- 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)