
Atlantic Ocean's Circulation Is Weakest in 1,600 Years - rgbrenner
https://www.scientificamerican.com/article/slow-motion-ocean-atlantics-circulation-is-weakest-in-1-600-years/
======
hoodoof
Becoming a doomsday prepper edges further away from "flat out crazy" with
every day of weird, weird weather.

Our climate has been extremely stable for a long time and I'm not expert but
it is my understanding that chaotic systems can suddenly flip from stable to
extremely unstable.

I think there will be a time, hopefully a long time away but possibly close,
when the world realises that there' going to be disaster on an unprecedented
scale and we all have reason to be very, very concerned.

If the entire Antarctic eastern shelf melts, there is enough ice there to
raise sea levels by _more than 70 meters_. Some say this is 100 years away....
but ice doesn't melt all at once. I wouldn't be surprised if it comes alot
sooner and what that world/civilization looks like I cannot imagine.

And if you have children, then 100 years away sounds very very soon because
you know this is the world they will live in.

~~~
aaronbrethorst
How about spending your energy working on fixing these issues instead of
focusing on prepper stuff?

~~~
hoodoof
There are many unselfish individuals in this world who work to fix things, but
as a group, and a group of countries, we are so selfish that the problem of
global warming will never be stopped.

Nor the many other gigantic crises that face the earth such as plastic
pollution.

As there is no way the people of earth will unify to fix this, better start
getting ready sometime in the next 20 years for a gigantic shift in where
people see civilization is headed.

~~~
dbasedweeb
There’s also no way that any amount of your preparations will materially
improve your chances. If you stockpile, and civilization collapses, you will
be raided for your stockpiles by stronger, better armed people. There will
always be stronger, better armed people. If you prepare to live off land, how
is that going to work when the land is dead?

There’s no escape for you or your family, except averting disaster in the
first place, or death. Unless your prepping amounts to a suicide pact, then
it’s just a fantasy to keep you from being too afraid. As comforting fantasies
go, prepping seems like a particularly expensive and time-consuming one.
Unless you’re desperate for the illusion of control, your time and money is
better spent elsewhere.

~~~
czechdeveloper
You should prepare for disasters as they really happen. Could you survive OK
in Portoriko (or your local type of similar disaster)? Would you have way to
generate power at least to have light and radio? Do you have friends in other
countries/places that would help you relocate? Do you have water and food for
few weeks to survive initial blast? What about medicine you need? Do you have
cash to buy basics until electricity is setup again?

But you are right that if you prepare too well. So well that it's visible, it
is likely that it will be taken from you. Or you can end up as that guy who
prepared for zombie apocalypse and lost it all (100k USD invested) in
hurricane.

It will never (with exception of all out nuclear war) be total world
annihilation. Yet most people seems totally unprepared for stuff that just
keeps happening. And it will likely be getting more frequent with climate
change.

------
smartbit
Two excellent talks from Potsdam Institute for Climate Impact Research (PIK)
at 34c3

A hacker's guide to Climate Change - What do we know and how do we know it? An
introduction to the basics of climate research and what we can do about
climate change
[https://media.ccc.de/v/34c3-9184-a_hacker_s_guide_to_climate...](https://media.ccc.de/v/34c3-9184-a_hacker_s_guide_to_climate_change_-
_what_do_we_know_and_how_do_we_know_it)

Simulating the future of the global agro-food system. Cybernetic models
analyze scenarios of interactions between future global food consumption,
agriculture, landuse, and the biogeochemical cycles of water, nitrogen and
carbon.
[https://media.ccc.de/v/34c3-8935-simulating_the_future_of_th...](https://media.ccc.de/v/34c3-8935-simulating_the_future_of_the_global_agro-
food_system)

------
dmix
> As the little ice age ended and temperatures warmed, ice melted and
> freshwater flooded into the North Atlantic. The results suggest the current
> state of the AMOC is the weakest it has been over that whole long record.
> Whether today’s state is just a continuation of that reaction or whether
> global warming has also started to chip in is not clear, he says. Caesar,
> meanwhile, put the turning point toward a weaker AMOC in the mid-20th
> century, suggesting it is due to the influence of human-caused warming. Her
> team’s record, however, does not extend as far back.

It's always difficult reading climate analysis like these articles where it
bounces back and forth between sounding confident of projections in the first
half of the article, to how it's all still really speculative without
consensus and needing better modeling in the latter half.

All I want is to know what the data says and a reasonable estimate of it's
probability of being true. Yet it's almost impossible to separate what the
scientists _hope_ the data may to point to and what it reasonably does in it's
current state.

I guess, as a casual reader, it'd be better to not jump on every new study
that comes out and wait for future consensus to form.

