[Rising ocean temperatures caused by climate crisis
increasing number of cyclones and intensity of storms, say experts]
By Neelima Vallangi
Last week India was battered by
Cyclone Tauktae, an unusually strong cyclone in the Arabian Sea, resulting in
widespread disruption. This week, another severe storm, Cyclone Yaas, formed in
the Bay of Bengal, leading
to more than a million people being evacuated into safe shelters.
The Indian subcontinent has been
facing the brunt of costly
and deadly tropical cyclones for decades. But scientists say global
heating is accelerating the rate of ocean warming, leading to an increased
number of cyclones and rapid intensification of weak storms, with severe
repercussions for the country.
Cyclones are much more likely to
gather intensity over warmer waters. The Arabian Sea, part of the west Indian
Ocean, generally has a sea surface temperature of below 28C (82F), and recorded just 93 cyclones between
1891 and 2000. By comparison, the warmer Bay of Bengal in the east Indian
Ocean, where temperatures are permanently above 28C, recorded 350 cyclones over
the same period.
Between 2001 and 2021, 28 cyclones
formed in the Arabian Sea, along with a marked increase in storm intensity,
fuelled by rising sea surface temperatures which reached as high as 31C (88F).
A 2016 Nature
study found anthropogenic global heating had contributed to the
increased frequency of extremely severe cyclonic storms over the Arabian Sea.
Roxy Mathew Koll, a climate
scientist at the Indian Institute of Tropical Meteorology, said: “The entire
Indian Ocean is warming at a faster rate compared to the Atlantic or Pacific.
And within the Indian Ocean, the western parts of the Indian Ocean are warming
much more. We see that it [sea surface temperature rise] is connecting well
with the changes in the intensity and frequency of cyclones especially in the
Arabian Sea and also the rapid intensification.”
The rapid intensification of weak
storms into severe cyclones has been observed in the Arabian Sea and the Bay of
Bengal over recent years. But the current forecasting models do not pick up
rapid intensification in advance, posing a huge challenge to both disaster
management authorities and the public in responding to the risk adequately,
according to Koll.
“Climate projections show that the
Arabian Sea will continue to warm at a faster rate than what we have seen
before, and there will be more extremely severe cyclones in the Arabian Sea,”
he added.
India is especially vulnerable
as 14%
of its 1.3 billion population live in coastal districts, and the number
living in coastal areas below 10 metres elevation is forecast
to rise threefold by 2060.
“The trail of destruction left
behind by Cyclone Tauktae is a grim reminder of India’s vulnerability to
extreme climate events,” said Abinash Mohanty, programme lead at the Indian
thinktank Council on Energy, Environment and Water.
Mohanty said the government should
invest in an improved emergency response framework that accounts for the
compounded impacts of extreme events, a detailed climate risk assessment and
climate-proofing of infrastructure.
Inland countries such as Nepal can
also be affected when strong Indian Ocean cyclones do not dissipate after
landfall, causing excessive snowfall in the Himalayan highlands, said Arun
Shrestha, a climate scientist at the International Centre for Integrated
Mountain Development. “The blizzard in Everest of 1995, Cyclone Phailin in 2013
and Cyclone Hudhud in 2014 are some examples of cyclones impacting the
Himalayas.”
Anomalous warming in the Indian
Ocean has
also been linked to locust swarms, flooding
in Africa, Australian bushfires, and changes in global
rainfall patterns.