Continued permafrost ecosystem carbon loss under net-zero and negative emissions

Area of Science:

• Earth System Science
• Climate Change Research
• Permafrost Studies

Background:

• Permafrost regions store vast amounts of carbon.
• Climate change mitigation pathways aim to reduce atmospheric carbon dioxide.
• Potential carbon release from thawing permafrost could impact climate goals.

Purpose of the Study:

• To investigate permafrost carbon dynamics under net-zero and negative emissions scenarios.
• To assess the impact of permafrost carbon loss on carbon dioxide removal efficiency.
• To evaluate changes in methane emissions from permafrost regions.

Main Methods:

• Utilized idealized emission-driven simulations.
• Employed a state-of-the-art Earth system model.
• Analyzed permafrost carbon budgets and methane emissions.

Main Results:

• Permafrost transitions from a carbon sink to a source before net-zero emissions.
• Cumulative net ecosystem carbon loss of approximately 14 petagrams of carbon is projected.
• Methane emissions increase due to irreversible inundated areas.

Conclusions:

• Permafrost ecosystem carbon loss is likely to persist under net-zero and negative emissions.
• This carbon loss could significantly reduce the effectiveness of climate change mitigation strategies.
• Further research is needed to understand and address permafrost carbon feedback loops.