
Where America's climate migrants will go as sea level rises - jdkee
https://www.citylab.com/environment/2020/02/climate-change-migration-map-sea-level-rise-coastal-cities/605440/
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ash
> In the worst-case scenario, in which sea levels rise by six feet by 2100,
> ...

Where does six feet come from?

It seems very suspicious. It contradicts NOAA Sea Level Trends data of tide
gauge measurements, going back to 1930 and sometimes earlier. According to the
map, in almost all places in US the projected sea level trend is no more than
1-1.5 feet by 2100:

[https://tidesandcurrents.noaa.gov/sltrends/sltrends.html](https://tidesandcurrents.noaa.gov/sltrends/sltrends.html)

What is more, the trend is clearly linear from the start of the measurement.
The trend hasn't changed in recent years.

For example, see data from the gauge in Sandy Hook, New Jersey, from 1932:
"The relative sea level trend is 4.09 millimeters/year with a 95% confidence
interval of +/\- 0.2 mm/yr based on monthly mean sea level data from 1932 to
2018 which is equivalent to a change of 1.34 feet in 100 years."

[https://tidesandcurrents.noaa.gov/sltrends/sltrends_station....](https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?id=8531680)

Gauge in Lewes, Delaware, data from 1919: "The relative sea level trend is
3.48 millimeters/year with a 95% confidence interval of +/\- 0.23 mm/yr based
on monthly mean sea level data from 1919 to 2018 which is equivalent to a
change of 1.14 feet in 100 years."

[https://tidesandcurrents.noaa.gov/sltrends/sltrends_station....](https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?id=8557380)

~~~
FooHentai
There's a major research initiative taking place right now into Thwaites
Glacier, as unexpectedly fast melting is occurring. It's thought this is due
to warm saltwater penetration underneath the glacier but other factors are
being considered.

The issue with Thwaites Glacier is it has a tapered edge that generally
resists thawing, but that widens out to a huge contact surface area once
erosion by salt water progresses.

This glacier alone will cause a global sea level rise of three feet.

[https://thwaitesglacier.org/](https://thwaitesglacier.org/)

~~~
smooth_remmy
> This glacier alone will cause a global sea level rise of three feet.

Where did you get that information? This source from Wikipedia says it would
cause a rise of 4 inches:

At the beginning of 2020, researchers from the ITGC took measurements to
develop scenarios for the future of the glacier and to predict the time frame
for a possible collapse: The erosion of the glacier by warmed ocean water
seems to be stronger than expected. The researchers noted with concern, that
at the baseline of the glacier, the temperature of the water is already more
than two degrees above freezing point. They confirm thawing of the Thwaites
glacier contributes about four percent of global sea-level rise. The collapse
of this glacier alone would raise the sea level by about 65 centimetres (25
inches).[25]

~~~
dflock
What?

Your quote says 4% of global sea level rise from this one glacier, not 4" \-
it says 25" at the end there.

------
vannevar
"Dilkina and her team used migration data from the Internal Revenue Service to
analyze how people moved across the U.S. between 2004 and 2014."

It looks like their analysis may have been skewed somewhat by the fracking
boom in America's oil shale country. That may explain the otherwise odd
migration pattern into sparsely populated areas running up from Texas through
the center of the country.

~~~
rcMgD2BwE72F
>skewed somewhat by the fracking boom in America's oil shale country.

Isn't it extremely ironic, given the topic hand?

------
scrumbledober
I find it hard to imagine 200k people leaving San Mateo County. most of the
county is above 6ft elevation, and there's just so much money I would think
dikes could be built to keep the flats dry. At the worst I would expect more
housing to be built in the hills.

~~~
klipt
Optimistic of you to expect the Bay Area to build more housing anywhere.

Look at the people displaced by fires in the North Bay who now can't afford to
live anywhere nearby.

~~~
Ididntdothis
I think the OP meant more expensive housing in the hills. Not affordable or
dense.

~~~
scrumbledober
Possibly dense, but almost certainly not affordable. There isn't really any
affordable housing in San Mateo County to begin with (source: my $2000/month
one bedroom apartment with no dishwasher)

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rilindo
I find it hilarious that even in a worse scenario with the climate crisis,
Chicago somehow did not get any migrants .

