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The Big Read in short: Fending off rising sea levels — the first steps of a giant task

SINGAPORE — Many people sat up and took notice when Prime Minister Lee Hsien Loong spoke at the 2019 National Day Rally about spending S$100 billion over the next 50 to 100 years to protect Singapore from rising sea levels.

The Big Read in short: Fending off rising sea levels — the first steps of a giant task

Each week, TODAY’s long-running Big Read series delves into the trends and issues that matter. This week, we look at the work of the team which has been tasked with protecting Singapore against rising sea levels in the decades to come. This is a shortened version of the full feature,​ which can be found here.

  • National water agency PUB’s coastal protection department was set up in April 2020 to protect Singapore against rising sea levels 
  • It recently concluded the first tranche of its site-specific study for City-East Coast coastline, which includes literature reviews of existing coastal protection measures used both locally and internationally
  • Moving forward, the team is in the process of identifying flood-risk areas and collecting site data to support the next stage of the study
  • Similar studies for the North-West Coast coastline have recently started, and another for Jurong Island will commence this year
  • Beyond developing strategies, there is also a need to educate and engage the public to increase awareness and understanding of the topic and what is at stake, says a senior team member. 

SINGAPORE — Many people sat up and took notice when Prime Minister Lee Hsien Loong spoke at the 2019 National Day Rally about spending S$100 billion over the next 50 to 100 years to protect Singapore from rising sea levels.

It was after all, a matter of "life and death", as Mr Lee put it.

Since then, the buzz has somewhat dwindled as more pressing issues occupied Singaporeans' minds. And there was also the not insignificant matter of a pandemic which seized Singapore and the rest of the world, and very much put everything else on hold.

Quietly in the background though, efforts to lay the groundwork to protect Singapore's coastal areas have continued unabated: For now, the gigantic task of preventing parts of the island from becoming partially submerged beneath the waves — possibly by the end of the century if nothing is done — falls onto a group of public servants comprising senior assistant director Sarah Hiong, 36, senior engineer Eugene Lim, 33, and their colleagues from national water agency PUB’s coastal protection department, which has over 40 members.

During Chinese New Year, or even at gatherings, when I tell them (friends and family) about my job, they will be like, ‘Oh, what is sea level rise and what do you do?’
Mr Eugene Lim, 33, senior engineer at PUB's coastal protection department

Not that any of them are fazed by the size of the undertaking — the urgency and significance of which, in fact, seem to be lost on some members of the public such as the team members' own friends and family.

“During Chinese New Year, or even at gatherings, when I tell them (friends and family) about my job, they will be like, ‘Oh, what is sea level rise and what do you do?’” said Mr Lim.

But instead of getting disheartened by the lack of awareness, Mr Lim said their curiosity often presents him with an opportunity to educate them on the need to get Singapore ready for rising sea levels caused by global warming and melting ice sheets.

Mr Lim’s team manages Singapore’s first site-specific study for the City-East Coast coastline which covers 57.8km of coastline across areas including Changi, East Coast, Marina East, Marina South as well as part of the Greater Southern Waterfront. The study was announced a year ago and is slated to complete by 2025.

Senior assistant director Sarah Hiong and senior engineer Eugene Lim from PUB’s coastal protection department.

Part of the job, said Mr Lim, entails understanding the characteristics unique to the area, which will then allow PUB to design suitable coastal protection measures.

According to data from the National Climate Change Secretariat, about 30 per cent of Singapore is less than 5m above sea level.

The sea levels are projected to rise by 1m by 2100. However, they could go up to 4m or 5m above today's mean sea level if factors such as daily tidal activity, storm surges and land subsidence — the sinking of land caused by tectonic movement — are taken into account, said PUB on its website.

Referencing these facts, Minister for Sustainability and the Environment Grace Fu said in March that this is “high enough to potentially flood one-third of Singapore”.

PUB was appointed in April 2020 to lead and coordinate the Government’s efforts to protect Singapore’s coastlines.

In any case, Ms Fu described coastal protection in her speech in March as a “long-term endeavour”.

Among those in the coastal protection department helping with this endeavour is Ms Hiong and her masterplanning and regulatory team.

Ms Hiong said her division is responsible for reviewing Singapore’s long term-coastal protection strategies, policies and regulations that need to be put in place.

“As climate science and projections are continuously evolving, we have to think about the implications of different scenarios of sea level rise on Singapore. This complicates the planning of coastal protection strategies,” said Ms Hiong, adding that coastal protection against rising sea level is a relatively new field here.

POSSIBLE SOLUTIONS BEING STUDIED

Among the suggestions given by Prime Minister Lee Hsien Loong to tackle rising sea levels during his 2019 National Day Rally was one that involved reclaiming a series of islands offshore from Marina East to Changi, connecting them up with barrages and creating a reservoir, similar to Marina Reservoir.

