Profound Implications of a Completely Salt-Free Arctic Ocean as recently as 60,000 Years Ago

Summary

Paul 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

00:00

🌐 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.

05:02

🌡️ 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.

10:05

🧊 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.

Keywords

💡Arctic Ocean

The Arctic Ocean is the northernmost part of Earth's water surface, encompassing the Arctic region and surrounded by the continents of Europe and North America. In the video, the Arctic Ocean is discussed as a key area where significant climate changes have been observed, particularly in terms of temperature increases and the melting of ice. The script mentions how the Arctic Ocean was completely fresh during certain periods, which is a crucial finding for understanding past climate changes.

💡Temperature Rise

Temperature rise refers to an increase in the average temperature of the Earth's atmosphere. The video highlights dramatic temperature rises in Greenland, with increases of up to 16.5 degrees Celsius over a decade or two. This rapid change is significant as it provides evidence of abrupt climate transitions, which are important for understanding the potential future impacts of climate change.

💡Ice Cores

Ice cores are cylindrical samples removed from ice sheets or glaciers, providing a record of the Earth's climate history. The video script uses ice cores from Greenland as evidence of past temperature changes, with the cores showing significant temperature increases. These records are vital for scientists to study and understand the mechanisms behind rapid climate changes.

💡Continental Drift

Continental drift is the movement of Earth's continents relative to each other, which has occurred over millions of years. The video discusses how continental drift has historically influenced the climate, particularly in the Arctic, by changing the passageways of the ocean and the distribution of land and sea. This geological process has played a role in the past warm periods mentioned in the script.

💡Beringia

Beringia refers to the land bridge that once connected Siberia to Alaska across the Bering Strait during periods of low sea levels. The script mentions Beringia as an example of how the Arctic Ocean was cut off from the Pacific during glacial periods, contributing to the unique environmental conditions that allowed the ocean to become fresh.

💡Sea Level

Sea level is the average height of the ocean's surface. The video discusses how sea levels were significantly lower during glacial periods, dropping by as much as 130 meters. This drop in sea level had a profound impact on the Arctic Ocean, isolating it from the Pacific and Atlantic Oceans and allowing it to become completely fresh.

💡Fresh Water

Fresh water refers to water with low concentrations of salts and other minerals, as opposed to saltwater. The video emphasizes the unusual finding that the Arctic Ocean was filled with fresh water during certain periods, which is unexpected given its connection to the salty Atlantic and Pacific Oceans. This fresh water accumulation and subsequent release are proposed as mechanisms for rapid climate changes.

💡Ice Shelves

Ice shelves are extensive areas of floating ice that are attached to a land mass, such as a continent or an ice sheet. The script describes how ice shelves in the Arctic Ocean extended far below the sea level, effectively blocking the exchange of water with the Atlantic and contributing to the ocean's fresh water state during glacial periods.

💡Dansgaard-Oeschger Oscillations

Dansgaard-Oeschger (DO) oscillations are rapid climate fluctuations that occur in the North Atlantic region, characterized by abrupt changes in temperature. The video suggests that the fresh water pulses from the Arctic Ocean, as discussed, could explain these oscillations, providing a new understanding of the mechanisms behind such abrupt climate changes.

💡Alfred Wegener Institute

The Alfred Wegener Institute is a German research center that focuses on the Earth sciences. The video credits the institute, along with the MARUM in Bergen, Norway, for the research that uncovered the surprising findings about the Arctic Ocean's past state. This research is a significant contribution to the field of paleoclimatology and our understanding of past climate dynamics.

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