------
brownbat
Additional background on the thermohaline cycle and the Younger Dryas period,
which saw a change of 10 degrees Celsius in a decade:
[https://www.ncdc.noaa.gov/abrupt-climate-
change/The%20Younge...](https://www.ncdc.noaa.gov/abrupt-climate-
change/The%20Younger%20Dryas)

Some more information on the period here:
[http://ocp.ldeo.columbia.edu/res/div/ocp/arch/examples.shtml](http://ocp.ldeo.columbia.edu/res/div/ocp/arch/examples.shtml)

~~~
akvadrako
That's quite interesting. What I can't tell by quickly reading those sources:
is this mostly based on the data from a single location?

It seems possible that that local climate can change a lot more wildly then
the global averages.

~~~
brownbat
I should have included above, but the wikipedia section on global effects
shows how it varied by continent. Massive effects in Europe and South America,
but with some evidence the Pacific wasn't as affected.

en.m.wikipedia.org/wiki/Younger_Dryas

The earlier intro section there lays out the discovery and some types of
evidence that led to the conclusion, and a theory based on geology from China
that these rapid changes tend to accompany deglaciation.

20 degrees Fahrenheit shift within a decade, even if just for one continent...
It's hard to fathom.

------
purplezooey
For a second I thought the headline referred to the circulation of _The
Atlantic_ , but then I realized, while a very good magazine, it probably
hasn't been around for 1600 years.

------
jcoffland
> The studies differ on the timing of when that weakening began. Thornalley’s
> record, which spans those 1,600 years, suggests it started at the end of the
> little ice age, a period from about A.D. 1350 to 1850

So the weakening current started before the industrial revolution could have
had an effect and well before any significant human caused CO2 and therefore
was not caused by man.

[https://www.acs.org/content/acs/en/climatescience/greenhouse...](https://www.acs.org/content/acs/en/climatescience/greenhousegases/industrialrevolution.html)

~~~
DoveBrown
From your link: "These increases in greenhouse gas concentrations and their
marked rate of change are largely attributable to human activities since the
Industrial Revolution (1800)." and "Data for the past 2000 years show that the
atmospheric concentrations of CO2, CH4, and N2O – three important long-lived
greenhouse gases – have increased substantially since about 1750."

I don't think your link supports the statement "the weaking started well
before the industrial revolution."

~~~
jcoffland
The link clearly shows that significant rise in CO2 did not occur until after
1900 so it could not have caused weakening ocean currents that began, at the
latest estimate in 1850. I do not understand where anyone got the idea that a
constantly changing climate is abnormal.

~~~
DoveBrown
I'm not a climatologist but as I understand it when looking at the climate
over the long scale there are cycles as the climate changes that are
predictable by natural processes (including effects of the Earths orbit and
co2 changes). Then from the 19th century the climate has been moving off the
known path as understood by these cycles. The difference has been attributed
to humans. The worry is that when you put the cyclic natural of climate change
together with the human caused climate change then what you may end up with is
a climate which is not conducive to food productive for the human population.

------
matte_black
Who is to blame for this?

~~~
IAmEveryone
Us, probably.

Traditionally, the circulating water gets colder as it reaches the arctic
circle and submerges, since cold water has a higher density than warmer water.

But: melting ice in the arctic releases freshwater. This reduces the salinity
at the surface of the Northern Atlantic. Water with lower salinity is lighter.
Therefore, this water no longer submerges, and the circulation is slowed down.

~~~
matte_black
Couldn’t it be fairly trivial to raise the salinity? We have tons of salt.
Enough at least to kick the can further down the road.

~~~
teraflop
Approximate annual world salt production: 0.3 billion metric tons

Approximate salt content of the Atlantic Ocean: 11,000,000 billion metric tons

~~~
tzs
The question was not if we produce enough salt to bring a completely
desalinated Atlantic ocean back up to normal Atlantic salinity.

It was whether we can produce enough to bring the fresh water that is being
added from melting ice up to normal Atlantic salinity.

~~~
maccam94
By my rudimentary estimation (based on numbers from
[https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/grl...](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/grl.50193)
Figure 3) I believe the annual ice melt in the Arctic each year is
approximately 10,000 km^3 of ice. Let's assume _all_ of it flows into the
Atlantic. Remove 10% of that volume to approximate the liquid volume of the
ice, then convert to kilograms of water = 9x10^15 kg. Average ocean salinity
is 35g of salt to 1kg of water. That comes out to ~3.15*10^14 (315 trillion)
kg of salt. You can pick a percentage that flows into the Atlantic, but it
would still require on the order of trillions of kilograms of salt.

------
throwaway2048
Shutdown of oceanic currents could easily become a civilization ending
disaster, this is an extremely concerning sign.

~~~
umanwizard
If you’re only realizing now that climate change will end civilization, you
haven’t been paying attention.

~~~
xor1
On the bright side, we'll have more civilizations after this one. It's not
necessarily the end of humanity.

~~~
mturmon
Not necessarily the end of humanity is a “bright side”?

~~~
Jare
It's brighter than without the "Not"

