Atmospheric chemistry increased methane removal during last ice age

An international study published in the journal Science reveals that the atmosphere was more efficient at removing methane during the last ice age, approximately 20,000 years ago. Researchers found that the decrease in methane levels was driven not only by reduced natural emissions but also by a chemical mechanism that shortened the gas's atmospheric residence time by about 20%.

The research, coordinated by the Instituto de Química Física Blas Cabrera (IQF-CSIC), utilized advanced climate modeling and geochemical analysis of ice cores from Antarctica and Greenland. The study demonstrates that high concentrations of mineral dust in the atmosphere interacted with sea salt to produce highly reactive chlorine species, which accelerated the removal of methane.

Italian researchers from the Institute of Polar Sciences of the National Research Council (CNR-ISP) contributed by interpreting chemical signals preserved in the polar ice, linking geochemical evidence to reconstructed atmospheric processes.