Affected systemHazard *Cascading effectObserved impacts, future risks and natural adaptations identified in SROCC (confidence level) Arctic marine ecosystems Primary producers (PP-1)Sea ice loss * Freshening * StratificationImpact: timing (earlier and later blooms), distribution and magnitude (>30% increase in annual net primary production since 1998) (high confidence) Acidification Adaptation: phytoplankton may compensate for decrease in pH Zooplankton * PP-1 Impact: changing production and community composition (medium confidence) Benthos * PP-1 Impact: changing production and biodiversity