Scenarios and models – IPBES' first methodological assessment completed: what's it about?


Elisabeth Marquard, NeFo, Helmholtz-Zentrum für Umweltforschung-UFZ


Portrait von Elisabeth Marquard
Elisabeth Marquard

After having adopted the thematic assessment on pollination a few days ago, IPBES adopted its first methodological assessment on scenarios and models yesterday, towards the end of its fourth plenary meeting in Kuala Lumpur (IPBES-4). However, the attention by the IPBES-interested community and the media was much lower for this assessment than for the one about pollination. Why hasn't there been a press conference yesterday by IPBES similar to the one for the pollination assessment? And what is the first methodological IPBES assessment actually about?

In the IPBES context, models and scenarios are regarded as pivotal to advance our understanding of the complex interactions between the natural world and human activities in the past, present and future. Models represent complex systems in a simplified manner, e.g. the conceptual framework of IPBES is a model that simplifies human-nature relationships and structures them along six main elements (nature, nature's benefits to people, anthropogenic assets, institutions, governance systems and other indirect drivers of change, direct drivers of change, good quality of life). Clearly, there are innumerable other relevant models to IPBES, many of them are composed of complex algorithms that quantitatively describe the relationships among its different components. Feeding or parameterising such models with different sets of data allows analysing these relationships in detail.

The term 'scenario' usually describes a possible future development of the driving forces within a system. Within the IPBES context, scenario analyses are used to describe and evaluate the impact of different development paths or policy options on elements of the IPBES conceptual framework. Usually, models are the tools with which alternative scenarios are scrutinized.

Thus, scenarios and models allow inferring statements on the ecological and societal consequences of certain changes in pressures on the natural environment or of alternative political interventions. This is of highest significance, because such statements are the key to rendering IPBES activities policy relevant.

Accordingly, the first methodological IPBES assessment[1] of scenarios and models of biodiversity and ecosystem services now adopted by IPBES-4 aims at providing "advice on the use of such methodologies in all work under the Platform to ensure the policy relevance of its deliverables" (IPBES/4/L.4). Unlike other IPBES deliverables, it does not analyse the status of or trends in biodiversity and ecosystem services. This explains why this IPBES deliverable has not caught as much attention as the assessment of pollination has.

The scenario and model assessment focuses on the following three aspects:

  • "Critical analysis of the state-of-the-art and best practices for using scenarios and models in assessments, policy design and policy implementation relevant to biodiversity and ecosystem services;

  • Proposed means for addressing gaps in data, knowledge, methods and tools relating to scenarios and models;

  • Recommendations for action by IPBES member states, stakeholders and the scientific community to implement and encourage those best practices in regard to the use of scenarios and models, engage in capacity-building and mobilize indigenous and local knowledge" (IPBES/4/L.4).

The bulk of the scenario and model assessment addresses an audience involved in IPBES activities or other scientific or political endeavours that use or draw on scenario and modelling approaches. To this group of experts, the assessment offers a "broad overview of the benefits of and limits to using scenarios and models" (IPBES/4/L.4). However, the SPM and Chapter 1 explicitly address a broad audience and do not require expert knowledge on the use of scenarios and models. Another targeted audience are the funding agencies that are provided with an analysis of key knowledge gaps and suggested ways to fill these.

Altogether, the IPBES assessment on scenario and models is of high conceptual and procedural significance for IPBES as well as of high information value for a broad scientific and non-scientific audience outside IPBES. Its direct political relevance is, however, rather low due to its technical nature. In this respect, it differs markedly from all other IPBES assessments that are expected to include partly politically or ideologically controversial issues.

The IPBES assessment on scenarios and models can be expected to have some mid-term impact on research funding strategies and on the prioritisation of capacity building needs. Its long-term impact will play out via future IPBES deliverables if it enables them to make better use of scenarios and models. Then, these future IPBES deliverables may explore possible ecological and societal consequences of present developments or political interventions more comprehensively and may ultimately inspire political decisions that safeguard biodiversity and ecosystems more effectively.

See also on this topic:
Article on how macroecology can contribute to IPBES

More about the content of the IPBES assessment of scenarios and models of biodiversity and ecosystem services:

A major issue analysed in the assessment are the impediments that hinder a widespread and effective use of scenarios and models of biodiversity and ecosystem services in policy- and decision-making (see key finding 1.4 in IPBES/4/L.4). The barriers identified include a lack of understanding among practitioners in the policy arena about the benefits of and limits to models and scenarios, data gaps and insufficient human and technical resources to develop and use these methodologies, deficiencies in the transparency of and therefore mistrust in the methodologies, and insufficient engagement or willingness by scientists to properly engage in real-world decision-making contexts. Furthermore, the assessment cautions against an unspecific use of scenarios and models that disregards the particularities of a given context (including the appropriate temporal and spatial scales, see key findings 2.2 and 2.3). Communicating limits and uncertainties is seen as vital for an effective and trustworthy application of scenarios and models (see key finding 2.5).

In addition to its high-level messages and key findings of which some are summarized above, the SPM of the scenario and model assessment provides explicit guidance points that are separated into "guidance for science and policy" and "guidance for IPBES and its task forces and expert groups". Under the first heading, practical steps are suggested for the audience outside IPBES that would help overcoming the identified barriers to the widespread and effective use of scenarios and models in policy- and decision making, such as amplified efforts for collecting data, improving and applying participatory scenarios, engaging sincerely with real-world contexts, improving accessibility to data, methods, or other knowledge as well as equipping the relevant experts and institutions with sufficient technical and human resources. Under the second heading, practical steps are suggested for the audience within IPBES that would support an effective and streamlined use of scenarios and models in work under the Platform and that would improve also their utility in the future. Among these suggestions are a close collaboration between IPBES and the knowledge holding community, the involvement of scenario- and modelling experts in all relevant IPBES activities, and an expansion of according capacity building measures. Possible next steps for IPBES are further outlined in a separate IPBES document. This "Proposal on the further development of tools and methodologies regarding scenarios and modelling" (IPBES/4/5) suggests the establishment of an expert group recruited from scenario and modelling experts already involved in IPBES assessments that would carry out its work until the end of the fist work programme. Its main tasks would be providing further advice on the use of scenarios and models to all IPBES expert groups and promoting the development of these methodologies by broader scientific community (IPBES/4/5).


[1] Under its first work programme, IPBES prepares different kind of assessments: those for a particular geographic entity (four regional assessments and the global one), those on specific issues that were proposed to IPBES by multilateral environmental agreements, national governments or other IPBES stakeholders (thematic assessments) and those that review and assess certain approaches that IPBES uses for its activities (methodological assessments). Thus, while the first two types of assessments (regional/global and thematic) primarily respond to the requests that were submitted to IPBES during the time when the IPBES work programme was developed, the methodological assessments are primarily meant to advice IPBES expert groups on methodological issues and to streamline methodological approaches across different IPBES activities (see also Blog by Axel Paulsch [in German]).