Profound Implications of a Completely Salt-Free Arctic Ocean as recently as 60,000 Years Ago
Summary
TLDRPaul Beckwith discusses a groundbreaking study revealing the Arctic Ocean was completely fresh during certain glacial periods due to lower sea levels and ice barriers, isolating it from the Atlantic and Pacific. This fresh water accumulation and subsequent release could explain rapid climate changes, such as the Dansgaard-Oeschger events, with temperature spikes of up to 16.5°C in a decade. The study, by the Alfred Wegener Institute and the MARUM in Norway, offers new insights into past climate tipping points and abrupt changes.
Takeaways
- 🌊 The Arctic Ocean was found to have been completely fresh water during certain periods in the last 150,000 years, which is a significant discovery.
- ❄️ The temperature in Greenland has been recorded to rise up to 16.5 degrees Celsius in a decade, indicating rapid climate changes.
- 🌐 The Arctic Ocean's connection to the Pacific and the Atlantic was effectively cut off during glacial periods due to lower sea levels and ice barriers.
- 🏔️ Sea levels were approximately 130 meters lower during glacial periods, isolating the Arctic Ocean and preventing saltwater inflow.
- 🌿 The Arctic region was much warmer in the Carboniferous period, supporting lush forests and tropical creatures like crocodiles and turtles.
- 🔍 The study's findings are based on the analysis of marine sediments, which revealed the absence of sea salt in certain periods, indicating fresh water.
- 🧊 The presence of up to 900-meter-thick ice shelves acted as a barrier, preventing the mixing of saltwater with the Arctic Ocean's fresh water.
- 🌡️ The rapid release of fresh water into the Atlantic and Pacific could have caused abrupt climate transitions, such as the Dansgaard-Oeschger events.
- 🌍 The research was conducted by scientists from the Alfred Wegener Institute and the University of Bergen, providing a new understanding of the Arctic's paleoclimate.
- 🔎 The absence of thorium in sediments during specific periods serves as evidence of the Arctic Ocean being fresh water, as thorium is a byproduct of uranium decay in saltwater.
Q & A
What is the main topic discussed in the video script?
-The main topic discussed in the video script is the discovery of a mechanism that explains the tremendous increases in temperature recorded in Greenland's ice cores, which show temperature rises of up to 16.5 degrees Celsius over a decade or two.
What is the significance of the Arctic Ocean being completely fresh during certain periods?
-The significance lies in the fact that the Arctic Ocean, which is typically salty due to its connection with the Atlantic and Pacific Oceans, was found to have been completely fresh during certain periods. This suggests a unique environmental condition that could have contributed to rapid climate changes.
How did the Arctic Ocean become completely fresh according to the script?
-The Arctic Ocean became completely fresh due to the sea level being 130 meters lower, which created land bridges and effectively cut off the ocean from the Atlantic and Pacific Oceans, preventing the influx of saltwater.
What role did the ice shelves play in the Arctic Ocean's freshwater state?
-The ice shelves, which were up to 900 meters thick, played a crucial role by extending far into the water, effectively choking off the connections to the Atlantic and Pacific Oceans and preventing saltwater from mixing with the Arctic's freshwater.
What evidence is used to support the claim that the Arctic Ocean was fresh during certain periods?
-The absence of thorium in the sediments during specific time periods is used as evidence. Thorium is produced from the decay of naturally occurring uranium in saltwater, so its absence indicates the water was fresh.
What are the implications of the Arctic Ocean being filled with freshwater on climate change?
-The implications include the potential for rapid climate oscillations and abrupt climate transitions, as the release of freshwater into the Atlantic and Pacific Oceans could have disrupted ocean currents like the Gulf Stream.
How does the study explain the Dansgaard-Oeschger oscillations?
-The study suggests that the sudden release of freshwater from the Arctic Ocean into the Atlantic during periods of ice melting could explain the rapid climate oscillations known as Dansgaard-Oeschger events.
What were the two time periods mentioned in the script when the Arctic Ocean was completely fresh?
-The two time periods mentioned were between 60,000 and 70,000 years ago and between 130,000 and 150,000 years ago.
What is the role of sea level changes in the Arctic Ocean's salinity?
-Sea level changes play a significant role in the Arctic Ocean's salinity by affecting the connectivity with other oceans. During glacial periods, lower sea levels created land barriers, isolating the Arctic Ocean and allowing it to become fresh.
How does the presence of freshwater in the Arctic Ocean relate to climate tipping points?
