Threats To Antarctica: Climate Change, Fishing & Tourism
- Climate Change in Antarctica
- Temperature Trends in Antarctica
- The Southern Ocean & Climate Change
- Antarctica Climate Change Impacts to Ice Shelves, Glaciers, and Sea Ice
- When Will Antarctica Melt & How Much Will Sea Level Rise?
- Climate Change Effects Observed in the Antarctic Ecosystem
- Legal & Illegal Fishing In Antarctica
- Impacts of Tourism in Antarctica
- Invasive Species
- How Can We Save Antarctica?
The gigantic, staggeringly remote, essentially uninhabited, almost entirely ice-bound continent of Antarctica might seem as secure as a landmass can be on Planet Earth. Yet even the bottom of the world is vulnerable.
That’s especially true when it comes to a warming climate, but even the act of visiting this mostly untouched land and its surrounding seas can have negative consequences. In this article, we’ll consider three of the main threats to Antarctica: climate change, overfishing, and increased tourism, and see how all three are contributing to a fourth threat: invasive species.
On some levels, the Antarctic climate is quite cut off from the rest of the world. The White Continent comes encircled by the unobstructed Antarctic Circumpolar Current—an oceanic current also known as the West Wind Drift—and the howling westerly winds of the Southern Ocean. Mostly insulated from major warm-air incursions, positioned at the southern pole and receiving limited amounts of solar energy, Antarctica’s piled with an incredibly thick ice sheet that gives it an average elevation of some 6,000 feet above sea level and creates a harsh ice-cap climate over most of the continent.
Yet the warming trend of our global climate, spurred by the increase in atmospheric greenhouse gases produced by human activities, is definitely impacting this frozen realm. Warming air and ocean temperatures, plus shifts in winds and other weather, are starting to transform the physical environment of Antarctica. And just as the White Continent’s frigid isolation belies how connected it is to the rest of the planetary system, it comes as a surprise to many that these alterations of its physical environment can have far-reaching global impacts.
Thus far, the Antarctic is, overall, warming less dramatically than the Arctic—which is a profoundly different polar realm, given it’s mostly a frozen ocean rather than a high-standing frozen continent. But evidence suggests average temperatures are indeed increasing across the White Continent. That’s been unquestionably true in recent periods on the Antarctic Peninsula, the mildest (and most-visited) part of the continent, which warmed by some 3 degrees Celsius from 1950 to 2000: a rate (as Discovering Antarctica explains) some five times the global average.
West Antarctica, of which the Antarctic Peninsula is an extremity, has also shown a clear warmup. A 2013 study suggested West Antarctica experienced roughly 4 degrees F of temperature increase between 1958 and 2010.
Data from the vaster redoubt of East Antarctica—ice-crusted to an overall higher elevation and more thoroughly continental in climate—have been less conclusive. Indeed, records at the Amundsen-Scott South Pole Station indicate a cooling trend the past several decades. But other parts of East Antarctica have experienced a warming trend. In March 2022, the exceptionally cold sites of Concordia and Vostok stations on the high Polar Plateau of East Antarctica both recorded dramatically unusual warm temperatures, during a time period when the Casey Station on the coast also saw above-normal heat and the Conger Ice Shelf collapsed.
Both West and East Antarctica, and the Antarctic Peninsula, have seen increasing numbers of heatwaves and “extreme high temperature days” in recent decades, the International Scientific Council’s Scientific Committee on Antarctic Research notes in a 2022 report, Antarctic Climate Change & the Environment.
The ocean around Antarctica is also warming. Measurements going back to the 1950s suggest the upper ocean west of the Antarctic Peninsula has heated up by close to 2.7 degrees F. The Antarctic Circumpolar Current, the aforementioned West Wind Drift swaddling the White Continent, appears to be warming faster than the World Ocean as a whole: by some 0.16 degrees F per decade between the 1980s and 2013.
The Southern Ocean is hugely important from the standpoint of Earth’s resilience to climate change. It absorbs a disproportionate amount of heat and atmospheric carbon; some 40 percent of the anthropogenic carbon dioxide in the atmosphere is thought to be absorbed by its waters. It thus serves as a heat/carbon sink that buffers the atmosphere against the warming influence of greenhouse gases. Much research is focused on better understanding that process—and how ocean/atmosphere processes, including the increasing windspeeds being observed over the Southern Ocean, could impact it.
