Mitigation and adaptation emissions embedded in the broader climate transition

Area of Science:

• Climate Science
• Environmental Science
• Energy Policy

Background:

• Climate change demands global efforts for greenhouse gas emission reduction and adaptation to climate risks.
• Large-scale climate interventions (renewable energy, coastal protection, cooling) generate CO2 emissions from energy and materials.
• The scale of these embedded emissions is unquantified, risking underaccounting and conflicts between mitigation and adaptation.

Purpose of the Study:

• To estimate the CO2 emissions embedded within the broader climate transition.
• To assess the impact of different decarbonization pathways on these transition emissions.
• To inform climate science and policy by highlighting the significance of transition-related emissions.

Main Methods:

• Utilized a suite of climate and energy system models.
• Simulated various decarbonization pathways, including gradual (2°C), rapid (1.5°C), and delayed (2.7°C) scenarios.
• Quantified CO2 emissions from both adaptation interventions and renewable energy deployment.

Main Results:

• A gradual 2°C pathway embeds ~1.3 GtCO2 from adaptation and ~95 GtCO2 from renewable energy deployment by 2100.
• These transition emissions represent 8.3% of the remaining carbon budget for 2°C.
• Rapid 1.5°C pathways reduce total embedded emissions by ~80% compared to delayed pathways, which nearly double emissions due to increased fossil fuel reliance.

Conclusions:

• Emissions embedded in climate transition interventions are substantial and require careful consideration.
• Ambitious energy decarbonization is crucial for minimizing these transition emissions.
• Emissions from mitigation efforts, and to a lesser extent adaptation, warrant greater attention in climate science and policy.