Mitigation Research

Opportunity Green: Top Climate Nonprofit Evaluation

Summary

What is Opportunity Green?

Opportunity Green is a UK-based nonprofit organization using legal, policy, and economic frameworks to advance climate action. It has historically focused on reducing emissions from aviation and maritime shipping, while seeking avenues that also deliver environmental justice co-benefits. It has more recently expanded its work to include other high-impact and neglected sectors, such as agriculture and steel.

How could Opportunity Green address climate change?

Most of Opportunity Green’s work to date has focused on reducing emissions from aviation and maritime shipping, incorporating four main strategies: 1) supporting contributions from climate-vulnerable countries in international policy discussions, 2) advocating for ambitious policies and regulations in the EU, 3) identifying and pursuing strategic legal action to influence policy, financial institutions, and industry, and 4) facilitating a private-sector coalition to promote hydrogen-based heavy transport. Opportunity Green’s advocacy efforts focus on accelerating the commercialization of low-carbon fleets and fuels, as well as reducing contrail emissions from aviation.

What is Opportunity Green’s cost-effectiveness?

In 2024, we developed a highly subjective cost-effectiveness analysis (CEA) to estimate the costs and impacts of Opportunity Green’s engagement with the IMO to enact regulations that decarbonize international shipping. Overall, we estimate it could plausibly be within the range of cost-effectiveness we would consider for a top nonprofit. We have low confidence in the accuracy of this CEA, and an analysis focused on Opportunity Green’s IMO engagement is unlikely to generalize to its overall cost-effectiveness. However, we generally view it as a positive input to our overall assessment of Opportunity Green.

Is there room for more funding?

Opportunity Green could use additional funding to increase staff capacity across its aviation and shipping programs. Alongside its ongoing work to strengthen international climate diplomacy, Opportunity Green would prepare for upcoming policy opportunities in the EU, including discussions to expand the EU Emissions Trading Scheme and regulate contrail emissions. Opportunity Green is also developing emerging workstreams in new areas such as addressing emissions from steel manufacturing, data centers, and agriculture. To support its expanding programs, Opportunity Green also wants to hire staff to increase its analytics, diplomacy, communications, and operational capacity.

Are there major co-benefits or potential risks?

We think Opportunity Green’s co-benefits and potential risks are tied to the technologies it advocates for. For example, co-benefits of green hydrogen-derived alternative fuels include lower air pollution and technological spillover to other low-carbon technologies, and potential risks include high energy demand and toxicity risks (for e-ammonia). See our strategy reports for reducing aviation and maritime shipping emissions for more information.

What are the key uncertainties and open questions?

Our key uncertainties include Opportunity Green’s organizational effectiveness in new impact areas, the scalability of aviation e-fuels, the effectiveness of international diplomacy across sectors, potential difficulties attracting industry members to a coalition with ambitious climate targets, and the technical feasibility of decarbonizing aviation.

What is the bottom line and what are the next steps?

We classify Opportunity Green as one of our Top Climate Nonprofits addressing climate change. We think Opportunity Green’s interdisciplinary expertise fills valuable gaps in the nonprofit advocacy ecosystem for the hard-to-abate aviation and maritime shipping sectors. It also has a compelling and impactful theory of change that leverages multiple pathways of influence, including coalition and capacity building, policy advocacy, and legal action. Opportunity Green has robust growth plans and the ability to utilize significant additional funding.

Donors interested in supporting their work can do so by donating to the Giving Green Fund or by making a direct donation to Opportunity Green.

Opportunity Green is a UK-based nonprofit. This non-partisan analysis (study or research) is provided for educational purposes. Unless otherwise cited, information in this evaluation comes from direct correspondence with Opportunity Green.

Questions and comments are welcome at hello@givinggreen.earth.