To compound matters, not only is it warming, but thanks increasing volumes of Antarctic meltwater, the Southern Ocean’s deep “overturning” circulation is also slowing, having ebbed 30% since the 90s and now predicted to rise to 40% by 2050 according to new modelling. As Antarctica melts, more freshwater flows into the ocean disrupting the sinking of the cold, salty, oxygen-rich water, and limiting the flow of the nutrient-rich waters to ocean basins globally, with will have major ramifications for global ocean ecosystems, climate, and sea-levels.
Prolonged warming threatens the integrity of the ice sheets capping Antarctica. Increased destabilization of Antarctic ice shelves—those floating coastal masses of ice banked against outflow glaciers off the interior ice sheet—is causing more than a few scientists the world over sleepless nights. Retreat, splintering, and all-out collapse of ice shelves have been observed as warm ocean water liquefies them from below and higher air temperatures promote meltwater infiltration from above.
The fracturing and dissolution of ice shelves alone doesn’t strongly influence sea level, given they’re already displacing the same volume as their meltwater would produce. But these ice shelves help constrain the flow of glaciers draining the continental ice sheets, and increased glacial flow with ice-sheet retreat would increase sea level worldwide by inputting ice previously above sea level or inland into the ocean.
Dramatic retreat and collapses of ice shelves on the Antarctic Peninsula such as the Larsen and Wilkins were an early warning sign in the 1990s. At one point in the rapid dismantlement of the Wilkins Ice Shelf, the ice retreated by more than a mile in one day.
A couple of ailing glaciers helping to corral the West Antarctic Ice Sheet along the Amundsen Sea appear particularly portentous. The Thwaites Glacier—the so-called Antarctica Doomsday Glacier, nicknamed for the risk its collapse poses due to sea-level rise—and the Pine Island Glacier have been termed the “weak underbelly of the West Antarctic Ice Shelf.” These glaciers are melting from below through the action of warm seawater dislodging their bellies from bedrock.
A 2021 study suggested the Thwaites Ice Shelf, which partly secures the Thwaites Glacier, could collapse within several years. The International Thwaites Glacier Collaboration, a U.S.-U.K. partnership, reckons that the melting of the Thwaites Glacier accounts for about 4 percent of the global rise in sea level. Its complete collapse could raise sea level by more than two feet.
How warming temperatures are affecting the extent and timetable of the sea ice that seasonally expands and contracts around the White Continent isn’t entirely clear. In some areas, such as parts of the Antarctic Peninsula coast, there’s been a steady decline in sea-ice cover. But other areas have seen increases, or seesaws between growth and reduction beyond the usual seasonal pattern.
“In just the last decade,” the U.S. National Oceanic & Atmospheric Administration (NOAA) wrote in 2019, “Antarctic sea ice has exhibited the two highest maximum extents on record (2013 and 2014) and the two lowest minimum extents on record (2017 and 2018). Antarctic sea ice behavior to date appears to have more to do with natural variability, including annual and decadal cycles in the surrounding Southern Ocean, than with human-caused climate change.”
When will Antarctica melt completely? Is that even possible? Will the overlying ice sheets disappear completely to reveal the scrawnier bedrock continent and island archipelagos that lie beneath? Well, that’s a process that would almost assuredly take many centuries. But some version of this question isn’t completely off-base.
According to the aforementioned 2022 Antarctic Climate Change & the Environment report, some forecasts suggest the West Antarctic Ice Sheet—smaller and more rapidly thinning than its East Antarctic counterpart across the Transantarctic Mountains—could disappear by 2300, raising sea level by approximately 10 feet (3 m). Should the East Antarctic Ice Sheet actually ever melt, sea level would rise significantly by some 200 feet (60 m). Given the melting of the smaller Antarctic Peninsula Ice Sheet would contribute less than a foot (0.3 m) more, if Antarctica melted completely the sea level could rise a staggering 210 feet in total.
Some trends in the Antarctic ecological web seem to reflect warming temperatures and associated impacts on sea- and land-ice cover. Dramatic declines in certain Antarctic penguin species dependent on ice, namely Adélie and emperor penguins, have been seen in places. A decline in krill connected to the Antarctic Peninsula’s reduced sea ice (which supports the phytoplankton krill munch on) has been suggested as the trigger for plunging numbers of krill-eating chinstrap penguins, even as gentoo penguins—more generalist feeders by comparison—are increasing.
