In 1570, construction was going strong on sod houses in Nunalleq, a village in what’s
now southwest Alaska.
There were two rivers close by, perfect for salmon fishing.
Near the village, seals and caribou were abundant.
And while this all sounds great, things weren’t quite the same as they’d been in the past.
It was colder than usual, there weren’t as many salmon in the rivers, and the glaciers
seemed to be expanding.
The village, it turns out, was actually living through a period now known as the Little Ice
Age.
Usually, “ice age” refers to glacial-interglacial cycles - or times when there are major ice
sheets and times when there aren’t - that last for thousands of years.
But this Ice Age lasted only a few hundred years, which is why it’s “little.”
During this period, ocean temperatures were just a few degrees colder.
That small change was enough to plunge most of Europe into cold so extreme that Dutch
canals froze solid, something that rarely happens now.
But Nunalleq seems to have thrived during this period, based on the evidence a team
of researchers has found in the remains of hundreds of animals who lived - and died - near
there.
So how did this village manage to survive and prosper during the Little Ice Age, and
what caused this period of climate change in the first place?
We don’t have all the answers yet, but the ones we do have come from some unlikely places:
caribou teeth, dead beetles, and maybe even the Sun itself.
The term “Little Ice Age” was first used in the 1930s to refer to a different 4,000-year-long
period, but the definition has changed over time.
Today, climate scientists and geologists use Little Ice Age to mean a few hundred years
of climate change in recent history - but exactly which few hundred years they mean
varies; it’s still an ongoing debate.
So, for this episode, we’ll call it 1400 to 1850.
Now, in the grand scheme of deep time, the Little Ice Age was basically just a blink
- but for life in the Northern Hemisphere, it was a game-changer.
It’s particularly interesting to climate scientists because it happened so fast.
And while the Little Ice Age has mostly been studied in Europe, researchers are now starting
to look at its effects in other places.
Which brings us back to Nunalleq, that village in Alaska.
From oral history passed down by community elders, people living nearby have known about
the site for a long time, but they left it alone to preserve it.
Things changed though, when the permafrost started to melt, exposing two sod houses and
thousands of artifacts to the elements.
Since 2009, researchers have been working with the Quinhagak Village Corporation to
excavate the site, and to catalog, stabilize, and store more than 100,000 artifacts as they
emerge from the permafrost.
These objects are currently housed in a museum in Quinhagak, the community closest to the
site.
It’s the largest museum collection of pre-contact Yup’ik artifacts in the world.
Based on radiocarbon dating, it looks like the site was primarily occupied from 1570
to 1675 - entirely during the Little Ice Age - making it incredibly valuable for understanding
how people there survived the colder climate.
And one way to study this is through their trash.
Refuse piles near the sod houses contain animal bones, antlers, and teeth that are a treasure
trove of environmental and archaeological data.
From these piles, we know that the residents of Nunalleq ate a combination of different
types of wild game, including fish and marine mammals, as well as land animals and birds.
And in 2020, more data emerged to help quantify the impact of the Little Ice Age on the village.
The research team used the remains of beetles from the site to find that temperatures were
at least 1.2 degrees Celsius colder than the modern average.
Which might sound like a small change, but it’s actually more extreme than other parts
of the Northern Hemisphere.
-- On average, summers were between 0.5 and 1 degrees Celsius colder during the LIA, compared
to the 20th century.
And between the archaeological data and the climate data, it looks like Nunalleq was doing
just fine during one of the coldest parts of the LIA.
But the landscape around it was changing throughout that period.
From tree rings, ice cores, and other chemical records, it’s clear that there was a climate
shift in Alaska and Canada that spanned the Little Ice Age.
And this brings us back to the caribou found in the village’s refuse piles.
Throughout the site’s history, caribou were an extremely important resource.
While the people there didn’t actually eat much of their meat, they did hunt a lot of
caribou for their antlers and skins, used to make tools and clothing.
And from teeth found in the refuse piles, the research team was able to study
four caribou and reconstruct their lives using isotopes.
These showed that the caribou used different breeding and calving grounds than the herds
that live in the region today.
Something made the caribou shift their ranges between the LIA and today.
And whether that was human adaptation to the climate or the changes to the environment
caused by the changing climate itself, we’re still not sure.
What it does tell us, though, is that this region of Alaska is part of the bigger global
story of changes caused by the Little Ice Age.
Decades of research have shown that the Arctic cooled more than some temperate regions, but
there were still impacts around the world.
