Some species of fig trees store calcium carbonate in their trunks – essentially turning themselves (partially) into stone, new research has found. The team of Kenyan, U.S., Austrian, and Swiss scientists found that the trees could draw carbon dioxide (CO₂) from the atmosphere and store it as calcium carbonate ‘rocks’ in the surrounding soil. 

In a study published in National Science Review, researchers present multiple lines of observational and modeling evidence for a ~4% decline in global atmospheric oxidation capacity in 2020, reflected by a drop in hydroxyl radical (OH) concentrations. Using satellite-based carbon monoxide data, as well as methane and methyl chloroform observations, the study reveals that this OH reduction occurred in both hemispheres—approximately 2.4% in the Northern Hemisphere and 5.7% in the Southern Hemisphere—driven by distinct mechanisms. In the Northern Hemisphere, reduced NO_x emissions due to COVID-19 lockdowns led to lower OH and tropospheric ozone levels, while in the Southern Hemisphere, massive emissions of reactive carbon from unprecedented Australian wildfires caused OH depletion but tropospheric ozone increases. This contrast in tropospheric ozone anomalies is further corroborated by satellite data. The findings help explain one of the record-breaking rises in atmospheric methane in 2020 and underscore the critical role of both natural and anthropogenic factors in shaping Earth’s atmospheric chemistry and global methane budget.