-The presence of freshwater in the Arctic Ocean, particularly when released suddenly into the Atlantic, can disrupt ocean currents and cause climate tipping points, leading to abrupt and significant changes in climate.
What were the environmental conditions in the Arctic during the Carboniferous period mentioned in the script?
-During the Carboniferous period, the Arctic was much warmer, supporting lush forests, and was home to creatures like turtles and crocodiles, indicating an extremely warm climate.
Outlines
🌐 Arctic Ocean's Freshwater Phases
Paul Beckwith discusses a groundbreaking study on the Arctic Ocean, revealing it was completely freshwater during certain periods. He explains that the Arctic's connection to the Pacific and Atlantic was blocked by land bridges and thick ice shelves, allowing freshwater to accumulate. This phenomenon occurred around 60-70,000 years ago and 130-150,000 years ago, leading to significant climate changes when the freshwater was released into the oceans.
🌡️ Impact of Freshwater Release on Climate
The study indicates that the rapid release of freshwater into the Atlantic and Pacific oceans could have caused abrupt climate transitions, such as the shutdown of the Gulf Stream. This new understanding challenges previous assumptions about the Arctic's role in climate change and offers insights into past climate oscillations, like the Dansgaard-Oeschger events, which saw temperature fluctuations of up to 16.5 degrees Celsius over a decade.
🧊 Evidence from Sea Floor Sediments
Scientists from the Alfred Wegener Institute and the MARUM in Bergen, Norway, conducted a detailed analysis of marine deposits to uncover the Arctic Ocean's past. The absence of thorium isotopes in sediments from two specific periods suggests the water was freshwater, as thorium is a byproduct of uranium decay in saltwater. This evidence supports the theory that the Arctic Ocean was covered by ice shelves and filled with freshwater, which could explain the abrupt climate changes observed in the paleo records.
Mindmap
Keywords
💡Arctic Ocean
💡Temperature Rise
💡Ice Cores
💡Continental Drift
💡Beringia
💡Sea Level
💡Fresh Water
💡Ice Shelves
💡Dansgaard-Oeschger Oscillations
💡Alfred Wegener Institute
Highlights
New research paper discusses a mechanism explaining rapid temperature increases in the Arctic.
Historic temperature rise of up to 16.5 degrees Celsius recorded over Greenland in a decade.
The Arctic Ocean was found to have been completely fresh during certain periods.
The Arctic's warmth in the Carboniferous period allowed for lush forests and tropical creatures.
Continental drift and changing ocean passageways influenced the Arctic's climate.
Sea levels were 130 meters lower, isolating the Arctic Ocean from the Pacific and Atlantic.
Ice shelves up to 900 meters thick acted as barriers, preventing saltwater exchange.
Evidence suggests the Arctic Ocean was freshwater during two glacial periods.
Freshwater release into the Atlantic could have caused climate transitions by shutting down the Gulf Stream.
The study's findings are significant for understanding past climate changes and their mechanisms.
The absence of thorium in sediments indicates the presence of freshwater instead of saltwater.
The Arctic Ocean's freshwater periods occurred 60-70,000 years ago and 130-150,000 years ago.
The research was conducted by the Alfred Wegener Institute and the University of Bergen.
The study provides a new understanding of the paleo records and climate tipping points.
The findings explain the Dansgaard-Oeschger oscillations and abrupt climate changes.
The research is a result of long-term studies and analysis of marine deposits.