~~~
beefalo
Their map doesn't make any sense to me. They show no expected migration to
really any of the cities in the midwest but somehow they expect a mass
migration of people from Miami to rural western Kentucky?

~~~
tomatotomato37
The whole concept doesn't make sense; 80 years in the future we won't even
know if the US exists as a singular entity anymore let alone where its centers
of population will end up. Imagine if 1920 Russia tried to predict where its
population would end up in 2000; nothing would match up.

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mc32
The map is very rough and relies on counties affected, rather than topography
(elevation and closeness to bodies of water and waterways) so some counties
can have coastal exposure but also have shelter (high elevation). King county
WA for example or Los Angeles co. CA

So it presents a more alarming picture than one would imagine.

~~~
Animats
Yes. That map shows entire counties in blue if any point in the county would
be flooded.

For almost all of coastal California, you don't have to go very far inland
until you're way above sea level. LA looks flat, but go three blocks inland
from the beach in Venice and you're up a few meters. The California coast is
the shelf of a mountain range.

Florida, though, does have real problems. Most of the state is barely above
sea level. And Miami is on permeable rock; sea walls won't help.

------
vkou
Sea level rise will not be the problem. It is going to happen on multi-
generational timescales.

Food insecurity, resource conflicts, extreme weather events, and a global
migrant crisis (caused by the first two issues) will be. Unlike sea level
rise, all it takes is one bad year to spark these.

~~~
FooHentai
Here in NZ, we already see issues where storms and 'king tides' cause
significantly worse outcomes when they coincide. As those king tides rise and
penetrate further inland, these increased weather events are going to be much
worse at the coast.

Also, Miami and Venice are on borrowed time.

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keanzu
In 1903 humans first achieved heavier than air powered flight. Less than 60
years later, in 1959, man landed on the moon.

I feel confident that in the next 80 years we'll manage to figure out how to
build some 6ft tall levees.

There will be little climate migration. People like living near the coast.

~~~
axaxs
I'm in full agreement, but that idea isn't popular here, where I find folks a
bit fatalistic. I understand why of course, assuming 'someone will solve it'
takes the urgency out of the problem. We do need to take action, absolutely.
But am I worried about sea level rise here in Florida? Not at all. There's
just too much money at stake to throw our hands up and run. And I don't mean
just here, or even the US... most of the world's wealth is on the coast.

~~~
keanzu
A third of the country will be underwater sounds a lot more scary than we'll
have to build some small walls, about 1ft per decade, in some areas.

About one third of the Netherlands lies below sea level, with the lowest point
being 22 feet (6.7 meters) below sea level. Doesn't make for much of a post-
apocalyptic visual - act now or end up like the Netherlands.

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slg
This seems to only be factoring in oceans. Won't the sea level rising have a
huge impact on the rivers and floodplains in the middle of the country that
this predicts will see a big influx of people? There is plenty of high
elevation coastal land that I would expect to be safer than land on the banks
of the Mississippi River.

~~~
AnimalMuppet
No. Why should it? If the sea level rises two feet, how does it affect rivers
that are, say, 100 feet above sea level? Or 500 feet? What's the cause and
effect here?

The sea level rise is due to more water in the ocean. That doesn't translate
into more water in a river, because water doesn't flow uphill.

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papreclip
It seems really unintuitive to me that there is enough ice on the globe to
raise the sea level by 6 feet (let alone 230). But then if I had to guess the
land area of Antarctica, I would have estimated something the size of Oklahoma
or Texas (when Antarctica is 40% larger than the USA)

~~~
HarryHirsch
Much of the Antarctic landmass is below sea level, if the Antarctic ice shield
melted the continent would look like an archipelago. There is much water tied
up in the Antarctic ice shield(well, it took 40 myr to accumulate, you get
this much even in a cold desert), on average it's 2 km thick. The IPCC
estimates that if it melts fully it would result in 50 m of sea level rise.