Key ideas: Opportunity Green’s Strategies
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Opportunity Green invokes four main strategies to reduce greenhouse gases from aviation and shipping:
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1. Increasing representation from climate-vulnerable countries at international regulatory bodies, such as the International Maritime Organization and the International Civil Aviation Organization, to promote more progressive policies.
2. Advocating for ambitious policies and regulations in the EU. For example, policies to mitigate contrail emissions, strengthen the EU Emissions Trading Scheme, and accelerate the commercialization of green hydrogen and hydrogen-based fuels.
3. Identifying and pursuing strategic legal action to influence policy frameworks, financial institutions, and industry.
4. Facilitating a private sector coalition to promote low-carbon fuels and zero-emission vessels based on green hydrogen.

Opportunity Green’s Strategies

Increasing Representation of Climate-Vulnerable Countries at International Fora to Promote More Progressive Policies

The International Maritime Organization (IMO) is a UN agency that regulates shipping globally and is considered an effective and comprehensive vehicle for establishing ambitious emissions standards.¹ The IMO has signaled ambitions to reach net-zero emissions by 2050 through its sector targets, but it has not enacted sufficient enabling policies to achieve this target.²

Opportunity Green believes that to align with international climate targets, the IMO needs to incorporate stronger regulations, standards, and commitments.³ Currently, Opportunity Green is working on negotiations for the IMO’s Net Zero Framework, on which members are due to vote in 2026. This work includes building support for the framework and raising the climate impact of regulations through advocacy for strong fuel intensity standards, revenue generation mechanisms, and life-cycle accounting methodologies.⁴

Opportunity Green aims to influence the IMO to set more ambitious targets by helping climate-vulnerable countries gain more representation and participation in IMO activities. Opportunity Green has begun capacity building by engaging with countries that have (i) historically been absent from IMO convenings and (ii) are disproportionately affected by climate change, such as Small Island Developing States (SIDS).⁵ For example, in 2025, it supported Costa Rica to make its first plenary intervention in five years.

Opportunity Green claims that because these countries feel climate change more acutely, despite accounting for very few emissions, they tend to support more progressive international policies; they especially favor policies that substantially reduce emissions from the Global North and generate climate finance for adaptation.⁶ It thinks that increasing the number of progressive voices could help move the moderate block. Opportunity Green also works with EU Member States to increase their support for policies supported by climate-vulnerable countries at the IMO, and facilitates research on the benefits of using revenues generated from shipping levies to support climate-vulnerable countries.

As part of this work, Opportunity Green has filed a submission to the International Tribunal for the Law of the Sea (ITLOS) in support of the Commission of Small Island States’ (COSIS’s) request for the Tribunal to clarify States’ obligation to protect the marine environment from pollution, asking it to recognize countries’ obligations to regulate shipping and aviation emissions in line with climate goals to limit the global temperature increase to 1.5°C.⁷ The Tribunal released an advisory opinion in May 2024 that was broadly in line with the submission made by Opportunity Green. Opportunity Green also made a similar submission to the International Court of Justice, which was also reflected in the Court’s opinion. Opportunity Green is now working with aviation and shipping policymakers to ensure they understand the full legal implications of this decision, such as by supporting some climate-vulnerable countries in their submissions to the IMO on this topic.⁸ The advisory opinions also open avenues for future climate litigation, such as challenges against national governments.

In addition to IMO representation, Opportunity Green is ramping up similar work to empower climate-vulnerable countries in the International Civil Aviation Organization (ICAO).

Advocating for Ambitious EU Policy

In 2024, Opportunity Green opened its Brussels office to deepen its EU policy engagement. The EU is an important strategic region for aviation and shipping policies because its regulations are arguably the most ambitious in the world.⁹ Opportunity Green’s policy advocacy works in tandem with its other strategies, such as its legal challenge against the European Commission’s green investment taxonomy and hosting SASHA Coalition events at the European Parliament.

Opportunity Green also plans to use its presence in Ireland to influence the EU’s 2026 Irish presidency, which coincides with planned discussions to revise the EU’s aviation ETS. The Presidency of the EU is also the first EU member state to speak in the IMO, making it important to ensure that Ireland’s position remains ambitious in 2026. Opportunity Green also plans to advocate to expand the ETS so that it includes 1) flights departing from the EU, which would increase the CO₂ emissions covered by the ETS from 60 MtCO₂ per year to almost 150 MtCO₂ per year, and 2) non-CO₂ emissions, mostly from contrails, which are at least as significant as aviation’s CO₂ emissions.¹⁰ Opportunity Green claims to be the first nonprofit in Ireland working to reduce aviation emissions, and we think it could be an important voice that is well-positioned to contribute to discussions on the ETS revision.

