Positive effects of sea-level rise

red and white boat bottom in the sea, positive effects of sea level rise

Sea level rise has been the centre of attention of many scientists over the past few decades, with a rekindling interest since the IPCC released its Fourth Assessment Report in 2007. As it is, the sea level has risen and fallen quite a number of times throughout Earth’s history. There were times when the sea level was 400 m lower and 120 m higher than today’s level. Sea level actually changes for many reasons and over varying spatial and time scales. It is estimated that there have been some 100 global fluctuations in sea levels over the geological time scale, with recurring swings of 50 m [1].

Rising sea levels

Today’s sea level rise is mostly associated with anthropogenic climate change. An increase in sea level was noted since the mid-19th century with observations changing from 1.4 mm yr-1 in the early 1900s to 3.6 mm yr-1 in 2015. Since the IPCC started research into climate change, subsequent effects of sea-level rise have become alarming. According to the latest report of the IPCC, global sea levels will increase by 0.29 m and 1.1 m by the end of this century.

Positive effects of sea-level rise

Nevertheless, as pointed out by Vaughan, one of the authors of the 2007 IPCC research, rising sea levels will result in both winners and losers. Thus, while we are mostly concerned with the dangers that sea-level rise present, some positive impacts will also come about.

1.      Increasing mangrove reforestation and afforestation against sea-level rise

One of the most important effects of sea-level rise is the increase in mangrove reforestation and afforestation programs. Mangrove trees play a crucial role in absorbing wave energy from the ocean. For millennia they have protected coastlines against violent waves while at the same time stabilizing the soil. Unfortunately, a pungent smell comes from mangrove forests and a large number of insects breed in them. Thus, regarded as useless and smelly, mangrove forests have been cleared in many regions around the world. Mauritius exemplifies this situation. In 2003, mangrove cover was estimated at 2000 ha; a new study in 2013 revealed that only 49 ha was left on the mainland. So, in the name of development, mangrove forests were massively wiped out on the island.

Intricate mangrove roots help retain sediment, positive effects of sea level rise, mangrove reforestation and afforestation globally
Intricate root system of mangroves helps to retain sediment that would otherwise get washed away by rising sea levels
Photo by icon0com form PxHere

Mangrove forest restoration

Today, due to the threat of rising sea levels, the situation is turning around. Mangrove reforestation and afforestation programs are at the top of the list of adaptation measures to sea level rise of many nations. From Brazil to Europe to Singapore, communities are actively taking part in planting mangrove trees. Again on Mauritius, both the public and private sectors are engaging in mangrove reforestation and afforestation projects. One hotel, Le Preskil Island Resort planted 2,000 mangrove propagules at the Pointe D’Esny mangrove site as an eco-responsible approach. Similarly, the Strategic Plan 2016-2020 of the Ministry of Agro-Industry and Food Security also states that 100,000 will be planted over the period 2016-2020 [2].

Ecological importance of mangroves

What’s more, mangrove forests are large carbon sinks and play an important role in climate change mitigation. Mangroves actually sequester some 14% of the total carbon in the world’s ocean though they cover only 0.5% of the total coastal ocean area [3]. When such natural ecosystems are rehabilitated, their valuable goods and services are also restored. These include stabilizing the shoreline, providing nursing and breeding grounds for marine species, reducing the impacts of natural disasters as well as providing food, medicine and various raw materials to humans.

2.      Restoration of coastal ecosystems

Similarly, many previously neglected coastal ecosystems are also being worked on as protective cover against sea-level rise. These include coral reefs, seagrass meadows, sand dunes and oyster clumps. Different countries, based on their coastal assets, are working intensively on ecosystem-based approaches to keep the sea at bay. Singapore, for instance, is consolidating its barrier islands to decrease the impacts of storm surges while the United States is investing in oyster clumps to blunt the impacts of wave actions. The commonly known eelgrass, Zostera marina, a species of seagrass is also attracting attention as a means to mitigate the impacts of sea-level rise. Just like terrestrial grass, it grows tall and holds sediment firmly on the seafloor. Due to pollution and coastal degradation, large expanses have been lost. Today, scientists are working on ways to facilitate its settlement on the seafloor in order to cushion wave shocks.

3.      Increase in biodiversity  

In general, most marine species will be able to keep pace with sea-level rise [4]. What will happen is that most species might migrate towards the upper layers of the sea. Some coral reefs may also find respite from fishing pressure as humans are forced to move from certain regions of the world, especially the low-lying atolls [5]. Consequently, biodiversity may flourish again in these regions.

4.      Sea-level rise will moisten dry regions

Sea level rise could prove beneficial to regions undergoing land uplifting. Land uplift is the vertical elevation of the land due to natural reasons such as tectonic processes. Thus, where land is lifting, the sea level is also going down. Along the Kvarken Archipelago in Finland for instance, the islands are actually rising despite sea-level rise. This is happening as a result of glacio-isostatic uplift that occurs when glaciers that were previously pushing land down melt. Consequently, in places where the land is uplifting, certain coastal wetlands may dry out due to a lack of water. Hence rising sea levels could intervene and moisten these parched habitats [6].

