For the past Strategic Plan, Sixth National Reports showed effective delivery of fewer than half of the contents of our sample of 58 NBSAPs. Furthermore, across our sample of CBD Parties, there was a marked decline in the number of commitments along each stage of the analysis: planned, action-reported and implemented. Moreover, a large proportion was not reported: 44% of planned activities with a completion date before 2020 did not appear in National Reports. Further, some actions that did appear in National Reports came with a report that no steps had been taken towards achieving them. Finally, not all actions undertaken were reported as effective by the Parties. This evidence, alongside other evidence that international ambition for biodiversity conservation has been too low^24,25, and the insufficient capacity to deliver on NBSAPs²⁶, helps explain why the Aichi Targets were not met⁴.

Where there is little evidence for implementation successes (especially where commitments have been reported as abandoned, unfinished or ineffective), we can infer that the barriers to achieving conservation goals have impacted progress in different ways. For example, the widespread reporting of commitments towards Target 4 (Sustainable Production and Consumption) as ineffective (or their omission from National Reports) may have arisen from the relatively low governmental priority that NBSAPs hold in many countries compared to other sectors like agriculture or industry. These sectors can have considerable influence on NBSAP formulation and implementation, but the government departments responsible for NBSAPs have little or no control over them²⁷. Additionally, entities in the private sector, especially transnational corporations, hold stewardship over much of the world’s resource production and its associated impacts on biodversity. Insufficient engagement of national strategies with these bodies means it may have been difficult to achieve and track many of the commitments made towards this Aichi Target²⁸. Finally, it has been previously suggested (using an analysis of commitments towards the Aichi Targets) that where commitments challenge institutional norms and historic governance, they are less likely to be effectively implemented⁹. Whilst this is not necessarily the full explanation of why targets such as Target 2 (Mainstreaming), Target 18 (Traditional Knowledge), and Target 20 (Resource Mobilisation) are among those targets with proportionally few reports of effective commitment implementation, it should be noted that commitments towards such targets may require additional support and cross-sector prioritisation if they are to succeed in the future. Some research has linked overall progress towards the Aichi Targets to their “SMART” characteristics²⁹: targets with more specific, measurable, ambitious, realistic, and time-bound characteristics were found to be more likely to be associated with higher levels of linked indicators. The results of this analysis are mirrored, in part, by our findings. Notably, Targets under Goal C (11, 12 and 13) were classified as having the most SMART characteristics; they were also all in the top 5 most effectively implemented Targets in this analysis. However, this was not universally the case, perhaps linked to the fact that in many national-level translations of the Aichi Targets, wordings were altered, potentially with different SMART characteristics.

This analysis provided further evidence that some Aichi Targets were harder to achieve at a national level than others, such as 9 (Invasive Alien Species) and 20 (Resource Mobilisation). For each of these, inferences can be made as to why reported national delivery was, on average, poorer. Target 9 (Invasive Alien Species) was predicated on high scientific and technical capacity both for their implementation and monitoring³⁰; given the variability of this capacity across Parties, such requirements are likely to have contributed to reported variation in achievement. Target 20 (Resource Mobilisation) relied on buy-in from national and international funding sources, including national treasuries. This means that often, monetary resources were limited by shifting national priorities and international conservation interests⁹. The parts of the new Kunming-Montreal Global Biodiversity Framework that engage other sectors and stakeholders will therefore be crucial to effective monitoring and implementation.

The lower proportion of commitments related to Aichi Target 9 (Invasive Species) reported as successful by Parties in the low HDI group suggests that difficulties arose in areas where financial and technical capacity may be lower when carrying out and monitoring the effects of commitments towards this Aichi Target. Evidence suggests that this may be a particular problem for the implementation of Aichi Target 9 (Invasive Alien Species), which requires high technical and scientific capacity for effective monitoring and control of invasive alien species (IAS)³⁰. Benefits could be derived from additional support in IAS-based commitments in lower-HDI Parties for both national-level achievement and overall global ambition³¹.

Broadly, commitments to Targets under Strategic Goal A (1–4), aimed at addressing the underlying causes of biodiversity loss, were reportedly better delivered by Parties in the Low and Medium HDI categories (Fig. 2). However, no group had significantly higher reported effectiveness in Target 4 (Production & Consumption), highlighting the pervasive difficulty of achieving this Target. There was also no overall pattern across Targets under Strategic Goals B and C, addressing direct drivers of biodiversity loss and biodiversity-positive commitments, respectively. Strategic Goals D and E, focusing on benefits from biodiversity and enhancing implementation of the framework, both showed an overall pattern where commitments made by Parties in the Medium HDI category were more likely to be reported as successful than commitments from other groups (Targets 14 (Ecosystem Services), 15 (Resilient Ecosystems), 16 (Nagoya Protocol), 17 (NBSAPs), and 19 (Science and Knowledge)). It could be suggested that, at least in terms of biodiversity benefits, such Parties may have achieved an adequate balance of resources to carry out commitments towards biodiversity while maintaining more direct dependencies on nature that may have been substituted in higher-HDI Parties³².