Identifying and Pursuing Strategic Legal Action

Opportunity Green sees litigation and non-judicial legal action and legal advocacy as complements to policy advocacy, especially for sectors where policy efforts have lagged. It claims that climate litigation, legal action, and advocacy have historically focused on governments and that increasing legal pressure on corporations is important. Opportunity Green has defined the scope of its legal strategy as “cases that seek broader systemic outcomes and social impacts, in contrast to traditional litigation that prioritises the immediate aims of an individual claim.”

Opportunity Green identified aviation, shipping, steel, agriculture, and finance as key sectors for strategic climate legal action. As an example, it identified aviation as a key sector for the following reasons:

The International Civil Aviation Organization (ICAO), the entity tasked with governing aviation internationally, is not considered an effective lever for standards setting or implementation.¹¹
Without strong global policies, countries are less likely to take action independently, given the sector's inherently international nature.
A legal victory against one major multinational corporation in the private sector could significantly impact the entire industry.
Aviation’s direct client-facing nature makes reputational damage a powerful lever to influence industry behavior change.

In 2024, Opportunity Green and four other NGOs launched a legal case against the EU Taxonomy rules for aviation and shipping.¹² The Taxonomy rules, as currently drafted, would give a ‘green’ label to ships and planes that run on fossil fuels, raising concerns over greenwashing. While it could take a couple of years for the case to reach a final decision, Opportunity Green claims that it has already had an impact, through 1) increasing investor uncertainty and reducing their likelihood of investing in fossil fuel transportation projects, and 2) causing other governments to establish stricter Taxonomy rules to avoid the risk of legal challenge.

Opportunity Green has also undertaken legal work in the maritime shipping sector and has conducted a similar scoping exercise to identify potentially impactful legal actions. In 2023, it compiled a report highlighting the cruise industry’s misleading claims about the climate benefits of LNG and filed complaints with the UK’s Advertising Standards Authority (ASA).¹³ The overall purpose was to delegitimize investment in LNG as a ‘transitional’ fuel in the shipping industry. As a result, the ASA ruled that advertising LNG as “eco-friendly” constitutes greenwashing and required MSC Cruises to recall its adverts. More recently, it has begun working to highlight the human rights impacts of pollution in ports caused by shipping emissions.

Facilitating a Private-Sector Coalition to Promote Hydrogen-Based Fuels

Opportunity Green established the Skies and Seas Hydrogen-fuels Accelerator (SASHA) Coalition to unite companies across maritime shipping, aviation, and alternative fuel production to advocate for policies that facilitate the commercial-scale production of ships, aircraft, and fuels based on green hydrogen. For example, this includes ships using e-ammonia or e-methanol, and aircraft powered by e-sustainable aviation fuels (e-SAFs) or hydrogen.¹⁴ Policy goals include increasing the ambition level of e-fuel targets in EU climate regulations (the Fit for 55 package) and ensuring safeguards against reliance on biofuels and liquified natural gas (LNG).¹⁵ To achieve these goals, Opportunity Green facilitates meetings between SASHA members and policymakers and coordinates the drafting of public and private letters.

SASHA was established in 2023, focusing on U.K. and EU companies and policy. As of October 2025, the coalition has 16 members, including industry leaders such as ZeroAvia. The Sustainable Shipping Initiative, Zero Emissions Ship Technology Association, PtX Lab Lausitz, and the Green Hydrogen Organisation have also joined as knowledge partners. In 2024, the SASHA Coalition co-hosted its first Parliamentary event, along with two members of the European Parliament.

Opportunity Green is also undertaking exploratory work related to steel, data center, and agricultural emissions. We have not assessed these workstreams.

