Marine ecosystem role in setting up preindustrial and future climate

Area of Science:

• Earth system science
• Oceanography
• Climate science

Background:

• The ocean is a critical component of the global carbon cycle, influencing atmospheric CO2 levels.
• Current models often simplify the complex land-ocean feedback mechanisms.
• Understanding ocean biology's role is essential for accurate climate projections.

Purpose of the Study:

• To investigate the intricate role of ocean biology in regulating atmospheric CO2.
• To assess the impact of shutting down the ocean's biological pump on global carbon levels.
• To explore the coupled land-ocean feedback in Earth system modeling.

Main Methods:

• Utilized an interactive Earth system model to simulate changes in the carbon cycle.
• Analyzed the new equilibrium state of atmospheric CO2 after disabling the ocean's biological pump.
• Quantified carbon exchange between the ocean and land components of the model.

Main Results:

• Atmospheric CO2 increased by over 50% (163 ppm) when the ocean's biological pump was shut down.
• Approximately half of the carbon released from the ocean was adsorbed by land.
• The abiotic ocean showed reduced capacity for anthropogenic carbon uptake due to warming and altered surface conditions.

Conclusions:

• Ocean biology plays a more complex role in carbon sequestration than previously understood.
• Land-ocean feedbacks significantly influence atmospheric CO2 responses to changes in marine ecosystems.
• Preserving marine ecosystem functioning is vital for climate change mitigation efforts.