Research stations and tourists are hastening snow melt in Antarctica

Pollution from increasing human activity in Antarctica is darkening the snow, causing it to melt sooner than usual near research facilities and popular tourist sites.

During Antarctica’s summer, which typically runs from November to March, up to 5500 research personnel live there. Between 2016 and 2020, 53,000 tourists also visited the continent each summer on average.

Rising human activity in the region has led to an increase in pollution, including black carbon, also known as soot, which comes from planes, ships and helicopters as well as the generators that power research stations.

Raúl Cordero at the University of Santiago, Chile, and his colleagues decided to measure the impact of this black carbon pollution on the snow in Antarctica.

Over four summers between 2016 and 2020, the team collected 155 samples of snow from 28 sites along the path of tourist routes and research stations. The sites spanned 2000 kilometres, from King George Island near the northern tip of the Antarctic Peninsula to the Union Glacier Camp in the south.

The researchers found there was an average of 3 nanograms of black carbon per gram of snow in the samples. This is up to four times higher than the levels in Antarctica’s more remote regions, says Cordero.

The highest levels of soot, of around 8 nanograms per gram of snow, were found in the north near the Argentinian Esperanza Base, where there are more research facilities.

The black carbon that settles on the snow can accelerate its melting. “When the snow becomes a bit darker, it absorbs extra solar radiation,” says Cordero. “That extra energy facilitates the melting of the snow.”

In the areas where the black carbon concentrations are highest, the researchers found that the snow melts earlier than usual and decreases in thickness by an additional 23 millimetres each summer.

They also estimated that between 2016 and 2020, each visitor resulted in around 83 extra tonnes of snow melting in the summer.

“We have to reduce the black carbon footprint, and that basically means we have to stop burning fossil fuels,” says Cordero. He suggests that research stations and transport should switch to cleaner power sources and the number of visitors to the continent should be capped.

Robert Mulvaney at the British Antarctic Survey says: “In calling for action by both the tourist industry and the national operators of research stations to mitigate fuel emissions or limit the expansion of activities, the authors catch the mood of what I hope is the majority of us that visit Antarctica in wishing to see the Antarctic environment maintained in its pristine and beautiful state for future generations.”