Transcripts
hello
i'm paul beckwith and uh
in the last video i started talking a
little bit about a very exciting
new finding paper just released
about the arctic ocean
and a mechanism to explain
why we could have these tremendous
increases in temperature
as may as recorded in the ice
in greenland green and ice cores of
up to eight to ten degrees celsius
in a matter of a decade or two and in
one case 16.5 degrees celsius
temperature rise
recorded happened over greenland in the
space of a decade or two
okay so these massive rises in
temperature from the cold ice age state
to a much warmer situation
so in this particular uh
case i'm talking about basically
the arctic ocean was
became essentially completely
fresh and we know that in the
carboniferous period
you know millions and millions of years
ago
the arctic was a much warmer place and
there's there there were forests growing
and there were
turtles in the water and
crocodiles and things like that warm
warm
you know is extremely warm those
creatures could only exist when it's
extremely warm so
you know it was it was lush
and and a completely different world so
we know that and a lot of that is
related to continental drift
changing passageways of the ocean et
cetera
but in the last 150 000 years we did not
know we had no idea
before now
that not only was there all of this
water stored in the
ice you know i said snow in the arctic
but there was water fresh water stored
in liquid form
in the entire arctic ocean so how can
that happen
you know the arctic ocean's connected to
the pacific and the atlantic and there's
flows of water so it's you know very
salty
environment and it's a how could it be
completely fresh water
under the ice so i'm going to explain
that
essentially the sea level was 130 meters
lower
so so therefore the bearing straight was
completely above sea level right so
there was no straight there was a land
bridge
beringia we know that ice age
mammals crossed that ice bridge and then
and people as well
there was no connection through the
canadian archipelago that was all dry
land
so no zero connection to the pacific
now on the atlantic side there's there's
two kind of choke points
um one you know through the f ram
straight over to
to um europe you know it's pretty
shallow in most places but there's still
some very deep
passages where water could flow but the
study
shows that that was all fresh water
but it was also fresh water down as far
as the
greenland to scotland passage
okay if you look on the bathymetry maps
which i'll show you
very very shallow waters when you have
130 meter sea level drop
a lot of it is land and the channels
that existed
well we had massive ice sheets
in europe covering europe and also
covering greenland and covering north
america
and these ice these glaciers on land
these ice sheets
where they met coastlines you had these
tremendous ice
ice shelves that were floating and those
ice shelves
some of them were like 900 meters thick
and that 900 meters 10 would be above
water above sea level
so 90 meters and 90 percent below so
over 800 meters below sea level the ice
would extend
combine that with 130 meter sea level
drop and that
that's about 930 meters or you know
close to a kilometer underneath the
present
level of sea level okay so
that basically choked off the connection
to the ark to the atlantic if you look
at the basimetry
so the combination of those two things
plus
you're getting you're always adding
fresh water to the arctic and rivers and
snow melt and rain etc
that basically that water that was stuck
under the under the ice and the sea ice
and the ice caps
pushed out all of the salt water so
you know we have solid evidence that
between 60 and 70
000 years ago and also between 130 150
000 years ago
the entire arctic ocean was fresh water
and this explains a lot because when the
ice started to melt and that fresh water
was
released very quickly into the atlantic
and also on the pacific side
then it did things like shut down the
gulf stream causing uh
you know rapid abrupt climate
transitions
you know before we couldn't account for
enough water doing that but
this totally changes the ball game i
can't emphasize over emphasize how how
important this
is so let's talk about that study and
then the related studies
on the arctic uh system changes
and then i'll and then in a subsequent
video i'll talk about the actual
peer-reviewed papers
in detail okay so you can just uh
google this the arctic ocean was covered
by a shelf ice
all of this stuff is available okay so
basically
this is what we have um in the case
that you know um where where the arctic
became complete fresh water
the sea level's 130 meters lower so on
the pacific side everything's locked up
this is all land here
okay right up to greenland through the
canadian archipelago
and the nearest strait right over to
greenland it's all land so there's no
exchange of water with the pacific ocean
meanwhile if you come there's a bit of a
choke point here but there's still
deep channels where water can flow but
the data shows there was this was
totally fresh water
this is from the sediment data and
totally fresh water here and if you look
at this greenland
to scotland ridge okay with iceland here
then then there's only a couple small
channels here and here but if the ice is
900 meters thick here
the ice shelves floating extending out
and and also ice shells because it you
know we're in a glacial period
you know very strong glacial period and
the ice shells move farther and farther
out into the
atlantic ocean so that combined with
very thick sea ice
you know there year round and we have so
we have basically ice covered here year
round
and fresh water building up and building
up and the only salt water is
is ejected out through these through the
passages that are the very bottom so
here's a couple images
so this is the ice shelf here
this is the the topography of the of the
ocean floor coming up here
this is the normal atlantic salty water
out here
and there's more and more fresh water
building up here
okay so there's only a little bit of
remaining
salt here and the fresh water
is is is coming like it's coming out
