Even if CO2 emissions remained at current levels until the end of the century, sea levels could still rise by 0.95m by 2150, according to the report. - PHOTO: ST FILE
SINGAPORE: Sea levels in Singapore could increase by 1.37m by 2150, in a scenario where a large amount of greenhouse gas emissions leads to global warming exceeding 4 deg C by the end of the century, a new study has found.
This was one of the projections revealed from a study conducted by the Nanyang Technological University’s Earth Observatory of Singapore, which aimed to extend projections of future sea-level rise beyond 2100 – by taking into consideration the different trajectories of global carbon dioxide emissions based on the latest available data.
Even if carbon dioxide emissions remain at current levels until the end of the century, sea levels could still increase by 0.95m by 2150.
The results hold scientific significance for better adaptation and mitigation measures, as scientists and policymakers can gain a more comprehensive understanding of the long-term impacts of climate change and rising sea levels for Singapore, said the Meteorological Service Singapore (MSS), a unit under the National Environment Agency, and national water agency PUB.
Both agencies told The Straits Times that 30 per cent of Singapore’s land area is less than 5m above mean sea level, which means that low-lying coastal regions and reclaimed land could experience more frequent and extensive inundation.
“A larger proportion of Singapore’s land, including densely populated areas and critical infrastructure, could be vulnerable to regular and even severe flooding if the rate and magnitude of the rise accelerates,” they added.
So far, the world has already warmed by almost 1.2 deg C, and humanity must keep global warming to 1.5 deg C to avert the more catastrophic impacts of climate change.
As global warming causes ocean temperatures to march upwards, the water expands as it heats up, causing sea levels to rise.
At the same time, global warming is accelerating the melting of ice sheets in Greenland and Antarctica, causing more water to be drawn to the equator – which affects low-lying nations such as Singapore.
The study, which was led by the observatory’s senior research fellow Timothy Shaw, found that projected changes in future sea levels will occur over timescales significantly faster than they have in the past.
During what was known as the last glacial maximum, the large and thick masses of ice were at their maximum area across the globe, leading to low sea levels and larger amounts of terrestrial space.
However, as the world exited this period of prolonged cooling, temperatures began to rise and the glaciers began to melt over the next 20,000 years into the Holocene, which is the current geological epoch.
“But today, we are witnessing much more rapid changes as temperatures rise in response to anthropogenic factors,” the paper noted.
The study was published in June in the scientific journal Communications Earth & Environment.
Hence, under a high-emissions scenario, the projected rates of sea-level rise by 2150 would be faster than any other period in the last 21,500 years.
Under a moderate emissions scenario, the scientists had statistically estimated that rates of sea-level rise were last exceeded only when ice rapidly melted during the last deglacial period between 14,000 and 9,000 years ago, which also led to significant landscape and population changes in South-East Asia.
Dr Shaw noted that the projected rates of sea-level change under moderate to high emissions scenarios could also make it difficult for coastal ecosystems such as mangroves to survive. Mangroves buffer the coastline from major storm events and sea-level rise.
A 2020 study by NTU found that existing mangrove habitats may not survive beyond 2050 if sea levels continue to rise at rates above 7mm per year. The current rate of increase is 4mm a year.
“The difference between our future climate pathways is clear. A low-emissions pathway that slows the rate of sea-level rise allows nature-based solutions such as mangroves to thrive and continue providing many ecosystem services,” he added.
The MSS spokesman also noted that the mean sea-level rise projections may vary at different locations in Singapore, depending on factors such as local vertical land motion changes, including sinking land, and ocean circulation changes.
The ongoing work at the Centre for Climate Research on Singapore’s sea-level projections, as part of the Third National Climate Change Study (V3) would potentially narrow down the current range of uncertainty at different locations.
The V3 study – which will be completed by September – looks to provide localised and advanced climate projections for South-east Asia, particularly for Singapore. - The Straits Times/ANN
