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.

Trees help clean the air in cities but they also contribute to smog formation. A recent study conducted at Beijing Forestry University analyzed six major urban tree species for carbon storage and biogenic volatile organic compound (BVOC) emissions using field surveys and satellite data. The findings revealed two tree species: Robinia pseudoacacia and Betula platyphylla, as the ideal for maximizing carbon capture while minimizing harmful emissions—guiding smarter urban forest planning in China.

In a paper published in National Science Review, a research team led by Chinese scientists quantifies changes in dissolved carbon storage within China's lakes and reservoirs alongside dissolved carbon fluxes in rivers over the past three decades, systematically revealing how climate change, anthropogenic disturbances, and water chemistry factors collectively drive the dynamics of dissolved carbon in inland waters. The study finds that dissolved carbon storage across China's inland waters has increased significantly during this period, with riverine carbon fluxes primarily driven by climate and human factors, while lake and reservoir carbon storage is dominated by water chemistry controls.

Researchers from the University of Copenhagen have gained unique insight into the mechanisms behind the collapse of Antarctic ice shelves, which are crucial for sea level rise in the Northern Hemisphere. The discovery of old aerial photos has provided an unparalleled dataset that can improve predictions of sea level rise and how we should prioritise coastal protection and other forms of climate adaptation.

Ship traffic in shallow areas, such as ports, can trigger large methane emissions by just moving through the water. The researchers in a study, led by Chalmers University of Technology in Sweden, observed twenty times higher methane emissions in the shipping lane compared to nearby undisturbed areas. Despite the fact that methane is a greenhouse gas that is 27 times as powerful as carbon dioxide, these emissions are often overlooked with today's measurement methods.

"Our measurements show that ship passages trigger clear pulses of high methane fluxes from the water to the atmosphere. This is caused by pressure changes and mixing of the water mass. Even if the pulses are short, the total amount during a day is significant," says Amanda Nylund, researcher at Chalmers University of Technology and the Swedish Meteorological and Hydrological Institute, SMHI.

Many wild Vanilla species are dependent on insects that pollinate them. But what happens if plants and insects are forced into different habitats? Researchers have examined if shifts in species’ geographic ranges could lead to future mismatches. They found that climate change may lead to reduced overlap in suitable habitats for wild vanilla and their pollinators. This could negatively affect the survival chances of these wild species, especially those dependent on specific pollinators, but also threaten the future of the vanilla crop and global vanilla supply.