The risk scenario is rapidly changing in the Arabian Sea and the Bay of Bengal as seen in the trend of rapid intensification of cyclones. This needs to be closely monitored at higher resolution and accuracy using on-site platforms such as buoys and moorings, ocean observation platforms and so on.
These systems help address the uncertainties associated with the impact of climate change on tropical cyclones, according to Sanjay Srivastava, Chief, Disaster Risk Reduction at UN-ESCAP, Bangkok.
Also read: Severe cyclone ‘Yaas’ hits home stretch, may intensify further
Cascading risk scenario
The ESCAP analysis on the intersection of the cyclones ‘Nisarga’ and ‘Amphan’ last year, and ‘Tauktae’ now, with the Covid-19 pandemic, presents a complex and cascading risk scenario, he pointed out.
While there is no evidence to suggest that ‘Tauktae’ triggered spikes in caseloads, hundreds of responders evacuating at-risk communities during ‘Amphan’ and ‘Nisraga’ cyclones later tested Covid-positive. The overlapping crises may spur respondents to eschew protective behaviour, contributing to spikes.
Global warming and cyclones
Cyclones draw their energy from warm waters, which is why they form over warm pool regions where sea-surface temperatures are above 28 degrees Celsius. The Arabian Sea used to be relatively cooler, but at the time of formation of ‘Tauktae’, SSTs were 30-31 degrees Celsius.
‘Tauktae’ clearly demonstrates the relationship between global warming and the genesis of cyclones.
The challenge lies in managing the cascading risks emanating from the interaction of the Covid-19 pandemic with cyclones. Integration of pandemic warning systems with multi-hazard early warning systems for natural and biological hazards will be the key, going forward.
Also read: Freaky weather and a mischievous track-changing cyclone
‘Tauktae’ batters West Coast
Starting from the south-western parts of Lakshadweep, cyclone ‘Tauktae’ had battered all states on India’s West Coast and the remnants caused rainfall even in the northern parts of India, Sindh province of Pakistan and Nepal during May 12-19. Its clouds advanced as far as China, observes Srivastava.
The cyclone has brought vast destruction along the west coast of India, said Srivastava. While the economic cost is yet unknown, the infrastructure (power grids, ports and roads) and agriculture sectors are hit the hardest. The cyclone also caused many maritime incidents.
Build resilient infrastructure
For instance, in Goa, disruptions in the power sector affected the supply of oxygen to critically ill Covid-19 patients. The Asia-Pacific Disaster Report 2019 highlights that a large proportion of existing critical infrastructure is located in multi-hazard risk hotspots.
A third of all power plants, ICT fibre-optic cables, airports, and over 42 per cent of road infrastructure are in multi-hazard risk hotspots. The coastal infrastructure therefore, must be made climate resilient through a combination of grey (man-made) and green efforts, including locale-specific and nature-based solutions.
Arabian Sea warms up fast
Climatologically, for every five cyclones forming annually in the Bay, only one develops in the Arabian Sea. A year ago, ‘Amphan’ gathered energy from the anomalously high SSTs in the Bay, and intensified into a super cyclone in 24 hours, Srivastava said.
A week later, ‘Nisarga’ formed over the Arabian Sea and struck India’s West Coast. The western basin of the tropical Indian Ocean (next to South Arabian Sea) has been warming for more than a century at a rate that is faster than any other region of the tropical oceans. It is now the largest contributor to the overall trend in the global mean SST.
Managing twin scenario
‘Nisarga’ struck during the first pandemic wave with limited pockets of infections, but ‘Tauktae’ hit during the second wave creating a perfect storm of an extreme climate event and the pandemic. Managing cascading risk scenarios is always challenging, he pointed out.
For instance, ‘Tauktae’ struck while India grappled not only with a major spike in Covid-19 cases but also an outbreak of black and white fungus or mucormycosis in some states. This forced officials to move hospitalised patients, protect critical supply chains and suspend vaccination campaigns.