This was the research essay I submitted for the CIA 1&2 for the course on Contemporary Issues. I got 35/40 for this.
(I was motivated to take this topic as this event occurred right as we were told to select our topics. I was also keen on this topic as i had picked up the National Geographic Magazine Issue in July and the cover issue was Secret Report: Antarctica which focused on how speed of melting of glaciers in the continent of Antarctica has increased and could result in rise of sea-levels.)
ICE CRISIS: MELTING OF ICE GLACIERS
-Reubyn Coutinho
INTRODUCTION
No place on Earth compares to the vast white wilderness of forces
of snow, ice, water and rock. Antarctica is simply stunning. (1) Antarctica is
the 5th largest contingent on the planet earth, twice the size of the island of
Australia. With an average elevation of 2.5 km, it is the highest continent and
with an average temperature of -50 degrees, it is the coldest continent. The
continent is 99% ice and is home to 90% of the world’s ice in an area just one
and half times the size of the United States of America. It has a two mile
thickness of ice on an average. (2)
70% of the planets freshwater is in the continent of
Antarctica in the form of ice. Despite this, the continent of Antarctica is
classified as a desert region (specifically an arctic desert) due to the fact
that it receives less than 6.5 inches of rainfall annually. (3)
Antarctica can be divided into two parts. They are West Antarctica and East Antarctica. The mountain range
known as the Transantarctic Mountains divides the desert continent of
Antarctica into West and East. (4) East Antarctica is the larger half of the
continent. It is considerably larger than West Antarctica. The ice sheet
covering East Antarctica has a thickness of five km in some regions. (4)
The East Antarctic Ice Sheet (EAIS) is more stable than the
West Antarctic Ice Sheet (WAIS) as a bulk of the ice sheet rests on bedrock
high above current sea level. (5)
The West Antarctic Ice Sheet is mostly grounded below sea
level. As most of this Ice Sheet lies below sea level it is a Marine Ice Sheet.
West Antarctica is the largest Marine Ice Sheet on Earth. Being a marine Ice
Sheet it is capable of rapid change and therefore could be unstable.(23)
Ice is constantly on the move at Antarctica. It moves faster
at the Ice Shelves and Glaciers.
The ice shelves are a thick, floating platform of ice that
forms where a glacier or ice sheet flows down to a coastline and onto the ocean
surface, typically in Antarctica or Greenland.(6) They are akin to floating
dams. They act as barriers which prevent inland glaciers and Ice Sheets from
slipping into the sea. (7)
Ice Shelves floating in the water
The ice shelves are
already floating in the water, hence they don’t add much to the sea level. But
as they weaken and split away to form Ice Bergs, the glaciers behind them
retreat as ice rapidly flow into the sea. (8)
Picture a dam, and imagine what happens if they dam breaks
or is opened. The commodity beyond just flows.
"Although floating ice shelves have only a modest
impact on of sea-level rise, ice from Antarctica's interior can discharge into
the ocean when they collapse. Consequently we will see increase in the
ice-sheet contribution to global sea-level rise.
Dr Hilmar Gudmundsson, British Antarctic Survey (9)
According to Helen Fricker of the Scripps Institution of
Oceanography in San Diego, the ice shelves – are the canary in the coal mine.
She adds that when an ice shelf melts sea level doesn’t rise but it’s like a
signal that a rise is imminent, as glaciers behind the shelf will accelerate.
A study published in The Cryosphere showed signs of an
initial crack in Larsen C in 2010. The crack’s developments were tracked
closely over the next few years by scientists. The crack’s growth began speeding
up in 2014. NASA’s operation Ice Bridge in late 2016, captured a photo of the
rift which now measured 113 km long and 91 m wide. In June the Antarctic
Research group Project MIDAS showed that 5 km of ice was all that held the ice
shelf to the continent. (13)
The Pine Island Ice Shelf has a thickness of 1,300 feet over
most of its area. It has thinned by an average of 150 feet over the last two
decades from 1994 to 2012. Pine Island Ice Shelf are shredded by rifts a
quarter mile across (16)
This essay will look at the recent event of Larsen Ice Shelf
C splitting away, ice shelves of the Amundsen Sea Glaciers, Larsen Ice Shelf A,
vulnerable glaciers of East Antarctica.
