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Rising sea levels are threatening the coasts. Do we know how to respond?

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Close to a billion of the world’s inhabitants live near coastlines — and people continue to move toward coastlines that will be more vulnerable as the planet warms. Climate research argues that it is not a matter of if these coastal dwellers will be impacted by rising sea levels, but how and when.

So how are we supposed to plan around this reality?

In a new paper published in Nature Climate Change, a group of internationally known climate change researchers — including Ohio State's Joyce Chen — assert that today’s global policy decisions concerning greenhouse gas emissions will be the driving force behind where people live and work in coastal areas.

Picture of Joyce Chen
Associate Professor Joyce Chen

The researchers say if policymakers start changing the incentives to live, work and invest in safer places, sea-level-rise-induced migration could be less expensive and disruptive down the line.

Leveraging advances in computation and modeling, the researchers developed a model that uses simulations to examine the effects of migration trends, specific policies and alternatives that could help researchers and policymakers better understand the range of realistic outcomes without having to experiment on vulnerable populations in the real world. This modeling approach will provide insight on what to expect, including more realistic numbers of future migrants.

Chen, one of the paper’s co-authors, is a development economist and associate professor in the Department of Agricultural, Environmental and Development Economics. Her past work on climate change, livelihoods and migration inland due to sea rise in Bangladesh helped develop the model, which can examine all kinds of scenarios to identify policies that might help people migrate and anticipate the policies that cause problems.

“We examined factors like economic opportunities, social networks, assets and which locations to consider that influence the decision to migrate,” Chen said.

 

Chen said these considerations guided how researchers quantified the relationship between climate factors and economic opportunities — such as the effect of flooding on farm revenue.

David Wrathall, the paper’s lead author and an assistant professor in Oregon State University’s College of Earth, Ocean, and Atmospheric Sciences, said a wide range of economic policies, planning decisions, infrastructure investments and adaptation measures will influence decisions to defend coastlines or retreat from them.

“Armoring coastlines against surging tides and rising waters could impact whether people are able to stay in their homes or need to relocate,” says Wrathall. “Policy decisions also need to be modeled for their impact on the communities or regions where migrants are relocating, since those arriving will have a significant impact on their new community as well.”

Co-authors of the paper include global experts on sea level rise and environmentally forced migration from the United States, the United Kingdom and Europe. The research was supported by the National Socio-Environmental Synthesis Center with funding from the National Science Foundation.