Comment: Turning to nature to protect coastal communities

Almost three-quarters of the world’s population live within 50 kilometres of a coastline, but these areas are becoming increasingly at risk from the effects of climate change.[1] Only 15% of the world’s coastal areas are ecologically intact – and by 2050, 800 million people will live in cities where sea levels could rise by more than half a metre.[2] 

To make these cities truly resilient to floods, storms, and sea level rise we need to think beyond traditional ‘hard’, grey infrastructure solutions like sea walls and dykes. and work with nature rather than against it. Designers, planners, and governments must integrate nature-based solutions into traditional defences for coastal cities to protect their communities.

Treating nature as a core part of design

When we think of dangers coastal cities face, we can’t afford to use any less than all the tools at our disposal. That means using sustainable grey infrastructure but also using green nature-based infrastructure where we can. Nothing is a silver bullet, but if we have the opportunity to restore the functions of natural coastal systems like dunes, wetlands and mangroves, we should. Nature-based solutions reduce environmental damage. And importantly, they actively enhance the natural environment by restoring ecosystems, reversing biodiversity loss, and improving water quality.

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One example is the development of Hunter’s Point South in New York City, a once abandoned industrial area that was heavily damaged by Hurricane Sandy. It’s now home to a newly constructed wetland designed to absorb coastal flooding. It includes bioswales, streetside stormwater planters, porous pavements, and a stormwater wetland. With exclusively native species selected to thrive in the marine environment, and networks of pipes under seemingly ordinary lawns, these solutions add to the park’s ability to absorb heavy rainfall, helping to fight against the risk of rising sea levels and increasingly severe storms.

Mangroves and coastal wetlands capture and store carbon at a rate ten times greater than mature tropical forests. [3] Restoring these environments not only increases resilience to climate change, but helps to fight climate change’s root cause. For instance, a single community-based mangrove restoration project in Mikoko Pamoja, Kenya, conserves 2,500 tonnes of carbon a year from avoided degradation and new planting.

This process of restoration can also have a transformative impact on local communities. As well as being better protected against climate change, residents enjoy improved availability of clean water, food security and aquaculture opportunities. And while the initial investment might be less than for traditional infrastructure projects, relatively high maintenance costs create long term opportunities for local employment.

A collaborative approach

We will only be able to make the most of nature-based solutions by taking a long term, collaborative approach, and by integrating them well with sustainable and existing grey infrastructure.

Nature-based solutions are often less well understood, so it’s essential to keep local communities and wider stakeholders on side through education and by getting them involved in design, operations, and maintenance. Only by understanding the full extent of the benefits of nature-based solutions will communities and decision-makers be prepared to take the required long-term view.

Turning to digital tools

Digital tools can prove invaluable both in measuring the risks of coastal erosion and flooding, and the impact of different solutions to build resilience. Tools such as Arup’s NatureInsight can help planners deploy nature-based solutions as effectively as possible, by identifying the appropriate placement for interventions and offering insights into the costs and benefits of implementing them.

It’s clear that the benefits of nature-based solutions are too significant to ignore; by fully embracing them we can build coastal resilience while regenerating local landscapes and communities. As extreme weather events caused by climate change become more frequent and severe, it’s more important than ever that we act now to protect coastal communities, and we need to do so by working with, not against nature.

Richard de Cani, Global Cities, Planning and Design Leader at Arup