New sources and quantities of air pollution in the tropics and the Arctic pose serious dangers for human health, sea ice and wildlife. Urban air pollution is increasing rapidly in the world’s middle latitudes, according to a new study in Science Advances. The additional pollution since 2005 is attributable to 180,000 deaths in large tropical cities in 2018 alone, with increasing concern for urban dwellers as people and pollution sources continue to concentrate. In the past, burning land to clear for agriculture was a main source of these pollutants, but lead author Karn Vohra said now that traffic and fuel use dominate, “we’re entering a new era of air pollution in these cities, with some experiencing rates of degradation in a year that other cities experience in a decade.”

Meanwhile, as climate change melts sea ice and opens northern shipping routes through the Arctic, in winter, and is heralded as a new era of shipping, pollutant-laden exhaust from shipping vessels burning cheap, low-grade fuel oil is increasing, the Guardian reports. So-called “black carbon,” soot pollution resulting from incomplete fuel combustion lands on sea ice, thus darkening it and contributing to a vicious cycle of accelerating melting. Black carbon pollution from shipping in the Arctic shot up by 85% between 2015 and 2019. Cleaner fuel requirements could cut black carbon pollution by 44% and filters could cut it by a further 90%. (New York Times $, The Guardian)