~~~
smooth_remmy
Any ice below sea-level will melt into water that will take up exactly the
same amount of space. So any ice below sea-level that melts will not cause sea
levels to rise.

~~~
elmo2you
Could you please elaborate on your claim? I feel confused.

I learned that ice has a (slightly) lower density than water, hence it usually
floats. I was convinced that submerged ice is doing so because of an
additional weight on top of it (above-water ice pack).

Maybe there is also ice that is submerged without this extra weight, but then
its density should be lower than water.

Either way, I don't see how submerged ice could take up exactly the same space
when melted. If it has a different density, it should change in volume
(elementary physics).

~~~
leereeves
Ice that is floating displaces an amount of water whose weight equals its
weight. That's why a little bit floats above the water and most is under the
water.

When that ice melts, it still weighs the same amount and fills exactly the
amount of space that it was displacing. In other words, it fits perfectly in
the space in the water that it was already occupying.

So floating ice that melts (above or below the water) doesn't change sea
levels at all.

Only melting ice that is currently supported by land will increase sea level.

~~~
Izkata
A reference for anyone unfamiliar with this explanation: this is Archimedes'
principle.

[https://en.m.wikipedia.org/wiki/Archimedes%27_principle](https://en.m.wikipedia.org/wiki/Archimedes%27_principle)

------
JackFr
Millions flee from Miami to Buffalo, and yet Venice and the Netherlands plod
on.

------
agumonkey
I had this wonky idea that maybe buildings in these area should be adapted to
have their first floors underwater yet still usable in some ways.

~~~
whatsmyusername
No because you'll get black mold growing that will spread throughout the
structure.

Maybe in otherwise dry areas, but I doubt it.

~~~
Izkata
Depends on how you go about it.

In the 1800s, Chicago was lifted up from nearly being at the same level as
Lake Michigan:
[https://en.m.wikipedia.org/wiki/Raising_of_Chicago](https://en.m.wikipedia.org/wiki/Raising_of_Chicago)

~~~
whatsmyusername
On a small scale sure, there's always exceptions.

I don't see this happening across the entire coastline of the US or (even less
likely) along the shores of affected tributaries.

------
madcaptenor
I live in Atlanta and I've been joking that if things get really bad, at least
I'll have beachfront property.

------
mring33621
There's going to be good money to be made in climate change-related real
estate trends!

------
IanDrake
In the free market of ideas, no one actually believes this will happen.

Just look at coastal real estate. Buyers and lenders would have to be colossal
fools to pay such premiums to be waterfront. Even Obama just plunked down 12M
on a waterfront mansion on the low lying island of MV.

~~~
lxcfan
Real estate prices are priced by mostly by current demand, not future oncoming
disasters.

Much waterfront property is _already_ vulnerable (and expensive to insure)
today, regardless of whether you believe in consensus climate science, due to
storms and flooding in current climatic conditions. That house by the ocean is
going to destroyed at some point, the only question is when and how.

~~~
josinalvo
I have seen ample consensus amonsgt reputable scientists that the earth is
getting warmer, and this fact is due to human activity (e.g
[https://climate.nasa.gov/faq/17/do-scientists-agree-on-
clima...](https://climate.nasa.gov/faq/17/do-scientists-agree-on-climate-
change/))

I have not yet, however, seen any such research on consensus for the effects
of climate change. Is there a large, documented consensus on any estimate of
sea level raise?

~~~
lxcfan
Sorry, perhaps the emphasis in the way I wrote that comment made it unclear
what I was saying.

My point was that real estate market prices are much more heavily influenced
by current conditions, and current demand, rather than hypothetical future
conditions. The price elasticity of demand has little to do with whether the
buyer believes that the property will flood in future decades due to climate
change. Someone who wants a beachfront mansion is probably going to buy it for
close to the same price whether or not s/he believe it will still be there in
50 years, just as s/he might buy an expensive car that will similarly degrade
and need expensive maintenance exceeding the original purchase price over
time.

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adamrezich
crazy how coastal real estate isn't tanking

~~~
milkytron
I think it's because insurance policies are still supporting real estate in
areas at risk.

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dumbfoundded
This is what I take away:

\- Everyone already knows rising sea levels will cause more flooding and
property damage.

\- What's new here is that they make attempts to estimate displaced
populations and where they will migrate.

\- The reception of American climate migrants will not be evenly distributed.
Cities nowhere near the coast will be impacted by climate change.

