Review of “CH4 and N2O fluctuations during the penultimate deglaciation” by Schmidely et al. (2020)

Abstract

Schmidely et al. provide new high-resolution CH4 and N2O datasets over the penultimate deglaciation from the EDC ice core, and based on their data suggest an interpretation of the last deglaciation that has more structure and richness that the "canonical" interpretation of just a long AMOC shutdown over H11 from 136 to 128 ka BP (Cheng et al., 2009;Clark et al., 2020). While the interpretation is somewhat speculative at times, I for one believe that they are mostly correct. It is always exciting to see that the climate is more complicated than we thought at first -it always pays off to evaluate ice core records at the highest possible resolution. I think the manuscript is suitable for publication after addressing some issues. In particular, the new analytical setup (a major achievement by itself) deserves some more attention, as well as the observed (and surprisingly large) offset with existing records.