The 2021 Glasgow climate conference (COP26) saw the launch of numerous sector-level cooperative initiatives involving national governments and non-state actors. Driven by a push for ambitious commitments on coal, cars, cash, and trees, these initiatives aimed to limit global warming to 1.5°C and achieve net-zero CO2 emissions by 2050. However, questions arose about their effectiveness in substantially contributing to these goals. Previous research highlighted both the potential emission reduction capacity of such initiatives and criticisms regarding their lack of substantive commitment, often fading after the initial COP announcements. Global emissions continue to rise, casting doubt on the initiatives' impact. This study investigates 14 major Glasgow sector initiatives to determine their collective mitigation ambition, institutional robustness, and the extent to which national governments incorporated their targets into updated Nationally Determined Contributions (NDCs). The three research questions addressed are: (i) the potential GHG emission reductions from full implementation; (ii) the institutional robustness of these initiatives; and (iii) the extent to which national governments integrated initiative targets into their post-COP26 NDCs.

Existing research on international climate initiatives presents a mixed view on their effectiveness. While some studies suggest significant emission reduction potential if fully implemented, others criticize a lack of substantive commitment and insufficient follow-through after COP announcements. Several studies have quantitatively and qualitatively assessed NDCs and long-term decarbonization plans at the national level, but few have examined countries' engagements with international cooperative initiatives and their relationship to national targets. This study builds upon prior research evaluating the effectiveness of orchestrated climate action and the emission reduction potential of international cooperative initiatives, addressing the gap in understanding country engagement with these initiatives and their reflection in updated NDCs.

This study assessed 14 Glasgow sector initiatives, including five Glasgow Breakthrough sector initiatives (power, road transport, hydrogen, steel, agriculture), the Global Coal to Clean Power Transition statement, the Powering Past Coal Alliance (PPCA), the No New Coal Compact, the Beyond Oil and Gas Alliance (BOGA), the Accelerating to Zero (A2Z) Coalition, the Clydebank Declaration for green shipping corridors, the International Aviation Climate Ambition Coalition, the Glasgow Leader's Declaration on Forests and Land Use, and the Global Methane Pledge. Data on national government signatories were collected from initiative websites using the Internet Archive for periods ending November 2021 and January 2023. Two scenarios were developed to quantify the potential GHG impact in 2030: the Glasgow Initiatives-Current Signatories (Glasgow-Signatories) scenario, assuming full implementation by current signatories, and the Glasgow Initiatives-Global Ambition (Glasgow-Ambition) scenario, estimating the impact if initiatives were globally implemented. The baseline NDC (BL-NDC) scenario assumed full implementation of existing NDCs and other targets as of mid-2021, while the benchmark 1.5°C (BM-1.5) scenario was based on IEA's Net Zero Emissions by 2050 scenario. Country-specific projections were developed for major emitting countries using data from the IEA and other sources. The study also examined mentions of Glasgow initiatives in updated NDCs submitted between December 2021 and January 2023. Finally, the institutional robustness of the initiatives was assessed using six indicators: secretariat, governance structure, budget, openness of membership, monitoring, and publications. Data for this assessment was collected using the Climate Cooperative Initiatives Database (C-CID).

The analysis revealed significant variations in national government participation across initiatives. The Glasgow Forests Declaration and Global Methane Pledge had relatively high global emission coverage among signatories. However, major emitters like China and India had limited participation in many initiatives. The highest participation came from high-income G7 countries and EU member states, suggesting a correlation between participation and capacity to achieve goals. The Global Methane Pledge showed a considerable increase in signatories post-COP26, while other Breakthrough initiatives saw varying levels of engagement in subsequent priority actions. The Glasgow-Signatories scenario, assuming full implementation by current signatories, projects emission reductions filling only about a quarter of the 2030 emissions gap, while the Glasgow-Ambition scenario projects filling around 65% of the gap if globally implemented. The land-use sector had the largest reduction potential in the Glasgow-Signatories scenario. Analysis of updated NDCs revealed that most national government signatories did not mention Glasgow initiatives in their submissions, with only the UK referencing all initiatives. The assessment of institutional robustness revealed significant gaps, particularly regarding budget transparency, clarity on membership arrangements, and monitoring frameworks for some initiatives. Several initiatives lacked clear implementation mechanisms beyond initial declarations. Initiatives with more robust institutional arrangements, such as the PPCA, Global Methane Pledge, and Glasgow Breakthroughs in various sectors, showed higher potential for success.

The findings indicate that while the Glasgow initiatives show promise in accelerating low-carbon transitions, their current contributions to closing the 2030 emissions gap are limited due to factors such as insufficient participation by major emitters, limited follow-up action in updated NDCs, and varying levels of institutional robustness. The limited emission reduction potential in the Glasgow-Signatories scenario partly stems from the fact that many signatory countries already had equally ambitious sector targets in their NDCs. The significant number of declarative initiatives without robust implementation mechanisms further hampers their impact. The study highlights the importance of broader participation, particularly from major emitters, and integration of initiative goals into national commitments for achieving greater impact. Initiatives with strong institutional capacity are better positioned to deliver emission reductions.

The Glasgow initiatives represent a significant effort to accelerate climate action, but their effectiveness hinges on increased participation, stronger national commitments reflected in updated NDCs, and improved institutional robustness. Future research should investigate implementation progress, assess the impact of subnational and corporate actors, and examine the broader implications of these initiatives for global climate governance. Three key policy recommendations include: expanding national government participation, integrating initiative goals into enhanced NDCs, and improving governance and transparency for all initiatives, particularly those of a declarative nature. The development of integrity standards and accountability mechanisms will be crucial for preventing inflated expectations and ensuring the credibility of future climate initiatives.

This study focuses on the potential GHG emission impact based on national government participation and its effects on territorial emissions, neglecting the broader political and economic impacts beyond national borders. The analysis does not encompass all GHG-emitting sectors or initiatives launched around COP26, and it primarily focuses on target ambition and institutional robustness rather than implementation details. Furthermore, the absence of a country from an initiative does not indicate a lack of climate ambition, as demonstrated by alternative approaches like South Africa's Just Energy Transition Partnership.