At the ends of the world, the sun’s reach is weak.
Life struggles or is entirely absent.
And indeed what life could survive in a world of freezing temperatures
for most or all of the year?
A treeless world of hardy shrubs, lichen and moss dominates the north, while a permanent
layer of ice covers the south.
These are the last of the biomes of our planet.
This is the Arctic and Antarctic.
This is the tundra and ice.
The poles of our world receive sunlight at only an oblique angle, bringing little in
the way of heat.
And for almost half the year there is no sun at all.
This dynamic of poor solar heating produces the coldest of the biomes -
the tundra and ice.
What separates these two biomes is only ten degrees of Celsius.
In the tundra, summer temperatures rarely exceed 10°C.
This prevents the growth of trees, and so marks the boundary between the boreal forest
or taiga, and the tundra.
Only hardy shrubs, herbs, moss and lichen can grow here, covering the bleak landscape
when it’s not already covered in ice as it is for most of the year.
These lands fringe the entirely of the arctic ocean, from North America and the coasts of
Greenland to the north of Russia.
The ice biome permanently covers ground that never sees temperatures rise above 0°C, which…
makes sense when you consider that this is the point at which liquid water freezes.
That liquid is essential to life, and so, in a permanent state of frost, no plant life
would have been possible even if the ground wasn’t covered in a kilometres-deep layer
of solid ice.
The overlap of these two biomes with their respective climate zones of the same names
is pretty much total – and so those climate zones are not misnomers.
Because of this, I have covered both zones in detail in my Secrets of World Climate series
in two episodes.
And you’ll find these linked top-right and also in the description.
For a full treatment of this subject, please watch these in conjunction with this video,
as unlike in real-life, I am not going to repeat myself here.
In our Holdridge Lifezones chart, we find the tundra and ice in the top two rows.
It is worth noting that the term desert is used, which is, technically accurate, since
the ice is deserted of life.
Note also that the cooling of the temperate scale is not just in terms of increasing latitude,
but also in altitude.
And so tundra and ice are found in the high places of the world, above the treeline in
the Rockies, Andes, Alps and Himalayas.
However, in terms of percentage of land area covered, these are tiny in comparison to the
Arctic and Antarctic regions.
The permafrost, a permanently frozen layer of soil and ice stretching up to a kilometre
down, is present in all Arctic tundra, as it is in the Taiga.
And like in that other biome, leads to extensive bogs and lakes, since liquid water cannot
drain into the rocks below.
The permafrost is all but absent in alpine tundra, and in the small tundra-like areas
and islands found around the southern ocean, such as Tierra del Fuego, the Falklands, the
South Sandwich Islands and so on.
Beneath the permanent icecap, no life exists, but in the tundra life does,
albeit in a limited form.
In the short tundra summer, there are only about 50-60 growing days permitted.
This is too short for tree species to germinate, and so this realm is dominated by plants that
can quickly flower and reproduce in such a short window.
Lichen – a mix of fungi and algae is the hardiest of all plant classes globally, and
is found in all parts of the tundra.
Mosses are the next-most hardy plant class and these simple and ancient plants are also
found throughout the biome.
Sedges and cotton grass can be found in the often boggy, peaty conditions existing in
the tundra plains while on slightly elevated sites, low willows, other grasses and rushes
can be found.
The tallest tundra species are found on better drained, sandy soils of river banks, and come
from species families that include willow, sunflower and legume.
Isolated stands of coniferous trees, known as forest tundra,
can be found in certain areas.
These are vestigial remnants of taiga from earlier times when the climate was once warmer,
and have survived as clonal colonies, unable to reproduce through the normal channel of
seed germination.
Fungi and bacteria are found throughout the soil and act as essential vectors in the breakdown
and recycling of dead plant material.
The fauna in the tundra is limited, but where it exists, is well-known.
Polar bears patrol the coasts, while inland areas feature large herds of grazing giants
such as reindeer, caribou, musk-ox, and their accompanying predators, arctic wolves.
As in the taiga, these species are larger than normal, since a bigger body is easier
to keep warm than a small one.
But not all tundra mammals are large, and arctic hares, foxes and lemmings are also
common, with many sporting seasonal white coats as camouflage during the long icy winters.
Antarctic fauna is well-known, in the form of enormous colonies of penguins, as well
as the seals that prey upon them.
But strictly speaking, these animals are not a part of the tundra or ice biome, as such,
since they rely entirely upon the ocean, instead of the land, for their survival.
In terms of threats, the tundra and ice are not directly threatened by human activity,
since so few people live in these regions, less than several hundred thousand in a planet
of billions.
However with the advent of climate change, whether man-made or natural, the permafrost
of the tundra is melting, as are the icecaps of Greenland and Antarctica.
The melting of the permafrost leads to the release of methane, a potent greenhouse gas,
while the melting of the icecaps will lead to sea-levels rising, and global consequences.
The tundra and ice make up the last two biomes in the LONS08 classification system.
And while other specialised biomes exist, such as in the subtropical highlands around
the equator, or the wetlands found across the globe, this will be all I’ll be covering
for now in this series.
We have travelled from the equator to the poles, exploring the amazing living landscapes
across our varied planet.
The greatest biodiversity of all within the broadleaf forests of the tropics.
The intense heat of the tropical savannahs and the great herds and their predators.
The desolation of the hot and cold deserts that by land area make up the largest of the biomes.
The unique and often-forgotten shrublands of the subtropics and Mediterranean areas.
The endless grasslands of the temperate regions, and their geographic neighbours - the beautiful
mixed forests of North America, Europe and Eastern Asia.
The dark and forbidding expanse of the taiga.
The wasteland of tundra and ice at the top and bottom of our world.
It’s been an epic journey, and I hope you learned or experienced something from it.
Thanks again for watching.
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I’ll see you all next time for the start of a brand-new series.
Look-out for the notification of the premiere in a few weeks from now.
Until then, stay green!