Chapter 03 The Climate Case for Superpollutant Action

The pathway to 2°C assumes deep superpollutant reductions by 2050

The IPCC scenario that keeps the world below 2 degrees Celsius of warming, SSP1-2.6, has served as the corporate and political goalpost for over a decade (henceforth “2 degrees C scenario”). It embeds a near-halving of superpollutant emissions by 2050 alongside a rapid decline of carbon dioxide, as shown in Figure 3. Methane and F-gases are the largest share of the superpollutant reductions in the 2 degrees C scenario—two of the gas groups this roadmap also identifies as highly actionable by companies.

Because it concentrates the warming effect of short-lived gases like methane into a shorter 20-year window rather than averaging it out over a century, superpollutants carry more weight in GWP-20 than GWP-100. Their emissions appear larger and more front-loaded in the GWP-20 chart (Figure 3) while calculations using GWP-100 dilute their impact by spreading that same warming over a longer horizon. See Appendix A for an explanation of GWP and why it matters.

The Reference scenario (SSP2-4.5) is shown in Figure 3 as dotted lines for comparison. Superpollutant emissions in this scenario remain close to flat across the entire century, while carbon dioxide emissions continue to rise until approximately 2040 before falling to roughly half of current levels by 2100. It does not assume that superpollutant abatement is technically unavailable but that available solutions fail to attract the attention, policy, and capital required to deploy them at scale. The Reference scenario ends the century with approximately 2.7 to 2.8 degrees Celsius of warming. (Note that the reference scenario was formulated prior to the Kigali Amendment, whose implications on the model are addressed in Appendix C.)

The variation between the 2 degrees C scenario and the Reference scenario amounts to the annual reductions by 2050 shown in Table 4.

Holding warming to 2°C requires global superpollutant emissions to fall approximately 50 percent by 2050. Cumulatively, this represents approximately 142 Gt CO₂e of avoided emissions by 2050, distributed across the three modeled superpollutant groups as shown in Table 5.

Reducing warming in the near-term requires cutting superpollutants

Translating the two emissions pathways into temperature outcomes helps to isolate the contribution of each gas group—with results shown in Figure 4. Of the 0.9°C separating the two scenarios, approximately half comes from carbon dioxide and half from superpollutants.

All scenarios in Figure 4 show continued near-term warming, with a pronounced increase in near-term temperature associated with the CO₂-only scenario. This occurs, in part, because fossil fuel combustion co-emits sulfate aerosols, which cool the climate by reflecting sunlight. So, as we decarbonize and phase out fossil fuels, we also remove the cooling effect, which effectively “unmasks” warming that had previously been offset. Superpollutant mitigation helps dampen this effect because reducing superpollutants delivers a benefit without triggering the same aerosol trade-off. This makes superpollutant action a more direct lever for near-term mitigation than decarbonization alone.

Moreover, given their mostly short-lived atmospheric lifetimes, mitigation of superpollutants can immediately have an effect on warming. A metric ton of methane abated in 2027 has largely ceased to influence the climate system by the 2040s, which means its comparatively outsized abatement benefit is fully realized inside the current century. Meanwhile, a metric ton of carbon dioxide abated in 2027 spreads its benefit across the following centuries.¹¹⁷ Two mitigation portfolios of identical carbon dioxide-equivalent tonnage therefore produce materially different temperature trajectories depending on their gas composition.

Each ~35 Gt CO₂e reduction in superpollutants would require about 300 Gt of CO₂ abatement to have the same temperature impact by 2050.

Implications for corporate strategy

Sequencing becomes a key strategic variable. The analysis indicates that early superpollutant action cannot replace carbon dioxide mitigation, but it does create the runway for action. Carbon dioxide abatement in heavy industry, aviation, and long-lived infrastructure depends on capital replacement cycles measured in decades. Much of superpollutant abatement—leak detection and repair, lifecycle refrigerant management, venting and flaring elimination, industrial abatement retrofits—occurs in cycles measured in months to a few years. Acting quickly on superpollutants extends the window in which carbon dioxide can scale without peak warming (and climate tipping points) being breached in the interim. Companies with credible net-zero commitments and limited near-term options should pay particular attention.

Superpollutant action complements rather than replaces carbon dioxide action. This analysis supports treating short- and long-lived gases along different time horizons within a single strategy: companies can invest in superpollutant projects to help with near-term temperature stabilization, as well as carbon dioxide mitigation and removal to support longer-term climate stabilization. Companies that structure their targets to reflect that distinction gain a clearer view of the climate impact their own portfolio and investments can deliver and when. Some companies, such as Google, are already articulating an approach to combating warming via combined action on superpollutant elimination and carbon removal,¹¹⁸ which could be highly effective in scaling both categories.

The required abatement is disproportionately cheap and disproportionately available. The finance gap identified above is large, but the marginal abatement costs behind it are among the lowest in the global mitigation portfolio. A substantial share of this opportunity sits inside or adjacent to corporate value chains.

Two features of superpollutant abatement pathways work in companies’ favor:

• First, a significant share of methane and F-gas abatement carries negative or low net cost, because the abated substance has commercial value and therefore pays for itself over time. Equipment upgrades deliver energy efficiency alongside emissions reductions or the intervention is a maintenance practice rather than a capital-intensive project.
• Second, many (though not all) superpollutant emissions are concentrated in identifiable point sources and specific equipment classes rather than diffused across every combustion process in an economy, as is the case with CO₂. Concentrated sources are easier to locate, attribute to a responsible party, fix, and, eventually, regulate.

A meaningful share of global superpollutant mitigation opportunities lies outside any single company’s direct value chain, often in geographies and sectors where the abatement is cheapest but the capital is scarcest. Companies can reach these mitigation measures through the carbon market lever described in Chapter 5 and can help build the policy and measurement infrastructure that unlocks it through the engagement lever described in Chapter 6. The value chain lever in Chapter 4 addresses the portion that sits within corporate control and influence, where numerous negative- or low-cost opportunities also exist.

Corporate action is imperative. The major reductions assumed in the 2 degrees Celsius scenario are concentrated in oil and gas systems, cooling and refrigeration, waste management, industrial chemical production, and agricultural supply chains. These predominantly reside in corporate systems. Although governments can regulate them and finance can support them, companies ultimately operate them. This modeling and its related research indicate that the 2 degrees Celsius pathway is not reachable without mitigation actions coming from corporate operations, ownership, and procurement.

Resource reallocation is needed. With this understanding, the present allocation of resources appears to be drastically disproportionate. Methane abatement, for example, is among the fastest and cheapest ways to slow near-term warming, yet a Climate Policy Initiative (CPI) study finds that less than 2 percent of global climate finance in recent years has been directed to methane action.¹¹⁹ A subsequent CPI study estimated that global methane abatement finance averaged USD 13.7 billion per year in 2021– 2022 against an estimated need of roughly USD 48 billion annually by 2030 under a 2 degrees Celsius pathway.¹²⁰ A commitment of that size simply cannot deliver half of the required temperature outcome.

Superpollutant action can no longer remain a corporate afterthought. It is one of the most significant pillars of climate change engagement needed in the coming years. With these takeaways in mind, the goal of this roadmap is to present the tools necessary to effectively and efficiently reduce a corporate superpollutant footprint across three key levers—value chain intervention, voluntary carbon markets, and policy engagement—not just because it is one of the best ways to extend the breadth of corporate environmental efforts, but because it simply cannot be done without corporate action.