- Recently, scientists have been finding some strange things
off the southeast coast of Greenland.
Whales that don't normally live there
are congregating in pretty significant numbers
and out-of-place fish are turning up in nets.
It's so significant
that when they noticed what was going on,
scientists became interested and a little worried.
- These whales, they didn't belong here.
They belong somewhere else.
Suddenly, we have them there on the coast
and that's not been observed before.
Well, something has changed here.
- Normally, a healthy pod of humpback or fin whales
is a great thing, but in such a sensitive area,
Mads and his team began to wonder
if this is a permanent change
and if it might mean something more significant
for the region.
- For the last 150 years where we have records from locals
show that they've never seen humpbacks
or never seen fin whales in the coast.
But today, you can see them regularly.
- In this episode, we're going to find out
what brought them to Southeast Greenland.
It turns out that these new migrants
are evidence of a much larger shift in the Arctic
that starts thousands of miles away
and has major implications for weather
throughout the United States
and the entire Northern Hemisphere.
Stay tuned as we unravel this mystery.
(ominous tones)
First, let's review some basics about the Arctic.
While Antarctica is a huge land mass covered in ice
and surrounded by ocean, the Arctic is a large body of water
covered in sea ice and surrounded by land.
No shade if you confuse North and South Poles.
It's a long way away.
And until recently, it was hard to study
many places in the ocean up there
because floating sea ice made getting there difficult.
- In the past like 40 years ago
when I was a little bit more risk tolerant,
I happily drove around in inflatables in fjord systems
in East Greenland and just stayed away
from this drifting pack ice, which was very dangerous.
- You don't wanna get crushed between huge ice chunks,
but with rising temperatures, sadly, there's much less of it
and scientists are now able to study the area more easily.
They're finding rapid changes that are likely permanent.
- I can also see the changes that you can read about
in the scientific papers or in the news
that the Arctic is changing.
I can also see them myself
and feel that something is going on here that is new.
- The Arctic Ocean is capped by seasonally changing sea ice,
which serves as an important regulator
for the Earth's climate.
The ice reflects solar radiation in the summer,
helping to keep our planet cool and livable.
But when the ice melts and exposes dark water,
the sun's energy is absorbed much faster.
A recent paper found
that the Arctic is warming four times faster
than the global average.
And since 1979, sea ice extent has been decreasing
by about the size of South Carolina each year.
So the whole system is delicate and not all ice is the same.
While glaciers form on land
and icebergs are chunks of glaciers that cab off
and float in the water, sea ice forms strictly in the ocean
and really specific conditions are needed for ice to form.
Usually cold water is denser and falls to the bottom,
but in the Arctic, there's a strong halocline
where saltier, denser water is at the bottom
and freshwater is at the top.
- So it has this kind of freshwater cap.
And it turns out that you can't grow sea ice
over oceans that don't have a halocline.
- That's because that freshwater cap
prevents the dense salt water which is warm
from coming to the surface,
and that dense warm salt water
prevents the cold freshwater from sinking.
So the fact that these layers don't mix
and disrupt this halocline is super important
to the global climate.
And there used to be more sea ice.
Old maps made by whalers
show sea ice extent in August of 1938.
It pushes south down the coast of Greenland,
creating an ideal environment for whale species
like narwhal and other Arctic marine life.
Sea ice also keeps temperate species from moving north
and competing with rare Arctic species.
- And that has been present there for the past 200 years,
but what we have seen recently
is that the ice has disappeared.
And it's only in the wintertime,
there's some ice that's passing in the area,
but there's very little ice
that's reaching the southern tip of Greenland.
- With almost no ice cover,
sunlight penetrates the surface allowing plankton to grow
which attracts feeder fish like capelin
and crustaceans like krill,
mackerel follow to feast on the smaller ocean life
and attract tuna who eat the mackerel.
Finally, whales and even dolphins come to take advantage
of the new areas with abundant food.
- Our estimate is about 6,000 fin whales
in this East Greenland coastal area
where they never used to be seen before.
There's about 3,000 humpbacks.
And then we have the the dolphins and also some pilot whales
and killer whales that are also new species to this area.
- While new species of whales and fish
might seem like an exciting opportunity,
especially for fishers and the Greenland locals,
other marine animals are getting pushed out.
- There used to be narwhals,
the tusked whale with the long tusk,
and they have disappeared and maybe they have moved north.
So these other more Arctic species
has disappeared from these areas.
But, of course, what is worrying
is that this is an interesting signal of a climate change
that happens 5,000 kilometers away in the Beaufort Sea
that affects the system in Southeast Greenland.
That gives us a hint about what kind of long distance effect
climate changes might have in unpredictable ways.
