Next-generation ensemble projections reveal higher climate risks for marine ecosystems.

Area of Science:

• Marine biology
• Climate science
• Oceanography

Background:

• Climate change projections indicate significant impacts on marine ecosystems.
• Global marine animal biomass is projected to decline, affecting fisheries.
• Previous models (CMIP5) provided initial estimates of these impacts.

Purpose of the Study:

• To project future ocean ecosystem responses to climate change using enhanced models.
• To compare new projections with previous model generations (CMIP5 vs. CMIP6).
• To assess the impact of different emissions scenarios on marine biomass.

Main Methods:

• Utilized an enhanced suite of global marine ecosystem models (Fisheries and Marine Ecosystem Model Intercomparison Project - Fish-MIP).
• Forced models with new-generation Earth system model outputs from Coupled Model Intercomparison Project Phase 6 (CMIP6).
• Analyzed projected changes in global marine animal biomass and net primary production.

Main Results:

• New ensemble ecosystem simulations project a greater decline in mean global ocean animal biomass compared to CMIP5-forced models.
• This decline is observed under both strong-mitigation and high-emissions scenarios.
• Elevated ocean warming is identified as a key driver, despite increased uncertainty in net primary production under high emissions.

Conclusions:

• Projected climate change, particularly warming, poses a substantial threat to marine animal biomass.
• Regional shifts in biomass changes necessitate localized adaptation planning.
• Reducing uncertainty in marine ecosystem responses to climate change is critical for effective fisheries management and conservation.