Global Warming Potential Table: 20 years vs. 100, and NY’s new “Trojan Horse”

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Global Warming Potential Table: 20 years vs. 100, and NY’s new “Trojan Horse”

New York State has a new Senate bill, S6030, which brings up several issues with climate accounting and Global Warming Potential. As noted here, the bill “purports to align New York’s emission accounting methodology with a federal methodology by shifting the measurement of GHG’s (greenhouse gases) warming effect from a 20-year time horizon to a 100-year time horizons.”

The 100-year vs. 20-year Global Warming Potential (GWP) discussion is sometimes seen as a discussion only relevant to policymakers, but it goes way beyond that. It has resonance for HVACR business owners as well.

Understanding the 20-year GWP value metric can help you with:

  • General improvement in carbon literacy
  • Understanding why we consider a 20-year time period and how it changes your approach to regulations and compliance
  • Adopting a common business vocabulary for ESG that reflects both urgency, best science, and operational need
  • Your role in the bigger climate system picture

At heart, 100-year vs. 20-year is an accountability issue. The story is about navigating the impact of what’s happening to the broader climate:

  • The 100-year GWP value is aligned with a general market interest in benchmarking and having common parameters for a discussion about climate change.
  • The 20-year GWP value is more about the immediate impact of what carbon dioxide, carbon dioxide equivalent, and refrigerants are doing to our world.

Let’s attempt to clear some of this up. To better understand what’s happening here around carbon dioxide emissions, greenhouse gases, Global Warming Potential, and more, we need to take a quick step back.


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What exactly is Global Warming Potential, again?

Different GHGs can have different effects on the Earth’s warming. Two key ways in which these gases differ from each other are their ability to absorb energy (their “radiative efficiency”), and how long they stay in the atmosphere (also known as their “lifetime”).

The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO2). The larger the GWP, the more that a given gas warms the Earth compared to CO2 over that time period.

All of the above comes from strict Environmental Protection Agency (EPA) definitions.

Global Warming Potential is essentially a common unit of measure for greenhouse gas emissions, and is thus helpful for both analysts and policymakers in terms of decision-making around climate change.

Then you get into the time horizon discussion.

The typical time period for GWPs is 100 years. However, you’ll often see GWP calculated across 20 years. The 20-year window first emerged in discussions in 2008 and is only now entering policy discourse at some level (more on that in a second).


A quick example of 20-year GWP vs. 100-year GWP values

Just like the 100-year GWP is based on the energy absorbed by a gas over 100 years, the 20-year GWP is based on the energy absorbed over 20 years.

This 20-year GWP prioritizes gases with shorter lifetimes, because it does not consider impacts that happen more than 20 years after the emissions occur.

Because all GWPs are calculated relative to CO2, GWPs based on a shorter timeframe will be larger for gases with lifetimes shorter than that of CO2, and smaller for gases with lifetimes longer than CO2.

For example, for CH4, which has a short lifetime, the 100-year GWP of 27–30 is much less than the 20-year GWP of 81–83.

For CF4, with a lifetime of 50,000 years, the 100-year GWP of 7380 is larger than the 20-year GWP of 5300.


More examples, per Atmosphere: Currently, the GWPs. of refrigerants is usually measured over a period of 100 years with reference to CO2.

As you can see above: Promoted as a “low-GWP” solution, R32 has a GWP100 of 704. However, this gas has an atmospheric life time of only 5.4 years and when its GWP is measured over 20 years instead, it is almost four times higher at 2,530.

In this view, presenting GWP100 data instead of more accurate GWP20 data is misleading the public as well as policymakers in terms of which refrigerants are in fact truly climate-friendly and sustainable.

The AR6 Synthesis Report from the Intergovernmental Panel on Climate Change (IPCC) generally emphasizes the urgency of near-term integrated climate action, and operates mostly off 20-year GWP values. Again, though, the EPA uses 100-year values. Most businesses we interact with still work off 100-year values in any GWP discussions or calculations they are involved in.

