Integrating Super Pollutants into NDCs: Strategies for Addressing Tropospheric Ozone and Its Precursors

The vast majority of NDCs prioritize the six greenhouse gases or groups of compounds regulated under the Kyoto Protocol and later reaffirmed in the Paris Agreement. However, they fail to account for the full spectrum of climate forcers that the IPCC has consistently highlighted in its scientific consensus reports since its inception. This omission limits the effectiveness of climate action by overlooking key pollutants that contribute to both global warming and air quality degradation. 

Few Nationally Determined Contributions (NDCs) mention tropospheric ozone directly, with notable exceptions such as Tunisia and Micronesia. However, its precursors are referenced in more NDCs, including those of Nigeria, Tonga, and Morocco. Despite this, most tropospheric ozone precursors remain largely absent from climate reporting under the United Nations Framework Convention on Climate Change (UNFCCC), as many countries lack comprehensive national and sub-national emission inventories. 

Tropospheric ozone poses serious health and environmental risks, particularly for vulnerable populations such as individuals with asthma, children, the elderly, and outdoor workers. Exposure reduces lung function, increases respiratory diseases, and leads to premature mortality, contributing to over 500,000 deaths annually. Economic losses from ozone pollution exceed $500 billion, while more than 90% of the global population is exposed to levels surpassing WHO guidelines. Beyond its health effects, tropospheric ozone accelerates global warming and severely damages crops and forests, threatening food security and biodiversity. Despite these widespread impacts, climate policies have long failed to integrate air pollution control, overlooking the synergies necessary for effective mitigation. Addressing both challenges in tandem is crucial, particularly for super pollutants like tropospheric ozone, methane, and black carbon, which significantly impact both climate and public health 

To bridge this gap, the Intergovernmental Panel on Climate Change (IPCC) is developing a Methodology Report on Inventories for Short-Lived Climate Forcers, expected in 2027, to provide guidance on reporting tropospheric ozone precursor emissions. Some governments, such as Mexico, have already taken the lead by incorporating these emissions into their national inventories and Measurement, Reporting, and Verification (MRV) processes alongside greenhouse gases. 

Urgent action is needed to realize the benefits of reducing short-lived climate forcers, including faster climate mitigation, cleaner air, and improved food security. This event will present scientific evidence on this issue and discuss the need for updated and increase the ambition of NDCs based on robust science knowledge. 

The objectives of this event are to: 

• Present the key scientific and policy arguments for integrating short-livedclimate forcers (SLCFs) into Nationally Determined Contributions (NDCs),emphasizing their critical role in accelerating climate mitigation, improving airquality, and enhancing public health.
• Explore how incorporating SLCFs into NDCs can enhance synergies betweenclimate action and air pollution control, leading to more comprehensive andeffective policies. Experts will present case studies of countries that have alreadyincluded SLCFs in their commitments, share best practices for measurement andreporting, and discuss the need for standardized methodologies and governanceframeworks to support their inclusion.

By providing a strong evidence base and policy recommendations, this session aims to encourage countries to enhance their climate ambition and integrate SLCFs into their updated NDCs, fostering a more holistic and impactful approach to global climate action.