Revealed: The 20 countries with the highest number of cities at risk of deadly floods – so is your home at risk?

Scientists have identified the 20 countries with the highest number of cities at risk of potentially deadly floods due to climate change.

Researchers are concerned because settlements are expanding into flood-prone areas rather than moving away from them – which could endanger lives in the near future.

The Netherlands tops their list, followed by Vietnam, the Southeast Asian country of Laos, Bangladesh and Fiji in the South Pacific.

The top 20 also includes Japan, China, Switzerland, Croatia, Austria, Egypt as well as South and North Korea.

Although the UK is not on the new list, previous research has found that one in six English properties could be affected by flooding by 2050 due to sea level rise.

Scientists have identified the 20 countries with the highest number of settlements at risk of potentially deadly floods due to climate change

Scientists issued a dire warning today: stop building homes in flood-prone areas (areas vulnerable to flooding due to climate change). Pictured aerial view of the same location in Quảng Nam, Vietnam, in 2002 (left) and 2021 (right). Note the expansion of buildings, primarily residential, in flood-prone areas near the water

The new study was led by Jun Rentschler, an economist at the World Bank, the global financial institution based in Washington, DC

Flood exposure has been found to be particularly high in countries where settlements are concentrated along river valleys and basins (such as Bhutan, Egypt and Bangladesh) and coastal areas (such as Fiji and Vietnam) or both (such as the Netherlands).

“Since 1985, human settlements around the world – from villages to megacities – have expanded continuously and rapidly into today’s food zones,” Rentschler and colleagues say in their study.

“In many regions, growth in the most hazardous food areas far exceeds growth in non-hazardous areas, particularly in East Asia.”

“Instead of adjusting their exposure to climate hazards, many countries are actively increasing their exposure.”

According to the experts, “there is growing evidence” that climate change increases the likelihood of “extreme natural disasters” such as floods.

Climate warming is driven by the release of gases such as CO2 and methane into the atmosphere, which trap heat (known as the greenhouse effect).

Global warming is already melting ice in the polar regions, and this meltwater is entering the oceans, gradually leading to sea level rise and severe flooding.

Warmer air can also hold more water, increasing average rainfall worldwide, increasing the risk of flooding, as was recently seen in New York.

Scientists already believe that those who live in coastal regions and are the first to become permanently submerged are most at risk from sea level rise.

The Netherlands tops the list, followed by Vietnam, the North African country of Laos, Bangladesh and Fiji in the South Pacific

Scientists blame the recent flooding in the New York metropolitan area on increased heavy rainfall caused by climate change (image). Warmer air can hold more water, meaning rainfall increases on average worldwide, according to the Met Office

READ MORE The Big Apple recorded its wettest day ever

Flooding across the city prompted Mayor Eric Adams and Gov. Kathy Hochui to declare a state of emergency, which remains in effect through Friday evening

For the study, the team combined global flood hazard data with annual “settlement footprint data” – which shows where people live and work in cities – from 1985 to 2015.

They found that global settlement area increased by 85.4 percent over this 30-year period.

But “high flood hazard” settlements – defined as areas at risk of flooding depths of more than 150 cm (60 inches) in a 100-year flood event – ​​grew by a whopping 105.8 percent.

Meanwhile, the number of settlements at greatest risk of flooding during this period rose by a worrying 121.6 percent.

Unfortunately, even in high-income countries like the Netherlands, many settlements are not protected from such once-in-100-year flood hazards.

Things are much worse in the top 20 low- and middle-income countries such as Laos and Vietnam, where funding to build such defenses is not available.

For example, in Laos and Vietnam there are many “highly exposed” settlements without strong protection systems.

Although the Netherlands leads the way in terms of settlements in danger areas, it is one of the few countries, along with Japan and the USA, that invest heavily in protecting settlements that were already in flood-prone areas in 1985.

For example, Dutch authorities have built sea dikes – man-made structures to protect low-lying areas – to protect against storm surges.

Although the total area of ​​settlements worldwide has increased by 85.4 percent, settlements at high risk of flooding have increased by 105.8 percent and settlements with the highest risk of flooding have increased by 121.6 percent

Pictured: new flood gates, part of a storm protection project, in a part of Middletown, New Jersey that was hit hard by Superstorm Sandy in 2012

Images of citizens struggling with flooding are becoming the norm. Pictured, flooded street in Lagos, Nigeria in September 2023

The researchers say their findings have “real implications for urban planners and policymakers” around the world – not just in the top 20 countries.

“In areas where the risk of flooding is already high, investments in disaster preparedness are crucial to limit losses,” they say.

“In areas where the risk of flooding is still low but increasing rapidly, there is an urgent need to revise land use and urbanization plans, as well as update risk-based building regulations and infrastructure master plans.”

“Although land scarcity and geographical constraints may mean that settlement in flood plains cannot always be avoided, flood protection systems and disaster preparedness measures can still support stable socio-economic development.”

The study was published today in the journal Nature.