Rising sea levels are a serious consequence of climate change and one that requires expensive mitigation efforts to help secure protection for homes and livelihoods. Floating cities may be one solution that scientists have found to offer an alternative living space, where land is either lost or in danger of flooding.
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Why Oceans Matter
Oceans cover 71% of the Earth’s surface and hold 97% of the Earth’s water. Everyone on earth depends directly or indirectly on the oceans and the cryosphere, the Earth’s frozen areas.
Ocean dependency includes homes, business, tourism, recreation, fishing, transportation, medicine, ecosystem functionality, and biodiversity maintenance.
Fresh water and half the world’s oxygen are provided by the water cycle itself, including transportation of heat, which regulates climate and weather patterns.
The ocean plays an important part in the carbon cycle, acting as a carbon sink, removing carbon dioxide from the atmosphere, and sequestering carbon in seabed sediments.
Oceans Under Attack
Our oceans are under constant threat from human activity, including pollution and man-made climate change.
Increased atmospheric warming results in warmer seas as oceans absorb heat. Thermal expansion, meaning an increase in volume combined with a decrease in density, causes sea level rise, as well as melting of land-based ice.
Oil slicks, plastics, and other debris kill marine life and enter the human food chain.
Acidification from ocean warming results in coral reef bleaching and threatens reef ecosystems. Over-fishing depletes marine life and biodiversity. Noise from military sonar and seismic exploration by the oil and gas industry affects whale and dolphin navigational ability, resulting in starvation and even death.
To find solutions that may help mitigate the effects of climate change and sea-level rise, scientists are researching how humans depend upon the oceans and how oceans are changing.
IPCC Climate Change Special Report and Rising Sea Levels
Satellite altimetry is a technique that measures the height of something relative to the entire Earth, rather than specific geological features. It provides an accurate measure of sea-level rise.
The Intergovernmental Panel on Climate Change (IPCC) uses satellite altimetry and tide gauge data that continuously measures sea level in relation to adjacent land to provide relative sea level. Data is combined to produce computer climate models.
Climate models and satellite altimetry combined show sea level is currently tracking the worse case IPCC projections. This means sea levels are rising faster than in the last century and could rise between 75 cm to 2 m by 2100.
The IPCC produced a Special report in September 2019, which examined the ocean and cryosphere in a changing climate. It examined the consequences for low-lying islands, coasts and communities, small islands, polar areas, and high mountains. These are all particularly vulnerable to change, such as sea-level rise and shrinking cryosphere.
Low-lying coastal zones are currently home to around 680 million people, around 10% of the global population. Small Island Developing States (SIDS) are home to 65 million people, and another 670 million live in high mountain areas. These populations are projected to rise between 8 and 9% by 2050.
Global warming has led to widespread cryosphere shrinkage of ice sheets and glaciers, reduced snow cover, and a reduction in Arctic Sea ice and thickness, as well as permafrost melts and air temperature rises.
Failure of the Paris Climate Agreement 2015 and COP26 Glasgow, has resulted in a failure to limit global warming to 1.5º Celsius.
This means mitigation to reduce the most harmful effects of climate change and adaptation are the next big challenges.
South Korea / UN Backed Climate Adaptation Plan
South Korea has signed a historic agreement with Oceanix, backed by the UN settlement project, known as UN-habitat, to build the world’s first floating city.
The project, designed by Bjarke Ingels Group (BIG), will be built off the coast of Busan, which has a population of 3.4 million residents, all of whom are at risk from sea level rise.
The city, designed in collaboration with a multitude of ocean engineers, architects, materials scientists, sustainability, and coral reef experts, aims to be fully sustainable. It will produce its own food, freshwater, and energy, and will generate zero waste using a closed-loop system.
It is also designed to withstand tsunamis, flooding, and level 5 hurricanes, in an effort to live with water and sea-level rise, as a climate adaptation strategy.
The city comprises hexagonal pods, resembling beehive honeycomb, that slot together for maximum efficiency. It will cover 75,000 acres and house 10,000 residents to begin with, with more pods being added over time.
Economic Necessity Bolsters Technological Development
Some of the major global financial centers around the world are situated on or near coastal locations, including London, New York, Hong Kong, Tokyo, and Singapore. Future investment in more floating island projects seems likely to gain momentum as a result.
The prototype city in Busan will cost around US $200 million and take around three years to build, serving as a model for other floating cities worldwide.
Although the water around Busan is relatively calm, historically it has been hit with devastating typhoons, the last of which, resulted in some 55,000 individual power failures across homes and industry. Therefore, there is perhaps both the political and economic will to ensure the project is successful.
The new city is based on a pontoon structure, with a newly developed limestone coating, two to three times harder than concrete, but which enables it to float in shallow waters.
Oceanix is by no means the first company to think up such a concept. Similar ideas throughout the 1950s, 1960s, and 1970s were often dismissed as too far-fetched.
Oceanix is different because it is the first to receive UN backing. This is significant because it is a direct adaptation response to rising sea levels, which offers a possible solution to how climate refugees may be housed.
Further advances in materials science and engineering technology mean further floating island projects may become possible, even in deeper water.
All that is required are social, political, and economic drivers, and climate change is already providing the environmental driver.
References and Further Reading
BBC. (2021) South Korea: World’s first floating city coming soon [Online] Available at: https://www.bbc.co.uk/newsround/59417045
ArchDaily (2012) Seoul Floating Islands / Haeahn Architecture & H Technology, [Online] Available at: https://www.archdaily.com/252931/seoul-floating-islands-haeahn-architecture-h-architecture
USGS gov. (1995) Sea Level Change: Lessons from the Geologic Record. [Online] Available at: https://pubs.usgs.gov/fs/0117-95/report.pdf
IPCC (2021) Special Report on the Ocean and Cryosphere in a Changing Climate. [Online] Available at: https://www.ipcc.ch/srocc/
Livermore, S (2021) five of the big threats to life in our oceans. [Online] IFAW. Available at: https://www.ifaw.org/uk/journal/five-biggest-threats-to-ocean
UNFCCC (2021) The Paris Agreement [Online] Available at: https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement
Design Boom (2021) BIG’s floating city to be built in South Korea as part of UN-backed plan. [Online] Available at: https://www.designboom.com/architecture/bigs-floating-city-to-be-built-in-south-korea-11-29-2021/
Wang, B. (2019) Floating cities: the future or a washed-up idea? [Online] The Conversation. Available at: https://theconversation.com/floating-cities-the-future-or-a-washed-up-idea-116511
Crook, J. (2021) How much will see levels rise in the 21st Century? [Online] Skeptical Science. Available at: https://skepticalscience.com/sea-level-rise-predictions.htm
Bendix, A. (2021) UN backed city floating city built to withstand category 5 hurricanes is headed to South Korea. [Online] BusinessInsider. Available at: https://www.businessinsider.com/floating-city-united-nations-south-korea-2021-11?r=US&IR=T