Arctic Ocean annual high in could shift from winter to summer

Area of Science:

• Marine biology
• Climate science
• Oceanography

Background:

• Rising atmospheric carbon dioxide (CO2) alters ocean CO2 partial pressure (pCO2) seasonally.
• Seasonal timing of ocean pCO2 is influenced by CO2 levels and other factors.
• Arctic Ocean typically has high pCO2 in winter and low in summer.

Purpose of the Study:

• Investigate how changes in the seasonal timing of ocean acidification affect marine organisms.
• Project future changes in Arctic Ocean pCO2 seasonality under different CO2 emissions scenarios.
• Analyze the impact of altered seasonality on extreme summer acidification events.

Main Methods:

• Utilized 27 Earth system models to simulate historical and future Arctic Ocean conditions.
• Analyzed projected changes in seasonal pCO2 trends under mid-to-high CO2 emissions.
• Quantified the influence of sea surface warming and sea ice retreat on pCO2 seasonality.

Main Results:

• Models project a shift in Arctic Ocean pCO2 seasonality, with summer lows becoming highs under future CO2 scenarios.
• This seasonal timing inversion is driven primarily by increased summer sea surface warming due to earlier sea ice melt.
• Extreme summer acidification is projected to increase by 29% due to these seasonal shifts.

Conclusions:

• The changing seasonal timing of ocean acidification exacerbates summer conditions in the Arctic.
• This worsening summer acidification may reduce the resilience of Arctic marine life to rising summer temperatures.
• Future climate change will significantly alter seasonal ocean acidification patterns with ecological consequences.