Parts of the Antarctic Peninsula have also seen increased colonization by land plants as the perennial snow and ice cover recedes.
Is fishing banned in Antarctica? No. Many believe the waters around the White Continent to be a completely protected sanctuary, but this isn’t the case—commercial fishing, while strictly regulated, is permitted. Among the main species commercially targeted in Antarctic waters are Patagonian and Antarctic toothfish, mackerel icefish, and Antarctic krill, which are not harvested for human consumption but rather used in dietary supplements and as fishmeal.
In the 1800s, the Southern Ocean was pillaged by heavy, unregulated whaling and sealing operations, the economic enterprise behind much of the early exploration of the Antarctic. Southern fur seals and blue whales were hunted to the edge of extinction, and while the fur seals have thankfully recovered well, the blue whale population remains below 5% of its pre-whaling figures. Commercial fishing, though, didn’t really reach Antarctica until the 1970s.
Overfishing quickly decimated many fish stocks: Hauls of the marbled rock cod (a member of the cod-icefish family) around South Georgia plummeted from better than 500,000 tons in the first two years of industrial fishing there to zero. Those sorts of impacts were part of the inspiration for the creation of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR), formed in 1980 to oversee the marine resources of the Southern Ocean in the Antarctic zone under the Antarctic Treaty, which quickly started closing many Antarctic fisheries.
Such closures along with more stringent controls have helped mitigate the impacts of industrial fishing in Antarctica, but many stocks have not yet recovered from the early years. Meanwhile, illegal, unreported, and unregulated (IUU) fishing continues to be a major problem. In 1997-1998, some 11,000 tonnes of Patagonian toothfish were legally harvested within the CCAMLR area, but an estimated 32,000 tonnes were taken illegally in the same period. As in other corners of the World Ocean, “ghost” fishing gear—that is, gear that’s been discarded or lost at sea by fishing boats—also poses a threat. A ghost gillnet some 80 miles (130 km) long held nearly 30 tons of Antarctic toothfish when it was recovered.
Overfishing in Antarctica remains a hot-button issue. Many biologists and conservation organizations fear levels of commercial fishing, including legal operations, are too high, especially in light of changing Southern Ocean conditions brought on by global warming. Antarctic krill stocks around the Antarctic Peninsula—the main area where the crustacean is fished—appear to be declining due to that area’s rapidly warming waters, and both rising temperatures and acidification of the Southern Ocean pose broad-scale threats to the species. Needless to say, the ripple effects of collapsing krill numbers on the Antarctic marine ecosystem as its keystone species could be catastrophic.
Tourism has increased significantly to the White Continent in recent years, with close to 80,000 visiting in the 2019-2020 season. Potential detrimental effects of tourist activity include disturbance to wildlife such as penguins and seals, trampling of fragile groundcover, vandalism to historical sites and artifacts, and increased pollution from ship traffic.
Fortunately, tour operators in Antarctica have generally shown admirable concern about the preciousness of the continent’s largely pristine ecosystem, and have been proactive in self-regulating to protect it. Guidelines issued by signatories to the Antarctic Treaty as well as the International Association of Antarctica Tour Operators (IAATO)—organized by seven companies in the early 1990s to help manage tourism at the bottom of the world—help ward against deleterious effects such as overcrowding and wildlife disruption. These include requirements for cruise ships of a certain size to refrain from landfalling, and specific “site visitor guidelines” at a network of popular destinations, including boot and clothing decontamination procedures between shore landings.
And to combat pollution, many Antarctic tour vessels run on cleaner marine diesel fuel, with increasing numbers also utilizing battery power.
Tourism to Antarctica, in turn, can have many benefits—most fundamentally in introducing visitors to the singular wonders of the White Continent, and thereby engendering awareness of, concern for, and activism about our planet’s greatest remaining terrestrial wilderness.
Given Antarctica’s native species have been isolated for the last 15–30 million years or so, it’s not surprising that the accidental introduction of any foreign ‘invasive’ species could be potentially devastating to its delicate ecosystems.
