in Vietnam has launched Climate adaptation strategy

Tamil Nadu State Action Plan on Climate Change:
1. Climate projections for Tamil Nadu include an increase of temperature by one degree celsius to 3.1 degree celsius between 2010 to 2100 with 1970-2000 data as baseline.
2. It identifies risks like sea level rise due to coastal erosion, storm surge, coastal flooding and salt water intrusion

Factfile:
1. The Sea Level Rise of one metre by 2050 will affect 143.23 square km of land
2. The total population at risk in Chennai, Kancheepuram and Thiruvalluvar districts is more than 15 lakh
3. The future storm surges in Chennai due to climate change would be 4.35 metres to 6.85 metres affecting large area of up to 1,963 square km.
4. The total economic loss of infrastructure is expected to be Rs 7.01 lakh crore (private properties not taken into account)
5. The total loss from the ports is expcted to be Rs 5.55 lakh crore   

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