Singapore has also already put in place some measures, including the use of polders, which are tracts of land that lie below sea level and are reclaimed through the building of dykes, drainage canals and pumping stations.

There is an ongoing polder project on Pulau Tekong, led by the Housing and Development Board, that is more than halfway complete and set to finish by the end of 2024.

Minister for National Development Desmond Lee said last month that the project, the first of its kind for Singapore, will help the nation to gain experience in developing polders, which “could be an option for coastal protection and resilience against sea-level rise”.

There are also plans to build infrastructure higher above the sea level. Professor Benjamin Horton, the director at the Earth Observatory of Singapore at the Nanyang Technological University, said that Changi Airport, for example, is building Terminal 5 at 5.5m above present sea level to protect against future rising sea levels.

“We can further think about engineering advances that will enable buildings to float,” he added.

PUB's coastal protection department is also looking at other possible solutions, with senior assistant director Sarah Hiong reiterating that it is “important to study all options, even long-term ones, comprehensively”.

Here are some other alternatives being studied by Singapore: 

SEA WALLS AND ROCK REVETMENTS

Both are hard structures that protect against coastal erosion. At present, PUB says they line about 70 per cent of Singapore’s coastlines.

“Building sea walls around the entire Singapore is a simple and direct but not an entirely feasible solution, because we also have to consider the interactions between the land and sea,” said senior engineer Eugene Lim from PUB's coastal protection team.

For example, this could include natural coastal habitats, recreation and industries that require waterfront access.

“It will also not be aesthetically pleasing for the public too. Try imagining having a great wall built around the entire coastline of Singapore,” he added.

NATURE-BASED HYBRID SOLUTIONS 

Mr Lim said PUB intends to explore hybrid solutions, which combine engineering solutions with nature-based elements, including the planting of mangroves, seagrasses or vegetation.

A benefit of this option, said Mr Lim, is that it provides an opportunity for Singapore to create habitats to enhance biodiversity.

However, it will not be possible to rely entirely on nature-based elements.

Taking mangroves as an example, Associate Professor Koh Tieh Yong, a weather and climate scientist from the School of Science and Technology at Singapore University of Social Sciences (SUSS), said that when sea level rises, the higher seawater will still infiltrate mangrove lands.

“During a storm, mangrove tree roots serve to break up the waves and hold down the earth, thus reducing coastal erosion. In this way, mangroves can protect areas further inland until the sea rises beyond a level where even mangroves cannot thrive.”

Thus, there will still be a need to pair it with man-made structures like sea walls as the main solution to sea level rise, he said.

Another downside is that most of Singapore’s coastal land is needed for residences, industries, maritime port, airport or recreational beaches and so cannot be replaced by mangroves.

MULTIFUNCTIONAL COASTAL DEFENCES 

Due to Singapore’s land scarcity, multifunctional structures such as Marina Barrage, would be an ideal solution, said Mr Lim.

The barrage not only provides a source of water supply, it acts as flood control and even a venue for recreation — a “hot spot for families” to have picnics, fly kites and spend quality time together, he said.

One overseas example that protects against sea level rise which Ms Hiong highlighted is the Katwijk underground parking garage in the Netherlands, where much of the country is below sea level.

Designed by the Royal institute of Dutch Architects, it was the winner of the Best Dutch Building of the Year in 2016.

Situated beside a popular beach, the project is a car park that is not only able to house 650 cars, but also plays a critical role as a dyke to protect the small, eponymous town against future floods.

What is interesting about the project, said Ms Hiong, is that “you can't even tell that it's actually a coastal protection measure” because it is concealed within a sand dune so that it blends in with the beachfront.

“So this is an example that really inspired us… to build something that not only has such an important use for the nation, but also something that the public will actually come to enjoy,” she said.

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THE PROGRESS SO FAR

One of the coastal protection department’s first tasks was to conduct studies on how to protect specific segments of the coastline along City-East Coast.

Mr Lim said that the first tranche of the study, which began in May last year, was completed in December.

Aside from completing literature reviews of existing coastal protection measures used both locally and internationally, he said it highlighted the need to integrate the “multifunctionality within our coastal defences” for land-scarce Singapore, as well as the importance of stakeholder engagement.

Another concept that the team learned from other countries and their expert panel is “adaptive planning”, said Ms Hiong.

Broadly, this involves implementing coastal protection measures, such as sea walls, first, and then raising it higher should sea levels rise faster than projected.

Additionally, the first stage of the study had also identified “data gaps” in biodiversity information, and a biodiversity survey has been commissioned to plug these gaps, said Mr Lim.

Moving forward, Mr Lim said his team is in the process of identifying flood-risk areas and collecting site data to support the next stage of the study, which involves the planning and design of coastal protection measures along the City-East Coast coastline.

