The destruction left behind by the first tropical cyclone of 2020, Cyclone Amphan, in West Bengal's Habra city in MayBCCL
The IBS supercomputer Aleph has confirmed that tropical cyclones in the Indian and the Pacific Ocean are likely to get more intense as climate change worsens, increasing the likelihood of them being worse than category three.
Aleph also found a previously unknown ‘saturation effect’.
It is the point when excessive flooding will replace these intense cyclones as temperatures increase by more than 5 degrees Celsius and carbon dioxide in the atmosphere quadruples.
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India’s coastal cities will need to shore up their defences with tropical cyclones in the Indian Ocean and the Pacific Ocean predicted to get worse by one of the largest supercomputers in the world — the IBS supercomputer Aleph.
Even if global warming reaches ‘saturation’ and the cyclones subside, India will have to deal with coastal flooding.
IBS supercomputer Aleph located in Daejeon, South Korea at the IBS Center for Climate Physics (ICCP) at Pusan National University IBS
It took 13 months, with the supercomputer generating 2,000 terabytes (TBs) of data, for researchers at South Korea's IBS Center for Climate Physics (ICCP) to find this previously unknown ‘saturation effect’.
According to the study published in Science Advances, if global warming exceeds 5 degrees Celsius, tropical cyclones will eventually be suppressed. But that will only make way for excessive coastal flooding as the rainfall from each prospective storm increases, resulting in higher sea levels.
The one silver lining The climate models running Aleph were able to find one bittersweet silver lining — as the cyclones get more intense, they will at least be less frequent.
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Climate model simulations shows cyclones getting more intense in the Bay of Bengal, next to the Indian coastlineIBS
This confirms the theory put forward by a 2013 study that ran a historical analysis of storms across the world since 1985. It found that the number of category 4 and category 5 storms had increased in recent history, while the number of category 1 and category 2 storms showed a proportional drop.
According to the US weather agency, the National Oceanic and Atmospheric Administration (NOAA), if global temperatures increase by 2 degrees Celsius — the global warming temperature limit set by the Paris agreement — the intensity of cyclones could still worsen by as much as 10%.
This means the increase in the destructive potential of a single storm would be even greater.
Areas of Chennai were flooded due to the heavy rain in the wake of Cyclone Burevi on 6 December 2020BCCL
What’s causing these cyclones to get worse? If the amount of carbon dioxide doubles, tropical cyclones will be less frequent but the storms that are already developing will have a better chance to intensify beyond category three.
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This is because the increased presence of carbon dioxide also means higher humidity and energy levels in the atmosphere.
Cyclone Amphan seen from space using NASA's MODIS in the North Indian basin as it made landfall, delivering substantial storm surge to coastal areasNASA
However, if the amount of carbon dioxide quadruples, global temperatures will increase by more than 5 degrees Celsius. And so, people living in coastal areas will have to worry about a more permanent disaster — flooding.
According to a study from 2019, more than two-thirds of Asia’s population is at risk of coastline flooding by 2050. India is only second to China, with one of the highest populations that’s vulnerable to shrinking coastlines.
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