The Antarctic is the planet’s last true wilderness. But the wildlife here is under threat. And so too is this region’s ability to offset carbon dioxide emissions and regulate our planet’s temperature.
CNN accompanied Greenpeace to Antarctica in March, for the last month of its campaign to raise awareness about the need to protect the Antarctic’s waters.
Antarctica covers around 5.4 million square miles, making it bigger than Europe. The Transantarctic Mountains divide it into the eastern and western regions.
NASA/Goddard Space Flight Center
Climate change has had a huge effect on parts of the continent. While East Antarctica hasn’t seen widespread warming, temperatures on the Antarctic Peninsula have increased by up to 3.2°C in the last 60 years – that’s around 10 times the global average.
British Antarctic Survey
Temperatures are also rising beneath the surface of the Southern Ocean. Last summer, Chilean scientists logged a water temperature rise of 3°C off the Antarctic Peninsula.
Warmer temperatures mean that Western Antarctica’s ice sheet has been losing mass; some ice shelves have collapsed and some glaciers are retreating. Although partly offset by increased snowfall, scientists fear this ice loss could be a major contributor to global sea-level rise.
European Environment Agency, Nature, AGU100
The Southern Ocean that surrounds Antarctica performs a vital service for the planet by absorbing heat and CO2. In all, the Earth’s oceans absorb and store about a third of our carbon emissions, and the Southern Ocean is responsible for about 40 percent of that.
CSIRO Marine Research, World Economic Forum
But when CO2 dissolves in the ocean it makes the water more acidic. That acidification especially impacts keystone creatures within the food chain, which could in turn affect the animals that eat them -- and, as scientists are discovering, affect all of us.
This small shrimp-like crustacean is part of an ocean ecosystem that helps sequester carbon. Near the ocean surface, phytoplankton -- microscopic marine algae -- take CO2 from the atmosphere.
When they are eaten by other creatures, including krill, that carbon eventually ends up on the ocean floor, where it can be sequestered for millennia.
British Antarctic Survey, Nicklin/Minden Pictures/Newscom
Krill are present in vast numbers in the Southern Ocean, but some studies show that their numbers have declined in recent decades. Krill larvae may have been impacted by a loss of sea ice in parts of the ocean where they thrive.
While fishing for Antarctic krill has fallen since its peak in the 1980s, there’s been a recent revival to service a growing demand for dietary supplements containing omega-3 fatty acids, and to provide feed for fish farms.
Krill fishing is highly regulated in the Southern Ocean but it occurs in areas that are also feeding grounds for whales, seals and penguins. A sustained fall in krill numbers could have a significant impact on the many animals that feed on it.
Buffer zones have been proposed that would ban all fishing in certain areas of the Antarctic, including a proposal for the Weddell Sea that would create the world’s largest ocean sanctuary.
Chilean scientists have found microfibers -- ultra-thin man-made fibers -- in the digestive tracts of Antarctic clams.
They are trying to determine if they are a byproduct of human activities in Antarctica, but the researchers suspect they originate from elsewhere.
On this expedition, Greenpeace took eight seawater samples: seven were found to contain microplastics and fibers.
Greenpeace also tested snow and water samples for toxic compounds known as PFAs -- chemicals used in outdoor gear and food packaging.
All the samples tested positive for PFAs, some of which Greenpeace say have been transported globally through the air and deposited in the Antarctic during snowfall.
Its icy landscape may look like an unspoiled wilderness, but the truth is that mankind’s footprint looms large across Antarctica.
We still have much to learn about it, but science is revealing just how vulnerable this remote continent is to the actions that humans take half a world away.