Commentary: How effectively can Singapore adapt to sea level rise?

Even as Singapore strives to adapt to rising sea levels, let’s not win that battle yet end up losing the larger war against climate change, says the Singapore Management University’s Winston Chow.
Winston Chow Channel NewsAsia 25 Aug 19;

SINGAPORE: Singapore isn’t alone in confronting the consequences of rising seas.

Several other coastal cities and small islands also face this hazard, and lessons can be drawn from how they plan for and adapt to it.

Recent research shows three general approaches can be considered when dealing with the threat of sea level rise. First, accommodate the threat, which includes flood-proofing existing buildings and infrastructure, or designating areas that would be allowed to flood during high tide.

Second, retreat from the threat, which includes the removal and reallocation of key infrastructure and assets to areas that the sea cannot inundate.

Third, protection from the threat, which includes planting and managing mangrove coasts, or engineered options like sea walls, land reclamation and polders described during Prime Minister Lee Hsien Loong’s National Day Rally speech.

THE PROBLEM: WE STILL CANNOT ANSWER MANY QUESTIONS DEFINITIVELY

Our best estimates suggest we can expect sea levels rising by at least a metre in Singapore under current emission scenarios by 2100.

It is very likely this magnitude is an underestimate, as recent measurements taken at Greenland indicate melt rates of its ice sheets are significantly increasing every year.

Herein lies the challenge: A major consideration in assessing the effectiveness of the options Singapore has in dealing with rising sea levels is that we are unable to definitively answer questions of how much and how fast sea level will rise for Singapore 80 years from today despite access to the best climate models available.

The reason isn’t so much the quality or accuracy of models used for gauging future sea levels in Singapore. The uncertainty arises because these levels depend on how much future global greenhouse gas emissions arise from our actions locally and globally.

The amount and rate of these emissions strongly affects how quickly large continental ice sheets in Greenland and Antarctica – these large kilometres-thick ice sheets are the main sources of global sea level rise – melt and contribute water to the oceans.

Hence, the recent governmental initiative to fund S$10 million into future sea level rise research is a welcome one, especially as improved understanding of physical processes affecting sea level rise is critical for adaptation decision-making.

DECISIONS WE NEED TO TAKE IN THINKING THROUGH ADAPTATION

The physical sciences can help in lowering uncertainties of long-term model forecasts of sea levels, but assessing the total effectiveness of coastal adaptation to rising seas requires an arguably more important social scientific approach.

How effective these adaptation measures are strongly depends on the confluence of several factors. First, the role of geography, such as questions of “is there a hinterland that enables coastal retreat?” or “how does the natural or pre-urban coastline historically adapt to rising sea levels?”.

Second, the types of coastal land use exposed, such as the proportion of commercial, residential or industrial areas subject to flooding from rising seas.

Third, the prevailing socio-economic context, with important questions such as “are there areas of commercial and cultural heritage are worth protecting more than others?”, or “are there socio-political and economic resources to implement these for the long term?”

In Singapore’s case, two relevant examples apply. First, identifying low lying flood-prone areas will not give a full picture of the total vulnerability to rising seas of a region.

What’s needed is an assessment of the costs accrued when installing and maintaining coastal protection, and the potential loss of natural ecosystems during its construction. These costs must then be balanced against the benefits of protecting critical infrastructure and property of financial and historical value.

This evaluation requires an in-depth socio-economic assessment of current and future land use, as well as the value judgments of existing natural capital or its ecosystem services provided. The net cost-benefits are needed prior to deciding on the coastal adaptation option.

WHAT’S NEEDED TO DECIDE ON LONG-TERM PROTECTION MEASURES

Second, evaluation of the long-term resilience of each protection measure to increasing sea levels is needed.

An engineered dyke or sea wall for polders may be relatively inexpensive and quick to construct, but it serves one protective function and can be prone to catastrophic failure under severe events.

In contrast, a reclaimed coastline with a restored mangrove buffer – like in Chek Jawa or Sungei Buloh – may take more time to develop and requires more careful management.

