Phys.org February 3, 2023
Sulfate aerosols are particles in the atmosphere that have a net cooling effect on the climate. One of the most uncertain aspects of climate modeling is the abundance of sulfate aerosols during the preindustrial era. Without knowing the amount of sulfate aerosols during the preindustrial times, it is difficult to estimate how much anthropogenic sulfate aerosols have offset warming from anthropogenic greenhouse gases. A team of researchers in the US (University of Washington, South Dakota State University, University of New Mexico, Michigan Technological University) examined preindustrial sulfate aerosols in a Greenland ice core. They found that sulfate aerosols from passive volcanic degassing contribute almost two thirds of preindustrial Arctic sulfate aerosols in years without major volcanic eruptions. Comparing this result to a state-of-the-art global model they found that most climate models used a volcanic emissions inventory that underestimated preindustrial passive volcanic sulfur emissions. That volcanic inventory only sulfur dioxide, but studies have shown that volcanoes emit hydrogen sulfide, which can also form sulfate aerosols. They showed that higher emissions of volcanic sulfur during the preindustrial era decrease the estimated cooling effect of anthropogenic aerosols during the industrial era. According to the researchers the underestimating preindustrial volcanic emissions in current climate models has significant implications for anthropogenic climate change in the Arctic…read more. Open Access TECHNICAL ARTICLE
Volcanic and dimethyl sulfide (DMS)-derived biogenic sulfate concentrations and volcanic fraction in ice core samples from preindustrial years (1200–1850 CE) … Credit: Geophysical Letters, Volume50, Issue1, 6 January 2023, e2022GL102061Â