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¹“The global scope of the IMO presents a unique opportunity to develop consistent, comprehensive global policy solutions for decarbonization.” Global Maritime Forum, 2022

²Taken in combination with the revision of IMO’s short-term measures (carbon intensity indicators), which have been extended with new increases in stringency to 2030, the new policy is only expected to achieve approximately 10% absolute GHG emission reductions relative to 2008 GHG emissions. This is significantly lower than the ‘at least 20%’, ‘striving for 30%’ that the IMO committed to in the Revised GHG Strategy in 2023.” Smith et al., 2025

³“The IMO’s strategy isn’t currently binding, and it lacks specific measures to achieve its stated targets. Nevertheless, it represents significant progress from previous positions. However, the absence of alignment with the 1.5° C target is a major shortfall.” ClimateWorks, 2023

⁴Section: Key areas for further ambition Opportunity Green, 2025

⁵“Opportunity Green has particular expertise in shipping policy at the international level. It specifically works with climate vulnerable countries, who are traditionally under-resourced and underrepresented at the International Maritime Organization (“IMO”), providing them with briefing notes, facilitating information sharing and networking events and hosting bilateral meetings as required to help in the preparation of countries’ positions.” Opportunity Green, 2023

⁶“This raises intriguing questions about how these divergent approaches will unfold. Fuel standard measures and pollution levies are of high interest to many countries because they can generate climate finance for adaptation and mitigation in countries most impacted by climate change. However, those countries aren’t necessarily in the room to help make those decisions.” ClimateWorks, 2023

⁷The International Tribunal for the Law of the Sea (ITLOS) is an independent judicial body established by the 1982 United Nations Convention on the Law of the Sea. The Commission of Small Island States on Climate Change and International Law (COSIS) is a UN commission with a mandate to “to promote and contribute to the definition, implementation, and progressive development of rules and principles of international law concerning climate change, including, but not limited to, the obligations of States relating to the protection and preservation of the marine environment and their responsibility for injuries arising from internationally wrongful acts in respect of the breach of such obligations.”

⁸See Publication: ITLOS advisory opinion — Opportunity Green for Opportunity Green’s briefing on this topic.

⁹Example regulations include the EU’s emissions trading scheme, ReFuelEU aviation mandate, and FuelEU Maritime initiative

¹⁰ Figure 2: Aviation CO₂ emissions for intra-EEA flights (current EU ETS scope) and all EEA departing flights (possible scope extension) CE Delft, 2024; “The climate impact of aviation's non-CO₂ effects is at least as important as the impact of aviation's CO₂.” T&E, n.d. (accessed September 3, 2025)

¹¹“In the past few years ICAO has faced criticism and been seen rightly or wrongly as an outlier even in the UN system for its lack of transparency in decision-making, its lack of access to information by the media, undue influence of industry (“captured by producer interests”: The Economist), restricted involvement of civil society and independent scientists, and its political interference in the culture and workings of the Secretariat.” Centre for Aviation, 2021

¹²“Five NGOs – Fossielvrij, Protect our Winters, Dryade, CLAW and Opportunity Green – have launched a legal challenge against the European Commission, requesting it to review its green investment rules on aviation and shipping. This is the first step in the challenge which may lead to court action before the European Court of Justice if the Commission does not address the legal issues raised.” Opportunity Green, 2024

¹³“As a result of the findings in the report, Opportunity Green has also filed a series of complaints to the UK’s Advertising Standards Authority (ASA) against some of the biggest international cruise companies to try to put an end to this apparent LNG greenwashing, which is potentially misleading consumers.” Opportunity Green, 2023

¹⁴We use e-SAFs to refer to sustainable aviation fuels (SAFs) that are produced using green hydrogen and sustainable CO₂.

¹⁵ The Fit for 55 package is an EU-level policy which aims to reduce the EU’s emissions by 55% by 2030; it contains the FuelEU maritime shipping and aviation initiatives targeted toward increasing the use of sustainable fuels.

Opportunity Green uses several levers to accelerate climate policy: 1) Supporting climate-vulnerable countries to increase the ambition of IMO and ICAO regulations, 2) direct advocacy with EU policymakers, 3) using legal challenges to deter policy and industry from actions that do not align with their stated climate goals, and 4) facilitating a private-sector coalition to promote green hydrogen fuels.

