Enhanced simulated early 21st century Arctic sea ice loss due to CMIP6 biomass burning emissions | CU Experts

The mechanisms underlying decadal variability in Arctic sea ice remain; an active area of research. Here we show that variability in boreal; biomass burning (BB) emissions strongly influence simulated Arctic sea; ice on multi-decadal timescales. In particular, we find that a strong; acceleration in Arctic sea ice decline in the early 21st century in the; Community Earth System Model version 2 (CESM2) is related to increased; variability in prescribed CMIP6 BB emissions through summertime; aerosol-cloud interactions. Furthermore, we find that the previously; reported improvement in sea ice sensitivity to CO2 emissions and global; warming from CMIP5 to CMIP6 can be attributed in large part to the; imposed increased BB emission variability, at least in the CESM model.; These results highlight the complexities of incorporating new; observational data into model forcing, while also raising the question; of a BB-forced contribution to the observed accelerated early 21st; century Arctic sea ice loss.

DeRepentigny P; Jahn A; Holland M; Kay J; Fasullo J; Lamarque J-F; Tilmes S; Hannay C; Mills M; Bailey D

VIVO