Secondary data from websites and magazine and newspaper
articles will be used in the essay.
MAIN BODY
Floating Ice Shelves of which West Antarctic is the largest,
buttress coastal glaciers and the inland ice behind them. As mentioned above,
when ice shelves break up to form ice bergs, the glaciers and land ice become a
part of the sea much faster.
STABLE
The ocean’s force on an ice shelf and the friction from the
bedrock of the continent keeps the glacier in place.
BREAKING APART
Ice Shelves break as warm air and sea water melt it. The
glacier’s flow could get lubricated by the melted ice draining to its base.
ACCELERATING LOSS
The glacier loses mass, causing the slopes to grow even
steeper. This hastens the flow of glaciers into the ocean.
ERODING FROM THE
BOTTOM
Warm Currents pushing under ice shelves are eating away at
the Totten Glacier in East Antarctica and the Amuldsen glaciers in West
Antarctica. As the Glaciers retreat down these slopes, they may pass a point of
no return.
ANCHORED GLACIERS
These glaciers sit in marine basins and are pinned at the
grounding line to a seafloor ridge.
RETREATING GLACIERS
Warm currents push back the grounding line, detach the ice
and speed it’s flow and retreat.
A large movement of water in one direction is a current.
Currents can be temporary or long-lasting; they can be near the surface or in the
deep ocean. The largest currents shape the Earth’s global climate patterns (and
even local weather conditions) by moving heat around the world. (10)
The Pine Island Ice Shelf is warmed from below by
Circumpolar Deep Water, which has resulted in system imbalances, more intense
melting, glacier acceleration and drainage basin drawdown. This is the so called
“Weak Underbelly” of the West Antarctic Ice Sheet, which may be prone to
collapse. Pine Island Glacier is thinning, and, combined with rapid basal
melting of the Amundsen Sea ice shelves, means that there is concern for the
future viability of its fringing ice shelves (11)
Strong winds on the East Antarctic generate waves which
circle the continent at approximately 700 kmph. These waves are generated 6000
km away from the Marine Ice Sheet of West Antarctica and when they meet the
steep underwater structures of this region, they push the warm water under the
ice shelves. This helps explain the high melt rate in the region which leads to
parts of trillion tonne ice shelves (Larsen C) to partly break away from the
continent.
The warm Antarctic Circumpolar Current passes quite close to
the continental shelf in this region, providing a source for this warm water.
According to Dr Paul Spence from the ARC Centre of
Excellence for Climate System Science, it is the combination of available warm
water offshore and its transportation to the shelves that has seen rapid
melting of Ice Shelves along West Antarctica for many years. (12)
“That remote winds on the opposite side of Antarctica can
cause such a substantial subsurface warming is a worrying aspect of the
circulation at the Antarctic margin."
The worrying aspect of circulation at the Antarctic margin
is that faraway winds on the opposite side of Antarctica can cause massive
subsurface warming.
The changes in the Antarctic coastal winds, particularly
along East Antarctica, might themselves be related to climate change. This is
because as Earth gets hotter the strong westerly winds associated with storms
over the Southern Ocean contract toward the poles and in turn changing the
winds near the Antarctic continent. (12)
When the researchers modelled the impacts of these altered
winds on Antarctica they found that they could drive warming of up to 1°C of
the waters at the depth of floating ice shelves along the Western Antarctica
Peninsula.
This could have significant implications for Antarctica's ice
shelves and ice sheets. Previous research showing that even small increases in
ocean temperatures can substantially increase melt rates around the Peninsula.
(12)
LARSEN ICE SHELF C
On 12th July, 2017 a part of Larsen Ice Shelf C broke away
from the highly vulnerable Antarctic Peninsula located in Western Antarctica.
The Larsen Ice Shelf is made up of a series of smaller Ice Shelves identified
by alphabets from A to G. Larsen Ice Shelf C follows Larsen Ice Shelf A which
broke away in 1995 and Larsen ice Shelf B which broke away in 2002. The Larsen
C Ice Shelf is the fourth largest Ice Shelf in Antarctica and is larger than
Larsen Ice Shelves A and B.
