Measuring the hazards of isolation caused by global warming-related sea-level rise

A method has been developed by three environmental engineers—two from the University of Canterbury in New Zealand and one from the University of Maryland—to demonstrate the impact of sea level rise caused by global warming.

Tom Logan, M. J. Anderson, and Allison Reilly describe mapping isolation areas along both coasts of the United States in their paper that was published in Nature Climate Change. They then used the maps to figure out how many people would be affected. In the same issue of the journal, Logan and Reilly have also published a research briefing outlining their work.

Ocean levels rise as mountain ice continues to melt in the Antarctic and arctic regions as climate change progresses. Most of the time, previous research has focused on areas that will be submerged, like islands and coastal cities. In this new effort, the analysts call attention to the fact that another issue will emerge—disengagement. They point out that rising sea levels along the coast could encircle some areas and isolate people who live or work on higher ground.

They also point out that rising sea levels could also cover some roads, making it impossible for people to drive from one location to another—an additional form of isolation. They point out that either type of isolation could be ongoing or sporadic, occurring in conjunction with high tides or precipitation. They also point out that people may be forced to relocate if they are unable to travel to places like the hospital, school, or grocery store.

In this new effort, the analysts looked to ascertain the quantity of individuals in the U.S. (the lower 48 states) that would be affected by such kinds of disconnection in view of three distinct degrees of sea rise: 0.5, 1.0, and 2.0 meters before the century’s over.

The team first created a map of the coastal areas at risk of isolation using OpenStreetMap before beginning their calculations. Then, they compared their maps to NOAA’s projected effects on sea level. Finally, they followed every one of these neighborhoods and compared them to important facilities like schools, hospitals, and grocery stores that were close by. They discovered that under the 0.5-meter sea rise scenario, approximately 500,000 people will likely experience isolation by 2080, while under the 1-meter sea rise scenario, the number will rise to over 1 million.

More information: T. M. Logan et al, Risk of isolation increases the expected burden from sea-level rise, Nature Climate Change (2023). DOI: 10.1038/s41558-023-01642-3

Risk of isolation increases the urgency and spatial extent of climate change adaptation, Nature Climate Change (2023). DOI: 10.1038/s41558-023-01647-y

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