Superpollutants Season 2: Revisiting a critical part of the carbon markets

July 16, 2026 - Research

We are starting a new series on super pollutants. Some of you may be wondering: Where was Season 1? Did I miss it?

Calyx Global has been writing about superpollutants since 2022. Why?

When Calyx Global first started rating carbon credits in 2021, our goal was coverage: rate as much of the market as possible. This led us to start by rating many large-scale grid-connected renewable energy (ACM0002) and REDD projects – together, these made up over 68% of voluntary carbon market (VCM) retirements in 2021. However, we quickly discovered that this was not very helpful to our customers, because the majority of ACM0002 credits have a high risk of non-additionality. Additionally, REDD credits had significantly overestimated baselines – something we wrote about in 2023, but is now well known.

So we pivoted. We asked our independent GHG panel where we might focus to find higher quality credits. They advised us to consider various superpollutant credit types: ODS destruction, landfill gas and others. We started to assess those projects in earnest. In 2022, we coined these credits the “ugly ducklings” – underappreciated and undervalued credits. The image below illustrates how the GHG integrity of superpollutant credits compare to REDD and ACM0002, the two credit types that dominated the VCM from 2020 to 2023.

Figure: Ratings distributions for different credit types

Superpollutants Season 2 Revisiting a Critical Part of the Carbon Markets - bar graph.png

Note: These distributions are based on the % of Calyx Global ratings for the relevant project types. Calyx Global has 245 REDD and ACM002 ratings and 251 superpollutant ratings.

It was therefore no surprise to us that the first methodologies approved by the ICVCM were superpollutant project types: landfill gas and ODS destruction. This is also true for the Paris Agreement Crediting Mechanism (PACM), where the first two approved methodologies are landfill gas and N2O abatement from nitric acid production.

Fast forward to 2026, and superpollutants are all the rage. They are the stars of New York and London Climate Weeks and other carbon jamborees around the world. It might have something to do with the Beyond Alliance members’ announcement in March – “lighthouse” corporations including Amazon, Autodesk, Figma, Google, JP Morgan Chase, Salesforce, Netflix and Workday committed $100 million to tackle these high global warming gases.

For this reason, we’re launching Superpollutants Season 2: a new series of articles exploring superpollutants based on our years of evaluating and rating these project types. In the months ahead, we’ll examine some of the biggest questions shaping the future of superpollutants, including:

How are superpollutants evolving from a carbon-market story to a policy story?
Are conventional carbon accounting methods accurately capturing superpollutants' climate impact?
Who should ultimately pay for superpollutant mitigation - the polluter, the taxpayer, or the carbon market?

Stay tuned or sign up for our newsletter to make sure you don’t miss an epsiode. If you want to catch up on Season 1, below is a list of our articles covering superpollutants over the past few years.

Season 1 sample: Calyx Global blogs on super pollutants