5.1 Opportunities and limitations

Data availability is a key challenge for ocean account development. This is a common finding shared by most GOAP pilot studies and other ocean accounting efforts from different regions of the world. Many countries face challenges where national data of suitable quality is not available. Limited available resources for research and monitoring often mean that gaps in national data cannot be closed in the short term through national data generation. Global data on ocean assets can be used to fill some of these gaps in order to enable the initial development and pilot testing of national ocean asset accounts. These pilot accounts, in turn, can help to make the case for investments in improved national data availability where it is needed most.

The consistent methodologies and standards often characterising global ocean datasets may offer potential advantages for use in ocean accounts as they provide:

• Consistency over large spatial scales,

• Consistency over time, and

• International comparability.

In turn, global ocean datasets currently still have weaknesses that limit their suitability for ocean accounts and/or need to be carefully considered when using these data. Key limitations include:

• Lack of time series, in particular for ecosystem extent data,

• Condition data are largely limited to oceanographic parameters as proxies for ecosystem condition,

• Global data often have low spatial resolution, and

• Errors and uncertainties may arise from the production of global datasets based on the assumptions and models they apply and how they combine different data.

It is important to highlight that global data should not be considered as the starting point for national (or subnational) ocean accounting. The priority should be to identify suitable national data first before consulting global data sources. However, as the country experiences from Vietnam, Indonesia, Fiji and Canada show, in the absence of suitable national data, global ocean asset data can support the development of initial ocean asset accounts.

The Global Ocean Asset Data Inventory and this Guide provide practical advice for the identification and selection of global ocean asset data for national ocean accounts. Advising on the best global data to use is difficult as this will be dependent on the national context, including ocean accounting priorities and available resources. For example, not all global datasets provide full and/or equal geographical coverage, and different satellite imagery may be best for different regions of the world. Data may require different levels of additional processing (e.g. point or polyline data need to be combined with other data types to calculate ecosystem extent) or computational capacity and technical expertise for use in accounting (e.g. raw data that can be processed using local algorithms for targeted interpretation, or pre-processed, analysis-ready data that allow streamlined account production).

The stepwise approach to using the Inventory guides national ocean accounts compilers through key considerations that will help them make informed decisions on the use of global ocean datasets that are varied in quality, accessibility and purpose. The Inventory is purposefully structured to support the consideration of criteria that are central to many data quality assurance processes implemented by national statistical offices: relevance, interpretability, institutional environment, accuracy and accessibility.

5.2 Gaps and future considerations

The updated Inventory presents 87 datasets for seven distinct account components and 59 different ocean asset types or conditions. While this represents a considerable volume of diverse data, the process of updating the Inventory also revealed a number of gaps in available global ocean data. Only a small number of marine and coastal ecosystems are represented in global datasets. For individual ocean environmental assets, produced assets and designated use, only a very limited number of spatial datasets were found. Another key gap remains the limited availability of time series data for marine and coastal ecosystems. Currently, only changes in extent of mangroves can be tracked using global data.

These gaps indicate areas where improving the availability of global ocean data would further support the development of ocean accounts. This may include efforts to use satellite data to track change in seagrasses and coral reefs.

The country experiences described here focused mainly on ecosystem extent. As countries move forward with their ocean account development, data for ecosystem service supply and use, as well as better data for ecosystem condition, will likely also be needed. Fiji and Vietnam have already started on this, working on estimating ecosystem service supply and tracking condition of mangroves.

One key point that came up across the consulted countries, is the importance of adequate ground truthing of global remote sensing and modelling data. While the experience from Vietnam shows that satellite data can provide an estimate of ecosystem extent, and identify new areas of seagrass, even if not perfectly calibrated, this did result in an overestimation of seagrass extent. For a country like Canada with a wide range of temperatures and a large ocean environment, datasets that have only been validated in areas with less seasonal variation or temperature extremes can lead to significant misrepresentations. To increase accuracy across their global coverage, it is therefore important to ground truth global datasets in a wide variety of locations and climates.

The United Nations Decade of Ocean Science for Sustainable Development (2021-2030) aims to drive the creation of a strong scientific knowledge foundation for improved management and sustainable development of the ocean, supporting delivery of the Sustainable Development Goals. Ocean accounts can play and important part in supporting science-based decision making for the ocean. The push to improve the global ocean knowledge base through the Decade is an opportunity to improve the availability and accessibility of global ocean data that can enable ocean account development.

Besides increasing the availability of ocean data, a key priority over the next decade for data producers and providers will be to work towards global ocean data that are FAIR – Findable, Accessible, Interoperable and Reusable^[11] – for human users and for computers. As the data search for the updated Inventory suggests, there is still room for improvement on the findability and accessibility of global ocean data, in particular for individual environmental assets, produced assets and designated use. For the development of ocean accounts under the SEEA framework, data interoperability is particularly important, as these accounts require the integration of a large diversity of data. To support this, in 2021, the United Nations Statistics Division, UNEP and the ARIES team have released an ‘Interoperability strategy for the next generation of SEEA accounts’^[12]. The strategy outlines proposed roles and responsibilities of data providers, modellers and data holding institutions in delivering interoperability for SEEA, as well as four steps for achieving the objectives set out by the strategy.