Coastal flooding is set to rise by around 50 per cent globally due to climate change in the next 80 years, a new study predicts.
UK and Australian researchers conducted climate change scenarios where carbon dioxide concentrations in the atmosphere continue to rise rapidly.
They found the associated flooding, due to the melting of polar ice, would endanger millions of people and cost more than £10 trillion.
Land exposed to extreme flooding will increase by more than 96,500 square miles globally – up 48 per cent or more than 308,000 square miles from today.
This would mean about 77 million more people will be at risk of experiencing flooding – a rise of 52 per cent to 225 million at the very least.
The areas predicted to be most impacted by flooding are north-west Europe, south-east and east Asia, north-east US and northern Australia, they found.
But even the UK and other parts of northern Europe will be at risk of ‘extensive flooding’ by the end of this century.
A catastrophic climate-related event that would usually only happen once every 100 years would also happen 10 times as often under the foretasted climate scenario.
‘A warming climate is driving sea level rise because water expands as it warms, and glaciers are melting,’ said study lead author Ebru Kirezci at the University of Melbourne.
‘Climate change is also increasing the frequency of extreme seas which will further increase the risk of flooding.
‘Our research shows that large parts of communities residing in low-lying coastal areas are at risk of being devastated so we need urgent action.
‘Vulnerable areas need to start building coastal defences, we need to increase our preparedness, and we need to be following strategies to mitigate climate change.’
The study should be a ‘wake-up call’ for governments to implement flood defences, safeguard coastal life and infrastructure and combat carbon dioxide emissions.
‘This is critical research from a policy point of view because it provides politicians with a credible estimate of the risks and costs we are facing, and a basis or taking action,’ said co-author Professor Ian Young, also at the University of Melbourne.
The research team, which included personnel from the University of East Anglia (UEA), combined data on global sea levels during extreme storms from 1979 to 2014 with projections of sea level rises under different greenhouse gas emission scenarios.
They then used this data to model maximum sea levels that may occur by 2100 and combined this with topographic data – the physical physical features of land surface – to identify areas at risk of coastal flooding.
Also using data on global population distribution and GDP in affected areas, they estimated the population and assets at risk from flooding.
With high greenhouse gas emissions and no sufficient flood defences implemented, land affected by coastal flooding could increase by 48 per cent at the turn of the next century, they reveal.
A total of 68 per cent of the global coastal area flooded will be caused by tide and storm events, with 32 per cent due to projected regional sea level rise.
Areas that could be at risk of extensive flooding include south-eastern China, Australia’s Northern Territories, Bangladesh, West Bengal and Gujurat in India, the US states of North Carolina, Virginia and Maryland.
In Europe, particularly at-risk regions are the north-west of the continent, including the UK, northern France and northern Germany.
The global population exposed to coastal flooding could be up to somewhere between 225 million and 287 million by 2100 – the latter of which would represent an alarming 4.1 per cent of the world’s population.
Infrastructure exposed to flood water could cost of up to $14.2 trillion (£10.8 trillion), which represents 20 per cent of global GDP.
‘This analysis shows the urgency of action to address sea-level rise via both climate mitigation to reduce the rise and adaptation such as better coastal defences, as some of the rise is unavoidable,’ said Lead UK author Prof Robert Nicholls, director of the Tyndall Centre for Climate Change Research at UEA.
The analysis does not take account of existing flood defences that in places like northern Europe already provide significant protection.
But without investment in flood defences or a reduction in greenhouse gas emissions, coastal flooding could have calamitous implications for the humans of 2021, many of whom have already been born.
The study has been published in Scientific Reports.