Geoscientists have studied all kinds of natural archives, from isotopes in bones in western
Argentina to flood deposits in Greece, that recorded change during the LIA.
Now, that doesn't mean that the world's climate cooled everywhere.
There's still a lot of debate about how exactly the LIA affected different parts of the world.
But it does look like it was a time of increased climate variability - one that seems to have
had many different causes.
One hypothesis with solid evidence is that several solar minima were partially responsible
These are times when there’s just less solar activity, meaning that the sun doesn’t send
as much light to Earth.
These are a part of the normal solar cycles that happen to this day.
But it wasn’t enough to cause the Little Ice Age by itself.
Another potential cause was changing land use in the Northern Hemisphere.
Computer models and climate simulations suggest that as humans disturbed natural land cover,
like forests, the new bare surface was more reflective.
Scientists call that reflectivity albedo.
High albedo means the surface reflects a lot of sunlight away from the Earth, and low albedo
means that the heat and light are absorbed.
The snow covered ground without trees increased albedo during the Little Ice Age, making it
colder, especially in the winter.
So far, estimates suggest that the impact of changes in land-use was about the same
as the impact of the solar minimum.
And those weren’t the only potential contributors to the cold - there were also volcanoes.
Increased volcanic activity can lead to cooling because it puts more particles in the atmosphere,
shading the surface of the Earth from the Sun’s energy.
One study noted 16 different eruptions linked to cooling events between 1630 and 1850, based
on particle data from ice cores.
And two of the eruptions - one in Japan and one in the Philippines - happened toward the
end of the time Nunalleq was occupied.
These eruptions, plus reduced solar radiation, might’ve also caused a major change in an
important ocean-atmosphere interaction, called the North Atlantic Oscillation.
See, there’s a delicate balance between sea surface temperatures and wind, and when
that balance is thrown off, it can have wide-ranging effects.
And it can be thrown off by things like volcanic eruptions triggering colder summers.
Man, to be honest, the Little Ice Age sounds like a really tough time: volcanic eruptions, changing
wind and temperature, and even a weaker Sun?!
Despite these changes, there’s no indication that food was scarce at Nunalleq, even though
there were famines and struggles in Europe during the same period.
So why the difference?
Well, one reason is probably that the people of coastal Alaska had a diverse diet, eating
a mixture of marine and land animals.
Life in the Arctic was often relatively extreme and unpredictable, so they were just more
used to change.
If Nunalleq had relied on just one source of food, or on agriculture, they would have
been in trouble.
But instead, they were able to adapt to the shifting environment.
In fact, the end of the occupation of Nunalleq doesn’t seem to have been directly caused
by an environmental disaster.
Instead, it looks like the settlement was attacked or involved in a war that occurred
roughly between 1645 and 1675.
However, some researchers have suggested the negative effects of the changing climate may
have triggered this conflict.
Eventually the sod houses sank into their surroundings and the artifacts they held were
trapped underground, perfectly preserved.
Though centuries have passed, Nunalleq lives on as a valuable cultural and environmental
archive as new data and artifacts emerge.
Those artifacts help draw connections between life in the village and the modern community:
Caribou hunting and salmon fishing remain an important part of life in southwest Alaska
today.
And perhaps there are lessons we can all learn from this village about resilience in the
face of extreme climate change.
A bunch of our PBS friends across YouTube are celebrating Earth Day — follow me over
to Overview on Terra for a look at one of the world’s largest garbage dumps (and how
this trash is being turned into usable energy).
Tell them Eons sent you!
One more thing — for those of you in the US, you should check out Greta Thunberg: A
Year to Change the World, a new 3-hour Earth Day broadcast event on your local PBS station.
The special is going to premiere on Thursday, April 22nd at 8/7 central, and will then repeat
starting Wednesday, April 28th at 8/7c.
A big thank you to the Nunalleq Archaeology Project for providing us with materials for
this episode!
If you want to learn more about Nunalleq, check out their very cool interactive educational
resources in the link in the description.
Also thanks to this month’s Eontologists for being so cool: Sean Dennis, Jake Hart,
Annie & Eric Higgins, John Davison Ng, and Patrick Seifert!
Becoming an Eonite at patreon.com/eons and you can get fun perks like submitting a joke
for us to read, like this one from Lil: What does a cow do when she is stressed?
She gets a moosage.
I need a moosage too
And as always thank you for joining me in the Konstantin Haase studio.
Subscribe at youtube.com/eons for more evolutionary escapades.