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Global Sea Level Rise Map

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Re: Global Sea Level Rise Map

#22
post #6

Are there any predictions for the next X-years of how high the seas might rise?

The currently quoted number in policy papers is around 1 meter in the next 100 years. The includes the assumption that sea level rise is accelerating beyond historical trends. For fun, you can get sea level rise satellite data for the past 20+ years from http://sealevel.colorado.edu and run your own math. If you just naively run forward the observed rate over the last 22 years, you get 1 meter of rise in 300 years. Y…

i heard more like 0.55m in the next 100 years

Re: Global Sea Level Rise Map

#25

Earlier quoted context omitted.

The currently quoted number in policy papers is around 1 meter in the next 100 years. The includes the assumption that sea level rise is accelerating beyond historical trends. For fun, you can get sea level rise satellite data for the past 20+ years from http://sealevel.colorado.edu and run your own math. If you just naively run forward the observed rate over the last 22 years, you get 1 meter of rise in 300 years. Y…

i heard more like 0.55m in the next 100 years

You are correct. That's far more likely, and probably still too high.

The one meter over 100 years figure is the worst case number in the reports. Of course the bigger number gets the most press.

The last one hundred years have had a .10 to .20 meter rise, depending on who you ask.

Re: Global Sea Level Rise Map

#26
It seems to me that maps like this are not very useful, and understate the problem. They treat sea level as something that only varies over long periods of time, ignoring daily and weekly variations.

The major problem with a 1m sea level rise isn't that land which is currently 1m above sea level becomes permanently flooded. The major problem is that land which is 2m or 3m or 4m above sea level becomes flooded way more often.

Local sea levels vary with winds, tides, and perhaps more importantly storms. A smallish rise in sea level might mean that catastrophic storm surge goes from a 500-year event to a 10-year event (numbers pulled out of my nether regions, just meant to illustrate the idea).

For example, much of the damage from Hurricane Sandy was caused by its huge 13ft storm surge. If sea level rises by 1m, then a storm with only 10ft storm surge will match it, which means damage on that level will happen way more frequently, and a repeat of Sandy would be vastly more damaging.

I think what a map like this needs is a setting which shows where the (for example) 100-year flood level is now, and where it moves with the given sea level rise. This is way more complicated, of course, but would do a much better job of showing the real problems.

Re: Global Sea Level Rise Map

#27
Neat! Here I thought I was sufficiently inland in South Florida. I never even considered that the Everglades would flood me out before the Atlantic did. Heck, my parents house near the beach would fare better than mine near the Everglades, and those lucky dogs would get beachfront property while mine was completely underwater!

Re: Global Sea Level Rise Map

#29

This map's default setting of a +7 meter rise would be reached in the year 4348 if sea levels continue to rise at the current rate. (You can get current and historical sea height satellite data from http://sealevel.colorado.edu/ )

There are reasons to assume that a linear fit is not smart.

If you assume the rate of melting is roughly proportional to the temperature, then we are in for an increase in rates.

But there are other things. Nonlinear ice effects - that are not very well included in IPCC projections, could cause a lot more sea level rise sooner. They are hard to predict.

http://phys.org/news/2015-09-eyes-oceansjames-hansen-sea.htm...

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