Importance of Natural Resources

Icecap – Secrets of World Climate, Episode 12


Scenes from another world, surely. No towns or cities. No greenery. Almost no life at all. Virtually all of the world’s fresh water
is here, locked up in ice sheets over a mile in thickness. The harshest of all climates, these lands
rarely see temperatures above freezing, and have the lowest on record anywhere on our
planet. A land of ice, snow, glaciers, freezing winds
and bitter cold. This is the icecap. In our series looking at climate zones from
equator to pole, we have at last reached journey’s end and the finale is anything if not dramatic,
because it is here, in the most northerly and southerly landmasses of Greenland and
Antarctica, that we find the most extreme of all climates, what is known by climatologists
as the Icecap. The climatic definition of Icecap is simple. Average temperatures never rise above freezing. The consequence of this will seem obvious. There is no rain, no running water, just snow,
usually blowing in from warmer regions around it, which builds up over thousands
of years into an ice sheet a mile deep or more, meaning the surface of the ice is high
above sea level, ensuring even lower temperatures and further guaranteeing the icecap’s survival. This process of thickening cannot go on indefinitely,
of course, gravity demands that the ice be pulled down to the sea, and as a large mass,
over enough time, the seemingly solid ice acts like a liquid, flowing toward the sea
as glaciers. When these glaciers reach the coast, then
break off into ice bergs, to eventually melt back into the ocean. In the highest mountains of Earth, there are
places where the temperature never rises above freezing point, and so glaciers form here,
in the Rockies, the Alps, the Caucasus, the Himalayas and the Andes. But by land area and amount of ice held, these
areas are insignificant compared to the two major ice sheets of the world – Greenland
and Antarctica. Despite qualifying under the temperature requirements,
for the purposes of climate classification, the Arctic around the North Pole is not usually
included in the icecap climate, since there is no actual land there, just frozen sea ice
up to several metres thick at most. Between them, Greenland and Antarctica account
for 99% of the world’s fresh water, with the vast majority of that share being in Antarctica. The Antarctic ice sheet is almost ten times
the size of Greenland’s, taking up an area equivalent to the United States and Mexico
combined. If all of this ice was to melt, the sea level
globally would rise by between 60 and 70 metres (approx. 200ft). In the case of Greenland, it’s at first
not clear why this land is covered in ice, when the surrounding islands are tundra. But unlike the surrounding lands, a wall of
high mountains makes up what is believed to be a giant set of three islands. Millions of years ago, an ice age would have
blanketed the whole area in a mile-thick ice sheet, but as the ice age retreated, it is
believed the mountains prevented this ice from escaping quickly, and the high altitude
of the ice cap maintained the very low temperatures necessary to preserve its survival into the
present day. On the western coast of Greenland, there are
a number of gaps in the mountains where the ice flows out glacially, and on reaching the
sea, these break off into icebergs which flow down into the North Atlantic. The ice berg that sank the Titanic began its
life many thousands of years ago as snow falling on the ice sheet that covers the world’s
largest island. In the case of Antarctica, there are multiple
reasons why this giant continent stays covered in ice, and why it is the coldest place on
our planet. The first is obvious – it sits right over
the south pole. In summer, sunlight strikes the earth here
at an oblique angle, providing little warmth, and most of what sunlight does arrive here
is reflected back from the blinding white ice. In winter, the sun remains below the horizon
for months at a time, with consequently no chance of any input of heat. Secondly, Antarctica is surrounded by the
unbroken Southern Ocean, allowing the prevailing westerlies and the circumpolar ocean current
at these latitudes uninterrupted travel, preventing any movement of tropical air or warm ocean
currents into the Antarctic region. Lastly, Antarctica has had millions of years
to build up its ice sheet, with the result that most of the continent’s surface of
ice is above 2000m (6500ft) in altitude, keeping temperatures even lower than they would be
at sea level. In both Greenland and Antarctica, these high
altitude ice sheets produce a special phenomenon whereby the cold mass of air above the ice
sheet seeks to fall into warmer air at the coasts, since cold air is more dense than
warm. This leads to near constant winds, known as
Katabatic winds, flowing out from the centre of these land masses to the sea, sometimes
reaching hurricane strength. As if these places weren’t grim enough already. In relative terms, despite the abundance of
fresh water locked up the ice, this climate zone is technically a desert, with most places
experiencing less than 250mm of precipitation per year (rain equivalent, not snowfall). This is because the air is so cold that it
can carry very little moisture. Most of the snow that forms on the great ice
sheets of Greenland and Antarctica blows in from either adjoining tundra regions, or relatively
warmer marginal icecap areas near the coasts. In places in Antarctica, this combination
of low precipitation and high winds causes certain dry valleys to be scoured of all ice
and snow. In other parts, snowfall has never been recorded
or suspected, suggesting that there hasn’t been precipitation in centuries or possibly
millenia. This would make these places even drier than
the Atacama desert in South America, which is otherwise regarded as the driest on our
planet. Since average temperatures never rise above
freezing, plant growth is impossible, and in any case, the ground is covered with a
moving layer of ice. In some parts of the periphery of the ice
sheets, moss and lichen grow on sunward facing rocks, but this is the limit of any vegetation. Despite this, however, a very famous set of
animals have made Antarctica their home – these little fellas, and these… big fellas… Some species of penguins live in the Antarctic
for the simple reason that there are no other species here – no predators to interrupt
their breeding cycles. With the waters surrounding the continent
being rich in fish, there is plenty of food to sustain sometimes gigantic colonies, and
these conditions seem to be worth paying the price of living in the most inhospitable region
on earth. In terms of seasons, temperatures in Antarctica
stay below zero throughout the year, but the continent “grows” and “shrinks” in
terms of area with the summer and winter, as sea ice melts and freezes over. During winter, only the extreme north of the
Antarctic peninsula is directly accessible by sea, with all other coasts blocked by frozen
ocean. Human settlement is confined to research stations
on both the Greenland ice sheet, and in Antarctica. The largest of these is McMurdo station on
the coast of the Ross Sea in Antarctica, which is accessible by ship in summer time, and
among other functions acts as a supply base for other research stations on the continent. Then there is the Amundsen-Scott South Pole
station, at the geographic bottom of our planet. But this is not the coldest place on earth. The official lowest recorded temperature at
a surface based weather station occurred at the Russian Vostok research station in East
Antarctica. On 21 Jul 1983, a temperature of -89.2°C
(-128.7°F) was recorded. More recently, a satellite recorded a temperature
at the surface near Dome Argus, a snow dome which is the highest part of Antarctica at
an altitude of 4093m, and on top of an ice sheet estimated to be at least 3km deep. The temperature observed by the satellite
was -93.2°C (-135.8°F). Compare this with the average surface temperature
of Mars, of -63°C, and you can see why the icecap is considered the most other-worldly of all of
Earth’s climate zones. So all good things must come to an end. I hope you’ve enjoyed the series, and learned
a little bit more about the climates that shape our world. It’s been quite a journey, travelling across
twelve very different zones of Earth. We witnessed… The biodiversity of the Tropical Rainforests The endless rhythm of wet and dry seasons in the Tropical Monsoon and Savannah. The lofty temperate paradise of the Subtropical Highlands The scorching drought of the Hot Deserts The great cities of the Humid Subtropical The idyllic coastlines of the Mediterranean The beautiful countryside of the Oceanic The remote and empty Cool Deserts The great plains and cities of the Continental The vast forests and extreme temperatures of the Sub-Arctic The barren wastes of the Tundra and the Icecap – as if it was in a different
world entirely In all these and so many other ways, it’s
a rich, varied and unique planet. It’s our planet. Our Earth. Our home.


