About Antarctica

A Gentoo Penguin in front of our ship

Before I talk about our adventures in the far, far south, I am going to diverge and talk about the entire continent of Antarctica. We visited only the Antarctic Peninsula, the little spike that trails off the continent toward South America, so this could be overkill. But, background is always nice.

The Earth's southernmost and least-populated (by far) continent, Antarctica is situated almost entirely south of the Antarctic Circle. The Peninsula extends above the Circle, which we almost reached, but never crossed. Surrounded by the Southern Ocean (also known as the Antarctic Ocean), Antarctica is the fifth-largest continent, with an area of 5,500,000 square miles. Most is covered by the Antarctic ice sheet, with an average thickness of 1.2 miles.

Map: Wikipedia

Antarctica is, on average, the coldest, driest and windiest of the continents. It is mainly a polar desert, with annual precipitation of more than eight inches along the coast and about two inches inland. About 70 percent of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost 200 feet. 

Antarctica holds the record for the lowest measured temperature on Earth at −128.6°F. The coastal regions can reach temperatures over 50°F in summer. We visited in the warmest month, experiencing temperatures ranging from just around freezing to 48°F (indeed, much warmer that back home in Colorado).

It looked colder than it was

The ice shelves of Antarctica were probably first seen in 1820 by a Russian expedition. The decades that followed saw further exploration by French, American and British explorers. The first confirmed landing was by a Norwegian team in 1895. In the early 20th century, there were a few expeditions into the interior of the continent. 

Chart: World Ocean Review

British explorers were the first to reach the magnetic South Pole in 1909, and the geographic South Pole was first reached in 1911 by Norwegian explorers.

The two "south poles" are almost 1,800 miles apart because the designations arise from different mechanisms. Earth's magnetic pole is determined by constantly shifting circulating currents of liquid iron in the outer core. 

The geographic south pole is a fixed map location.

Antarctica is governed by about 30 countries, all of which are parties of the 1959 Antarctic Treaty System, which prohibits military activity, mining, nuclear explosions and nuclear waste disposal. Tourism, fishing and research are the main human activities in and around Antarctica.

Argentina's Almirante Brown Antarctic Base research station in Paradise Bay

Despite its remoteness, human activity has a significant impact on the continent via pollution, ozone depletion and climate change.

The name given to the continent originates from a word that means “opposite to the Arctic.” But, the name isn’t what it should have been.

Europeans had long-believed that there was a vast continent in the far south that balanced the northern lands of Europe, Asia and North Africa. They called it Terra Australis (“Southern Land”).

Southland!

During the early 19th century, explorer Matthew Flinders doubted the existence of a detached continent south of Australia, which was then called New Holland, and he advocated for the "Terra Australis" name to be used there. In 1824, the colonial authorities in Sydney officially renamed the continent of New Holland to Australia, leaving the term "Terra Australis" unavailable as a reference to Antarctica.

Two very different places; Right photo: ThoughtCo

Over the following decades, geographers used phrases such as "the Antarctic Continent" as they searched for a more poetic replacement, suggesting names such as Ultima and Antipodea. Antarctica was adopted in the 1890s.

Antarctica has an 11,200-mile-long coastline: 44 percent is floating ice in the form of an ice shelf; 38 percent is ice walls resting on rock; 13 percent is ice streams or glacier edges; and the remaining 5 percent is exposed rock. It has saline and freshwater lakes, mainly in the McMurdo Dry Valleys or oases. Lake Vostok, discovered beneath Russia's Vostok Station, is the largest subglacial lake and one of the largest lakes in the world.

Mountains, snow, ice and ocean

Antarctica is divided into West Antarctica and East Antarctica by the Transantarctic Mountains, which stretch from Victoria Land to the Ross Sea. The majority is covered by the Antarctic ice sheet that extends to all but a few oases, which, with the exception of the McMurdo Dry Valleys, are in coastal areas. West Antarctica is almost completely ice-covered.

We didn't see any ice sheets (over land) or ice shelves (over water); Photo: Singularity Hub

East Antarctica comprises Coats Land, Queen Maud Land, Enderby Land, Mac. Robertson Land, Wilkes Land and Victoria Land and is largely covered by the East Antarctic Ice Sheet. 

