A fter Cyclone Phyan struck the western coast around Mumbai in 2009, the region has been ravaged twice in less than a year by two monster cyclones. From Karnataka’s coast, past Goa and Mumbai to Gujarat, Cyclone Tauktae has just completed its destructive run—49 ONGC men drowned on high seas and there are over 60 deaths in Gujarat’s coastal areas. The loss of houses, livestock, and infrastructure is still being computed. Last June, it was Cyclone Nisarga that made landfall in Maharashtra’s Raigad district killing six and destroying property estimated at over Rs 500 crore.
This was just after Cyclone Amphan struck last year in May with wind speeds of 240 kmph along the Eastern coast, leaving 128 dead in West Bengal and Bangladesh. Global warming, triggered by the effect of greenhouse gases, has led to a rise in the temperatures of ocean surfaces; and that is churning up these cyclones with deadly regularity. There is a double whammy: warmer temperatures are also melting the ice line at the two Earth’s poles and raising the level of oceans, thus increasing flooding of coastal belts.
THE DIPOLE EFFECT
The impact of climate change is not just in the idiot head of some environmentalist. They can be seen in the increasing climatic distortions—from the bushfires in Australia to locust swarms in Africa and India. The Bay of Bengal was earlier the cradle of cyclones as it was boxed in by land mass on three sides. This did not allow warmer surface temperature of the ocean to dissipate. Cyclones are generated when sea temperatures touch 28.5 degrees Celsius and above. This ‘warm pool region’—which sees 3-4 cyclonic events annually for over a century—is now finding competition from the Arabian Sea in both numbers and ferocity. The increased cyclonic activity in the Arabian Sea and the Indian Ocean is due to what climate scientists call the ‘dipole’ effect.
The phenomenon, where the warmer waters move to the West of the ocean near Africa and the cooler waters drift to the East towards Australia, has been triggered over the last decade due to ice melts and rising temperatures, that has been pushing more warm water towards the African coast. Caroline Ummenhofer, a key researcher on the ‘dipole effect’ from the Woods Hole Oceanographic Institution in Massachusetts, quoted by The Guardian, points out that while ocean currents and winds in the Atlantic and Pacific can disperse heated water, the Indian Ocean on the other hand is susceptible to retaining heat because of the large Asian landmass to the north.
The warming water in the Indian Ocean has also begun affecting the Indian monsoon, one of the most important climate patterns in the world. “Climate models (are) suggesting a tendency for such events to become more frequent and becoming stronger,” Ummenhofer was quoted as saying.
RISING OCEANS
Simultaneously, the rising temperature is impacting the vast oceans in two ways—one, thermal expansion of the water with increasing heat; and two, the melting of ice deposits such as glaciers which is pushing millions of tonnes of water into the oceans. Global sea levels have been rising over the past century, but the process has speeded up in recent years. The National Ocean Service, of the US Department of Commerce, reckons the 2014 global sea level was 2.6 inches above the 1993 average, and continues to rise at a rate of about one-eighth of an inch per year.
“The oceans are absorbing more than 90 per cent of the increased atmospheric heat associated with emissions from human activity,” says a department report. The higher sea levels, when they come with the push of a cyclonic storm, leads to destructive water surges deep into inland populations. Globally, eight of the world’s 10 largest cities are near a coast. Mumbai, one recent unpublished report by city architects has predicted, is under threat of losing as much as 20 per cent of its land mass to flooding over the next decade.
The chain, which ends with cyclonic storms mowing down houses killing scores, is a long one. It starts with global warming through the greenhouse effect—the heat that is trapped by greenhouse gases, carbon dioxide, methane and nitrous oxides, wrapped around the Earth like a sweltering blanket. From 1990 to 2019, the total warming effect from greenhouse gases added by humans to the Earth’s atmosphere increased by 45 per cent. Maybe those who survived Cyclone Tauktae would find some sense in child activist Greta Thunberg’s famous rant at the United Nations Climate Action Summit in 2019: “You have stolen my dreams and my childhood with your empty words. And yet I’m one of the lucky ones. People are suffering. People are dying. Entire ecosystems are collapsing,” she said. “We are in the beginning of a mass extinction, and all you can talk about is money and fairy tales of eternal economic growth. How dare you!”