Super cyclones, also known as hurricanes and typhoons depending on where they are located, are some of the most destructive weather phenomena on the planet.
However Wind speeds within these storms can reach 270 km/h, the largest loss of life comes from the flooding they cause – known as a “storm surge” – when sea water is pushed onto the coast. Climate changeThey are expected to worsen FloodsCyclone clouds with swelling More waterDriving rising sea levels that allow storm waves to be blown furtherinland.
In May 2020 Super Cyclone AmphanThe cyclone swept across the border between India and Bangladesh, bringing heavy rains and strong winds to more than 13 million people. Storm surges of 2 to 4 metres caused flooding in coastal areas of the Bay of Bengal by the cyclone.
This is the view from the ocean Category five storm – that’s a storm’s highest possible rating – became the strongest cyclone to have formed in the Bay of Bengal since 1999, reaching wind speeds of up to 260 km/h. It weakened to a Category twoStorm following landfall, it remained to be the strongest cyclone that hit the Ganges Delta Since 2007.
Amphan had Serious consequencesfor the environment, agriculture, local economy, and people. It tragically led to more than 120 deaths as well as the destruction or destruction of homes and power lines. MillionsIn the midst a pandemic, there is no electricity or communication.
Help and relief efforts were Hamperedflooding of roads and bridges; coronavirus restrictions. Large areas of cropsMangos, rice, sesame, and mangos were all damaged. Fertile soils were also washed away by salty sea water. Super Cyclone Amphan, which resulted in more than $1.5 billion in losses, was the most expensive event to occur in the North Indian Ocean. $13 Billion (£10 billion) of damage.
In a Recent studies led by the University of Bristol and drawing on research from Bangladesh and France, we’ve investigated how the effects of storm surges like that caused by Amphan on the populations of India and Bangladesh might change under different future climate and population scenarios.
Mark II: Amphanage
Rising sea levels – thanks largely to melting glaciers and ice sheets – appear to be behind the greatest uptick in future riskThese storm surges can reach further inland, which makes them vulnerable to cyclone flooding. It’s therefore key to understand and predict how higher sea levels might exacerbate storm-driven flooding, in order to minimise loss and damage in coastal regions.
Our research used climate models from CMIP6This is the latest in a series that aims to improve our understanding about climate by comparing simulations produced worldwide by different modeling groups. We first modeled future sea-level rise based on different future emissions scenarios. Then we added that data into storm surge estimates derived from a Super Cyclone Amphan model.
We ran three scenariosThere are three possible scenarios: a low emission scenario; a business-as usual scenario; and a high emission situation. We also calculated future population in India and Bangladesh, to see how many people storm surges could impact. We found that most cases of population growth are likely, especially in urban areas.
Our findings showed that flooding from cyclone surges is very likely to increase. India’s exposure increased ranged from 50-90% to the lowest emission scenario to a 250% rise for the highest. We found that Bangladesh had a 0-20% increase in exposure for the lowest emission scenario, and a 60-70% rise for the highest emission scenario. The difference in exposure between these two countries is mainly due to the declining coastal population as a result urban migration inland.
Imagine we’re now in 2100. Even in a scenario where we’ve managed to keep global emissions relatively low, the local population exposed to storm surge flooding from an event like Amphan will have jumped by ~350,000. This is compared to a high emission scenario where an additional 1.35 million people are now at risk of flooding. And for flood depths of over one metre – a depth that poses immediate danger to life – almost half a million more people will be exposed to storm surge flooding in a high emission scenario, compared to a low emission scenario.
This research provides yet more support for rapidly and permanently reducing our greenhouse gas emissions to keep global warming at 1.5°C above pre-industrial levels.
Although we’ve focused on storm surge flooding, other cyclone-related hazardsThey are also expected to worsen, Heatwaves can be deadlyFollowing cyclones that hit land. Amphan was the victim. InterplayCoronavirus and climate change have likely made it worse for people living on the ground. As the world warms, we mustn’t avoid the reality that pandemics and other climate-related crises are only forecast to Increase.
Urgent action EmissionsProtecting your valuable assets is crucial. climate-vulnerable countriesExtreme weather can cause death. Amphan Mark II need not be as destructive as we’ve projected if the world’s governments act now to meet Paris agreementClimate goals.