There are many islands surrounding Antarctica, most of which are volcanic and very young by geological standards.

Some volcanos are still active; Deception Island

Antarctica has the highest average elevation of all the continents. Vinson Massif is the highest peak in Antarctica at 16,050 feet. Mount Erebus is the world's southernmost active volcano and erupts around 10 times each day. There are volcanoes under the ice, which could pose a risk to the ice sheet. The ice dome known as Dome Argus in East Antarctica reaches 13,422 feet.

Originally, Antarctica was part of the supercontinent Gondwana, which had a mild climate. What is now West Antarctica was partially in the Northern Hemisphere, and during that time, large amounts of sandstone, limestone and shale were deposited. East Antarctica was at the equator, where seafloor invertebrates and trilobites flourished.

Map: Watershed3

Gondwana drifted southward and the climate cooled. Sand and silts were laid down.

Antarctica became glaciated about 360 million years ago as it drifted closer to the South Pole. Then it warmed and deglaciated, after which the land was dominated by glossopterids, an extinct group of seed plants with no close living relatives. As climate became drier and hotter, the glossopterid ecosystems collapsed.

My how you've changed; Illustration: Live Science

Continued warming dried out much of Gondwana and Antarctica was dominated by seed ferns, which grew as trees. Four-legged creatures first appeared 252-201 million years ago and mammal-like reptiles became common.

The Antarctic Peninsula (where we went) began to form 206 to 146 million years ago when ginkgo trees, conifers, horsetails, ferns and cycads were plentiful. In West Antarctica, coniferous forests and, later, southern beech trees dominated up until about 66 million years ago. Ammonites were common in the seas and dinosaurs roamed.

A fossil found in Antarctica on display at a German museum; Photo: U.S. Antarctic Program

Gondwana slowly broke apart, creating multiple continents: Africa separated from Antarctica around 160 million years ago, followed by the Indian subcontinent about 125 million years ago.

Around 53 million years ago, Australia-New Guinea separated from Antarctica, opening the Tasmanian Passage. The Drake Passage opened between Antarctica and South America around 30 million years ago, resulting in the creation of the Antarctic Circumpolar Current that completely isolated the continent and caused the creation of small yet permanent polar ice caps. 

The Drake Passage preserves the cold

The ice began to spread rapidly, replacing the forests. Tundra ecosystems continued to exist on Antarctica until around 14-10 million years ago, when further cooling led to their extermination.

West Antarctica was formed by the merging of several continental plates, which has resulted in volcanism along the border between West and East Antarctica, as well as the creation of a number of mountain ranges.

Glacier-covered rock

East Antarctica is built on rock topped with coal, sandstone, limestone and shale. There are oil and natural gas fields in the Ross Sea.

East Antarctica is colder than its western counterpart because of its higher elevation. 

Weather fronts rarely penetrate far into the continent, leaving the center cold and dry, with moderate wind speeds. Heavy snow is common on the coastal portion of Antarctica, where snowfalls of up to 48 inches in 48 hours have been recorded. At the continent's edge, strong katabatic winds off of the polar plateau often blow at storm force. During the summer, more solar radiation reaches the surface at the South Pole than at the Equator because of the 24 hours of sunlight received there each day.

We saw snow, sun, fog, wind, calm and temperatures from 33°F to 48°F

West Antarctica has been the second fastest-warming place on Earth (after the Antarctic Peninsula, which I will talk about in my next post), but temperatures rose less rapidly during the early 21st century. Conversely, the South Pole, located in East Antarctica, barely warmed during much of the 20th century, but temperatures rose three times the global average between 1990 and 2020. In February 2020, the continent recorded its highest temperature of 64.9°F. There is evidence that surface warming in Antarctica is due to human greenhouse gas emissions.

Our weather was warmer than I expected; Photo: Scott Stevens

Precipitation in Antarctica occurs in the form of snow, which accumulates and forms the giant ice sheet that covers the continent. Under the force of gravity, the ice flows towards the coast. The ice then moves into the ocean, often forming vast floating ice shelves. These shelves can melt or form icebergs that eventually disintegrate when they reach warmer ocean waters.

