Decadal increase in Arctic dimethylsulfide emission.

Area of Science:

• * Atmospheric Chemistry
• * Oceanography
• * Climate Science

Background:

• * Dimethylsulfide (DMS) is a crucial biogenic gas produced by marine microbes.
• * DMS influences aerosol formation, impacting cloud radiative forcing and precipitation.
• * Arctic ecosystems are undergoing rapid changes, necessitating an assessment of DMS emissions.

Purpose of the Study:

• * To quantify trends in summertime pan-Arctic DMS emissions (EDMS) from ice-free waters.
• * To assess the impact of sea-ice retreat on EDMS.
• * To provide constraints for understanding future Arctic climate feedbacks.

Main Methods:

• * Utilized a remote sensing algorithm to analyze summertime EDMS data.
• * Analyzed data north of 70°N between 1998 and 2016.
• * Correlated EDMS trends with sea-ice extent and atmospheric measurements of methane sulfonic acid.

Main Results:

• * Summertime EDMS from ice-free Arctic waters increased by 13.3 ± 6.7 Gg S decade⁻¹ (∼33% decade⁻¹).
• * The observed trend is primarily driven by sea-ice reduction.
• * Extrapolation suggests a potential 2.4-fold increase in EDMS in an ice-free Arctic summer.

Conclusions:

• * Arctic sea-ice retreat is significantly increasing DMS emissions.
• * Future EDMS may deviate from predictions due to ecosystem regime shifts.
• * Increasing DMS emissions and subsequent aerosol-cloud interactions may moderate or accelerate Arctic warming.