It’s also worth understanding how these GWP values are arrived at. It’s typically based off of nearly a decade of research around atmospheric concentrations, which are then peer-reviewed. It can take a government roughly 15 years to adopt policy adjustments reflective of the best science we have.

As a result of that relatively-slow adoption process, 20-year GWP has become more popular because it conveys a greater sense of urgency about what the world is facing climate-wise. The thinking on 20-year GWP is often, “We’re already behind the eight-ball here, so we need to be reporting these short-term, immediate values and getting attention.”



But even the path to a 20-year life cycle has taken time: it was initially published in 2008, and is only now arriving in official policy results, in 2023-2024.


Why does GWP matter in terms of refrigerants?

As we mentioned in our longer post on GWP:

When it comes to refrigerants, their GWP is of particular concern, as refrigerants are potent greenhouse gases. Some refrigerants, like hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), have much higher GWPs than CO2, making them more harmful to the environment when released.

The EPA and other regulatory bodies use the 100-year GWP factor to determine which refrigerants are more harmful to the environment and regulate their use accordingly. This helps to encourage the use of refrigerants with lower GWP values and drive innovation in the development of more environmentally friendly alternatives.

In addition to the AIM Act, refrigerants have come under increased scrutiny due to their classification as fugitive emissions, which are unintentional greenhouse gas (GHG) emissions that occur during the production, processing, transmission, storage, and use of various substances, including refrigerants in HVAC/R systems.




Fugitive emissions from refrigerants contribute to climate change and are now being incorporated into ESG (Environmental, Social, and Governance) reporting as part of Scope 1 emissions. Scope 1 emissions refer to direct greenhouse gas emissions that occur from sources owned or controlled by a company or organization. Including refrigerants in Scope 1 emissions reporting reflects a growing recognition of their environmental impact and the need for organizations to monitor, manage, and minimize these emissions.


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How should HVAC/R owners be thinking about GWP, carbon dioxide, and more?

HVAC/R system owners, service professionals, engineers, architects, compliance team members and sustainability reporting experts realize that it is becoming increasingly important to understand the GWP of the refrigerant used in your system due to several factors:

  1. Environmental considerations: High GWP refrigerants contribute to climate change by trapping more heat in the atmosphere. By using low GWP refrigerants, you can minimize your system’s environmental impact and promote sustainability.
  2. Compliance with regulations: Many countries and regions are phasing out high-GWP refrigerants and promoting eco-friendly alternatives. Ensuring your HVAC/R system uses low-GWP refrigerants will help you comply with these regulations and avoid penalties or equipment replacement costs.
  3. Improved energy efficiency: Some low-GWP refrigerants offer better energy efficiency, which can lead to lower energy consumption and reduced operating expenses for your HVAC/R system, ultimately saving you money.
  4. Enhanced brand image: For business owners, adopting low-GWP refrigerants demonstrates a commitment to environmental responsibility, which can improve your company’s reputation and attract eco-conscious customers.
  5. Future readiness: By transitioning to low-GWP refrigerants, you can prepare your HVAC/R system for upcoming regulatory changes and industry trends, minimizing disruptions to your operations and reducing costs associated with retrofitting or replacing equipment in the future.

Calculating, tracking, and managing the GWP of refrigerants is often complicated, since refrigerants are broadly used, poorly tracked, and often managed by operations people focused on other priorities. Thus, asset data is poorly developed.

There is also a discussion around “Net Zero” here. Based on 100-year factors, the belief is that refrigerants currently account for 10-15% of net global emissions. However, if we were to universally apply 20-year values, the refrigerant impact would likely go up to 20-25% of net global emissions. That means most companies are likely under-reporting their impact, and their carbon balance sheet is 10-15% off-base.


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This is where it can get tricky: the discussion about Global Warming Potential often remains at the 100-year level, because that’s a common way to standardize and benchmark climate discussions. And for business owners, 20-year benchmarks can create angst. That means you need to fundamentally redo your carbon accounting process, and adhering to future legislation and policy based off 20-year might also fundamentally shift your operations. 100-year windows are significantly more comfortable for those who own and operate businesses (longer-term, deferred accountability and they likely won’t be running that business in six decades or so anyway), but 20-year windows represent more immediate realities that could help set policy for greater common good.