Reader Comments

  1. Another awesome episode! As beautiful as enlightening!
    I'm just a bit sad thinking this series is almost ending! I hope you can continue doing more. I've never have seen an explanation of climates such this in my life! And is all the work and effort in it that makes it really awesome, the well selected music for each episode, the drones views are breathtaking and the hyperlapses too and even the way you narrate it denotes a great passion. I'm so glad to have seen this series and interact with you! Thanks a lot!

  2. In the timelapse of the summer ice sheets in Antarctica, at around 9:00, is it just me or does it look like the ice is slowly rotating clockwise? Would that be a result of the circum-polar current or am I seeing things?

  3. Beautiful series! Now I’ll make up climate classifications for climates on other celestials:

    Mercury: Xa (scorching vacuum)
    Venus: AAAf (scorching runaway greenhouse)
    Moon: Xb (vacuum)
    Mars: Bxc (cold low-pressure) at the equator and EBx (carbon dioxide ice cap low-pressure) at the poles

    AAA means over 400c with significant atmosphere, X means airless, Bx means low pressure, etc.

  4. Brilliant job – great use of data, NASA imagery and statistics; Well done! It would be excellent if a video could be made explaining the changes in recent years to our climate. Has there been shifts in data? Has precipitation reduced in certain climate zones? Congratulations on presenting such a world-class documentary series.

  5. brilliant job done by this series! very enlightening and knowledgeable episodes, beautifully created. sad thats it ending, hoping some new learning experience to come! great job!! ?

  6. Can you start a new series a little bit more in to depth of ecosystems? For example how rivers shape habitat or whatever. From this point on its just waiting till you go viral, the quality is most certainly there! I enjoy your voice very much as well! Thanks for the time and effort!

  7. Happy New Year B.J. Ranson!!! Hope this year brings great things to you!!! Here I am waiting for the summary!!! :)))) hope you are fine my friend!

  8. Amazing! I binge watched the whole series. I had already generally mapped out climate zones for a worldbuilding project of mine, but had no way to relate what exactly all the zones meant. Thanks to your series, I was able to refine those zones and get an idea of what cultures would develop in these areas.
    Thank you so much for these beautiful videos!

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