21st-century Asian air pollution impacts glacier in northwestern Tibet

Abstract

Over the last 4 decades, Asian countries have undergone substantial economic development, leading to rapid urbanization and industrialization. Consequently, fossil fuel consumption has risen dramatically, worsening the air quality in Asia. Fossil fuel combustion emits particulate matter containing toxic metals that can adversely affect living organisms, including humans. Thus, it is imperative to investigate the temporal and spatial extent of metal pollution in Asia. Recently, we reported a continuous and high-resolution 1650–1991 ice core record from the Guliya ice cap in northwestern Tibet, China, showing contamination of Cd, Pb, and Zn during the 20th century. Here, we present a new continuous and high-resolution ice core record of trace metals from the Guliya ice cap that comprises the years between 1971 and 2015, extending the 1650–1991 ice core record into the 21st century. Non-crustal Cd, Pb, Zn, and Ni enrichments increased have since the 1990s relative to the 1971–1990 period, reaching a maximum in 2008. The enrichments of Cd, Pb, Zn, and Ni increased by ∼75 %, 35 %, 30 %, and 10 %, respectively, during the 2000–2015 period relative to 1971–1990. The observed trace element (TE) enrichments likely originated primarily from fossil fuel combustion and biomass burning, with contributions from industrial processes and agricultural activities from South Asia (Pakistan, Afghanistan, India, and Nepal), Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan), and the Xinjiang province in western China. This new record demonstrates that the current emissions in Asia impact remote high-altitude glaciers in the region.