
Seas Are Rising at Fastest Rate in Last 28 Centuries - hvo
http://www.nytimes.com/2016/02/23/science/sea-level-rise-global-warming-climate-change.html
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tomkat0789
I actually just attended an incredibly interesting seminar about sea level
rise! (ChemE grad student: the our department required it. It was way cooler
than watching yet another presentation about catalysis!)

Based on what I saw, I think it's wrong to think of the ocean level as ONLY
rising or ONLY sinking. Sort of like how its wrong to call global climate
change "global warming": climates are complicated, and some places may end up
cooler in the brave new world even if the global average is rising.

Besides the raw amount of water in the ocean, lots of other factors go into
sea level rise. Some surprised me! A few interesting ones I remember:

\- thermal expansion of the water: i.e. increasing the temperature of a
constant amount of water causes its volume to increase

\- rising or sinking land: in places like Norway or Greenland, the land is
rising from all the glaciers melting. He talked about some piers he saw in
Northern Europe many meters away from the seaside.

\- flow of ocean currents: the ocean isn't a big bathtub, all the water is
moving around. The movement causes the water to rise in some places and go
down in others

\- additional gravity stuff that I didn't understand.

Among many fascinating figures, he plotted where the sea level rise would be
the most dramatic, and the US East Coast was one of the worst in the world.
Besides the general rise in sea level affecting most of the planet, something
in the ocean currents causes the water to be especially high over there.

~~~
fjarlq
Related: [http://nautil.us/issue/33/attraction/why-our-intuition-
about...](http://nautil.us/issue/33/attraction/why-our-intuition-about-
sea_level-rise-is-wrong)

... discussed here 4 days ago:
[https://news.ycombinator.com/item?id=11138242](https://news.ycombinator.com/item?id=11138242)

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oortcloud
Nowhere in the article does it say what the actual rate of rising is. That
seems like important information to omit. Anybody know what it is?

~~~
USNetizen
_" In the 19th century, as the Industrial Revolution took hold, the ocean
began to rise briskly, climbing about eight inches since 1880."_

 _" The sea is rising at what appears to be an accelerating pace, lately
reaching a rate of about a foot per century."_

 _" That body [The Intergovernmental Panel on Climate Change] found that
continued high emissions might produce a rise in the sea of 1.7 to 3.2 feet
over the 21st century."_

It's all in there. Towards the bottom, so if you just skimmed you may miss it.

~~~
joshuaheard
Yes, but what is the delta? Since we are coming out of an ice age a mere
12,000 years ago, we should expect sea level rising. The issue is how much
extra sea level rise are we seeing due to anthropomorphic climate change.

I seem to remember from the first IPCC report that it was on the order of a
few centimeters per century, which is why I am not greatly concerned about
this. But I could be wrong.

~~~
epistasis
>Since we are coming out of an ice age a mere 12,000 years ago, we should
expect sea level rising.

Given that the headline is that the rate is higher than the last 2800 years,
I'm not sure why you would think that the change that started 12,000 years ago
is going to be a significant factor.

The IPCC summary for policymakers [1] has highlevel quick facts, from that:

>Proxy and instrumental sea level data indicate a transition in the late 19th
to the early 20th century from relatively low mean rates of rise over the
previous two millennia to higher rates of rise (high con dence). It is likely
that the rate of global mean sea level rise has continued to increase since
the early 20th century. {3.7, 5.6, 13.2}

>I seem to remember from the first IPCC report that it was on the order of a
few centimeters per century

Sure, that's the _currently_ observed rate; about 3.2 mm/year +/\- 0.4
mm/year, from Table 13.1 of IPCC AR 5. [1]

Of course nobody's really concerned about 3.2 cm in a century. The problem is
when that increases by a couple orders of magnitude due to increased warming,
which it will unless we stop forcing the climate with additional CO2 within
the next 30-50 years.

[1]
[http://www.climatechange2013.org/images/report/WG1AR5_SPM_FI...](http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf)

[2] [http://imgur.com/vadnlXJ](http://imgur.com/vadnlXJ)

~~~
martinpw
> Of course nobody's really concerned about 3.2 cm in a century.

You mean 32cm in a century at the current rate of 3.2mm/year. I think people
are concerned about even that number, although the real value is likely to be
significantly higher.

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vixen99
Actually "scientists reconstructed the level of the sea over time and
confirmed that it is most likely rising faster than at any point in 28
centuries, with the rate of increase growing sharply over the past century"

'Confirmed it is most likely' is stronger than 'most likely'?

~~~
shawabawa3
It's a bit awkwardly worded but what they mean is this:

The hypothesis was that the sea is rising faster

The scientists confirmed the hypothesis, for some level of accuracy

That level of accuracy is "most likely"

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sageikosa
Has anyone seen a study on the sea levels since the eoarchean?

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danielvf
With ice cores, we have an Antarctic temperature history going back 400,000
years.
[https://upload.wikimedia.org/wikipedia/commons/c/c2/Vostok-i...](https://upload.wikimedia.org/wikipedia/commons/c/c2/Vostok-
ice-core-petit.png)

These ice cores show sudden, massive ice ages every 100,000 years. We are
currently near (or overdue for) one of the big ice ages.

In such a case it would seem that a warm world, even with a higher sea level
and the human movement that would require, would be less disruptive than much
of current civilization being under 200 feet of ice.

~~~
deanCommie
> "We are currently overdue for an ice age"

That's a very convenient interpretation of the data. We are within the
rounding error on a scale of several thousands of years.

If the ice age was coming RIGHT NOW, and our carbon emissions were offsetting
it, and the situation could be a LOT WORSE, then MAYBE you'd have a point.
(Though even in this highly unlikely scenario, you'd think we'd be able to
come up with a better strategy to offset global cooling than acidifying our
ocean, melting our glaciers, and inadvertently creating more extreme weather
events).

But if that's NOT Happening, if that scheduled ice age is actually "due" 500
years from now, at the rate at which we are going right now, we can do a LOT
of damage to our habitat, and the other living creatures on the planet before
it shows up. Before the cooling comes to offset our warming we'd have created
hundreds of millions of refugees from low lying watersheds, caused hundreds of
species extinctions, and decreased the quality of life for every single person
on the planet - not just the poor fuckers who couldn't afford new sea-walls.

Is that worth it to you? Or are you happy tasting sand with your head buried
below the ground? If you are, that's great because you'll be dealing with a
lot more sand in your life before it's all said and done.

~~~
danielvf
About ten or fifteen years ago, I got to visit several of the Hawaiian
islands. On the big island I saw new land being "created", live in front of my
eyes, as lava flowed into the sea. It just kept coming.

All my life I'd thought of land as essentially permanent, only shaped by man.
I realized that this was wrong - sometimes nature shifts into unstoppable
mode, and the only thing we can do is to adapt - and/or get out of the way.

If there were no global warming, the next scheduled move on the Earth's
climate cycle would be an ice age. I don't think that's scientifically in
dispute? Besides a lot of land going under ice, and the world getting a
colder, the sea levels have historically dropped around 400 feet in the mega
ice ages. It would be epic.

People have survived them in the past, but it's certainly something that gets
a lot of people moving.

~~~
deanCommie
Your capacity for self-deception is alarming. Yes, nature can be more powerful
than man. But we are not powerless. The scientific consensus is not in
dispute. The next asteroid to hit the earth will also be a big problem, but we
need to survive until then, and the next ice age. Or, how about THRIVE,
instead of survive