In short: GWP is becoming an essential metric in the HVAC/R industry, guiding decisions for refrigerants, which account for over 600 million tons of CO2 equivalent emissions.


OK, so back to what’s happening in New York now

New York was using the 20-year GWP values, which is in accordance with the Intergovernmental Panel on Climate and more direct action around carbon dioxide and emissions. The benefits of using the 20-year model were:

  1. Better assess the short-term climate impact of various refrigerants and prioritize the phase-down of those with the highest GWPs.
  2. Encourage the development and adoption of alternative refrigerants with lower GWPs and shorter atmospheric lifetimes.
  3. Set more effective policies, regulations, and incentives to reduce refrigerant emissions, promote proper management, and minimize leaks and losses from existing systems.

Now, however, they want to shift to a 100-year model. As you can see above, the 100-year model is more accepted by the general business community — but by others as well, including the EPA itself, and this post does a solid job of explaining the benefits of a 100-year model:

There have been proposals for the UNFCCC to adopt a dual-term greenhouse gas accounting standard: 20-year GWPs alongside the presently accepted 100-year GWPs. Because countries set emission goals under a ‘basket of gases’ approach, where the physical emissions of GHGs are weighted by GWPs, shifting GHG reduction goals to be set under 20- year GWPs increases the weighting of short-lived gases in any target. This would have the consequence of significantly increasing the reductions of gases like methane (CH4), or HFC- 134a, compared to CO2 and other long lived GHGs. It is argued that the advantage of such a change would be to more rapidly reduce short term warming and buy time for CO2 reductions.




In sum: we’d increase reduction in methane and HFC-134a, and do less on carbon dioxide co reduction to make our 20-year policy targets. This could create a perverse incentive for businesses and countries to refrain from the deep reductions of CO2 emissions that already have been delayed for far too long.


How can Trakref help you navigate global warming potentials?

Trakref can help organizations better manage their refrigerant usage and minimize environmental impact through real-time data, compliance management, analytics, and education.

Our software allows you to track, manage, and understand your carbon footprint. We also regularly study legislative shifts, the Panel on climate change, each new assessment report, atmospheric concentrations, science best practices, and other metrics and leading voices re: climate change, climate action, and the climate system.

As such, over three decades we’ve become a leader in:

We’d love to help you understand the changing climate around ESG in general and regulatory environments specific to where you operate.


How might the market be changing in the next five years around GWP values and greenhouse gas understanding?

As the concept of carbon competency and literacy gains traction in refrigerant management, the markets are likely to experience several noteworthy changes:

  1. Demand for low-GWP refrigerants (and more training): The increasing emphasis on carbon literacy will drive the demand for low-GWP refrigerants, pushing manufacturers to innovate and develop more sustainable alternatives.
  2. Market differentiation: Companies that successfully incorporate carbon literacy into their decision-making processes and adopt environmentally responsible practices will have a competitive edge, positioning themselves as leaders in sustainability.
  3. Growth of sustainable cooling technologies: With a more profound understanding of the environmental implications of refrigerants, the market will likely see an uptick in the development and adoption of energy-efficient and sustainable cooling solutions.
  4. Regulatory changes: The growing importance of carbon literacy and GWP considerations could lead to stricter regulations and policies governing refrigerant use, pushing the industry to adapt and comply with new environmental standards.
  5. Investor preferences: Environmentally conscious investors may be more inclined to invest in companies that demonstrate a commitment to carbon literacy and responsible refrigerant management, driving capital towards sustainable businesses.
  6. Enhanced corporate reputation: Companies that embrace carbon literacy and take action to reduce their environmental footprint will likely see improved reputations, attracting customers and stakeholders who value sustainability.

We’ll remain here to help guide you — and we’ll keep an eye on New York legislation in the process. If you have any questions about any of this or the calculations and discussions involved, feel free to reach out.


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