here and it's pulling out
basically the the salt water so there's
very little salt water so you go down
thousands of meters and it's basically
all of
fresh water here okay so that was
the the um two time periods
um 60 to 70 000 years ago
and 130 250 000 years ago
and then what happens is as you start
getting the ice
melting and calving here okay the fresh
water goes out into the ocean
right this is all fresh water and
warm salty water goes over the ridge and
it's denser so it just falls back in so
this starts filling up with salt water
and when you get a sudden melting of the
ice sheet
then the fresh water all surges out you
get fresh water hosing
which goes into the you know atlantic in
this case here
and then the salt water comes in and
then you and then when this completely
retreats you have the situation today
where we have a lens of fresh water near
the surface and then salt water but the
arctic ocean is mostly salty
so the arctic ocean was covered by up to
900 meter thick shelf ice and was filled
entirely with fresh water at least twice
in the last 150
000 years this surprising finding
is a result of long-term research by
scientists from the alfred wegener
institute and the marim
which is in bergen norway i believe
with a detailed analysis of the
composition of marine deposits
this study showed that the arctic ocean
as well as the nordic seas did not
contain sea salt in at least two glacial
periods
these oceans were filled with large
amounts of fresh water under a thick
ice shield the water could then be
released into the north atlantic in very
short periods of time
when the ice started retreating and
these sudden fresh water inputs
fresh water hosing it's called in the
simulation
could explain rapid climate oscillations
for which no satisfying explanation has
been previously found
okay so 60 to 70 000 years ago
particularly cold part of the last
glacial period
you know large parts of northern europe
and north america were covered by ice
sheets
the european ice sheet spanned a
distance of more than 5000 kilometers
from ireland
to scotland by a scandinavia to the
eastern rim of the kerosee in the arctic
ocean and in north america we had the
couple two large ice sheets covering
greenland of course and the bering sea
coastline were glaciated
so what was the ice situation like even
further north in the arctic ocean was it
covered by thick sea ice or maybe with
the tongues of these vast ice sheets
floating on it far beyond the north pole
okay
so it we don't have scientific answers
to these questions have been more or
less hypothetical so far
because you know we have glaciers on
land they deposit boulders moraines
glacial valleys
you know and we get lots of traces in
the in the
in the geography of the existence of the
prior
ice sheet okay but in the arctic over
the ocean
um there's very few traces of these vast
ice shelves
okay but they're but their evidence is
being taken from
uh cores in the sea floor sediments and
they're giving a surprising conclusion
they show that the floating parts of the
northern ice sheets covered large parts
of the arctic ocean in the past 150
000 years and about 70 to 60 thousand
years ago
and 150 to 130 000 years ago
fresh water accumulated under the ice
and
created a completely free completely
fresh arctic ocean for
thousands of years okay this changes
everything in about the paleo records it
changes our complete understanding it
happened not once but twice
in you know the last 150 000 years this
is a huge finding so how do we know for
sure
well thorium there's no thorium in the
sediments for those time periods
if there's no thorium in the sediments
that means that there was no salt in the
water
okay because uh what you do from you do
a core
through the sediment and you get the
dating and
you find out that in salt water
the decay of naturally occurring uranium
always results in the production of the
isotope thorium-230
and then thor that would accumulate on
the sea floor where it remains
detectable for a very long time due to
its half-life of 75 000 years
okay well no thorium
in the sediments for this period of time
therefore no uranium therefore no salt
in the water therefore it's totally
fresh water
all the way through the water column
essentially you know
the thorium isotope is like a natural
clock
so its repeated and widespread absence
is a giveaway that reveals what happens
the only reasonable explanation for no
thorium in the sediments
under the arctic ocean for those two
time periods in the last 150
000 years was that the arctic was filled
with fresh water
so that you had frozen water you know
the ice cap on top and the sea ice
and then it was all liquid it was all
fresh water underneath liquid water
fresh water huge amount so this is a
completely new picture for the arctic
ocean
so how is this possible how can a large
ocean basin
connected by several straits with the
north atlantic and the pacific ocean
turn entirely fresh
so you real you have to realize that in
glacial periods
there was so much water in the ice form
building up that it lowered sea levels
up to 130 meters lower than today
multiplied by 3.3 that's uh
300 that's about 420 feet lower than
today
now the ice masses in the arctic the
floating ice shelves extending far
down into the water they restricted
ocean for
circulation even further so shallow
connections like the bering strait or
the sounds of the canadian
archipelago were above sea level so it
cut off the connection
entirely to the pacific ocean in the
nordic seas the large icebergs extended
to the sea floor and stopped the
exchange of water mass
there was at least 1200 cubic kilometers
per year of fresh
water added to the arctic basin from
flow of glaciers ice melt rivers
draining
and therefore so we have these barriers
and therefore
you know the salt water that filled um
and then once the ice went the salt
water could then go back in
this is a huge huge deal and it does
explain
the dansgard osher oscillations the
eight to ten degrees and climate tipping
points
and abrupt climate change huge huge new
finding thank you for listening
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