A massive iceberg on its way north where it will melt

Sea ice extent expands annually during the Antarctic winter, but most melts in the summer. The average reach of sea ice around Antarctica has changed little since satellites began to observe the Earth's surface in 1978; unlike the Arctic, where there has been rapid sea ice loss. A possible explanation is that currents push warmed water to deeper layers in the Southern Ocean so that the surface remains relatively cool.

The ice shelf during our visit; Source: G Adventures Trip Log

Melting ice shelves do not contribute much to sea level rise because floating ice displaces its own mass of water. However, ice shelves stabilize land ice and, when they melt, the land ice loses its "buttressing." This has been identified as the major cause of ice loss on the West Antarctic ice sheet, but has also been observed around the East Antarctic ice sheet.

In 2002, the Antarctic Peninsula's Larsen-B Ice Shelf collapsed. 

Collapse progression: 1/31, 2/23, 4/13; Photos: National Snow and Ice Data Center

In early 2008, about 220 square miles of ice from the Wilkins Ice Shelf on the southwest part of the peninsula collapsed, putting the remaining 5,800 square miles of the shelf at risk. The ice was being held back by a "thread" of ice about 4 miles wide.

Antarctica contains about 90 percent of the world's ice, but the continent is losing mass due to the increased flow of its glaciers toward the ocean. Future projections of ice loss depend on the speed of climate change. When a certain threshold warming is reached, some parts of the ice sheet may start melting at a significantly faster rate and ultimately disappear. If average temperatures were to begin to fall, the ice would not immediately be restored.

Most animals in Antarctica are the descendants of species that lived there millions of years ago. This includes Microscopic Mites, Lice, Nematodes, Tardigrades, Rotifers, Krill and Springtails.

Antarctic Krill; Top photo: Earth.com; Bottom photo: Polar Journal

Antarctic Krill, which congregates in large schools, is an important food for animals that include Whales, Seals, Orcas and Colossal Squids ...

Humpback Whale feeding on Krill in Leith Cove

... and about 40 bird species, including Petrels, Penguins, Shags, Gulls and Terns.

An Antarctic Tern with a Krill lunch

Various other bird species visit the ocean around Antarctica, including some that normally reside in the Arctic. More than 235 marine organisms live in both polar regions, traveling 7,456 miles from pole to pole.

It is not all ice and snow

About 1,150 species of fungi live in the Antarctic region. Many fungi, algae and bacteria have metabolisms that can remain active at very low temperatures, short life cycles and high resistance to UV radiation. This has led to speculation that life on Mars might have been similar.

Of the 700 species of algae in Antarctica, half are marine phytoplankton. Multicolored snow algae are especially abundant in the coastal regions during the summer. Bacteria have been found as deep as a half mile under the ice.

Lichen provides some color

Freezing temperatures, poor soil, aridness and lack of sunlight inhibit plant growth, causing limited species diversity and distribution. The flora consists of 25 species of liverworts, 100 species of mosses and three species of flowering plants.

The first international agreement to protect Antarctica's biodiversity was adopted in 1964. An international treaty that came into force in 1980 regulates fisheries, aiming to preserve ecological relationships.

An agreement reached in 1998 bans all mining, designating the continent as a "natural reserve devoted to peace and science.”

The Southern Ocean Whale Sanctuary that was established in 1994 by the International Whaling Commission bans all commercial whaling in 19 million square miles completely surrounding the continent. Japan has continued to hunt Whales in the area, ostensibly for research purposes.

A Humpback Whale swimming past the G Expedition

Still, the biodiversity in Antarctica is at risk from human activities. Specially protected areas cover less than 2 percent of the continent and provide better protection for animals with popular appeal than for those less visible. For example, protecting Penguins gets more traction than protecting Lice. There are more terrestrial protected areas than marine protected areas. Ecosystems are affected by local and global threats, notably pollution, the invasion of non-native species and climate change.

Human Presence

I could give a long history of Antarctic exploration, but instead will just say that people did not live there before exploration began in the 1800s and there are long lists of who was first where (some disputed).

