For 200 years, the Antarctic has been a goal of explorers, researchers and, finally, even tourists. The Antarctic Peninsula is one of the first points of contact because of its relatively easy accessibility, and up to today it is one of the most frequented regions of the white continent.
That is not without consequences. Despite strict environmental obligations, human activity there has left its traces. A current study in which EOC is also participating was able to verify for large areas the presence of soot from local emissions in the snow of the Antarctic Peninsula. This barely visible grey blanket furthers summertime melting processes.
The exhaust cloud emitted by a C-130 Hercules in a landing approach on the Union Glacier Blue-Ice Runway is an example of soot emissions in the Antarctic caused by human activity.
The study is investigating the effects of the soot residue known as black carbon that is generated by the combustion of fossil energy sources in the operation of ships, aircraft and research stations and deposited on the snow cover. This slight grey covering may at first be invisible to the human eye and limited to the immediate vicinity of research stations and tourist hotspots. An assessment of snow samples at 28 locations along the peninsula from 62°S to 79°S has now shown that although there is high variation in the amount of black carbon from place to place, at many locations it has a significant influence on the melting behaviour of the near-surface snow cover. Depending on how much of it is present, the black carbon changes the optical characteristics of the snow surface and reduces the normally very high reflectivity of the natural snow cover. Lower albedo, the ratio of reflected to incoming solar irradiation, means at the same time an increased absorption of energy at the snow surface, which can initiate an acceleration of the melting processes. Corresponding to the black carbon concentrations measured at the 28 sampled locations, the additional mass loss of the snow cover can be estimated at 5 to 23 kg/m² per summer season. The area that is affected by black carbon emissions from tourist and science activity along the Antarctic Peninsula is estimated at 100 up to 500 km² (by comparison, the area of the city of Munich is 310 km²). For the Antarctic Peninsula this means an annual snow mass loss of 4.4 ± 2.3 million tons that can be attributed to anthropologic black carbon deposits. The wide range of estimates of the area affected by black carbon and how much of it is found in the samples corresponds to differences in the duration of station operations (year-round or only in the summertime) and, for areas hosting tourists, on the amount of ship traffic.
The collection of this so-far unique dataset took place from the 2016/2017 to 2019/2020 seasons and covered a transect of more than 2000 km. In November and December 2016 EOC participated in an expedition led by Chile to Union Glacier. During this expedition, instruments were used to measure snow albedo and the first snow samples were collected from the most southern measuring point of the transect in the Ellsworth Mountains of the Transantarctic range.
Left: EOC’s Paul Wachter digs a snow shaft to take snow samples. Right: spectrometer to determine snow albedo on Union Glacier.