It’s an honor being part of the BIG: North Pole 2022 (Before It’s Gone) Project, which has been sampling snow and ice across the Arctic, looking at presence and impacts of heavy metals, microplastics and black carbon (BC). Last week in Iceland, I picked up their collected samples (from 2022 and this year) to bring back to a lab here in Boulder, Colorado, for BC analysis – and also had a chance to sample the summit snows of Iceland’s high point, Hvannadalshnukur. Thank you to the B.I.G. team and Felicity Aston for this science collaboration! Thank you to Laurent Jegu for beta on mountain conditions and weather forecast, allowing Ricardo and me a small window to summit and sample!
Black carbon, also known as soot, is a type of fine particulate matter that is produced from the incomplete combustion of fossil fuels, biomass, and other organic materials. When BC is deposited on snow and ice surfaces, it reduces their albedo because it absorbs sunlight, causing the snow or ice surface to become darker. With lower albedo, more sunlight is absorbed rather than reflected back into the atmosphere. As a result, the snow or ice surface warms up, accelerating the melting process. This creates a positive feedback loop where the darker surface absorbs more heat, leading to further melting, and exposing more underlying dark areas that absorb even more heat. This process can significantly amplify the melting of glaciers, ice caps, and seasonal snow cover.
Black carbon also affects the characteristics of the snowpack, including its thermal properties and stability. By reducing the snow’s albedo, black carbon increases the absorption of heat within the snowpack, leading to a warmer and less stable snowpack. This can alter the timing and amount of snowmelt runoff, affecting water availability and ecosystems downstream. Finally, BC can also have indirect effects on snow and ice through its influence on atmospheric processes. When the particles are suspended in the atmosphere, they can absorb and scatter sunlight, thereby modifying the radiative balance. This can impact cloud formation, precipitation patterns, and atmospheric circulation, potentially affecting the distribution and deposition of snow. It’s worth noting that while black carbon does contribute to the melting of snow and ice, it is not the sole driver of these processes. Other factors, such as greenhouse gas emissions and land use changes also play significant roles in the changing state of snow and ice in various regions.
photo: Ulyana Peña, Vatnajokull icecap, Iceland