Targeted support for Parties based on where they are most likely to face shortfalls could have been applied across the suite of Aichi Targets. For example, low-HDI countries could have, according to the Sixth National Reports, minimised the largest shortfalls with support towards Target 8 (Pollution), 9 (Invasive Alien Species), 14 (Ecosystem Services), and 19 (Science and Knowledge). Similarly, it would appear from the Sixth National Reports that medium-HDI countries could have benefitted most from support in delivering commitments to Aichi Target 3 (Incentives), 4 (Sustainable Production and Consumption), 8 (Pollution), and 9 (Invasive Alien Species).

The group identified as “Like-Minded Megadiverse Countries” had, on average, reported the effective delivery of a higher proportion of the commitments in their NBSAPs than Parties outside this group (Fig. 3). The reported effective commitment delivery in megadiverse countries was particularly prominent when the commitments concerned certain Aichi Targets, including Targets 3 (Incentives) and 20 (Resource Mobilisation), Targets 6 (Sustainable Fisheries) and 9 (Invasive Alien Species), Target 14 (Ecosystem Services), and Targets 18 (Traditional Knowledge) and 19 (Science and Knowledge) (Supplementary Fig. 2). This suggests a particular willingness amongst the like-minded megadiverse countries to prioritise biodiversity, delivering commitments that may challenge institutional norms or require considerable prior funding, capacity, and engagement. Megadiverse countries have previously been shown to also have more consistent use of indicators in their reporting³³. Our results lend weight to the idea that, in general, these Parties have more readily participated in the CBD and acted with greater consciousness of the importance of biodiversity and its equitable and sustainable use. However, our results show no difference in the reported success of commitments from megadiverse countries towards Aichi Targets such as 4 (Production and Consumption) and 5 (Habitat loss). This is of concern, as habitat loss and other pressures on species from productive sectors in the megadiverse countries will contribute to much greater losses in global biodiversity than the same pressures elsewhere. The engagement of other government sectors, the private sector, and environmental non-governmental organisations could help to close this gap in the future for megadiverse countries.

This analysis focuses on the Sixth National Reports, which were first submitted in 2014. This cycle of reporting does not necessarily line up exactly with the timings of the NBSAPs, as the earlier Fifth National Reports may have included some assessment of commitments omitted from the reports in this analysis. Additionally, the Sixth National Reports contained over 100 sets of measures that did not correspond to commitments in their corresponding NBSAP, and though they do not necessarily contribute to the fulfilment of commitments made in NBSAPs, they are still likely to contribute to the Aichi Targets.

The principal caveat to these findings is that they are founded on the Sixth National Reports. These documents are, to all extents and purposes, self-reported evaluations of progress. This means that there can be no direct qualification of progress made towards national and international biodiversity goals through methods using reporting documents alone unless a thorough and transparent system for evidence-based reporting can be established. Though evidence and supplementary report documents are often provided in current reporting, this is not consistent across parties or commitments within. Considering this, we do not draw direct comparisons between individual Parties in this analysis.

The subset of Parties in this study may also have affected the spread of results. As our methods exclude Parties which have not precisely reported the outcomes of their objectives, this may introduce a bias towards certain Parties. Geographically, there are relatively few Parties in the Western Europe category, as few of these Parties met the criteria for inclusion and were also represented by the wider EU plan. However, the geographical spread of the other assessed Parties was more representative. Africa and ‘Asia and the Pacific’ were the largest groups, followed by ‘Latin America and the Caribbean’.

Further, the focus of this analysis on single commitments as the unit of measurement could lead to misinterpretation of Parties’ achievements towards the Aichi Targets. It is possible that, even with a small proportion of commitments effectively implemented, the most important and ambitious commitments were still completed. Without a way to properly measure the importance of every commitment, it is important again to stress that the methods here should not and do not address the progress of any one Party towards achieving the Aichi Targets.

Though this study is correlative, and the potential of confounding effects cannot be excluded, associations of effective commitment delivery with economic capacity and biodiversity exist over a large number of Parties. From this, we can reasonably infer the existence of barriers to progress that differed in different countries when addressing various types of goals.

