Addressing scale in nature-based solutions

Introduction

Nature-based solutions (NbS) are “actions to protect, conserve, restore, sustainably use and manage natural or modified terrestrial, freshwater, coastal and marine ecosystems which address social, economic and environmental challenges effectively and adaptively, while simultaneously providing human well-being, ecosystem services, resilience and biodiversity benefits” (United Nations, 2022). The literature on NbS often alludes to the need to implement such projects with a landscape approach, but the term is ill defined. The term has recently evolved to recognize the importance of landscapes for people’s quality of life, highlighting the need to adopt a more comprehensive approach that incorporates human well-being.

This shift raises important issues for the design, monitoring and governance of NbS. Where does a landscape begin or end? What is the right scale for landscape interventions? How should one assess performance in relation to the many and sometimes contradictory goals for biodiversity, societal benefits, mitigation and adaptation today and in the future? What metrics should be measured to understand whether NbS are adequate and effective?

ThisweADAPT article is an abridged version of the original text, which can be downloaded from the right-hand column. Please access the original text for more detail, research purposes, full references, or to quote text. Other briefs in the SEI series introduce NbS; explore principles for just and equitable NbS; and assess finance for NbS.

Different Dimensions of Scale

These questions are essentially about scale and the governance of processes that determine scale. Scale is a complex concept with many dimensions, including temporal, spatial, jurisdictional, and analytical elements:

• Temporal aspects or time frames of NbS – these are complex, dynamic and difficult to assess within conventional planning and policy-making periods. It can take years, or even decades, to realize the effectiveness of some NbS interventions.
• Jurisdictional scales – political cycles are far shorter than natural ones, and, as a result, short-term planning may lead decision-makers to prioritize solutions with fast results to deliver to their constituents more quickly.
• Spatial scale – refers to the extent of a process or issue. The spatial scale considered for planning NbS substantially affects their ability to deliver expected outcomes for various reasons.
• Analytical scale – the effectiveness of measures is also connected to scale. In contrast to the standardized measures available for grey infrastructure projects, each type of NbS intervention is unique.

Implications for Governance

While much of the effort to address scaling of NbS has focused on spatial and temporal issues, more work is needed to tackle the combined implementation challenges of time and space. The governance of NbS is aligned to the bounded and organized political units in which they are located (e.g., cities, towns, counties, states, provinces and nations). There are usually jurisdictional implications when proposing NbS, especially at large spatial scales; this is because interventions often require involvement, negotiations and collaboration with multiple stakeholders including diverse landowners. However, there are benefits to including different sources of knowledge in the context of scale to bridge the gaps between different kinds of information.

The very nature of NbS translates into implementation challenges that raise issues of scale. The promises of multiple benefits may be attractive for tapping into different global discourses concerning sustainability, adaptation, and green recovery; but from a planning approach, NbS demands shared responsibilities and a requirement for the coordination and cooperation across administrative levels, governmental structures, and jurisdictional boundaries.

Key Messages and Conclusions

• Despite the growing interest in the use of nature-based solutions (NbS) to adapt to climate change, little is known about how to effectively scale up such measures to achieve wider benefits for society, biodiversity and the climate.
• NbS planning should thus seek to explicitly model cumulative and combined effects to inform the design of projects to address issues involving scales of time, landscapes, and jurisdictions involved.
• NbS designs should set quantitative targets and create monitoring systems to systematically measure outcomes and report on progress.
• NbS designs should implement “no regrets” options – that is, they should devise strategies to maximize positive outcomes and minimize negative outcomes in the short and long terms and irrespective of climate change. This is particularly important in light of the longer time scales that NbS often entail, the time pressures to adapt fast enough to reduce risk, and the desire of politicians facing short elective cycles to respond to constituents’ needs.

Such steps will help shed light on the spatial scales and timeframes over which NbS can deliver benefits to society, biodiversity and climate.