The Ice Berg which broke away has been equated to about a
quarter of the size of Wales, or four times as big as London (9) twice the size
of Luxembourg (14)
After the ice berg, which has been christened as A68,
detached and floated away. Dr Anna Hogg, an ESA Research Fellow in the Centre
for Polar Observation and Modelling (CPOM) from the University of Leeds and Dr
Hilmar Gudmundsson, from the British Antarctic Survey have tracked the iceberg
A68 - using the European Space Agency (ESA) and European Commission's
Copernicus Sentinel-1 satellite. (15) The Antarctic report tweeted that the
iceberg will be the third largest since satellite tracking began.
The gap between the Larsen Ice Shelf C and the Ice Berg A68
is now 5 km wide and increasing by the minute. (15)
11 smaller ice bergs
have been formed. The largest of these 11 is a 13 km long berg. These bits have
broken off from Ice Berg A68 as well as from Larsen ice Shelf C which is still
attached to the Western Antarctic Ice Sheet, which can be termed as collateral
damage. It measures 200 m thick and its depth below sea level could reach 210
m, according to the European Space Agency (ESA). (13)
This calving left the Larsen C Ice Shelf about 12% smaller
in area and at its lowest known extent. (14)
Dr Anna Hogg has gone on to say that it looks like the
Larsen C Story may not be over yet as satellite images are showing continued
action on the Larsen C Ice Shelf. The cracks are growing towards a feature
known as the Bawden Ice Rise. The ice rise provides structural support for the
remaining ice shelf. In the event of an Ice Shelf losing contact with the ice
rise(it could happen here) due to a large ice berg calving event (A68 has been
calved from Larsen C) there can be a massive increase in ice speed, and may
even result in further destabilisation. (15). If the entire Larsen C
disintegrates, it is estimated to increase sea water levels by 10 cm.
MIDAS had reported on their website that glacial flow in the
Antarctic Peninsula had tripled in speed, resulting in high-record flow.
According to MIDAS, it’s not man- made climate change, but natural causes are
the reason behind the calving. (13)
Ice that Larsen C had lost cannot be entirely blamed on
warming air temperatures. Two other factors are linked to the loss of ice. (13)
First is the loss of air in its snow covering, called firn.
Tiny pockets of air in the firn act as an insulator for the ice sheet beneath.
As the firn melts, it loses this air. The resulting meltwater ponds and the
absorption of heat and sunlight drive further melting.(13)
The second factor is the melting of its mass from below. The
ice melts as it is exposed to warmer waters of the Weddell Sea from south-east
Argentina (the closest continental mass near Antarctica). Like Larsen B before
its collapse in 2002, Larsen C is experiencing sinking of the shelf because of
the ice loss phenomenon. (13)
Lastly, scientists suggested that as the firn melts, the
water fills the surface cracks and acts as a wedge, opening the ice sheets
further. (13)
LARSEN A
Hernan De Angelis, a scientist with the Glaciology Division
of the Instituto Antartico Argentino in Buenos Aires and his colleague Pedro
Skvarca discovered that when Larsen A Ice Shelf disintegrated in January 1995,
the glaciers behind it surged towards the sea. It was this discovery that
presented positive evidence that glacial surges are hot on the heels of an ice
shelf collapse. Scientists revived a discarded theory that ice shelves act as
dams that prevent glaciers from slipping into the sea. (7)
De Angelis and Skvarca found that five of the six major
streams of ice that fed into the northern section of the Larsen Ice Shelf
dramatically surged towards the sea and then retreated in the years following
the 1995 disintegration of the shelf.
Their evidence is in the form of blocks of ice in several
locations that are stranded 20 to 40 metres above glacier surfaces. Ice
terraces are formed when a glacier suddenly lowers as a result of a surge. De
Angelis has said that maps of glaciers in March 2002, have shown a retreat in
their surge. This is an indication that glaciers have dumped much of their ice
into the seas. (7)
The Pine Island Glacier and the Thwaites Glacier are major
causes for concern. They are the most rapidly draining glaciers in West
Antarctica.
PINE ISLAND GLACIER
The Pine Island Glacier of the West Antarctic Ice Sheet like
the Ice Shelf, has thinned and it’s melting has speeded up in recent years.
