Researcher Says We Must Adapt to Sea-level Rise in different ways – Depending on Coastal Type

Climate change is causing sea levels to rise and extreme weather events to become more frequent. Millions of people live along vulnerable coasts. Geologists play a key role in understanding which coastal areas are most at risk – and why.

“Coastal types respond differently to flooding and sea-level changes,” says geologist and researcher at the University of Bergen, Björn Johan Emil Burr Nyberg.

He is one of the researchers behind a new study, "Global coastal exposure patterns by coastal type from 1950 to 2050", which maps seven different coastal types worldwide. The research team has examined how these coastlines have changed since 1950, and what may happen by 2050 if sea levels continue to rise.

“In some places, towns and villages are located on flat sandy islands, while in others they sit on robust cliffs or in river deltas. These landscapes react differently to rising waters and storm surges. Many people imagine the sea level as simply going up or down. But coastlines are dynamic systems that respond in different ways. We need to take that into account when planning for the future,” Nyberg says.

Mapping coastal types worldwide

The researchers examined global coastlines using satellite data and sediment analyses.

“This is an attempt to provide a comprehensive overview. Earlier studies have often focused on specific regions, particularly river deltas. Such areas are indeed very vulnerable, but our study shows that barrier islands and sandy shorelines will also see a large increase in flood-exposed populations by 2050, especially in Africa,” he explains.

Looking ahead, more areas will be affected by storm surges and coastal flooding – when strong winds or low-pressure systems push seawater toward the coast, often coinciding with high tide.

“It surprised us how vulnerable some African regions are. Many people already live on exposed shorelines there, and the population is growing rapidly,” says Nyberg.

No one-size-fits-all solution

The researchers hope their analysis can help policymakers develop better, more tailored strategies for climate adaptation.

“A solution that works for one coastal type won’t necessarily work somewhere else. For example, if you build levees or seawalls on a sandy beach, you may end up causing the entire beach to disappear,” Nyberg points out.

Understanding the risks in Norway

In Norway, we have many rocky coasts, and land uplift since the last Ice Age still provides some protection against sea-level rise. But there are also vulnerable areas here.

“We have many beaches and river mouths that could be affected. It’s important that we understand the risks at home as well. More research is generally needed on this,” Nyberg says.

A tool for future planning

Nyberg’s study is part of a four-year basic research project funded by the Bjerknes Centre, aiming to improve sea-level projections and provide policymakers with better foundations for climate adaptation.

“There hasn’t been much focus on the fact that coastlines are dynamic. Our study contributes a broader perspective, which will hopefully serve as a basis for more detailed studies in the future,” Nyberg concludes.

Reference:

Björn Nyberg, Albina Gilmullina, William Helland-Hansen, Jaap Nienhuis, J.E.A. Storms: Global coastal exposure patterns by coastal type from 1950 to 2050. Cambridge Prisms: Coastal Futures, 3, Article e12, 2025.