5.      New housing structures businesses due to sea-level rise

Economically, sea-level rise will also benefit many businesses. With coastal flooding, new structural and architectural measures are required to withstand such impacts. In light of this, companies that offer risk-based technological support and services will profit in the long run. To illustrate this, KRADLE Structural Lifting Systems is a business that invests in innovative structural designs. The company specializes in structures and lifts that can elevate houses and commercial structures during coastal flooding. KRADLE operates in various parts of the United States and recently made negotiations with partners in New Zealand. As the rising sea gains more ground and causes more damage, KRADLE makes more money.

6.      Sea-level rise naturally creates and enlarges estuaries

Increases the number of estuaries

Estuaries are amongst the most productive and resilient marine ecosystems of the world and are valuable both ecologically and economically. They are quite rich in organisms which add to coastal biodiversity and are an integral part of the marine food web including humans. Over the past ten thousand years, many estuaries have formed on the Earth. Since the planet is currently in an interglacial period with rising sea level, the lower parts of river valleys are flooding thus creating large bodies of the estuary. With more estuaries, more creatures can survive such as the ‘Near Threatened’ Black-tailed godwit birds.

Flock of Black-tailed godwit birds flying over water in a marsh, positive effects of sea level rise thus increases marsh areas for birds
Flock of Black-tailed godwit birds
Regarded as ‘Near Threatened’, these birds breed mostly in estuaries
Photo by marliesplatvoet from needpix

Enlarges estuarine channels for navigation

In addition to this, estuaries provide a haven for boats allowing commercial trading and land exploration. It is in fact through estuarine navigation that many countries have become accessible. Many cities like Jakarta, Tokyo and New York are located on estuaries where they act as gateways to continents. Rising sea levels will prove beneficial over the years to come as they will naturally widen such estuaries. As the sea level increases, tides and waves will propagate further inland thus enlarging and deepening estuaries and channels. In this way, not only will there be no human intervention but associated costs with such development will remain too. Also, as the process occurs naturally, benthos life would be unhampered.

7.      Increased community engagement

As the threat of sea-level rise looms closer, people are getting more engaged in the issue. Thanks to the refining models that scientists use to make future projections of sea-level rise, concern for the future of the planet has increased. As people visualize such impacts, they are more committed to reducing their carbon footprint in order to reduce global warming. Thus more and more people are switching to renewable energy sources, choosing closer holiday destinations or supporting climate change mitigating actions as concrete actions to decrease climate change effects like sea-level rise. Likewise, they encourage their peers to do the same or actively invest/engage in coastal rehabilitation projects.

8.     Sea-level rise creates new opportunities 

Interestingly, melting sea ice in the northern hemisphere that is contributing to sea-level rise could also open up the navigation route. Since most of the Arctic sea is covered in ice, navigation is impossible in that region. As the ice eventually melts, it is probable that by 2050, 125 days per year would be suitable for navigation. At the same time, this would also permit oil and gas exploration in that zone. What’s more, ecotourism would also shoot up for many destinations in the northern sea such as Alaska, Canada and Norway as they are excellent spots for killer and grey whales’ sightings.

The good news about sea-level rise

So, although sea-level rise is bound to be catastrophic regarding certain matters, it will also be beneficial regarding others. Currently, positive effects of sea-level rise include increasing mangrove reforestation and afforestation programs, restoration of coastal ecosystems, moistening uplifted areas, generating new investment opportunities, forming more estuaries and widening them, increasing community engagement and creating new opportunities like navigation, gas and oil exploration and ecotourism.


  1. Miller, K.G., 2009. Sea level change, last 250 million years. Encyclopedia of Earth Sciences Series. [online] Available at https://www.researchgate.net/publication/290612959_Sea_Level_Change_Last_250_Million_Years [Accessed 08/03/2020]
  2. Government of Mauritius., 2016. Strategic Plan (2016-2020) for the food crop, livestock and forestry sectors. [pdf] Available at http://agriculture.govmu.org/English/Documents/Book%20Final.pdf [Accessed 12/03/2020]
  3. Alongi, D.M., 2008. Mangrove forests: resilience, protection from tsunamis, and responses to global climate change. Estuarine, Coastal and Shelf Science76(1), pp.1-13.
  4. Harley, C.D., Randall Hughes, A., Hultgren, K.M., Miner, B.G., Sorte, C.J., Thornber, C.S., Rodriguez, L.F., Tomanek, L. and Williams, S.L., 2006, The impacts of climate change in coastal marine systems. Ecology letters9(2), pp.228-241.
  5. Brierley, A.S. and Kingsford, M.J., 2009. Impacts of climate change on marine organisms and ecosystems. Current biology19(14), pp.R602-R614.
  6. Buenfil-Lopez, L, Robollar-Plata, M., Munoz-Sevilla, N.P. and Juarez-Leon, B., 2012. Sea level rise and subsidence/uplift processes in the Mexica South Pacific Coast. Journal of Coastal Research, 28(5), pp. 1154-1164.

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