How rising sea levels are threatening coastal communities

Rising sea levels affect fish numbers in a variety of ways. Estuaries can become siltier, tidal patterns can change, storm surges can push seawater upstream, and estuaries can become more salty. This affects fish, because many species reproduce in estuaries or on the coast, so they might end up losing their breeding grounds. With fewer fish breeding, there is less catch for the fishermen. 

But it is not just livelihoods in coastal communities changing due to climate change. It's affecting people's health, too. Climate change is making people in Sri Lanka less food secure, which results in malnutrition, and disproportionately affects marginalised communities. Some, like Abesinghe, are having to relocate to find new lines of work. 

 Golam Mathbor, a professor in the School of Social Work at Monmouth University in New Jersey, USA, says that coastal regions are the "major victim" of environmental degradation from recent global ecological changes. Coastal communities, for example in Bangladesh, are experiencing acidity and loss of fisheries, which heavily impacts their quality of life. "Coastal regions of Bangladesh are on the verge of extinction because of sea level rise," says Mathbor, when this results in the loss of fisheries vital for local livelihoods, and that an "alternative source of income is necessary for coastal people" now that fishing is increasingly unsustainable. 

Then there are whole nations who face an existential crisis as seas rise. Raised no more than 2m (7ft) above sea level at its highest point, Kiritimati is one of the most climate vulnerable inhabited islands on the planet. A 2016 UN report has shown that half of households have already been affected by sea level rise. The nation is grappling with the very real prospect of having to move large number of its population elsewhere, making international steps to mitigate climate change and slow sea level rise an urgent matter of national survival. 

On Pacific islands like Kiritimati, these rising tides can also bring pollution like nuclear waste, which in some places is already above safe limits of background radiation, and threatens food security. 

And there are more everyday sources of pollution, too. "[For example], microplastic is one of the leading causes of coastal climate health risks as there is very little compliance of proper dumping of these materials," says Mathbor.  

Plastic pollution has been found on beaches of remote, uninhabited islands and shows up in sea water samples across the planet. One study estimated that there are around 24.4 trillion fragments of microplastics in the upper regions of the world's oceans.

 Microplastics contain harmful chemicals linked to health problems, including cancer, heart disease and poor foetal development. Studies have linked microplastics in fish to significant health issues in humans.  

Abesinghe has experienced his business being affected by plastic pollution, noticing plastic in the fish he sources. However, microplastics aren't the only problem.  

Many feel that sea level rise is a "faraway problem", says Thomas Herrington, associate director of the Urban Coast Institute at Monmouth University, though education is one tool to help people in coastal communities. "[But] if your community is already struggling with economic disadvantages or health disparity, there is a lack of capacity to adapt." Engaging communities in co-developing solutions can help develop the most locally effective responses, while also strengthening community resilience. In the aftermath of some disasters, locals, rather than search and rescue experts, often rescue the greatest number of people. 

Countries at risk of rising sea levels need more local experts, says Harrington. But there are reasons to be optimistic. There are mitigations being trialled to limit coastal erosion, from intentionally inundating land to create saltwater marshes, using bio-concrete in coastal areas instead of concrete (sprayed with microbes which fill gaps in the concrete as it cracks, extending its lifespan), to creating oyster reefs. The latter can be very successful, not only limiting erosion, but also cleaning waterways – and providing food.  

While these are promising solutions, the will not prevent sea levels rising further and only offer local contingencies to a growing, global problem. 

Anjalika Gunawardhana, a student studying coastal and marine resources at The Ocean University of Sri Lanka, which was founded to educate and train the next generation of marine experts, agrees that "educational programs can help people understand... potential solutions for rising sea levels. This collaborative approach is essential for addressing sea level rise's complex and interdisciplinary nature." 

The Sustainable Island Solutions through Science, Technology, Engineering and Science (Sisstem), a multinational research and education programme, also aims to encourage people to collaborate on local socio-economic issues. Anouk Mertens, a project manager with Sisstem in Aruba, works with talented young locals who would previously travel to other countries to be educated and achieve their qualifications, such as the Netherlands or the US, consequently never return, causing a "brain drain" on the island.