Dust Darkens/Melts Snow at High Mountain Altitudes in Asia, Soot Dominates Lower Down

Nature, October 5

Dust carried by winds from the Middle East and Africa and deposited on snow is now the leading factor in snow melt at higher elevations (above 4000 m) in Central Asia and the Himalayan Plateau, playing a much bigger role on water resources than previously documented. Below 4000 m, the deposition of black carbon, otherwise known as soot, still dominates. Deposition of both these light-absorbing particles on snow or ice substantially darkens them, accelerating warming and melting. Dust storms and long-range transport of dust may be growing due to increased desertification from climate change and from damaging agricultural practices, especially use of fire; both of which make soils more prone to wind erosion.  High-mountain Asia has the largest snow and ice mass on Earth outside of the poles, and its winter snowfall and spring snowmelt provide more than 50% of the annual freshwater needs of nearly 700 million people in South Asia. Increasing dust from climate change therefore has a critical impact on water supplies, including for agriculture, hydropower generation, and household use.

https://www.nature.com/articles/s41558-020-00909-3

艾米·伊姆迪克编