However, this buffer has multiple functions; mangroves can naturally “adjust” to rising sea levels to protect inland areas while reducing coastal erosion, as well as providing both a natural habitat for wildlife, and a recreational park space for visitors.

In this case, multi-disciplinary research suggests that nature-based adaptation solutions, which often provide more than one function when protecting coasts from hazards, likely result in more resilient outcomes.

Such research, combining science with humanities and social sciences, is clearly needed before deciding on long-term protection measures to sea level rise in Singapore.

WINNING THE BATTLE BUT LOSING THE WAR

Even when all relevant research is completed, and the “best” measure selected to protect Singapore from rising seas, we must not lose sight that adaptation to climate change alone is insufficient.

Mitigation, through reductions of total carbon emissions causing climate change, must go hand-in-hand with adaptation.

The S$100 billion that may be spent on adaptation is likely an underestimate; especially when climate science indicates it is virtually certain sea levels will continue to rise beyond 2100, and more resources would have to be spent on maintaining coastal protection in Singapore in the 22nd century.

Further, there are other short-term climate risks that will affect Singapore before sea level rises beyond a metre.

These include direct climate impacts such as heatwaves, severe storms, droughts and floods, and their indirect effects on food, water, and disease. These cumulative impacts also require potentially costly adaptation measures.

It would thus be sensible to place greater attention on climate change mitigation to greatly lower these risks. While the global response on mitigation is slow but steady, local action can be enhanced considerably.

In Singapore, aside from the government-led mitigation measures like the carbon tax, or individual actions involving lowering personal carbon footprints, local companies in the private sector can also act.

For instance, financial divestment from fossil-fuel industries, and R&D towards renewable energy technologies in the power generation and transport sectors can be effective in significantly reducing carbon emissions.

To extend the military analogy used by PM Lee, ensuring Singapore’s survival from climate change requires fighting multiple battles simultaneously. A strategy of focussing only on the battle against sea level rise may end up being a Pyrrhic victory, especially if other fronts are neglected.

Winston Chow is an Associate Professor of Humanities at the Singapore Management University’s School of Social Sciences and Office of Core Curriculum. He is a Lead Author for the chapter on Cities, Settlements and Key Infrastructure, and the Cities and Settlements by the Sea paper for the Intergovernmental Panel on Climate Change’s Sixth Assessment Report to be published in 2021.

Source: CNA/sl

Commentary: As ice caps melt, Singapore a hot spot for sea-level rise
Global warming doesn't only just lead to higher sea levels, it also changes which places see a disproportionate rise in sea levels, says Earth Observatory of Singapore's Benjamin Horton.
Benjamin P Horton Channel NewsAsia 23 Aug 19;

SINGAPORE: Prime Minister Lee Hsien Loong’s National Day Rally speech on Sunday (Aug 18) warned of a future where East Coast Park and the beach was no more. It was totally gone and in its place was nothing but seawater.

Why is the Prime Minister so concerned? Global sea level rose faster in the 20th century than in any of the 27 previous centuries, and observations and projections suggest that it will rise at a higher rate during the 21st century.

THE CONSEQUENCES OF RISING SEA LEVELS

At this rate, the ocean could be above 1m higher than today by 2100. Here’s what that amount of extra water could mean in terms of probable events unfolding over the next 80 years:

As many as 216 million people displaced.
Seawater moving inland, contaminating aquifers and agricultural soil.
Fish, bird and plants losing their habitats.
Floods on a scale that once occurred every 500 years averaging every five years instead.
Bigger storms with more powerful storm surges.
Low-lying islands completely submerged.
Weather patterns becoming more unpredictable.
Increased shortages of food and water.

THE CRISIS WE FACE

I am very worried about climate change and sea-level rise. I have spent the last 25 years studying the mechanisms that have determined sea-level changes in the past, and how they will shape such changes in the future.

Fundamental to this aim is bridging the gap between short-term instrumental records and long-term geological reconstructions and model predictions.

We have unequivocally shown that the rate of sea-level rise is greater now than at any time in the past 2,700 years.