The main outcomes of Opportunity Green’s work include stronger regulatory frameworks to reduce aviation and shipping emissions from the IMO, ICAO, and the EU, as well as increased funding for innovation in low-carbon fuels and vessels. We see an enabling policy environment as a key lever in our theory of change for Opportunity Green, as it shapes the actions of the aviation and shipping industries. Key assumptions behind this model are examined in the following section.

Figure 1: Theory of Change diagram for Opportunity Green

Examining the Assumptions Behind Opportunity Green’s Theory of Change

Below, we discuss and evaluate the main assumptions related to Opportunity Green’s theory of change. For each of the assumptions, we rank whether we have low, medium, or high certainty about the assumption.¹⁶ Our assessment is based on both primary and secondary evidence, as well as our general impression of the plausibility of the assumption. Importantly, a number of the stages of Opportunity Green’s theory of change may not be amenable to easy measurement or quantification, are not supported by a robust evidence base, or are expected to occur in the future but have not occurred yet.

Increased participation of underrepresented, climate-vulnerable countries leads to more ambitious IMO policy. (medium certainty)

We think that increasing the participation of underrepresented, climate-vulnerable countries could increase pressure to implement policies and regulations in line with the IMO’s 2050 net-zero target.¹⁷ Opportunity Green claims that small countries have historically achieved outsized impacts. For example, it gives the Pacific Island States most of the credit for the IMO’s recent adoption of ambitious decarbonization targets in July 2023.¹⁸ Additionally, in May 2024, the International Tribunal for the Law of the Sea (ITLOS) issued a unanimous ruling on the request submitted by the Commission of Small Island States on Climate Change and International Law, affirming that “States Parties to the [United Nations Convention on the Law of the Sea] have the specific obligations to take all necessary measures to prevent, reduce and control marine pollution from anthropogenic GHG emissions and to endeavor to harmonize their policies in this connection.”¹⁹

However, the countries with which Opportunity Green has stronger engagement are relatively new to IMO negotiations. Our impression is that they are less likely to be drivers of highly ambitious regulation, but that their support for motions proposed by other countries is still likely to be significant in shifting the outcomes of negotiations to be more aligned with emissions targets.

Furthermore, climate-vulnerable countries tend to be less wealthy and can be vulnerable to retaliatory measures if they oppose key powerful allies. This vulnerability could stifle their ambition. For example, the U.S. was accused of pressuring countries at the IMO’s convening in October 2025, with reported threats of visa ramifications and tariffs, leading countries to change their previously held positions and vote to delay the Net Zero Framework.²⁰

SASHA can influence the adoption of ambitious policies for sustainable fuels. (medium certainty)

We believe that coalitions can be a powerful form of political advocacy, especially when involving the private sector. One of SASHA’s first initiatives was to produce an in-depth report demonstrating that insubstantial policy support of green hydrogen has slowed demand and investment. We think this analysis helps build the case for policy intervention and is an important resource for potential new members. SASHA has also gained allies in the European Parliament and co-hosted its first parliamentary event with two MEPs in 2025.²¹

Opportunity Green expressed that it plans to ensure that SASHA promotes ambitious targets and policies, and that companies must align with these levels to be considered for membership. We think that if SASHA’s size and influence grow, it will be well-positioned to encourage other industry actors to support more progressive policies. However, if ambition levels are too high, especially in the absence of a successful track record, SASHA may struggle to attract members. We are cautiously optimistic given (i) the growing number of relevant climate tech start-ups and (ii) the seemingly relatively progressive nature of these startups relative to more established companies.

Strategic litigation can substantially influence policy and industry to accelerate transition. (medium certainty)

Giving Green has historically been skeptical regarding the effectiveness of legal action as a climate intervention. However, we think that Opportunity Green’s legal strategy takes a comprehensive, impact-centered approach that could lead to strong outcomes. Prior to starting work, Opportunity Green conducts an in-depth analysis and ranking of possible legal strategies to identify feasible approaches that can influence large-scale emissions. We think Opportunity Green’s experience across legal, policy, and the private sector gives it insight into the likely effectiveness of possible strategies.

