A Down To Earth magazine investigation points to an emerging threat facing the world’s vulnerable regions – climate change is changing the chemistry of cyclones in ways we do not understand yet. At speeds which are almost impossible to tackle
Despite being better prepared this time, experts were left guessing by Fani about its trajectory till 24 hours before landfall. Cyclones are becoming more unpredictable and hence, deadlier. A slowing down of wind speeds across the world is said to be one of the key reasons.
“All these years, we have been talking and warning persistently about the increasing intensity and ferocity of extreme weather events like cyclones, brought about by climate change. What we have now started noticing is another extremely disturbing trend – that of cyclones becoming more and more unpredictable in the way they travel. This has serious implications for our disaster preparedness. Our latest cover investigation in Down To Earth, with Cyclone Fani as its backdrop, delves into the proverbial eye of the storm to understand and demystify this phenomenon,” explains Sunita Narain, editor of Down To Earth, the environment, health and development fortnightly published from New Delhi.
According to the magazine, Fani was the second severe cyclone to have formed in April and made a landfall in India in the last 128 years; usually, cyclonic disturbances over the Bay of Bengal have been recorded in May or after the monsoons. “But this was not the only aspect that made Fani unique,” reports the magazine.
As it moved landwards, Fani unexpectedly overturned the India Meteorological Department’s (IMD) forecasts a few times. On April 29, the IMD had forecast that Fani would intensify into a ‘very severe cyclone’ in the next 24 hours – Fani reached that level in just half the predicted time, prompting the IMD to change its forecasts. Again, the cyclone reached Puri at 8.30 AM on May 3, well ahead of the initially predicted time of ‘afternoon’. The magazine says IMD was forced to change its predictions about Fani no less than nine times.
“There is a trend that is becoming evident here,” says Down To Earth managing editor Richard Mahapatra. “Cyclones Titli, Luban and Ockhi, which happened over 2017 and 2018, had also flummoxed scientists and experts with their extremely erratic behaviour.”
Why is this happening?
One of the main reasons behind the increasing fury of cyclones is the fact that oceans are heating up. Rising ocean temperatures lead to seawater expansion and to rising sea levels. Higher sea levels mean cyclones start at a height, putting coastal and low-lying areas at risk.
But there are other factors influencing cyclones, and wind patterns – very difficult to predict – are becoming a critical deciding element. Wind systems either slow down or change directions, triggering unpredictability in cyclones. These systems remain one of the least understood aspects of climate science. According to Josef Aschbacher, director of the Earth Observation Programme at the European Space Agency (whom the magazine quotes), “The World Meteorological Organization has identified the lack of direct global wind profile measurements as a major deficit in the current Global Observing System.”
Experts say that winds across the world are slowing down close to the land surface, in a phenomenon known as ‘stilling’. Rapid urbanisation is one of the reasons for this loss of speed, they say.
In her editorial on the subject in the same issue of Down To Earth, Narain writes: “Fani tells us many things. One, we must invest in the science of weather and in our governance capacity. Two, we must not count the number of tropical storms to conclude whether the world is risked or not. But most importantly, Fani teaches us that the future is even more risked and unpredictable than we imagined. It is time we woke up to this reality.”