A car gets trapped on the flooded Zhongshan West Road on August 25, 2008 in Shanghai, China.
The Coastal City Flood Vulnerability Index (CCFVI) developed by British and Dutch scientists shows that Shanghai is the most vulnerable city to serious flooding.
According to the study published in the journal Natural Hazards
, researchers considered exposure, susceptibility and resilience to coastal flooding, as well as social and economic factors of cities.
"Very often we look at these sorts of things in a very deterministic way," said co-author Nigel Wright of the University of Leeds' School of Civil Engineering. "We look at physical exposure, so if you live by a river you are exposed to the risk of flooding."
According to Prof. Wright, the CCFVI used a range of data, consisting of 19 components.
"We still use the physical ones but also economic and social ones, such as how much attention is given by local or national governments to protect citizens and citizens' property through investing in various forms of resilience," he told the state-funded BBC.
The team focused on Shanghai, Dhaka (Bangladesh), Casablanca (Morocco), Buenos Aires (Argentina), Calcutta (India) and Rotterdam (the Netherlands), all coastal cities built on river deltas.
They considered the percentage of a city's population living close to the coastline, the amount of time needed for it to recover from flooding, the amount of uncontrolled development along the coastline, and the volume of measures to physically prevent floodwater entering a city.
"What this index tries to do is to widen this out and look at social indicators too," said Prof. Wright. "You can have people who live in the same area but their vulnerability is actually different.
Age is one of those things; if you are over 65 or under 18 then you are more vulnerable than an adult because you are not able to take the actions necessary to protect yourself or evacuate."
"Economies that are developing rapidly have not had to implement resilience in the past because there has not been the economic output to protect.
"At the other end of the scale, somewhere like the Netherlands, where there have been serious floods in the past that have had an impact so they know they need to do it."
Experts are always concerned about the global economic consequences of flooding as well as its local and physical impacts.
"After the Japanese tsunami a lot of hard disk manufacturing was moved to Bangkok, then there were the floods in Bangkok and the price of hard disks went up dramatically because the factories had to close down and there was a shortage of hard disks," Prof. Wright explained.