READ: Commentary: The ocean is changing – it’s getting more acidic
What’s more, the Earth Observatory of Singapore has found a consistent link between changes in the average global surface temperature and sea level over the same period.

Climate isn’t a pendulum and Earth has had periods of ice and heat before, but this is different. Our Earth, the only place we have to live, is being altered by our fossil-fuel-driven industry. We are creating a planet where flooding will become more common and more destructive for the world’s coastal cities.

The Earth's average global temperature has risen by 1 degrees Celsius since the 1880s. Decades of data show a long-term uptick in the release and build-up of carbon dioxide and other greenhouse gases in the atmosphere which is trapping heat and warming up the land, oceans, and atmosphere and the sea levels are rising.

SWALLOWED UP

Global sea-level rise is one of the more certain impacts of human-induced global warming. Rising seas are posing a threat in the Maldives, where more than 90 inhabited islands are experiencing annual flooding.

In the Pacific, five of the Solomon Islands have disappeared already, swallowed up by the ocean.

Closer to home, Cua Dai Beach near the magical Vietnamese town of Hoi An reportedly has several resorts on the brink of collapse and two newly-built resorts never opened because of erosion.

Global warming affects sea level in two ways. About a third of its current rise comes from thermal expansion — when water grows in volume as it warms. The rest comes from the melting of ice on land.

So far it’s been mostly mountain glaciers, but the big concern for the future is the giant ice sheets in Greenland and Antarctica. If all the ice in Greenland melted, it would raise sea levels by 7m.

Antarctica has enough water to raise sea-levels 65m. That’s more than a third of the height of the Singapore flyer and 7 times the height of the Merlion statue. And you only need to melt a few per cent of the Antarctic ice sheet to cause devastating impact.

Satellite-based measurements of the Greenland and Antarctic ice sheets show that this melting is accelerating.

For example, Greenland's glaciers went from dumping only about 51 billion tonnes of ice into the ocean between 1980 and 1990, to losing 286 billion tonnes between 2010 and 2018.

SINGAPORE A HOT SPOT FOR SEA-LEVEL RISE

The amount of sea-level rise will vary from place to place. Regional sea-level trends include land subsidence or uplift due to geological processes, the influence of ocean currents and gravity.

The relative influence of these regional factors determines whether rates of local sea-level change are higher or lower than the global average, and by how much.

One of these hotspots is Singapore. Because Greenland and Antarctica are so large they exert a significant gravitational pull on water, which means that all the water on the planet is drawn towards the poles.

As the ice melts, however, the force of this pull to the poles weakens. This means more water is drawn to the equator instead.

So, when ice caps melt, a place such as Singapore, which sits almost on the equator, will actually get much more than its regular share of water - about 30 per cent more.

READ: Commentary: As time runs out on the climate crisis, Singapore prepares to address the cost of adapting
As PM Lee said, Singapore has already taken action to reduce carbon emissions, introducing a wide variety of efforts.

The Government also announced in March that it will start a National Sea Level Programme this year to bring together research expertise and better understand how rising sea levels will impact Singapore.

TIME TO ACT BOLDLY

Individual governments, although signed up to various international agreements, still show reluctance to take actions on the scale and with the urgency necessary. Hopefully PM Lee’s speech will change the dialogue.

But for Singapore to decide on the path forward requires robust accurate local projection of sea-level rise. Singapore must invest in the science of sea-level rise before it spends S$100 billion on adaptation measures.

The Asian School of Environment and the Earth Observatory of Singapore at NTU will be a leading research unit in this endeavour.

At NTU, we believe if we act boldly and swiftly, if we set aside our political interests in favour of the air that our young people will breathe, and the food they will eat, and the water they will drink, if we think about them and their hopes and dreams, then we will act, and it won’t be too late.

We can leave behind a world that is worthy of our children, where there’s reduced conflict and greater cooperation – a world marked not by human suffering, but by human progress.

Benjamin Horton is Principal Investigator at the Earth Observatory of Singapore and Chair of the Asian School of the Environment at Nanyang Technological University.

Source: CNA/sl