- So there are two dominant circulation systems
in the Arctic.
There is the transpolar drift stream,
which blows from the coast of Siberia
out through the coast of Greenland,
straight across the Arctic Ocean.
The winds blow surface waters
and also sea ice from the Arctic into the North Atlantic.
And then there's the beaufort gyre,
which is about 800 kilometers across
and it's this big bowl that circulates clockwise.
It takes about two years
for water parcels to make their way,
all the way around the perimeter of the gyre.
- [Maiya] Ice builds within the beaufort gyre each year,
growing before it eventually exits the Arctic
through the Fram Strait,
where it can be pushed as far south as Southeast Greenland.
But in recent years, there's been more ice melting
and that critical beaufort gyre
that used to be a nursery for ice
has instead become a graveyard.
Ice that's older than five years has all but disappeared
from the Arctic Ocean.
- Large parts of beaufort gyre now are ice-free in summer.
- And so when it's exported through the Fram Strait,
it's much thinner ice and it's not being produced
in the same amount as it used to be.
- When we look at the sea ice index,
we could see there was a variability in it.
And there was a time in the 1930s and '40s
where it was actually lower.
It was warmer climate.
You did have less sea ice,
but you also had reoccurrence of high sea ice in years.
We haven't seen that to the same extent
in the past 20 years,
and that's what really is a difference here
in terms of the climate.
And it corresponds in time when we see a marked change
in the ecosystem composition.
There's also a tendency for warming in the warm waters
coming towards Greenland,
so it's probably a combination
of both the decreasing sea ice
and the warming of the Atlantic waters.
- And this is why we're seeing temperate species
moving into the Southeast Greenland waters.
While Arctic species like narwhal
spend long periods of time under sea ice,
more temperate whales like humpbacks
tend to avoid ice with less sea ice to contend with
and an overall Atlantification of the Arctic.
They can move freely and find food to eat.
- The gradual changes all over the Arctic
where we can see that more temperate species are moving in
and replacing more high Arctic species
that are then again moving further north,
but many of these areas,
it's little subtle changes in temperature
that triggers the changes,
whereas in East Greenland, we have a very abrupt change.
You have an ice situation
that has lasted for the past couple hundred years
and probably even longer,
and it's suddenly changed to an open water situation.
I think that's unprecedented.
It's a warning about how long-range climate effects
can impact local areas that were so far away
from the source of impact.
- And there are reports of other changes
that are triggered by this loss of sea ice.
Svalbard has been hit by extreme rainfall
in the past 10 years and seabird die-offs,
something that used to happen infrequently,
has become increasingly common.
- This fall when we were up in the Canada base
in north of Canada and Alaska,
there were big rolling waves in the sea ice pack
which is something that I've never seen before.
- The Arctic may seem like a distant mysterious place,
but what happens there is having far-reaching impacts.
Most of the Arctic's land ice
is locked up in the Greenland ice sheet.
Scientists predict that if the entire sheet melted,
it will raise sea levels by seven meters.
Now, much like ice cubes in a glass of water,
melting sea ice doesn't contribute directly
to sea level rise, but with less sea ice in the summer,
more dark water is exposed,
which absorbs more solar radiation
which causes more warming and the cycle continues.
- We talk about global temperature increases
and the fact that we like to keep
global temperature increases below two degrees
above pre-industrial values.
While the Arctic has long surpassed that,
and the Arctic is one of the regions of the Earth
that is undergoing the most change,
and there is still fundamental things about the Arctic
that we don't understand.
- In a previous episode,
we explored theories about Arctic amplification
and the possibility that it's causing huge changes
to global weather, making the jet stream weaker
and also shifting it northward.
Some scientists suggest that these changes
might slow down weather systems
and make extreme weather events more likely.
And here's perhaps the scariest
most uncertain change in the Arctic
that exotic whale species and ice-free waters point out.
We don't know what will happen
when all summer ice disappears from the Arctic.
With such fast warming, that summer will come.
Without a surface layer of ice,
will wind and waves cause so much turbulence
and mixing that warm deep salt water
rises to the surface and prevents even winter ice?
Sea ice can only grow over an ocean
that's stratified by salinity.
So changes in ocean stratification in the North Pacific
like in the Bering Sea
and the Northern North Atlantic Greenland Sea area
can change the boundary between the polar ocean
and the mid-latitude oceans.
And this will change the wintertime extent of sea ice.
- So it's critical that we understand
how the Arctic is changing
since these changes affect us all.
We'd love to hear from you.
Are you seeing changes where you live?
Do you think these ecosystem shifts
are something to be worried about?
Let us know in the comments and see you next time.
(gentle music)