Having grown up internalising the eastern coast most of my life, I am going to try and put together a few facts that can help us understand the synthesis of the IPCC (Intergovernmental Panel on Climate Change) report on sea-level rise and in doing so, establish the urgency in all of us having to develop some sense of knowledge on coastal processes and their increasing vulnerability to climate change.
Ocean currents worldwide, start with the formation of ice at the poles due to the cold temperatures. The salt in the water that morphs into ice is left behind in the sea, creating an imbalance (both in terms of salinity and temperature) in the local system. This makes the water with increased salt-content (with higher density) sink and the less dense water from the surrounding rushes to fill in the gaps.
This in turn, triggers currents in the ocean that circulate around the world. The water, as they go further along the current, increase in temperature and become warm by the time they circulate all the way back to the poles and since they will have lower density, will rush in to fill the gap caused by the water with increased salt-density sinking, thereby causing the loop to start again.
The oceans, having absorbed more than 90% of all greenhouse gas emissions since the 1970s, is warming up. The poles are heating up too. These two factors majorly increase the water content in the oceans and trigger events like tsunamis. The sea-level rise, increasing at a rate of 1.7 mm/year (1901-2010), rose at a rapid rate of 3.2 mm/year from 1993 to 2010 alone, almost twice the long-term average, according to the IPCC report.
What does this mean for the Indian coast and its population? The country has about 25% of its population residing along the coast with the number only increasing as they provide to be areas with high economic productivity. A 1 mm rise in the sea level, in the western coast of India, results in a 1m retreat of the land.
This would be a bigger number for the east coast since the east is a lot less steeper along the coast than the west owing to the physiology of the continental shifts. This would mean that the population along the sea, fishermen and the villa-dwellers alike, will be sunk gradually if it isn’t for sudden storm surges like the 2004 Tsunami.
With global emissions increasing at the current rate, the sea-level is to rise by 62 cm in the next few decades, an easy 2 km (that’s approximately 19 football fields or 11, 300 bananas long!) submergence of coastal land for a city like Chennai.
With urban pockets and local communities heavily dependent on the shore for its economy/leisure, this scares me. For the Bessie (Elliot’s Beach) lovers, this means a massive change in your beach-related activities including the disappearance of all of your favourite outlets along the road, let alone the fancy houses of your friends who stay there.
The IPCC also predicts that this 62 cm can be brought down to a 47 cm if the emissions are stabilised at the current rates and a 40 cm if the local governments are to implement policies to drastically cut down the existing emission rates.
Vegetation (especially mangroves – plants that grow in brackish/coastal waters) along the coastline will increase the resilience of the coast by helping in its self-stabilising. This is a process that is far more sustainable than the construction of concrete structures among other anthropogenic interventions that are gaining significance.
Wetlands, including the Pallikaranai marsh will act as a sponge absorbing the excess water as the sea levels gradually increase. Wetlands, in turn, connected with the lakes around, will redirect this water to them, recharging the aqueducts as they flow through them. This ensures water stability for the entire region, an issue that’s of crucial importance for cities like Chennai that are faced with frequent drought spells. But this isn’t enough.
The conservation of such ecosystems also comes with us, the common citizens, taking up the responsibility of keeping the water bodies from getting deteriorated through the discharging of untreated domestic sewage, industrial effluents and solid waste.
The implementation of the Coastal Regulation Zone notification, in its intended rigour and sentiment, can help in drafting coastal zone management plans that attend to regions that are vulnerable to an increase in the sea-level rise. With less emphasis on eco-tourism and promotion of development along the coast and more on trying to keep the shores stable and the population safe, we can have mitigation strategies that can be a lot more efficient in addressing this environmental crisis.
Imagine the little difference you can make by being conscious of your contribution to the GHG emissions with an intent of trying to lower them, and choosing not to just discard a plastic bag as finish up the food packed inside of it. The plead to adopt to a #sustainable lifestyle isn’t to ‘save’ the planet but in hindsight, to save ourselves from its adaptation to the human-induced changes. For its adaptation need not necessarily go together with optimum conditions for our survival.
Note: this article was first published here.