SINGAPORE: Planting mangrove forests to complement sea walls could slow the tide when it comes to rising sea levels - this is one example of a nature-based solution that Singapore can adopt to deal with the effects of climate change.
And compared to stone and concrete, mangroves would provide more than coastal protection by conserving biodiversity and helping to reduce carbon emissions. Mangrove forests, which once lined much of Singapore’s coastline, are able to store carbon more efficiently than other ecosystems such as tropical rainforests.
“I think in Singapore, the focus has traditionally been on human-engineered solutions - sea walls and breakers and so on. I think there is also scope to use mangroves or sea grasses and other natural coastal habitats to help with reducing the erosion effects,” said Professor Koh Lian Pin, who heads the new Centre for Nature-based Climate Solutions at the National University of Singapore (NUS).
Nature-based solutions include protecting natural ecosystems, restoring them and improving the management of agricultural lands to reduce greenhouse gas emissions that result from deforestation.
“We want to remove emissions from the atmosphere, by making use of the forest’s natural ability to convert carbon dioxide into organic carbon that will be stored in the biomass above ground as well as in the soil below ground,” said Prof Koh.
However, he added that these solutions may not be suitable everywhere as that depends on many factors. In the case of planting mangroves, factors include where the coastline is, the waves, weather events and more.
Such complications are part of what he and his colleagues study in order to inform the strategies, policies and actions on climate change in Singapore and the region.
A prominent researcher in the field of sustainability and environmental science, Prof Koh has worked in institutions across Switzerland, Australia and the United States over the last 16 years.
He is the sixth Singaporean scientist who returned under the National Research Foundation’s Returning Singaporean Scientists Scheme to lead research in areas important to the country.
The Centre for Nature-based Climate Solutions was announced by NUS in March and is due to officially open by the end of the year, but it has already been active, publishing one research study in August and another one soon.
The first paper, on the potential and constraints of reforestation, found that 121 million ha of land across Southeast Asia are suitable for reforestation, and could potentially contribute to climate mitigation at a rate of 3.4 gigatonnes of carbon dioxide a year.
In contrast, Singapore generated 52.5 million tonnes of greenhouse gases in 2017. One gigatonne is equivalent to 1 billion tonnes.
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But when “layers of constraints” are taken into consideration, such as how much of the land may be used by local farmers, as well as the manpower and resources required to manage these reforestation projects, the area of land available for reforestation can quickly shrink.
The study estimated it could be as little as 33 million ha instead, which would provide only 0.9 gigatonnes of carbon dioxide sequestration potential a year.
While barriers to reforestation can be overcome, studying both the potential and limits of such nature-based climate solutions is needed for climate policies that are workable.
For example, if a company or the government were interested in a reforestation project somewhere in Kalimantan, and if the land is being used by local communities for growing food crops, then there will be the risk of impact on the land users’ rights, security and livelihoods, he explained.
“Understanding both these kinds of opportunities and risks can help decision-makers policymakers prioritise what, when, and how these solutions should be implemented, to help them maximise the benefits of distributions and minimise the conflicts and negative impacts,” Prof Koh said.
The second research study, which the centre has just completed, is a carbon prospecting map showing where the highest, investable carbon is stored around the world in the biomass and soil of forests.
Interest in such information is growing as global demand for nature-based carbon credits is outpacing their supply. Carbon credits are traded by governments, companies and other entities to offset their emissions, and nature-based credits can be generated by funding forest conservation and restoration projects.
This year, the Trillion Tree Campaign was announced at the 2020 World Economic Forum in Davos - aiming to plant one trillion trees worldwide by the end of the decade. Singapore is doing its part by pledging to plant a million trees by 2030.
It has been estimated that nature-based solutions can provide up to a third of the mitigation needed to hold global average temperature rise to below the 2 degree Celsius target in the Paris Climate Agreement.
“Even if we managed to decarbonise through energy transitions or improving our energy efficiency, we still may not meet the targets, unless we also act on the nature-based part of the solution,” Prof Koh said.
Singapore can also invest in better understanding the less obvious and insidious impact of climate change, he said. This includes its effect on the security of its regional food supply, its water resources, as well as the impact on the regional economy and political stability.
“Because whatever happens to our neighbours because of climate change, the impacts will eventually trickle down to Singapore,” he said.
The centre’s role is to provide the science that can help show where the trade-offs are when implementing climate solutions.
“That’s why science is important to inform decisions on where we should be prioritising the implementation of our solutions to maximise the benefits … after careful consideration of, not just the environmental issues, but also the socio-economic, cultural and geopolitical contexts of the region. That's the kind of interdisciplinary science that the centre is focussing on,” he said.