Similar studies for the North-West Coast coastline have recently started, and another for Jurong Island — led by site developer JTC Corporation — will commence this year. PUB said it hopes to complete formulating coastal protection plans for these three areas by 2030.

Once that is done, Mr Lim said implementation of the measures will start.

As for the other coastlines in Singapore, he said that the respective site-specific studies “will be rolled out progressively”.

Sea levels are projected to rise by 1m by 2100. However, they could go up to 4m or 5m above today's mean sea level if factors such as daily tidal activity, storm surges and land subsidence are taken into account.

Beyond these site-specific studies, Ms Hiong said PUB had also embarked on the development of a Coastal-Inland Flood model in April last year, which will help assess the impact of climate change on Singapore’s coastal and low-lying areas.

This means that in theory, it would be possible to see how extensive the damage caused by rising sea levels would be if there are no coastal protection measures in place.

While no deadline for when the purpose-built model will be completed, Ms Hiong said it will be continually updated with the “latest climate data to help us evaluate the effectiveness of proposed coastal protection infrastructure”.

‘A STEP AT A TIME’

Due to Singapore’s “very limited land”, Mr Lim said there is a need to be creative and find coastal protection solutions that optimise land use or serve multiple uses in order to balance coastal resilience with other land needs.

While it is useful to learn and adapt what other countries or cities have done, Mr Lim said there is a need to understand why these measures work, and “critically review if they will be equally effective when implemented in Singapore, as our conditions are different”.

Ms Hiong also said that the coastal protection department does not work in isolation, as a large part of the work involves engaging different stakeholders such as other government agencies, nature groups, businesses or even residents.

Be that as it may, Ms Hiong said there are still segments of society who think that rising sea levels is a “future problem”, and with almost eight decades to go till the next century, it may be deemed too far down the road for them to be concerned with now.

But because planning for coastal protection and the construction of the physical coastal protection structures take time, it has to start now.

Ms Hiong added that “beyond developing Singapore's coastal protection strategies, there is also a need to educate and engage the public” to increase awareness and understanding of the topic and what is at stake.

One way PUB has gone about this task is through a three-part edutainment series about coastal protection, “The Investigations of Sea-rius Li”, featuring local actor Alaric Tay. The series, in which Ms Hiong also makes an appearance, was launched on PUB’s website and social media channels in February.

RISING SEA LEVELS — A CLEAR AND PRESENT THREAT

As global warming continues its relentless march, rising sea levels are not a distant threat, scientists told TODAY.

As it is, global sea level has been rising in the 20th and 21st centuries at an “unmatched rate” for at least the last 3,000 years, said Professor Benjamin Horton, the director at the Earth Observatory of Singapore at the Nanyang Technological University.

Prof Horton, whose research concerns sea-level change, said since 1900, the sea level has risen by 20cm and the “waters are only rising faster”.

He said the average rate of sea level rise has increased from 1mm per year between 1901 and 1971, to 4mm per year between 2006 and 2018.

No matter how quickly nations lower emissions now, the world is looking at about 15 to 30 cm of sea-level rise through the middle of the century, given the long-drawn impact of global warming on the oceans and ice sheets.
Professor Benjamin Horton, the director at the Earth Observatory of Singapore at the Nanyang Technological University

While this might seem like a miniscule amount, its impact has already been felt by some of Singapore’s neighbours, such as Indonesia where its capital Jakarta is sinking at a rate of 10cm a year due to a confluence of rising sea levels, land subsidence and rapid development.

The Indonesian government has since made a decision to shift its capital from the megacity, which has already sunk by at least 2.5m in 10 years according to a 2020 article by CNA, to Nusantara on the east coast of Borneo Island near Balikpapan.

Said Prof Horton: “Here’s a depressing fact: Sea-level rise through to 2050 is fixed.

“No matter how quickly nations lower emissions now, the world is looking at about 15 to 30 cm of sea-level rise through the middle of the century, given the long-drawn impact of global warming on the oceans and ice sheets.”

As such, Prof Horton said that adaptation to sea-level rise should be a long-term obligation.

The average rate of sea level rise has increased from 1mm per year between 1901 and 1971, to 4mm per year between 2006 and 2018.

SINGAPORE’S WATER STORY V2.0?

Despite the somewhat bleak outlook, both Mr Lim and Ms Hiong see similarities between the coastal protection department’s current objective and Singapore’s other long-standing existential issue — an adequate water supply.

“Singapore is one of the most water-stressed countries in the world, but through a combination of grit and ingenuity, we have managed to develop a robust and diversified water supply with the four National Taps strategy,” said Mr Lim.

“Today, Singapore is recognised as a model city for its successful water management,” said Mr Lim.

While rising sea levels are indeed a multi-faceted and complex challenge, Mr Lim added that his team is optimistic that PUB will, in the same way, turn this vulnerability into an opportunity.

Related topics

PUB coastal flood risk rising sea levels climate change

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