The location of the Altai Mountains at the limits of both the Pacific and Atlantic influences implies that this mountain range is an important climatic boundary. Based on pollen data of 188 samples of a 390-cm core from Narenxia Peat in the southern Altai with a chronologic support of 11 accelerator mass spectrometry (AMS) dates, we reconstructed the Holocene climatic change at Narenxia Peat. The reconstruction revealed five stages of climatic change: a cold and dry latest deglacial (prior to ~11,500 cal. yr BP), a warm and wet early-Holocene (~11,500 to ~7000 cal. yr BP), a considerably cooled and dried middle Holocene (~7000 to ~4000 cal. yr BP), a resumed warm and wet late-Holocene (~4000 to ~1200 cal. yr BP), and a relatively cool and dry latest Holocene (past ~1200 years). The reconstructions of mean annual temperature (MAT) and mean annual precipitation (MAP) from Narenxia Peat well resemble the reconstructions of North Atlantic Oscillations (NAO) and El Niño–Southern Oscillations (ENSO). The resemblance implies that the Holocene millennial-scale changes in MAT and MAP in the Altai might have been causally associated with the variations in NAO and ENSO.

Antibiotic-resistant pathogens pose a significant threat to human health. Several dispersal mechanisms have been described, but transport of both microbes and antibiotic resistance genes (ARGs) via atmospheric particles has received little attention as a pathway for global dissemination. These atmospheric particles can return to the Earth’s surface via rain or snowfall, and thus promote long-distance spread of ARGs. However, the diversity and abundance of ARGs in fresh snow has not been studied and their potential correlation with particulate air pollution is not well explored. Here, we characterized ARGs in 44 samples of fresh snow from major cities in China, three in North America, and one in Europe, spanning a gradient from pristine to heavily anthropogenically influenced ecosystems. High-throughput qPCR analysis of ARGs and mobile genetic elements (MGEs) provided strong indications that dissemination of ARGs in fresh snow could be exacerbated by air pollution, severely increasing the health risks of both air pollution and ARGs. We showed that snowfall did effectively spread ARGs from point sources over the Earth surface. Together our findings urge for better pollution control to reduce the risk of global dissemination of antibiotic resistance genes.

The Holocene drying trend in the northern Altai Mountains and the wetting trend in the southern Altai Mountains inferred from the paleoclimatic studies indicated it is needed to understand the modern climatic characters in this region. However, a detailed analysis of modern climate variations in the northern and southern Altai Mountains is lacking. Here, we investigate the monthly temperature and monthly precipitation data from seventeen meteorological stations during 1966–2015 in the northern and southern Altai. The result shows that temperature increases significantly in the northern (0.42 °C/10 yr) and in the southern (0.54 °C/10 yr). The precipitation decreases insignificantly (−1.41 mm/10 yr) in the northern, whereas it increases significantly (8.89 mm/10 yr) in the southern. The out-of-phase relationship of precipitation changes is also recorded at different time-scales (i.e., season, year, multi-decades, centennial and millennial scales), indicating the Altai Mountains are an important climatic boundary. Based on the analysis of modern atmosphere circulation, the decreased precipitation in the northern corresponds to the decreasing contribution of ‘Northern meridional and Stationary anticyclone’ and ‘Northern meridional and East zonal’ circulation and the increased precipitation in the southern are associated with the increasing contribution of ‘West zonal and Southern meridional’ circulation.