Additionally, we think that Opportunity Green’s legal expertise adds a unique angle to the existing advocacy arguments in shipping and aviation, since most organizations we have encountered do not have in-house legal teams. The IMO’s Civil Society Advisor has cited Opportunity Green as the only organization providing legal analysis in the broader shipping decarbonization dialogue.²²

We are encouraged by the progress of Opportunity Green’s legal strategies thus far. For example, the accepted ruling against greenwashing by cruise ships and its challenge against the EU’s green investment taxonomy, which is still in progress, but has shown some promising signals. Opportunity Green’s legal cases have garnered media attention from major news outlets, which we think signals they have the potential to influence climate discourse at large.²³ However, we are unsure how this will influence concrete decisions by policymakers and industry players. We will update our assessment as Opportunity Green progresses with its legal strategy.

Low-carbon shipping can become cost-competitive with conventional shipping. (medium certainty)

Although the current green premium remains a barrier to the adoption of low-carbon technologies, we think that a combination of declining costs resulting from commercialization and increasing regulatory pressure on fossil fuel prices could plausibly lead to price parity between conventional and green technologies. In fact, estimates for e-fuel parity range from 2030 to 2040.²⁴ Notably, under existing EU regulations, e-ammonia ships built today could already achieve cost competitiveness over their lifetime compared to conventional vessels.²⁵ We see policy as a key lever to incentivize industry investment in low-carbon shipping technologies.

We think reducing costs for low-carbon shipping depends heavily on scaling renewable energy, increasing the availability of green hydrogen, and building out global e-fuel infrastructure. Given cross-sector demand and the uptick in supply-side hydrogen policies, we have medium certainty that green hydrogen can become cost-competitive and be scaled as a feedstock for these fuels.

Policies set by the IMO and national regulations will influence the private sector to transition to low-carbon technology. (medium certainty)

We think government advocacy is a necessary lever to influence private-sector decarbonization trends. For example, pricing emissions can narrow the green premium for low-carbon shipping technology, thereby improving the business case for low-carbon technologies like e-fuels.

Furthermore, well-designed policies with ambitious targets, like the FuelEU Maritime initiative, can provide long-term market signals to reduce investor uncertainty. The IMO’s proposed fuel intensity targets have been credited for giving a clear signal towards low-carbon fuels—meaning that incremental solutions are unlikely to remain competitive in the mid/late 2030s—but there remains uncertainty regarding their ambition levels, which may lead some investors to take a wait-and-see approach.²⁶

While the industry is still at the relatively early stages of its transition, strong policy signals can reduce the risk of locking into infrastructure that uses transitional or conventional fuels, such as biofuels and LNG, that are cheaper and more mature than e-fuels but have less mitigation potential.²⁷ Reducing the risk of lock-in is especially important given the long lifetime of shipping vessels (several decades).²⁸

The IMO’s global role in international coordination also reduces the risk of carbon leakage, where firms shift activity to avoid stricter national or regional rules. Harmonized regulations ensure a level playing field across the sector, increasing the certainty of demand for low-carbon technology.

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¹⁶We describe our certainty as low/medium/high to increase readability and avoid false precision. Since these terms can be interpreted differently, we use rough heuristics to define them as percentage likelihoods the assumption is, on average, correct. Low = 0-60%, medium = 60-80%, high = 80-100%

¹⁷“This Strategy sets clear targets and actions to decarbonize international shipping: Net-zero GHG emissions from international shipping by or around, i.e. close to 2050.” IMO, 2023

¹⁸“[O]ur team knows that the final outcome we got could have been much weaker. The fact that it wasn’t is mostly thanks to the immense diplomatic effort and tireless work of the Pacific Island nations and other ambitious Member States” Opportunity Green, 2023

¹⁹“Under article 194, paragraph 1, of the Convention, States Parties to the Convention have the specific obligations to take all necessary measures to prevent, reduce and control marine pollution from anthropogenic GHG emissions and to endeavour to harmonize their policies in this connection. “ ITLOS, 2024

²⁰“US officials were accused of “bullying” and “intimidation”, as nations met in London for what should have been the rubber-stamping of a decision made months ago to place a small levy on the greenhouse gases from global shipping.” The Guardian, 2025; Minutes 23 to 26, Cleaning Up Podcast, 2025

²¹“In early July, we were thrilled to be hosted by MEP Gerbran-Jan Gerbrandy and MEP Jan-Christoph Oetjen at the European Parliament for our event on delivering on EU mandates and scaling e-fuels for shipping and aviation decarbonisation.” SASHA Coalition, 2025

²²“for their timely and pointed legal analysis (which no other organisations provide)” Andrew Friedman, quoted in Opportunity Green, 2025

²³For example, features in Forbes, the Guardian, Euractiv, Financial Times, and The Independent.