(17)
In 2015 and 2016, a 225 square mile chunk of the Pine Island
Ice Shelf broke away and floated away into the Amundsen Sea. This Ice Shelf
acts as a dam to the Pine Island Glacier, one of several large glaciers (along
with the Thwaites Glacier, the Pope Glacier and the Smith Glacier) that
together drain a large dome of ice called the West Antarctic Ice Sheet into the
Amundsen Sea. This Ice Sheet has a thickness of approximately two and a half
miles and covers an area twice the size of Texas. It rests atop a series of
islands, however most of it is on the floor of a basin 5000 feet below sea
level.(8)
In March 1994, a U.S. icebreaker ship called Nathaniel B.
Palmer reached the Palm Island Ice Shelf. It was able to spend just 12 hours
there before sea ice forced it back. In those 12 hours the crew discovered a
current just below the ice shelf. This current was slightly less salty than the
sea water around it. Why? This water was freshened by melted ice (Antarctica is
home to Freshwater). Beneath this less salty layer of water, at a depth of
approximately 2,000 to 5,000 feet warmer seawater was streaming along a sea
floor canyon. The sea Floor canyon ran parallel under the ice.(8)
The ice was fresh as it originated as snow falling on West
Antarctica.
Stan Jacobs, an oceanographer - Lamont-Doherty Earth
Observatory in New York, quickly understood what was going on. The warm water
was arriving at Antarctica’s Amundsen Sea from the Pacific Ocean more than 200
miles north. As it was heavy with salt it sunk below the lighter melted
freshwater of less salt content and followed the floor of the submarine canyon.
This submarine canyon sloped down to the glacier. (8)
The warm ocean water was being channelled under the Pine
Island Ice Shelf. This water was ultimately finding the grounding line. The
warm water was hitting the wall of ice and eroding it. This was producing the
stream of melt laden seawater with less salt content. Due to it being cooler
and fresher it had less density.
Now that same canyon was channelling warm ocean water under
the Pine Island Ice Shelf. Somewhere tens of miles inland, the warm water was
finding the “grounding line”: the place where the glacier lifts off the
seafloor and becomes a floating ice shelf. Hitting that wall of ice, the warm
water was eroding it, producing a steady stream of melt-laden seawater. Because
it was cooler and fresher, it was less dense, and so it was rising above the
warmer, incoming water and flowing back out to sea just under the shelf.
As Pine Island Ice Shelf and Pine Island Glacier have a base
at the bottom of the ocean due to West Antarctica being a marine ice sheet,
they are vulnerable to the gradually warming ocean. In the event of all this
ice cracking and drifting away from the continent the warm sea water will cause
the grounding line to retreat and the glacier will thin and its melting will
speed up. Sea levels would rise by 10 feet which would see coasts around the
world get submerged. (8)
The anchored glaciers
will begin retreating, the warm seawater below the shelf will cause the
grounding line to retreat and the ice to flow away faster. (18)
In January 2009, the Palmer found that the melt rate had
increased by about 50 percent. As the Pine Island Ice Shelf has weakened and
the glacier behind it has accelerated, the ice has stretched and thinned for
150 miles inland from the coast. These destabilizing effects spread farther
into West Antarctica every year.(8)
THWAITES GLACIER
The Thwaites glacier is worrisome as it could destabilize
the entire Marine Ice sheet that is West Antarctica, were it to collapse. This
glacier by itself could raise global sea level by about four feet.(8)
Dr Rignot is a glaciologist at the NASA Jet Propulsion
Laboratory at Pasadena, California. He has been a principal investigator on
several NASA-funded projects to study the mass balance of the Greenland and
Antarctic ice sheets using radar interferometry combined with other methods;
the interactions of ice shelves with the ocean; and the dynamic retreat of
Patagonian glaciers. He is a member of the American Geophysical Union, and the
International Glaciological Society. (19)
According to Eric Rignot, these are the fastest melting
glaciers on Earth (8)
EAST ANTARCTICA
This is the bigger part of the continent which due to its
base and setting on high ground was considered secure.
However despite it being stated in the Introduction that the
east is safe, mapping with ice-penetrating radar has revealed a low-lying
region cut by glacially carved channels that drop as far as 8,500 feet below
sea level. This is perfect for guiding warm ocean water deep into the heart of
the ice sheet. The Totten Glacier is the largest coastal outlet in this region.
