Climate scientists from Nanyang University of Technology, Singapore (NTU, Singapore) have extended Singapore’s famous sea level record to almost 10,000 years, providing a more reliable set of data to help future sea level rise forecasts.
One of the main challenges in studying climate change is to restore its history over thousands of years. To have a better sense of the potential causes and consequences of future change, scientists need to learn and understand the past.
Extracting ancient sludge from a depth of up to 40 m underground on site at the Singapore Marina, an international team led by NTU researchers performed the samples using rigorous laboratory methods (eg, identification of microfossils such as foraminifera) and statistical analysis to obtain the history of the sea level of Singapore.
For climatologists, the further sea level records go back in time, the clearer the picture for future forecasts can be. The transition to the beginning of the Holocene (10,000-7,000 years ago) was the last major episode of natural global warming in Earth’s history, when melting ice sheets and warming oceans led to 20 meters above sea level. For the past 3,000 years, sea levels in Singapore have been stable, before the recent acceleration in the 20th century due to climate change.
The lead author, Dr. Stephen Chua, who completed the research as part of his doctoral dissertation at the Earth Observatory in Singapore (EOS) and the Asian Environmental School (ASE) at NTU Singapore, said, “By dating the sea level record in Singapore until 10,000 years ago, we received new important information from the early Holocene period. This is a period characterized by rapid sea level rise, but remains poorly understood – so far. “
“This more accurate record at sea level also has wider implications. For example, this would lead to a more stable and accurate local forecast of sea level rise, offering strategic guidance for Singapore as it adapts to climate change.”
Professor Maureen Reimo, co-founder of the dean of Columbia Climate School at Columbia University, who was not involved in the study, said: “This is the kind of crucial information needed to effectively plan adaptation measures in the face of continuing sea level rise due to global warming. Our past really gives information about our future. “
Why Marina South Investigations Site?
The development of an accurate ancient record at sea level requires the extraction of sludge from the “ideal” place where deposits such as sea mud and mangrove peat are available.
To choose the best possible site for drilling accurate results, the researchers looked at thousands of available drill logs – records of holes drilled in the ground for infrastructure projects.
Associate Professor Adam Sweezer, who heads the ASE and EOS Coastal Laboratory and who headed Dr. Chua, said: “Finding the right place to drill was a huge effort. Stephen spent more than a year reviewing information on old wells from various drilling efforts. construction over the last 30 years, just to find suitable records. As a result, our understanding of the geology of the whole area has also improved dramatically. “
Findings useful for Singapore’s defense plan against sea level rise
The study, published in a peer-reviewed journal The Holocene on June 4, 2021 also found the first convincing evidence that mangrove germs existed only in the area of Marina South for about 300 years before succumbing to floods associated with rising sea levels at that time.
At a depth of 20 meters below modern sea level, researchers have found abundant mangrove pollen, indicating that the mangrove coastline existed in southern Singapore almost 10,000 years ago. The NTU’s findings reveal that sea level rise during this time reached 10-15 mm per year, which probably led to the death of the mangrove forest.
The findings provide Singapore with useful information on current and future adaptation methods, as the island nation appears to go beyond engineering solutions and include natural methods to protect the country’s coastlines.
Despite its adaptability and effectiveness as a coastal defense, the study highlights the limitations of mangrove forests in the event of a rapid rise in sea level. This is confirmed by an earlier study co-authored with NTU, which shows that mangrove forests will not survive if sea levels rise above 7 mm per year in a high-carbon scenario.
Co-author of the study, Professor Benjamin Horton, Director of EOS, said: “Sea level rise is a potentially catastrophic result of climate change, as rising temperatures melt ice sheets and warm ocean waters. Scenarios for future rise depend on understanding the response of Climate change. Accurate estimates of past sea level variability provide context for such projections. “
Providing an independent comment on the study, Professor Philip Gibbard, a Quaternary geologist at the Scottish Polar Research Institute at the University of Cambridge, stressed the importance of recording settlements from remote regions such as Singapore.
“They offer a model of the process of sea level change, uncomplicated by factors related to deforestation, meltwater run-off, etc. This important systematic contribution from Singapore and the region provides a valuable record covering the post-glacial Holocene, thus allowing a general model of sea level change in the region to be established. This record can then be further refined as more research becomes available in the future. ”
Corals in Singapore are likely to survive rising sea levels
The Holocene (2021). DOI: 10.1177 / 09596836211019096
Provided by Nanyang University of Technology
Quote: Scientists find new records of sea level history in Singapore (2021, June 4), retrieved on June 6, 2021 from https://phys.org/news/2021-06-scientists-singapore-sea-level -history.html
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