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.
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...
ReplyDelete"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."
ReplyDeletehttps://oceanservice.noaa.gov/facts/sealevel-global-local.html
Subsidence has nothing to do with global warming.
ReplyDeleteOcean 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.
It's called fluid mechanics and fluid dynamics. It is what drives all currents in both air and water.
ReplyDeleteFluid mechanics: Two points in the same sea can easily have different levels, even though they are at the same pressure, if the water density varies. Density can vary with temperature of the water column at each point, or the salinity.
Fluid dynamics: If the same two points have the same levels, but different pressures, a current will result. If the two points have different current velocities, even though the density is the same, the level will be different.
Water Properties: Water density varies considerably with temperature. Warm water is less dense and has a larger volume than cool water, hence 1000 lbs of hot water will have a higher level in its container than if it was cooler.
The Earth's atmosphere is subject to the same principles, although currents, pressures and densities of air are much greater for a similar change in temperature.
These can be seen in simple form by studying the Bernoulli Equation.
Both horizontal and vertical movements can be detected by a number of methods, even remotely from space based satellites, to mm levels. They're called radar, laser measurement and GPS. The Atlantic Ocean is widening by an average of 1.2cm per year. Think about how far London will be from you at 50 million years from now. 600km or 378 miles farther away.
ReplyDeleteI didn't say it wasn't measurable, it's barely measurable(3.5"/century). Explain how this one island can have such a drastic rise in sea level yet all those tiny atolls just a few thousand miles away, that we invaded 80 years ago are the same size today? You're also ignoring the 600lb gorilla in the room, 7mm/year over 28 years is 20CM. That's an incredible rise. Whole islands should be missing, yet they are not.
ReplyDeleteYou've already learned a lot about the science water levels and currents, so maybe you can now explain that to us. I don't have your data about the other islands you mentioned.
ReplyDelete20cm is just under 8". Although some obscure coral atolls might go under, there's not a lot of islands that are going to totally disappear with only an 8" water rise. 100cm and there could be a noticeable loss of coastline, but probably still unlikely to disappear any whole island, at least any that are actually inhabited today.
ReplyDeleteIt's simple. Find a map from ww2 of an island we invaded, then compare it to google earth. There will not be much difference, if any. Those atolls are so flat, that 8 inches would swallow a massive percentage of their total land area.
ReplyDeleteBut the real danger at this time is fortunately the not the total disappearence of any given island, but the increase in flooding and high tide levels. For such events, even 8" can result in a massive increase in damages and loss of usable land. If it only takes another 8" to overflow the London flood gates, or another 8" of flooding on Staten Island, or Miami, or New Orleans, or Houston, a great amount of land and properties and lives can easily be affected. Water level increases are always relative to what is, or is not holding the water back.
ReplyDeleteMy point is that: There, Is, No, Danger. Because there isn't an 8" rise. If there was, those islands would be significantly smaller than they are now.
ReplyDelete