Open Letter on the Importance of Short-Lived Climate Pollutants (SLCPs) in National and Corporate Climate Action Plans

March 04, 2024

The CC Lab is proud to be a signatory on the Open Letter on the Importance of Short-Lived Climate Pollutants.

At the CC Lab, our Anthropogenic Program focuses on reducing emissions from hydrofluorocarbons (HFCs) and methane, which belong to a group of greenhouse gases collectively known as short-lived climate pollutants (SLCPs). Because of their high potency and shorter atmospheric lifetimes, SLCPs have an outsized effect on near term warming. To keep warming below 1.5°C, we need to make big cuts to SLCP emissions, and quickly. Many cost effective abatement technologies for SLCPs already exist, but have been historically neglected and underfunded. Recently, the world has begun to direct more attention and resources towards SLCP mitigation, but there is more that can and must be done. 

In light of this, we are proud to share this open letter that highlights the critical role that SLCP mitigation plays in the climate fight and provides concrete steps that organizations can take to do their part. We hope you will join us in these efforts to keep 1.5°C in reach.

To add your organization as a signatory, or for any other inquiries, please send an email to info@urgentclimateaction.org.

Read the letter below:

Most climate action today focuses on reducing emissions of carbon dioxide and, to a lesser but growing extent, removing carbon dioxide from the atmosphere. These efforts are necessary and need to continue growing rapidly.

However, other climate pollutants, especially Short-Lived Climate Pollutants (SLCPs), are underappreciated and must also be a part of the solution. SLCPs, such as methane, HFC refrigerants, black carbon, carbon monoxide, and aviation contrails, account for nearly half of industrial-era global heating

Unlike CO2, which remains in the atmosphere as a long-lived greenhouse gas for hundreds to thousands of years, SLCPs have much shorter atmospheric lifetimes on the scale of years to days. Cutting the rate of SLCP emissions — even if gross SLCP emissions do not reach zero — can therefore rapidly reduce the rate of atmospheric warming.

Feasible SLCP cuts from existing technologies today can avoid up to 0.6° C by 2050four times more in that time period than CO2 cuts alone. These short-term cuts are our best chance to reduce the risk of hitting near-term tipping points which could create vicious climate feedback loops. These reductions can also annually avoid millions of air pollution deaths and crop loss tonnes. In short, global climate goals can only be met with swift and decisive action on both long-lived and short-lived pollutants.

The good news is that SLCP abatement includes a large number of “low-hanging fruits” that are technologically ready to deploy today. These solutions include improved refrigerant management and deployment of low-GWP refrigerants, methane leak management in fossil fuel production, reduced N2O and methane emissions from water-efficient rice cultivation, soot-free transport and cooking solutions, reduced food waste, and more.

Building on the momentum from COP28, we call on global leaders in government and business to prioritize SLCP mitigation in their climate action plans, and for entities such as standards bodies and think tanks to support these efforts.

We are inspired and encouraged by existing initiatives on SLCPs, including: the Global Methane Pledge, the new Global Cooling Pledge from COP28, the Climate and Clean Air Coalition (CCAC), the Madrid Call on Fast Action on Super Pollutants (and following work under FAST), the Refrigerant Emissions Elimination Forum (REEF), the Astra ProjectClimate and Ozone Protection Alliance (COPA) and others. However, more needs to be done. We call for an increase in resources and support to existing projects, the development of new efforts focused on these strategies, and increased prioritization of these issues by countries and corporations alike.

On the national level, for example, CCAC has delivered a variety of tangible wins and supported longer-term efforts such as the development of National SLCP Plans, which we applaud. However, there is still much work to be done: over 100 countries have yet to join CCAC, fewer than 20 countries have endorsed national SLCP plans, and only 54% of countries’ Nationally Determined Contributions (NDCs) included HFC reduction according to the latest UNFCCC synthesis report

There is also a gap in corporate climate action on SLCPs. We call for:

  • Standards bodies to develop new corporate standards (or amend existing ones, as appropriate) to incorporate urgency on SLCPs across reporting, mitigation efforts, and beyond-value-chain mitigation (BVCM).

  • Forward-thinking corporations to experiment and try their own SLCP-informed approaches while such standards are being developed or amended.

Currently, the GHG Protocol Corporate Standard requires reporting of individual Kyoto Protocol gases, and the Science Based Targets Initiative (SBTi) calls for “deep reductions in non-CO2 emissions from all sectors”. However, there is substantial room for improvement and expansion. For example, SBTi’s cross-sector pathway includes only CO2, CH4 and N2O, but excludes HFCs, a major SLCP.

At a deeper level, both the GHG Protocol Corporate Standard and SBTi provide guidance to compare emissions of different gases on the basis of cumulative warming impact over a 100-year timescale (GWP-100). However, GWP-100 does not provide a complete picture of temperature impacts, and there are a variety of emissions metrics available, including: GWP-20 (cumulative radiative forcing over a 20-year timescale), GWP*, and CGTP. Because no emission metric can be perfect, we advocate for a more nuanced treatment of SLCPs in corporate emissions accounting. It is clear that GWP-100 by itself is inadequate for meeting our near-term climate goals.

We believe better standards are needed to guide corporations on accounting for SLCP emissions and mitigation, as well as incorporating SLCPs into their Beyond Value Chain Mitigation (BVCM). Until standards are improved, corporations can do the following.

First, report separate emissions for each climate pollutant, as recommended by leading climate scientists. They can then set separate reduction targets for each pollutant.

Second, when a unified metric is required, corporations can report multiple such metrics. At the very least, we would suggest that GWP-20 always accompany GWP-100. This change requires negligible additional effort to prepare and would be straightforward to interpret. Side-by-side reporting could allow corporations and watchdog organizations to explicitly assess and prioritize progress across both short-term and long-term mitigation opportunities.

Third, beyond these fundamental steps, corporations can pursue an SLCP-informed approach to climate action, both inside their emissions boundary and outside it. They might choose to set their Scope 1, 2 and 3 reduction targets separately for different pollutants over time. They could choose to pursue BVCM efforts across different pollutants in a way that is science-informed, or set targets based on their own emissions profile across these pollutants. Some corporations retire voluntary carbon credits as part of their BVCM efforts, and have already begun to separate CO2 avoidances from carbon removal in their procurement. These companies could carve out a third category of avoided SLCP emissions to explicitly recognize the importance and urgency of these efforts.

The signatories to this letter take a wide variety of perspectives on the most promising pathways and approaches to SLCP mitigation. However, all signatories agree that SLCP emissions are a neglected and critical area to invest in over the next five years to prevent the worst impacts of climate change.

We therefore call upon governments, the private sector, and civil society to recognize the scientific rigor and moral urgency surrounding short-lived climate pollutants, and to take broad and swift action to abate their emissions. We look forward to partnering with you on this critical mission.



Project Drawdown


Carbon Containment Lab

International Fugitive Emissions Abatement Association


Refrigerant Emissions Elimination Forum

LIFT Economy

Frost Methane



The Sky Foundation

Kristen Taddonio

Prof. dr. ir. G.J.M. (Guus) Velders, Utrecht University

Dr. Tom Hooper, University College Dublin

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