Potential for reducing air-pollutants while achieving 2 °C global temperature change limit target.

Area of Science:

• Climate change mitigation strategies
• Environmental policy analysis
• Energy systems modeling

Background:

• Global efforts are underway to limit global temperature rise to 2°C above pre-industrial levels.
• Air pollution reduction is a critical co-benefit of climate change mitigation.

Purpose of the Study:

• To estimate mitigation potentials and costs for 2°C, 2.5°C, and 3°C global temperature targets.
• To assess the co-benefits of reducing air pollutants (NOx, SO2, BC, PM) under these scenarios.
• To analyze sectoral contributions to emissions reductions in Annex I and Non-Annex I countries.

Main Methods:

• Utilized the bottom-up optimization model, AIM/Enduse[Global].
• Analyzed various carbon tax scenarios to determine required price levels for different temperature targets.
• Quantified mitigation potentials, associated costs, and air pollutant co-benefits.

Main Results:

• A carbon tax of 50 US$/tCO2-eq in 2050 exceeds the emissions reductions of the 3°C target scenario.
• Achieving the 2°C target necessitates a carbon price around 400 US$/tCO2-eq by 2050.
• Significant co-benefits include 60-80% reductions in air pollutants by 2050 compared to the reference scenario when meeting the 2°C target.

Conclusions:

• The 2°C global temperature target is achievable, albeit requiring substantial carbon pricing.
• Climate mitigation policies offer significant co-benefits for air quality improvement.
• Sectoral analysis is crucial for understanding differentiated responsibilities in global climate action.