Asia’s coastal cities at greater risk from sea-level rise, UN warns

A large part of Asia’s population is concentrated in coastal regions and so will be more impacted by climate change. UN Secretary-General Antonio Guterres warns Pacific Ocean countries are also under threat; many residents are already migrating. Between 2013 and 2022, sea levels rose by 4.5 millimetres a year, a rate three times higher than between 1901 and 1971.

Milan (AsiaNews) – Rising sea levels are a threat to countries with coastal cities, the World Meteorological Organisation (WMO) says in a report, most notably in Asia, which has the most populated urban centres in the world.

Mumbai, Shanghai, Dhaka, Bangkok and Jakarta are particularly at risk, followed by Maputo, Lagos, Cairo, London, Copenhagen, New York, Los Angeles, Buenos Aires and Santiago.

At least 900 million people living in coastal areas around the world will be impacted by rising sea levels, while the residents of small Pacific Ocean countries such as Fiji, Vanuatu, and the Solomon Islands, are already migrating since they are partially below sea level and lack the economic means to fight climate change on their own.

“If temperatures rise by 2 degrees, that level rise could double,” UN Secretary-General Antonio Guterres told the Security Council on Tuesday. “Under any scenario, countries like Bangladesh, China, India and the Netherlands are all at risk.”

“Meanwhile,” he added, “the WMO tells us that even if global heating is miraculously limited to 1.5 degrees, there will still be a sizeable sea level rise.” In fact, “every fraction of a degree counts.”

According to the WMO report, thermal expansion contributed to 50 per cent of sea-level rise during 1971-2018, while ice loss from glaciers contributed to 22 per cent, ice-sheet loss to 20 per cent and changes in land-water storage 8 per cent.

As a result, sea levels rose by 4.5 millimetres per year between 2013 and 2022, three times higher than between 1901 and 1971.

At least 15 million people in Asia will be affected by coastal flooding by 2030, this according to previous studies that assessed the impact of sea-level rise on Bangkok, Hong Kong, Tokyo, Jakarta, Seoul, Taipei and Manila. Overall, more than 1,800 square kilometres of land could be below sea level.

If all of Asia’s coastal regions are considered, the number of people affected rises to almost 600 million.

As a result of rapid urbanisation over recent decades, a large part of Asia’s population now lives along the continent’s coastline, in cities like Dhaka, Yangon, and Ho Chi Minh City in addition to those already mentioned.

Extreme sea-level rise could impact US$ 724 billion in gross domestic product; depending on the city, the losses could range from 0.4 per cent to 96 per cent.

With respect to flooding, more than 96 per cent of Bangkok's land area could be flooded by 2030, threatening the lives of 10.45 million people.

In neighbouring Indonesia, the government has already launched a plan to move the capital to a new city, Nusantara, on the island of Borneo, since 40 per cent of the current capital, Jakarta, is below sea level, with the northern part of the city sinking at a rate of 4.9 centimetres per year.

The problem of rising seas is not limited to built-up areas; in Mumbai, where 80 per cent of the city could end up underwater by 2050, food security is already being been compromised because of saltwater intrusion’s impact on local freshwater fisheries.

China's coasts are also threatened, particularly the cities of Tianjin, Shanghai, and Guangzhou.

A report last year suggested that sea levels rose by 84 millimetres in 2021 compared to the average recorded between 1993 and 2011, an annual average increase of 3.4 millimetres since 1980, higher than the global rate over the period.

In Shanghai, the authorities have begun to examine the possibility of building drainage channels and barriers against rising tides, but climate experts warn that rising sea levels combined with higher temperatures will also increase precipitation and the frequency and intensity of storm surges, damaging China's coasts more intensely than direct flooding.