The Arctic isn't too cold?

Arctic

Earth's North

The total area exceeds 21 million square kilometers

Arctic Zone

(Arctic region range diagram, the countries shown are those with part of their territory in the Arctic region, map by @张伟&王申雯/Planet Research Institute)

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1.84 million square kilometers of glaciers

Covering land

(Part of the Greenland ice sheet, image source: @Visual China)

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11 million square kilometers of sea ice

Frozen Ocean

(Large expanses of floating Arctic sea ice, image source: @Visual China)

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High in the sky

Extremely cold Arctic vortex

Ready to go south

Use cold waves to invade all directions

(Due to the temperature difference between the Arctic and other regions, there are long-term Arctic vortices and polar front jets over the Arctic and surrounding areas, which bind the cold air in the polar regions; the figure below is a schematic diagram of the Arctic vortex and polar front jet, drawn by @王申雯/Planetary Research Institute)

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but

Frozen polar regions

But this is not the normal state of the earth

Icehouse Earth at the poles

In the 4.6 billion years of Earth

Very few occurrences

But for humans

This frozen Arctic is very important

In a world that is getting hotter

The fate of the remote Arctic

It will affect each of us

(A polar bear jumps on the ice, photographer @沈辉)

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Who froze the North Pole?

What kind of power is it?

Let it melt quickly?

Everything started thousands of years ago.

The coming of "winter"

Winter is coming

Unlike Antarctica, which is mainly land

The Arctic is centered on the Arctic Ocean

Surrounded by land

There are only a few channels such as the Bering Strait and the Norwegian Sea

It can connect the Arctic Ocean to the outside world

(Schematic diagram of the Arctic Ocean. Different organizations have different definitions of the Arctic Ocean. This article uses the marginal seas shown in the figure as the boundary of the Arctic Ocean. Map by @Zhang Wei/Planetary Research Institute)

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This also makes the Arctic Ocean

The world's smallest ocean

Only more than 14 million square kilometers

7.7% of the Pacific

Nickname: "Arctic Mediterranean"

A vast continental shelf extends into the seabed of the Arctic Ocean

Except for the three mid-ocean ridges

The four basins separated by the sea are deeper.

The average depth of the Arctic Ocean is only about 1,200 meters.

The shallowest ocean in the world

(Please watch in horizontal mode, the topography of the Arctic Ocean seabed is shown here. Map by @张伟&王申雯/Planetary Research Institute)

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Such a sea-land pattern

After tens of millions of years of geological evolution

Early in this evolution

The earth is still very warm

The surface temperature of the Arctic Ocean can even reach 23°C

Comparable to today's subtropical

But geological movements thousands of kilometers away

It is about to plunge the earth into bitter cold

About 80 million years ago

Extensive and sustained mountain building

From the European Alps

Zagros via Iran

To the Himalayas of Asia

Create a huge super orogenic belt

And continues to this day

(Sketch of global plate movement since the late Cretaceous, drawn by @王申雯&郑艺/Planetary Research Institute)

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The mountains gradually rise

A large amount of fresh rock exposed on the surface

Gradually destroyed by rain, snow, wind and frost

Complex chemical reactions with the atmosphere

Consumes a lot of carbon dioxide

Reduces greenhouse effect

So much so that in the last 55 million years

The Earth is beginning to cool down

About 13 million years ago

The surface waters of the Arctic Ocean are gradually freezing

Formation of extensive year-round sea ice

(Please watch in horizontal mode, Arctic sea ice, image source: @Visual China)

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As the Earth continues to cool

The Arctic Ocean will soon be completely frozen

Land around the Arctic

It also began to be covered with ice and snow

About 7 million years ago

Snow in Greenland

Gradually compacted into ice

Glacier formation

(Glaciers in Greenland, image source: @Visual China)

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As global temperatures gradually decrease

Glaciers expand from high to low

From land to sea

Become a white cliff standing on the sea

Thick and magnificent

(Please watch in horizontal mode, the glaciers extending to the sea in the Svalbard Islands, photographer @梅元皎)

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When extended to the sea

Glaciers are affected by gravity, waves, etc.

Break, collapse, disintegration

Formed icebergs floating on the sea

(Icebergs in the waters near Greenland, photographer @Thomas Look at the World)

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The volume of glaciers on land is growing

The scope is getting bigger

About 2.75 million years ago

The vast glaciers surrounding the Arctic Ocean

They have connected to each other to form a huge, thick ice body

It can cover all the valleys and ridges below.