The prime historic examples, certainly for the sub-Antarctic island of South Georgia, were the unintentional introduction of rats who stowed away on visiting ships some 250 years ago, and the intentional introduction of reindeer for their meat in the early 1900s. The rats drove certain ground nesting birds to extinction, while the reindeer’s grazing habits altered the vegetation, causing erosion and suppressing indigenous plants. Thankfully the reindeer and rats (and other rodents) were removed from the island by 2016 and 2018 respectively.
More recently European earwigs have made their way to and become a pest on the neighboring Falklands, where, devoid of any predators, they have been free to decimate crops. Work is currently being done to find a way to remove them in a biological way using parasitic fly species.
Visiting vessels, whether fishing boats or expedition ships, or even research and supply ships, may unwittingly be transporting invasive species into Antarctic waters, and not only in their holds (or passenger luggage). Their hulls can be a haven for clinging aquatic species such as mussels, barnacles, crabs and algae which can be unsuspectingly carried and deposited elsewhere in a process termed ‘biofouling’. This danger is even more worrying given that a recent study has shown that Antarctica has logistical connections to 1581 ports across the globe via an extensive shipping network, increasing the potential for invasive species to arrive from almost anywhere. Of particular concern is the possible movement of species from pole to pole, given that many tourist and research vessels operate in both the Arctic and Antarctic, especially as such species will already be cold-adapted.
Not only are the tourism and fishing industries vehicles for invasive species, but climate change is also a worry. Milder sea temperatures are making the once inhospitable shallower waters of Antarctica attractive to the Antarctic king crab, who, having been absent from its continental shelf for some 16 million years, have now been spotted there. Should they continue to make their way upslope, brittle stars, sea cucumbers and other species that have no natural defenses to their claws will be at considerable risk.
Whilst the Ross Sea Marine Protected Area is the largest marine protected area in the world at 2.09 million km2, 95% of the Southern Ocean remains unprotected. Creating one giant protected marine sanctuary covering the entire Southern Ocean, and banning all commercial fishing activities would go a long way to saving Antarctica, but a good start would be to create more Marine Protected Areas (MPAs), and three have already been proposed in East Antarctica, the Peninsula and the Weddell Sea, but are yet to be agreed to.
Continued scientific research, campaigning and awareness around the detrimental impact of fishing activities and climate change on Antarctica will hopefully provide the foundation, data and drive to persuade the world to more readily recognise and address climate change, and the CCAMLR and other bodies such as the International Maritime Organisation (IMO)—who are responsible for the environmental performance of worldwide shipping—to create more MPAs and ban fishing in Antarctica before it is too late.
In the meantime, given the rising concerns over invasive species, improved biosecurity protocols and environmental protection measures need to be put in place in all ports linked to Antarctica—not just the small group of recognised ‘gateway ports’ currently subject to such countermeasures.
What can you do to help? If you’re coming to Antarctica, choose a tour operator affiliated with the IAAO and abide by that organization’s detailed visitor guidelines (not least those around ‘packing a pest’) which you can explore ahead of your trip online. Taking steps to minimize your own carbon footprint is also a means of protecting Antarctica, given its vulnerability to the greenhouse-gas emissions produced far away.
And consider supporting the work of worthy organizations and charities dedicated to studying and preserving the Antarctic environment. For example, Oceanites is a D.C.-based non-profit group focused on White Continent research and education, with a central mission of “assisting science-based conservation recommendations in Antarctica and increasing the awareness of climate change worldwide.”
Oceanites conducts fieldwork on the Antarctic Peninsula, including important surveys of penguins and seabirds; its yearly State of Antarctic Penguins report is a widely used resource. The non-profit’s groundbreaking Antarctic Travelers’ Code helped inform the visitor guidelines formalized by Antarctic Treaty signatories. Oceanites also attends meetings of the group responsible for oversight of Antarctic fisheries—the Commission for the Conservation of Antarctic Marine Living Resources—as an independent and non-governmental observer.
Another organization doing critical work in Antarctica is the Norway-based Antarctic Wildlife Research (AWR) Fund, which investigates the foundational krill-based food web here from a variety of different angles. Donations to AWR help support research projects on everything from the movement of krill themselves to identifying foraging zones of humpback whales and brush-tailed penguins.
Seeing the rookeries, crags, and icebergs of Antarctica can inspire you to a lifetime of action better understanding the biosphere as a whole. And even when you’re back home, there’s much you can do to help protect the White Continent that casts such a mesmerizing spell.
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