A British humanitarian organization says the world needs to act now to prevent a billion people in coastal cities from being threatened by catastrophic flooding by 2060, due to climate change..
The new report released by Christian Aid, an organization that raises contributions for disaster relief and tries to call attention to root causes of international poverty, calls for fighting the flooding threat on multiple fronts. In addition to cutting carbon emissions to reduce the severity of global warming, the world's developed countries need to dramatically increase the amount of spending on efforts to protect populations against flooding.
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The report says that by 2070, the most populous city at risk from flooding with be Kolkata, India, whose population is projected to swell to more than 14 million. Another Indian city, Mumbai, will have the next greatest number of people at risk, with 11.4 million. Dhaka, Bangladesh, Guangzhou, China, and Ho Chi Minh City in Vietnam round out the top five at-risk cities. The greatest property risk is faced by a U.S.city - Miami, which will risk an estimated $3.5 billion in property losses by 2070.
Though the report didn't detail the needed measures, they could include building seawalls, restoring wetlands to absorb water, and building better systems to collect and redirect water flow during storms. Relocation of people living in low-lying areas is another potential solution. (This 2013 article from Carnegie Endowment for International Peace details various climate resilience strategies.)
But reducing the risk will be expensive. Christian Aid is calling for developed countries to increase the amount of aid provided for flood protection to $5 billion worldwide by 2020 - a ten-fold increase over present levels.
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The Christian Aid report cited United Nations Secretary-General Ban Ki-moon, who has said that every $1 spent on reducing the risks of disasters now will save $7 in damages later.
The report reiterates information that's previously been published in scientific journals or compiled by other international organizations. In a 2015 PLOS ONE article, for example, a team of researchers from several institutions estimated that 1 billion people would live in coastal cities at risk from catastrophic flooding by 2060. A list of at-risk cities was published by the Organization for Economic Co-Operation and Development.
"I think it's cities like Kolkata, Dakar, the big mega-cities of the south and the emerging economies where the people are most vulnerable to exposure to sea-level rises and to higher rain events," the Christian Aid report's co-author, Alison Doig, told BBC News.