By 2020, national commitments toward the Aichi Targets had not led to the achievement of the original goals⁴. Still, at the commencement of negotiations on the Kunming-Montreal Global Biodiversity Framework, hundreds of new pledges were already being made under the Action Agenda²³; work on revising new NBSAPs and reporting documents is also underway. With the Kunming-Montreal Global Biodiversity Framework comes the Monitoring Framework, linking the outcomes of the framework to measurable indicators³⁴. Considering how many commitments fell out of the reporting framework in this analysis and how patterns among target themes emerged, it is important to carry forward lessons from the Aichi Targets when considering how to get the most out of this framework and make it effective in achieving the new Goals and Targets.

Our analysis shows fewer and fewer actions taken at each stage of the implementation process of the last strategic plan for biodiversity. Some of this, as we hoped to investigate, is linked to commitments that weren’t successfully implemented, were cancelled, or otherwise implemented without their desired impact. However, the bulk of “lost” commitments were simply not reported on. This may be due to unwillingness to report on failed objectives or simply the fact that the evidence for those commitments was not available. However, this shortfall in reporting has clear implications for new plans for monitoring commitments. Compiling National Reports with this current coverage of commitments into a global progress report, as planned for the Kunming-Montreal Global Biodiversity Framework’s monitoring framework³⁴, would provide an inadequate and flawed perception of the implementation and success of commitments.

A recent perspective highlighted several key steps that may be necessary to enhance the national and subnational implementation of the new global biodiversity targets³⁵. One challenge they identified was ‘imperfect review mechanisms’; they suggested that one way to improve this would be a new compliance and accountability mechanism. For the monitoring framework to succeed, the coverage of commitments in each National Report should increase urgently. We suggest that a full review of specific Parties’ contributions to international targets, from commitment-setting to implementation monitoring, in the style of the analysis presented here, should be a key part of this process. Knowing explicitly about failures as well as successes and the specific conditions that led to them will be invaluable for increasing the effectiveness of the Kunming-Montreal Global Biodiversity Framework. In particular, doing this consistently could provide an evidence base with which Parties could learn from one another, co-developing knowledge of “what works” in national biodiversity policy. Further, where systematic issues with implementation arise, such a system could help identify pathways to resolving them. Even under the current system, we suggest missing commitments be counted as unimplemented in the compilation of National Reports to avoid any misrepresentation of missing commitments, providing an overly optimistic view of implementation progress.

The Kunming-Montreal Global Biodiversity Framework aims for a “Global review of collective progress in the implementation of the Kunming-Montreal global biodiversity framework including the means of implementation, based on national reports and, as appropriate, other sources”²². In our observations of commitments’ successes and failures in the National Reports, we see the compilation of National Report data as one possible route to such an analysis. However, for this to comprehensively capture the implementation of national commitments to biodiversity, direct links between clear commitments and the reporting of those commitments are needed. When paired with new indicator data, comprehensive reporting could also aid an understanding of how implemented commitments can lead to a true improvement in the state and trends of biodiversity, providing better inference for what actions work well in achieving biodiversity goals.

Our work with NBSAPs and reporting to the last strategic plan for biodiversity provides considerable insights for the implementation of the new GBF and its monitoring framework. For example, disaggregating the steps between setting national targets and measuring changes in national-level indicators added to our understanding of where and how shortfalls in commitment-making and implementation may have prevented the achievement of the Aichi Targets. As such, an enhanced monitoring system, such as the one planned for the new Global Biodiversity Framework, using harmonised planning and reporting data that brings in multiple lines of input data, could enhance transparency and accountability in the national implementation of commitments to biodiversity. It could also enable targeted interventions from Parties to prevent certain national targets and pledged commitments from being “left behind” as shown in this analysis.

If individual commitments are clear, and reporting against each of these commitments is consistent, it is possible to identify where progress has been made and where challenges exist in the national implementation of global biodiversity targets. An effective monitoring process could combine consistent reporting of commitments (such as in this analysis) with assessments of how delivering commitments contributes to the achievement of biodiversity goals, for example, by scaling commitments to impacts through a Global Biodiversity Observation System linked to a detection and attribution framework³⁶. This has been done for some Parties such as Germany¹², and indicator-led analyses of the impact of national commitments are partly available across all target elements and Parties¹⁸. Additionally, a consistent and transparent reporting procedure could allow for fairer comparison between Parties, as well as provide a workable estimate of the extent to which national action plans are being carried out^10,35. Finally, if the new Global Biodiversity Framework can improve reporting transparency and accountability against targets and indicators, this will significantly help efforts to achieve the CBD 2050 vision of living in harmony with nature.