Passage: Albedo, the measure of the reflectivity of a surface, plays a crucial role in the Earth's energy balance. Surfaces with a high albedo, such as snow and ice, reflect most of the incoming solar radiation back into space. In contrast, low-albedo surfaces, like open ocean or dark soil, absorb the radiation and convert it into heat. The 'ice-albedo feedback' is a critical component of Arctic warming. As temperatures rise, sea ice melts, revealing the darker ocean surface beneath. This lower-albedo surface absorbs more heat, which further raises temperatures and leads to even more ice melt. Recent research suggests that this feedback loop is being reinforced by the deposition of 'black carbon'—soot from wildfires and fossil fuel combustion—on the surface of Arctic snow. Even small amounts of dark particulate matter can significantly reduce the albedo of the snow, accelerating melting even in areas where air temperatures remain below freezing. This suggests that the stability of the Arctic cryosphere is threatened not only by global temperature increases but also by the long-range transport of atmospheric pollutants.