²⁴ “Some estimates show that such policy support could help achieve price parity between green ammonia and current fossil fuels between 2030 and 2035.” ClimateWorks, 2025; Fuel production cost estimates and assumptions. Lloyd’s Register, 2019

²⁵ “All three ammonia fueled ships evaluated were able to comply with or outperform the new FuelEU Maritime targets at a cost equal to or below that of a conventional heavy fuel oil powered ship.” CATF, 2024

²⁶ “The introduction of a fuel intensity target (base GFI), which sets to decrease by at least 65% by 2040, means that incremental solutions are unlikely to remain competitive in the mid/late 2030s” “This raises concerns about whether the fund will be able to simultaneously support early deployment of ZNZs and deliver the promised support for a just and equitable transition. This may therefore lead to a cautious, wait-and-see approach.” IDDRI, 2025

²⁷“If investors expect pressure to reduce carbon emissions (regulatory or otherwise) to be delayed or weak, transition pathways that can make use of mature but less-scalable or sustainable elements (e.g., bioenergy, LNG) may gain an advantage. If expectations are that the speed of the transition will be in line with the 1.5-degree pathway described in Chapter 1, then these pathways may feature risks of disruption and stranded assets.” UMAS, 2021

²⁸ “Given that the life of shipping investment spans over several decades, there is therefore a risk of carbon lock-in and/or stranded assets to public and private investors in the sector.” IDDRI, 2025

In 2024, as a rough plausibility check, we developed a cost-effectiveness analysis (CEA) to estimate the costs and impacts of Opportunity Green’s work with the IMO to enact regulations that decarbonize international shipping. We chose to model this subset of Opportunity Green's work because we think a CEA covering all of Opportunity Green's work would include too many uncertain parameters to have confidence in the results. Focusing this CEA on Opportunity Green's work with the IMO is unlikely to be generalizable to Opportunity Green's overall cost-effectiveness, and given the highly subjective guess parameters used in this CEA, we have low confidence in its accuracy. Since we use CEAs only as a rough plausibility check, we opted not to spend more time reducing these uncertainties.

Despite the narrow focus of this CEA, it includes highly subjective guess parameters and should not be taken literally. In particular, we estimated:

The number of years that Opportunity Green’s advocacy has brought forward the adoption of ambitious regulations.

The relative increase in ambition levels of IMO regulations due to advocacy.

The likelihood of achieving ambitious regulations as a result of increased participation of climate-vulnerable countries and the ITLOS ruling.

The extent to which the changes in these likelihoods can be attributed to Opportunity Green.

Overall, we think Opportunity Green could plausibly be within the range of cost-effectiveness we would consider for a Top Climate Nonprofit. We have low confidence in our CEA's ability to estimate Opportunity Green’s general cost-effectiveness, but view it as a slightly positive input into our overall assessment of Opportunity Green. See below for a high-level explanation and the model for additional notes and citations.

Costs: Based on its 2023 spending, we estimated Opportunity Green’s spending on IMO workstreams at around $575,000.

Avoided emissions: We compared the shipping sector's cumulative emissions from 2025 to 2050 under two scenarios with different ambition levels. The high-ambition scenario assumes that IMO enacts sufficient regulations in 2025 to meet its decarbonization plan, while the BAU scenario is a counterfactual scenario in which regulations are enacted but are insufficient to meet IMO's decarbonization targets. We assumed that regulations for the BAU scenario catch up to the high-ambition regulations within ten years due to future increases in political momentum and technological capabilities for green shipping.

