Contesting against sea level rise in Singapore

• Many of the world’s most significant cities have urbanized next to the sea and have even expanded into the sea through extensive land reclamation.
• Due to climate change the coastal storms are becoming more intensified and sea levels are rising, and this is a huge challenge that governments have to face.
• The goal of the Singapore Sea Level Rise Design Competition is draw awareness to the impacts of sea level rise and its possible solutions.

For thousands of years, humans have built settlements and lived in coastal areas to take advantage of maritime transportation, trade, and abundant fisheries. In recent history, many of the world’s most significant cities like Miami, Hong Kong, New York, Shanghai, Tokyo, Bangkok, Ho Chi Minh City, and others have urbanized next to the sea. Many cities like San Francisco and Singapore have even expanded into the sea through extensive land reclamation. The United Nations now estimates that over 600 million people live within 10 meters of sea level. This has created significant challenges as climate change intensifies coastal storms and sea level rise.

According to the 2021 Intergovernmental Panel on Climate Change’s Sixth Assessment Report, the global mean sea level is expected to rise between 0.28 and 1.01 meters by the year 2100 under the very low to very high greenhouse gas (GHG) emissions scenarios. However, uncertainty in ice-sheet processes means that sea levels could rise as high as 2 meters by 2100 and 5 meters by 2150. Additionally, floods and storm surges could augment the impacts of sea level rise on coasts. For governments, the challenge remains in how to plan for and adapt to rising sea levels. For 65% of coastlines, it is estimated that it is not economically viable to defend against sea level rise.

To draw awareness to the impacts of sea level rise and its possible solutions, Water Science Policy hosted the Singapore Sea Level Rise Design Competition in partnership with the Institute for Environment and Sustainability (IES) at the Lee Kuan Yew School of Public Policy at the National University of Singapore. The competition asked students and young professionals to design a Singapore coastline in 2100 in a high sea level rise scenario. The competition holistically involved multiple Sustainable Development Goals: 

• SDG 13 (Take urgent action to combat climate change and its impacts)
• SDG 11 (Make cities and human settlements inclusive, safe, resilient, and sustainable)
• SDG 14 (Conserve and sustainably use the oceans, seas, and marine resources for sustainable development)

As a low-lying island city state, Singapore is especially vulnerable to sea level rise. Around 30 percent of Singapore has an elevation of less than 5 meters above the Singapore Height Datum (NCCS, 2022). In his 2019 National Rally Day Speech, Prime Minister Lee Hsien Loong announced that it could cost Singapore over S$100 billion over the next 50-100 years to prepare for the effects of rising Sea Levels.

The winning design came from Michelle Meaclem and Micheala Chan (World Federation of Engineering Organisations Young Engineers / Future Leaders Working Group for Climate Action). Their design included a combination of artificial reefs, restoration of existing reefs, mangrove restoration, shellfish prisms, and barrier islands.

New Artificial Reefs and Restoration: Reef restoration and the conservation of the existing reefs found skirting the islands south of mainland Singapore is imperative as reefs provide a buffer against waves, storms, and floods. These reefs have been harmed as a result of land reclamation and associated turbidity increases, as well as oil spills. Conservation and restoration can ensure that the rich biodiversity in Singapore’s remaining reefs continue to protect Singapore and bolster coastal tourism.

Artificial reefs are proposed along the Johor Straits. While artificial reefs cannot replace real reefs, they provide similar breakwater and coastal protection properties. A number of novel techniques are recommended, including modular Lego reef cultivation and Biorock Technology.

Mangrove Restoration: Mangrove restoration is proposed on the coastline along the Johor Straits, which is largely composed of mangroves and mudflats. Such blue carbon ecosystems provide multiple benefits aside from coastal protection. They filter run-off, build fish stock by offering refuge and breeding grounds, and store carbon. With the majority of seafood in Singapore being imported, the additional benefits of food security cannot be discounted.

Shellfish Reefs and Prisms: Shellfish protection is proposed near the port on the southern coast. This will help improve the water quality and aquatic health (therefore, encouraging more marine growth), and dissipate wave energy. There are several case studies of shellfish protection, including the use of mussel ropes at Waitemata Harbour, New Zealand, shellfish reefs at Eastern Scheldt, Netherlands, and Oyster Prisms at Cedar Key, USA. A mixture of these shellfish protection mechanisms can be implemented in the suitable locations (i.e mussel ropes at the docks, oyster prisms situated downstream of the port near beach, and shellfish reefs downstream).

Barrier Island: An artificial barrier island is proposed off the south-eastern coast of Singapore to protect the beaches. This will act like a breakwater, made of low carbon materials (such as x-blocs) which will encourage marine growth and protect a larger footprint than the existing breakwaters. Although there will be some ecological impacts with the implementation of an artificial barrier island, it is expected that these impacts will be mitigated in collaboration with marine ecologists.

The winning design reflects the growing interest in nature-based solutions, which are hybrid solutions that combine engineering solutions with nature-based elements. This includes the suggested ocean-based solutions of planting of mangroves, seagrasses, or nearshore vegetation. For example, it is estimated that $1 spent on wetland and reef restoration will save $7 in storm damages in the Gulf of Mexico. This is because the consequences of disaster events can be reduced by proactive actions taken to mitigate them.

The recommendations set forth in the winning design will likely be incorporated in the future alongside static walls and landforms like sea walls, floodwalls, levees, dikes, and breakwaters. With a Greenpeace Report estimating that 15 million people and 1,829 square kilometers land in seven major Asian cities could be affected by extreme sea-level rise and coastal flooding by 2030, cities will be eager to implement optimal solutions to mitigate the impacts of climate change.