The Ice Sheet is Born

(Please watch in horizontal mode, overlooking the ice sheet of Greenland, image source: Visual China)

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So far

The entire Arctic and surrounding areas

Became the white dome of the earth

Plus, from about 34 million years ago

The Antarctic is gradually covered by ice sheets.

The Earth is officially frozen at the poles

"Icehouse Earth"

(When both the North and South Poles of the Earth are covered with a large amount of ice, it is called "Icehouse Earth". The "Icehouse Earth" period we are in now is only the third time in the history of nearly 500 million years; please watch it in horizontal mode. The picture shows the glaciers on the Svalbard Islands. Photographer @陈建伟)

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However

Under the overall cold tone of the earth

There is also a small alternation of cold and warm

Every hundreds or even tens of thousands of years

The Earth's orbital posture changes slightly

The amount of solar energy received fluctuates

The climate also changes between glacial periods and interglacial periods.

During the coldest ice age

The Arctic ice sheet is extremely large

It can extend southward to 37°N

Greenland, most of North America, northern Eurasia

Almost completely covered

Plus the contribution of the Antarctic ice sheet and the alpine glaciers on land

Global sea levels could drop by more than 100 meters

(As the Earth's climate changes periodically, the range and volume of the ice sheet have also been changing. The Last Glacial Maximum, about 20,000 years ago, was the coldest moment closest to us, when the sea level dropped by about 130 meters. The figure below shows the range of the ice sheet during the Last Glacial Maximum, with the coastline showing the position after the sea level dropped by 130 meters. Map by @王申雯&张伟/Planetary Research Institute)

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But the interglacial period after the glacial period

The global climate will warm up again

About 12,000 years ago

The most recent ice age ended

Rapid warming

The vast ice sheet retreated again

The modern Arctic as known to humans

Beginning to take shape

Ice and Snow Trail

Ice retreats toward the mountains and north

On the land outside the Arctic

Leaving behind many glacial landforms

In the Arctic and surrounding mountains

Glaciers retreat from the foothills to the top of the mountain or disappear

Leaving many sharp edges

Sharp horns

There is also a U-shaped glacial trough

(Glacier landforms in Gates of the Arctic National Park in Alaska, image source: Visual China)

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Whether it is the Scandinavian Mountains in Northern Europe

Brooks Range, Alaska

The Arctic and surrounding mountains

Because of the extremely rich glacial landforms

Showing a fierce attitude

(Glacier landforms on the Norwegian island of Senega, which is part of the Scandinavian Mountains, photographer @Cycad)

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Fjords shaped by glaciers in the coastal mountains

Particularly special

(Please watch in horizontal mode, the fjord landscape of Greenland, photographer @Thomas looks at the world)

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In the cold ice age

Glaciers have carved out many U-shaped valleys among the mountains.

As glaciers retreat, sea levels rise

Seawater gradually floods the U-shaped trough

And continue to extend inland

The deep and narrow fjord was born

(Schematic diagram of fjord formation, drawn by @王申雯/Planetary Research Institute)

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Located in Greenland

Scoresbysund Fjord

Length reaches 350 km

And has many branches like branches

It forms one of the largest fjord systems in the world.

(Satellite image of Scoresbysund Fjord in Greenland, image source @NASA)

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The Scandinavian Mountains

Norway across the country

There are nearly 1,200 fjords.

The coastline has become extremely winding

Total length exceeds 25,000 km

About 90% of them are located on both sides of the fjord.

(Distribution of fjords along the Norwegian coast, map by @Chen Zhihao/Planet Research Institute)

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Beyond the mountains

Glaciers retreating northward

The secrets of the world beneath the ice were revealed

In more distant times

As these glaciers developed and expanded southward

In the weak spots of the surface rock

Many depressions were carved out

Now, as the glaciers retreat, they are gradually exposed.

