Monday, November 08, 2021

Rising Seas in the Pacific

Since 1993 the sea around the Pacific Islands has risen by an average of 7mm a year, which is more than double the global average. This means that global heating is already proving an existential threat to the Marshall Islands. 58,413 people live on the five islands and 29 coral atolls which make up the Marshall Islands. Due to the very low elevation of these islands the whole country is threatened by climate change and rising sea levels.

The World Bank's Adapting to rising sea levels in Marshall Islands uses Esri's storymap template to visualize how different levels of rising seas will affect the islands. The storymap looks at the impact that three different sea level rise intervals (0.5 meters, 1m, and 2m) would have on the coastal communities of the Marshall Islands. 

A sea level rise of only 1 meter rise will inundate 37% of the building stock in the capital city of Majuro. A 2 meter rise would see all of Majuro's buildings at risk of permanent inundation. The Marshall Islands are already experiencing more frequent flooding than historical averages and more intense cyclonic storms. 

The World Bank's storymap explores different adaption pathways which could be taken by the Marshall Islands in response to rising sea levels. These pathways include relatively benign measures such as building sea walls and revetments. However at the extreme level these pathways include relocation and migration to other areas of the world. The World Bank says that out-migration from the Marshall Islands is already occurring - mainly for economic reasons. However climate induced migration could become the adaption pathway of last resort for the islanders.

If you want to know how rising sea levels could affect other locations across the world  you can use Climate Central's Coastal Risk Screening Tool. This interactive map allows you to see which areas around the globe are most threatened by sea level rise and coastal flooding. The map uses coastal elevation data with the latest projections for future flood levels to model how rising seas will impact coastal communities.


Birdog357 said...

How can an area of the globally connected ocean rise at a rate double that of any other part of the ocean? That flies in the face of all logic and common sense. And 7mm over 28 years is almost 20cm, or around 8 inches. In the south pacific with it's low atolls, that would be extremely noticeable and yet, they are all still there...

Keir Clarke said...

"Sea level rise at specific locations may be more or less than the global average due to many local factors: subsidence, ocean currents, variations in land height, and whether the land is still rebounding from the compressive weight of Ice Age glaciers."

Birdog357 said...

Subsidence has nothing to do with global warming.

Ocean currents might affect it, but I'm having a real hard time imagining how it would because the current should affect the baseline water height before any hypothetical rise and the rise just adds to it.

Variations in land height have nothing to do with the water rising more in a specific location than anywhere else. Either the water is 20cm higher or it's not. All land height can affect is how far inland the rise travels.

The south pacific never had glaciers... I live somewhere that had 2 miles of ice on it 50k years ago and the land is rebounding at a level that is almost impossible to measure because it's so minute.