Effectiveness: We assumed that support for high-ambition regulations in the IMO would increase because of the 1) greater participation of climate-vulnerable countries in negotiations and 2) greater likelihood of a favorable ruling from ITLOS in favor of COSIS’s submission. We then assigned Opportunity Green a degree of influence for these results. We estimated Opportunity Green’s expected emissions mitigation by multiplying the emissions reductions from adopting more ambitious regulations by the change in the probability of adoption due to Opportunity Green.‍

Results: Our best guess is that Opportunity Green’s IMO advocacy will avoid one tCO₂e for around $0.76 (range: $0.03-$7.70).

Organizational effectiveness in new impact areas: Opportunity Green plans to expand its work into new impact areas such as green finance, agriculture, and data centers. It selected these impact areas through a detailed scoping exercise, analyzing the potential impact of transferable tactics from its current work, as well as considering nexus points with existing sectoral work (such as the use of green hydrogen across agriculture, aviation, and shipping). We are unsure how the scale of impact will translate from heavy transport to these new sectors and whether Opportunity Green’s technical expertise will translate easily to these sectors. We will update our assessment as Opportunity Green solidifies and implements its strategies in these new areas.

Effectiveness of international diplomacy across sectors: We think the effectiveness of intergovernmental organizations varies widely across sectors, depending on factors like the ambition levels of their secretariat, the funding need of the NGO advocacy ecosystem, the enforcement mechanisms of agreements, and the strength of incumbent lobbies. We think the IMO is among the strongest of these organizations, even with recent setbacks in adopting its proposed Net Zero Framework. In contrast, ICAO is not considered a key political lever by most advocacy groups. Opportunity Green also aims to expand its international diplomacy work, targeting the Food and Agriculture Organization (FAO) as an advocacy lever. We are unsure whether the FAO will be amenable to advocacy and whether its work will result in large-scale emission reductions, given that it has been criticized for falsely minimizing the impact of emissions-intensive agricultural practices such as livestock farming.³¹

Scalability of e-SAFs: As discussed in our aviation strategy report, we have some hesitations about whether e-SAFs can scale and deliver deep emissions reductions given their high cost and energy intensity. Electricity demand for using e-SAFs to fuel 2019’s aviation demand is as high as 24-39% of the world’s 2019 grid, and with costs 3.1-6.7 times as much as using kerosene.³² While e-SAFs are a major part of Opportunity Green’s aviation campaigns, the organization also works on other pathways to reduce aviation emissions, such as ZEAs, market-based regulations, and contrail mitigation.

Industry coalition strength: Opportunity Green seeks to ensure that SASHA coalition members share ambitious policy goals. We think a high ambition level could reduce the coalition’s size and influence, especially if it excludes more established industry players. As SASHA membership expands, we will have more information to assess its progress and standing.‍

Feasibility of decarbonizing aviation: Aviation is one of the most difficult sectors to decarbonize, as there is no clear, viable technological pathway. We believe that Opportunity Green’s multifaceted strategy to promote multiple pathways to reduce aviation emissions is pragmatic, but it is still possible that none of these approaches will be able to significantly reduce aviation emissions. In this scenario, the aviation sector may not fully decarbonize and could instead rely on carbon dioxide removal to compensate for significant unabated emissions.

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³¹“The livestock industry is essential for food security and economic development, according to a draft report by the United Nations’ Food and Agricultural Organization (FAO) that reinforces its defence of practices in the emissions-heavy sector in recent years. Former and current FAO officials and academics have criticised the document, seen by Climate Home News, for pro-industry bias, cherry-picking data and even “disinformation” about the environmental impacts of animal farming.” Climate Home News, 2024

³²Line: Power-to-liquid, RECCE tool AIA, 2022

Opportunity Green: Top Climate Nonprofit Evaluation

Summary

What is Opportunity Green?

How Could Opportunity Green Reduce Greenhouse Gases?

Opportunity Green’s Theory of Change

What is Opportunity Green’s Cost-Effectiveness?

Is There Room for More Funding?

Are There Major Co-Benefits or Potential Risks?

Key Uncertainties and Open Questions

Bottom Line and Next Steps

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