After being filled with meltwater

Forming a network of glacial lakes

(Schematic diagram of the formation of glacial lakes, drawn by @王申雯/Planetary Research Institute)

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Finland has a quarter of its territory within the Arctic Circle

There are nearly 190,000 lakes

Like countless gems inlaid on the earth

(The heart-shaped glacial lake in Finland is a small lake affiliated with Lake Pagani. Image source: Visual China)

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The largest lake, Saimaa

The area reaches 4,400 square kilometers

Embracing thousands of islands

(Please watch horizontally, Lake Saimaa, the largest lake in Finland, picture source: Visual China)

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Ancient glaciers

Shaped the face of parts of the Arctic

But the Arctic is still cold

Widespread permafrost

It also created some more bizarre landscapes

When groundwater freezes and expands

The upper soil was lifted up

Many hills were formed on the earth

Frost heave

(Frost heaves in Tuktoyaktuk, Northwest Territories, Canada, photographer @Kristian Binder)

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For surface water bodies in permafrost areas

Due to repeated freezing and thawing

The ground gradually collapsed and water accumulated

Forming countless melt lakes

(Schematic diagram of the formation of a thermal melt lake, drawn by @王申雯/Planetary Research Institute)

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When looking down from a high altitude

These melt lakes are densely distributed and have various shapes.

In the vast northern land

Depicting unexpected patterns

(Dense thermal melt lakes in the Yamal Peninsula of Siberia, image source @Visual China)

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After a long period of ablation and retreat

In today's Arctic

Glaciers have largely retreated from the continents outside the Arctic

Only remains on the islands outside the Arctic Ocean

For example, among the mountains of Svalbard

More than 1,600 glaciers meandering

This archipelago covers an area of only more than 60,000 square kilometers.

More than half of the land

Covered by glaciers

(Glaciers on the Svalbard Islands, image source: @Visual China)

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Greenland

The Arctic's remaining ice sheet is preserved

Total area exceeds 1.7 million square kilometers

Covers 85% of Greenland's landmass

(Greenland ice sheet scene, image source: Visual China)

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Glaciers from the Arctic land

A big retreat

The extent of sea ice

It is no longer as good as the Ice Age

(Arctic Sea Ice, image source: Visual China)

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It changes with the seasons.

March after winter

The Arctic Ocean has the largest sea ice area

It can extend to the Pacific and Atlantic Oceans

The total area reaches 15.4 million square kilometers

And in September after midsummer

Only 6.4 million square kilometers remain

Retreat to the Arctic Ocean

(The above data are the average values of the Arctic Ocean sea ice extension range in March and September from 1981 to 2010; the figure below is a schematic diagram of the Arctic Ocean sea ice extension range in winter and summer, drawn by @张伟/Planetary Research Institute)

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Small warming against the backdrop of an icehouse Earth

Retreating Arctic ice

It not only reshaped the face of the Arctic

It also makes various plants and animals

Return to the Arctic

Turning the Arctic into

A hot land for living beings

(Sea ice and polar bears in the Arctic Ocean, image source: Visual China)

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A land of living beings

Land near the Arctic Circle

The Arctic is a relatively warm place

Although the annual average temperature is often less than 5℃

But the forests composed of coniferous trees such as pine, spruce, and fir

Still growing here in patches

This is the boreal forest.

Taiga

(Please watch in horizontal mode, the northern taiga in Siberia, image source: @Visual China)

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Its scope

Extends from 50 degrees north latitude to 70 degrees north latitude

Covers most of Eurasia and northern North America

With about 11.5% of the Earth's land area

The largest biota in the world

It is also the northernmost forest in the world.

(Sketch of boreal coniferous forests, drawn by @张伟&王申雯/Planetary Research Institute)

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Whenever winter comes

These conifers will stop growing.

Entering hibernation

There is also a slight separation of the cell wall and the intracellular material

Even if ice forms between cells

It is also difficult for ice crystals to form inside cells

To avoid damage

When summer comes

They are "awakened" at lower temperatures.

To take advantage of the short summer growing season

(Landscape of the northern taiga in the Western Sayan Mountains in southern Siberia, image source: @Visual China)

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With such ability

They grow densely in the Arctic

Spreading thousands of miles

Become a world of ice and snow

King of the Forest

(Please watch in horizontal mode, the northern coniferous forest in the Ural Mountains in winter, image source: @Visual China)

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In places with higher latitudes and colder temperatures

Nor can northern coniferous forests grow

Another plant community

Begin to show their abilities

This is made up of mosses, lichens, herbs

And some small shrubs, etc.