Melting Antarctica's ice sheets would raise oceans around
the world by 200 to 210 feet. (60 to 65 meters)
TOTTEN GLACIER
The Totten Ice Glacier according to Dr Rignot is one Ice
Glacier in the East that if it were to collapse would contribute a sea level
rise of 13 feet. 13 feet is just a fraction of the rise in sea level that would
occur in the event of the Entire East Antarctic Ice Sheet melting. This 13 feet
is equivalent to the sea rise that would occur in the event of West Antarctica
melting completely.
“One glacier alone,
roughly as much as all of West Antarctica,” says Eric Rignot.
The Totten Ice Glacier is losing two cubic miles of ice per
year. In Antarctic terms and in comparison to the ice lost in Western
Antarctica on the Antarctic Peninsula and the Amundsen Sea Glaciers, this can
be considered a fraction of a loss. Small Potatoes in Antarctic terms.(8)
21 years after Palmer’s voyage to Pine Island an Australian
Icebreaker Aurora Australis reached the front to Totten an just like Palmer at
Pine Island this icebreaker detected warm water flowing under the ice shelf at
a speed of 4.5 cubic miles per day. (8)
Donald Blakenship of the University of Texas has undertaken
surveys which have identified two seafloor grooves which are deep enough so as
to permit warm water to creep below the Totten Ice Shelf.(the same thing that
is happening to the Pine Island Ice Shelf)
The particular type of warm water near Totten Glacier is
saltier (therefore denser), so it remains at depth, filling canyons in the
seafloor. Seafloor valleys connecting this deep warm water to the coast can
especially compromise glaciers, a process previously known to be occurring
along the coast of the West Antarctic Ice Sheet. (8)
According to a Nature Geoscience paper authored by Jamin
Greenbaum and an international team of collaborators in March, 2015.
Warm ocean water has been observed since 1996, below 400 to
500m of cool surface.
Using airborne gravity and magnetics, Greenbaum revealed two
deep seafloor valleys that could allow the warm ocean water to reach the base
of the glacier’s floating section and drive rapid melt. The discovery likely
explains the glacier’s extreme thinning and raises concerns about how it will
impact sea level rise. The result is of global importance because the ice
flowing through Totten Glacier alone is sufficient to raise global sea level by
at least 13 feet. (20)
ANIMALS
"The sea temperature is going up in a way that wasn't
predicted and this makes me more worried for the marine animals. The evidence
we've got and the models we've been looking at said sea temperature was not
likely to change much in the Antarctic. A one degree increase puts us into the
region where the animals are pushed to one end of their biological,
physiological and ecological capabilities."
- Lloyd
Peck, Marine Biologist, British Antarctic Survey.
The rising temperature of Oceans result in melting and we
think that sea levels will rise and low lying regions will be flooded. But they
also affect animals of this region. These animals are sensitive to a minimal
shift in temperature.
Increase in temperatures and losses of sea ice could spell
big problems for krill. Studies show that krill numbers had fallen by 80% since
the 1970s. Experts linked its collapse to shrinking sea ice. This endangers the
Adelie Penguin which live on the Krill. Krill find food and shelter on the
undersides of ice sheets which are retreating thus causing krill population to
drop. Penguins are having to expend excessive energy to find food, which makes
them less successful at breeding and raising young.
CONCLUSION
Some say that the sea level will rise by 216 feet, some say
189 feet. The bottom line is that ice melting is contributing to a rise in the
sea levels. How does that affect us? We will lose our land masses as the sea
water will submerge our homes.
Former U.S.President Barack Obama in Before the Flood states
that the Pentagon doesn’t label this as an Environmental issue but as a
national security issue. This is because people from coastal regions will begin
to migrate.
“If they start moving, then you start seeing, um, scarce
resources. The subject of competition between populations.”
It is proved that melting is happening faster as the years
go by. The melting at Pine Island ice Shelf has increased by 50%. The National
Geographic documentary ‘Before the Flood’ states that sailing across the North
Pole could be a reality soon. It won’t happen with the South Pole as that is
located of the continental mass of East Antarctica.
