Researchers from the University of Bristol in the UK examined the 2020 Super Cyclone Amphan – the most costly cyclone to make landfall in South Asia — and predicted its implications under several scenarios of sea-level rise caused by global warming.
The study, published in the journal Climate Resilience and Sustainability, showed that if greenhouse gas emissions continue at the current rate, more than two and a half times (250 per cent) of India’s population would experience flooding of greater than one metre, compared to the event in 2020.
“South Asia is one of the most climate-sensitive regions in the world, with super cyclones causing tens to hundreds of thousands of deaths in historical cases,” said study lead author Dann Mitchell, Professor of Climate Science at the University of Bristol. “Comparatively, very little climate impact research has been done in South Asia, despite the Intergovernmental Panel on Climate Change highlighting it as such a critical region,” Mitchell said in a statement.
The study presents a critical piece of evidence in support of ramping down greenhouse gas emissions to achieve the Paris Agreement climate goals, where other lines of evidence all too often focus on high-income countries where impacts are lower, and adaptation is more easily achievable, the researchers said.
They used sophisticated climate model projections to anticipate the scale of those affected by cyclones in the rest of this century. Although the increasing number of people at risk is anticipated to be more modest in Bangladesh, estimated to rise by 60 per cent to 70 per cent, this factors in declining coastal populations in the future, the researchers said.
They noted that if the Paris Agreement climate goals of 2 degrees Celsius warming above pre-industrial levels are adhered to, population exposure to flooding dropped close to zero in Bangladesh. However, even in this climate warming scenario, the exposures in India still showed an alarming increase of between 50 per cent to 80 per cent is expected to experience flooding in the future, the researchers said.
The main objective of the Paris Agreement, a global framework to tackle climate change, is to hold the global average temperature increase to well below 2 degrees Celsius above pre-industrial levels and endeavour to limit the temperature increase to 1.5 degrees Celsius.
“The latest IPCC report has mentioned with high confidence that tropical cyclones with higher intense categories will be more frequent in the future,” said Saiful Islam, Professor of Hydrology at the Bangladesh University of Engineering and Technology (BUET), and contributing author of the study.
“This study shows that population exposure in Bangladesh and India will be increased up to 200 per cent in the future for extreme storm surge flooding (greater than 3 metres) from intense cyclones under high emission scenarios,” Islam said.
The researchers noted that a strong, rapid and sustained greenhouse gas reduction is essential to achieve goals of the Paris Agreement and to reduce losses and damages of highly vulnerable countries.