And, I can say it wasn't easy; Photo: Ernest Shackleton's Endurance, History.com

The number of people living on the continent and its nearby islands varies from about 1,000 in winter to about 5,000 in the summer and almost all are involved in research. Some research stations are staffed year-round, the winter-over personnel typically arriving from their home countries for one-year assignments.

Chile's currently inactive González Videla Base at Paradise Bay

There are over 70 permanent and seasonal research stations on Antarctica. The largest, the United States' McMurdo Station, is capable of housing more than 1,000 people at a time. The British Antarctic Survey has five major research stations, one of which is completely portable. Belgium has the most modern station and the first to be carbon-neutral. Argentina, Australia, Chile and Russia also have a large scientific presence on Antarctica.

Geologists study plate tectonics, meteorites and the breakup of Gondwana. Glaciologists study the history and dynamics of floating ice, seasonal snow, glaciers and ice sheets. Biologists, in addition to researching wildlife, are learning how low temperatures and human presence affect adaptation and survival strategies in organisms. Biomedical scientists have made discoveries concerning the spreading of viruses and the body's response to extreme seasonal temperatures.

The United State's McMurdo Station; Photo: Wikipedia

The high elevation of the interior, the cold, the dry climate and the long winter polar nights facilitate better astronomical observations than anywhere else on Earth. Antarctica provides a unique environment to study meteorites: the dry polar desert preserves them well, the dark stones stand out in the ice and snow and the flow of ice accumulates them in certain areas.

Illustration: British Antarctic Survey

The Antarctic Treaty System defines Antarctica "all land and ice shelves south of (latitude) 60°S." The Antarctic Treaty was was signed in 1959 by 12 nations: Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the United Kingdom, the United States and the USSR.

Since then, a further 42 countries have acceded to the treaty. Countries can participate in decision-making if they can demonstrate that they do significant research on Antarctica. As of 2022, 29 countries have this “consultative status.”

Decisions are based on consensus. Despite this, seven countries have unrecognized (other countries don't accept them) sovereignty claims over regions of Antarctica. New claims have been suspended since 1959, although in 2015, Norway formally defined Queen Maud Land as including the unclaimed area between it and the South Pole. In 2012, after the British Foreign & Commonwealth Office designated a previously unnamed area as Queen Elizabeth Land in tribute to Queen Elizabeth II's Diamond Jubilee, the Argentine government protested.

Tourists have been visiting Antarctica since 1957. Most arrive by small or medium-sized ship at specific scenic locations with accessible concentrations of iconic wildlife. 

We saw a couple of other boats, but never shared a landing with other tourists

More than 74,000 tourists visited during the 2019-2020 season, of which 18,500 never left their cruise ships to explore on land. That’s because different ships must follow different rules based upon the ship’s size, the number of passengers and the ship’s environmental rating. Large ships can tour, but passengers cannot leave the boat. Ships like ours are allowed landings – we were allowed up to two per day. I can’t imagine going and having to just watch from the deck of a mega-ship.

The Zodiacs were the best part!

Boots; Photo: Scott Stevens

We had to follow strict environment rules, including having all our gear inspected and vacuumed, wearing G Adventures rubber boots, not sitting or kneeling on the ground, not placing our backpacks on the ground and stepping in a vat of disinfectant every time we left and reboarded the ship. 

This activity is in concert with the guidelines of the International Association of Antarctica Tour Operators (IAATO), of which G Adventures is a member. 

Their guidelines are designed to protect animals and the environment, reduce waste, protect scientific research activities and keep visitors safe.

We all followed IAATO's environmental guidelines

Overland sightseeing flights operated out of Australia and New Zealand until 1979, when an Air New Zealand plane crashed into Mount Erebus, killing all of the 257 people onboard. Qantas resumed commercial overflights to Antarctica from Australia in the mid-1990s. There are many airports in Antarctica. 

Airports support research programs; Photo: Glenn Jackson, Australian Antarctic Program

So, I have given you a little overview of the entire continent to provide context for our visit. But, we were not headed to the main continent. I'll talk about our planned destination in my next post ... 

Our furthest south location

Trip date: December 30, 2023  - January 12, 2024