South America is one of the closest land masses to the
vulnerable West Antarctica Ice Sheet. The National Geographic article, ‘What
the World Would Look Like if All the Ice Melted,’ says that the Amazon Basin
and Paraguay River Basin would be converted into Atlantic inlets. This would
wipe out Buenos Aires and coastal part of the country of Uruguay. (24) In North
America the entire Atlantic sea board would be submerged. California’s hills
would become a cluster of Islands. (24) Closer to home in Mumbai, we saw how much just under 300mm
of rain disrupted life. Ice Melting would result in a massive high tide that
would flood the city.
A United Nations report published prior to U.N. Environment Assembly estimated that nearly 40 million Indians will be at risk from rising sea levels come the year 2050. People in Mumbai and Kolkata are in risk of maximum exposure to this issue. (26)
This report also listed Guangzhou along with Shanghai from China, Bangkok, Ho Chi Minh, Hai Phong, Yangon and Dhaka as those which are projected to have largest population exposure to coastal flooding in 2070. (25)
Redrawing the world’s map may be a necessary option if the ice were to melt. It won’t happen for hundreds of years, but we are the generation that knows about it, we know the challenge and its up to us to answer it. In the words of Leonardo Dicaprio at the United Nations in 2014. “The time to answer the greatest challenge of our existence on this planet is now. You can make history or be vilified by it.” (27)
WORKS CITED
1. http://www.lonelyplanet.com/antarctica-1007062/introduction
2. https://www.livescience.com/21677-antarctica-facts.html
3. http://www.whatarethe7continents.com/facts-about-antarctica/
4. https://blogs.nasa.gov/icebridge/2014/11/19/east-and-west-the-geography-of-antarctica/
5. http://www.antarcticglaciers.org/antarctica/east-antarctic-ice-sheet/
6. https://www.sciencedaily.com/terms/ice_shelf.html
7. http://news.nationalgeographic.com/news/2003/03/0306_030306_glaciersurge.html
8. http://www.nationalgeographic.com/magazine/2017/07/antarctica-sea-level-rise-climate-change/
9. http://www.independent.co.uk/news/science/larsen-c-ice-shelf-iceberg-huge-record-antarctic-climate-change-global-warming-a7873411.html
10. http://ocean.si.edu/ocean-news/currents-waves-and-tides-ocean-motion
11. http://www.antarcticglaciers.org/glaciers-and-climate/ice-ocean-interactions/marine-ice-sheets/
12. http://www.business-standard.com/article/news-ians/strong-winds-in-eastern-antarctica-melting-ice-on-opposite-side-117071800326_1.html
13. https://observer.news/featured/ice-land-need-know-a68-iceberg/
14. https://www.theguardian.com/world/2017/aug/02/what-happened-next-to-the-giant-larsen-c-iceberg
15. https://phys.org/news/2017-08-larsen-c-iceberg-breakaway.html
16. http://www.nationalgeographic.com/magazine/2017/07/antarctica-sea-level-rise-climate-change/
17. https://svs.gsfc.nasa.gov/vis/a000000/a004100/a004103/index.html
18. https://earthobservatory.nasa.gov/IOTD/view.php?id=82392
19. https://www.nasa.gov/vision/earth/environment/sealevel_rignot_bio.html
20. http://www.earthexplorer.com/2015/Southern_Surveys_Unravelling_the_mystery_of_East_Antarctica.asp
21. https://www.washingtonpost.com/news/wonk/wp/2012/11/01/can-we-stop-the-seas-from-rising-yes-but-less-than-you-think/
22. http://www.worldbank.org/en/news/feature/2013/08/19/coastal-cities-at-highest-risk-floods
23. http://www.antarcticglaciers.org/antarctica/west-antarctic-ice-sheet/
24. http://www.nationalgeographic.com/magazine/2013/09/rising-seas-ice-melt-new-shoreline-maps/
25. http://timesofindia.indiatimes.com/home/environment/global-warming/40-million-Indians-at-risk-from-rising-sea-levels-UN-report/articleshow/52358198.cms
26. http://www.hindustantimes.com/analysis/india-will-be-in-trouble-if-breakaway-antarctica-iceberg-leads-to-sea-level-rise/story-QbzYQ2PUh98a3vhJqQAZsI.html
27. https://www.globalcitizen.org/en/content/leonardo-dicaprio-quotes-on-climate-change-environ/
