SINGAPORE: The official projection, by the Centre for Climate Research Singapore, is that the country could experience a mean sea level rise of up to a metre by 2100.
But climate scientist Benjamin Horton thinks Singapore, of all places, should be worried because it could get higher.
“What about a high emission (scenario)?” questions the professor at Nanyang Technological University’s Asian School of the Environment. “We’re looking at a full 1.5 metres for Singapore … That’s our best estimate.”
To protect residents and infrastructure, he says Singapore must look at an even higher number. “You’d want to know what the extremes are … what the one-in-20 possibility is. We’re looking at greater than 2.5 metres.”
The implication is that inland areas as far as Bishan and Toa Payoh could be at risk.
That is how badly climate change could affect the island, even as the government prepares to spend probably S$100 billion over the coming decades to protect Singapore.
READ: Climate change one of the 'gravest challenges facing mankind', impact on Singapore to worsen, says PM Lee
READ: It could cost S$100 billion or more to protect Singapore against rising sea levels, PM Lee says
And as the programme Why It Matters finds out, Singaporeans might see the effects of the climate crisis sooner than they think. (Watch it here.)
TIP OF THE ICEBERG
The present-day sea level rise of 3.2 millimetres a year is “the fastest … we’ve seen for around six or seven thousand years”, notes Horton. And that does not add up to only six centimetres over the next 20 years.
“What you want to think about is totalling that … with an acceleration,” he says. “For Singapore, in the next 20 to 30 years, we’ll get about 20 to 30 cm of sea level rise.”
WATCH: Singapore in deep water: A flooded future (3:51)
Singapore is a “hot spot” because the effects of the melting ice at the poles are “amplified in the tropics”.
“These ice sheets are massive. Anything that has mass has attraction to it … (As) the ice sheets lose mass, that attraction is diminished and the water flows away,” he points out. “And it goes back to the tropics.”
Greenland, if it were all to melt, would raise global sea levels by six metres, while Antarctica has enough ice to raise sea levels by 10 times that.
“And all our observations of Antarctica and Greenland are indicating that we’re approaching a tipping point,” he adds.
Singapore’s rainfall trend is already enough to cause concern, reckons senior research scientist Muhammad Eeqmal Hassim from the Meteorological Service Singapore.
Annual rainfall has trended upwards at a rate of 9 mm per decade from 1980 to last year.
“Nine millimetres doesn’t seem a lot, but … we’ve seen an upward trend in terms of the intensity and also the frequency. So heavy rainfall events are becoming more frequent and more severe,” he says. “When it rains, it pours.”
He notes that heavy rainfall occurring over a short period is a “key ingredient” for a flash flood, “so with climate change, we can expect more of these events”.
Adam Switzer, a principal investigator for NTU’s Earth Observatory of Singapore, is inclined to agree that there is an increased likelihood of inland flooding, especially if such rainfall events coincide with a storm surge.
A storm surge occurs when low atmospheric pressure causes a swell in the ocean and wind blows the water mass against the coastline — which means a “temporary elevation of sea level”.
“So we’ll see … up to 30, 40 cm over several hours, moving through the Singapore Strait,” says the associate professor.
“You have a baseline of rising sea level, but on top of that, you have these temporary storm surges. This is where you get to the perfect storm.”
How often Singapore will experience these perfect storms, however, is a question mark, he acknowledges.
“In Southeast Asia in particular, the data gap is so significant that it’s hard to put solid numbers on where we’re going to be in 2050 or 2100.”
EVALUATING THE COSTS
NTU’s head of economics, Euston Quah, says “proper data” is also needed to measure, in dollar terms, the damage flooding could cause.
Between 2000 and 2015, economic damages from floods were estimated to have exceeded S$32 million. Just the floods in June to July 2010 had cost S$23 million, from 868 insurance claims for business interruptions, property damage and motor vehicle damage.
But there is more to measuring damages than that, says the professor of environmental economics.
There is a cost to health, including treatment delays caused by traffic congestion; productivity loss is another aspect, for example if people cannot get to work or goods cannot be delivered; and there is lost tourism.
Any loss of life must also be factored in, Quah points out, citing a study he and a colleague did in which the valuation of a person’s life here was S$4 million.
There are also intangible costs, such as loss of reputation, lost recreation and the psychological impact on people. “All of these feed back to the economy,” he adds.
This is why Singapore is spending S$400 million upgrading and maintaining drains in the next two years, on top of the S$1.8 billion spent since 2011.
But care must be taken not to overspend, says Quah, an expert in cost-benefit analysis. “If the cost of damages is S$10 million, (and) let’s say the cost of (the control measures) is S$12 million, then it makes no sense.”
He calls for a “more detailed study” of the two costs so that a “better decision” on spending can be made.
RISK TO WATER SUPPLY
Political and business leaders must also understand the scale of the “missing risks” in climate change, according to a recent joint report by the London School of Economics, the Columbia University and the Potsdam Institute for Climate Impact Research.
“Economic assessments of the potential future risks … have been omitting or grossly underestimating many of the most serious consequences for lives and livelihoods because these risks are difficult to quantify precisely and lie outside of human experience,” the report states.
One obvious scenario, however, is that a warmer climate means more droughts, so the reservoirs here and in Malaysia will be less than reliable.
NEWater and desalinated water can close the gap, but they cost more. Their production requires between five and 17 times more energy, compared with the treatment of rainwater.
These two water sources will also be affected by climate change, points out Nanyang Environment and Water Research Institute executive director Shane Snyder.
“If we don’t have enough fresh water to begin with, we can’t recycle what we don’t have,” says the NTU professor.
Seawater is not a simple solution either, as the warming of the oceans increases the amount of plankton such as algae.
Most planktonic organisms, which drift in water, are microscopic. But in the right heat and light conditions, they can multiply and create blooms that are visible even from space. And scientists predict that climate change could make blooms more frequent.
“We could have a decrease in the quality of the water,” says Snyder, who has focused on water issues for two decades and is a member of the World Health Organisation’s Drinking Water Advisory Panel.
“In Singapore, we rely primarily on membrane technology that separates the salt from the fresh water … So essentially, the increasing plankton in the ocean is more than the current filters were designed to handle," he adds.
“They can still filter the water, but they can’t filter as much water. So it lowers production, and it makes the entire system less efficient.”
Watch the episode here. Why It Matters is telecast every Monday at 9pm.