Tundra

(Tundra vegetation near the Greenland Ice Sheet, image source: @Visual China)

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These seemingly fragile plants

In the northernmost land of the earth

Showing vitality

Its distribution area exceeds 11 million square kilometers

(Sketch of the range of tundra in the Northern Hemisphere, drawn by @张伟&王申雯/Planetary Research Institute)

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Winters here often drop to -30℃

Tundra plants tend to have a slow pace of life

Two years or even longer

Complete it slowly

The entire life cycle of germination, growth and flowering

To prevent freezing

Some tundra plants also have

Store fat, sugar and other substances

To lower the freezing point

Gain the ability to resist cold

(Tundra vegetation under Ula Peak in Greenland, photographer @Thomas Look at the World)

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Beyond Plants

Arctic Animals

They have also evolved ways to cope with the cold.

Cold seawater can dissolve more oxygen

Plus the continuous sunshine for several months in summer

Large amounts of phytoplankton are blooming in the Arctic Ocean

Various fish, krill, etc. feed on it

Attracts a variety of predators

(Killer whales in the Arctic Ocean, image source: Visual China)

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17 species of whales including killer whales, narwhals, bowhead whales, etc.

Every year I come to the Arctic

They have extremely thick skin and fat layers.

Some species have a fat layer up to half a meter thick.

Become an excellent cold-resistant "equipment"

(Two humpback whales, also known as humpback whales, in the waters near Greenland, picture source @Visual China)

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Pinniped mammals such as walruses and seals

They have a similar strategy to whales to keep warm

There is also a lot of fat accumulated under the skin

Make them look cute

(A bearded seal lying on the Arctic sea ice, photographer @徐征泽)

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But don't be fooled by their slow movement on land

Thick fat also brings a streamlined appearance

Very good for underwater activities

Make them the most flexible fat people in the polar regions

(Walrus underwater, image source: Visual China)

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On the Arctic land

Herbivorous animals such as reindeer and musk ox

Have strong hooves

In winter when the ground is covered with snow

Uncovering tundra plants hidden deep beneath the snow

(Two musk oxen on the snowfield of Wrangel Island, Russia, photo source: @Visual China)

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Carnivorous animals such as Arctic foxes

The color of the hair changes in different seasons

Snow-white in winter

In summer, it changes to brown like rock soil

Blending in with the environment

Help them hide in the dark and wait for opportunities to hunt

(An Arctic fox on the Svalbard Islands, photographer @徐征泽)

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And has a huge body of 2-3 meters

And the whole body of milky white hair

Polar Bear

The undisputed star of the Arctic

(Polar bear standing on ice, image source: @Visual China)

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The world's largest extant terrestrial carnivore

It has a huge weight of 350-700 kg

Can run on ice at a speed of 40 kilometers per hour

and swim in water at a speed of 10 kilometers per hour

Athletes in the Arctic

The powerful forefoot

Huge, sharp canine teeth

And the patience to wait for a long time

This makes polar bears the northernmost species on Earth.

Top terrestrial predator

Even large animals such as seals, walruses, and even whales

It’s also in their recipes

(Polar bear mother and cub looking for prey, photo source: @Visual China)

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Rich in Biodiversity

Energizing the Arctic

More than 10,000 years ago

Modern humans continue to migrate

Finally set foot in this far north land

They live and hunt here.

Adapting to the extreme environment of the Arctic

(Reindeer are of great significance to human society in the Arctic, photographer @LuDi__)

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People adapt to local conditions

They make a living by hunting seals, whales and other animals

The prey is rich in fat

Providing them with food security to resist the severe cold

Eating raw meat also makes them lack fruits and vegetables.

Able to get enough vitamin C

No risk of sepsis

(Inuit hunting, picture source: Visual China)

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The wisdom of mankind

They also gradually learned

Using ice and snow as houses and animal skins as clothing

Raising sled dogs and reindeer

As friends across species

Also used as a means of transportation

(Sami village and reindeer, photographer @吴邺霖)

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With a unique lifestyle

Humans spread across the Arctic

In Greenland, Northern Europe, Siberia, etc.

Formed the Inuit, Sami, Yakut, etc.

Unique Arctic Aboriginal Culture

And it continues to this day

(Tent camp of nomadic reindeer, picture source: @Visual China)

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But outside the Arctic

The world we live in is changing rapidly

Especially in modern times

Huge amounts of greenhouse gases are emitted by industrial activities