The world has been facing increasing impacts of tropical cyclones due to changing climate and India is no exception. Tropical cyclones form in certain favourable conditions, one of them being sea surface temperature (SST) reaching a particular threshold (28°C) or higher. Higher the SST, the quicker the storm amplifies and gets intense.
The fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC) informs that oceans have absorbed over 93 percent excess heat due to greenhouse gas emissions since 1950s. Data also shows Indian Ocean’s rapid basin-wide warming of ~1degC over the last 60 years exceeds that of the global average of ~0.7 degC.
A Brewing Storm
A recent scientific assessment by the Ministry of Earth Sciences attributes such warming to the sea level rise over Indian Ocean while global sea level rise continues to be attributed to glacial melting. Data from the last 129 years shows a total of 524 cyclonic storms over the Bay of Bengal, with 237 in the severe category, while 139 storms over the Arabian Sea with 79 in the severe category. Historically, the Arabian Sea is less prone to cyclone generation with just one cyclone seen compared to four in the Bay of Bengal each year. Lately this trend shows a change with the Arabian Sea reporting 13 cyclones in the past five years itself.
Scientists attribute this to higher warming seen over the Arabian Sea in the past decades. As per the India Meteorological Department, the last decade has seen an 11 percent rise in cyclones over Indian seas with around 32 percent of them in the past five years alone. Not only are the number of cyclones in the Arabian Sea increasing, but the storms are becoming more intense owing to warmer seas.
Lessons From East
Cyclones such as Phyan (2009), Vayu (2019), Nisarga (2020) and recently Tauktae (2021) have devastated the western coast and caused damages in billions of dollars. While investments in cyclone tracking models have helped in early evacuation and reduction in loss of lives, the economic losses due to cyclones have constantly seen considerable increase with no sign of reduction in the foreseeable future. Unplanned urbanisation has rendered more to be destroyed on coastlines.
The eastern coastline has had a long-standing acquaintance with frequent cyclone landfalls, which has resulted in improved disaster preparedness, management strategies and recovery mechanisms. The 1999 Super Cyclone that hit Odisha completely obliterated the coastal region causing ~10,000 fatalities. Learning its lessons, the state considerably invested in disaster risk reduction measures, improved its disaster mitigation strategies along with strengthening co-ordination between Centre and state agencies that resulted in reduction of the loss of lives to below 100 during Fani (2019) and less than half a dozen during the recent landfall from Yaas (2021). A similar story can be seen from Andhra Pradesh and Tamil Nadu that proudly showcased the success in mitigating the impacts from cyclones such as Phailin (2013) and Nivar (2020).
India’s west coast with big urban centres like Mumbai are now being exposed to such havocs. The impact of cyclone Tauktae (2021) has been hard on west coast leaving over 190 dead and billions of dollars in damage. The data from World Bank-funded National Cyclone Risk Mitigation Project (NCRMP), which is being implemented by the National Disaster Management Authority and state agencies, shows that the western coastal states are lagging behind their eastern counterparts in enhancing coastal resilience measures such as building multi-purpose cyclone shelters that act as line of defence against the cyclone impacts and laying underground cables to minimise the downtime of power supply.
With cyclones coming close to highly urbanised cities in Goa, Maharashtra and Gujarat, it’s imperative that inclusion of regionally tweaked risk strategies to answer the ‘Science of where’ should be carried out. Developing and investing in resilient infrastructure and creation of holistic, scalable and community level disaster risk plans is need of the hour.
Climate models show that coastal cities would continue to face increasing threat from compounding risks viz. cyclone winds, storm surges, sea level rise and flooding in the future. Hence, concerted focus on protecting and rebuilding natural defences such as coastal vegetation, mangroves, coastal sand dunes, salt pans and wetlands should be of high priority.
The east coast can show the west coast how to effectively invoke citizen awareness and a unified response mechanism by the administration. Local level climate and disaster risk assessments, supported by granular data tools and implementation of a holistic and effective disaster management plan can help assist in timely action over coastal cities in current times where the disasters seem to be increasing and response time decreasing.