Notoriously, there is often a disconnect between research and policy. Academic researchers study how the world works, and policymakers plan and shape how the world should work. Ideally, cutting-edge research informs policymaking so that the best understanding of how the world works guides the governing of power structures. However, important barriers tend to prevent this linkage. The articles in this issue offer some directions to overcoming these longstanding barriers.

To achieve this goal, this issue debuts our ‘Policy Brief’ series. Not only is it impractical to expect policymakers to remain up to speed on the latest academic literature across disciplines, but also scientific researchers may not be trained to formulate recommendations in ways that are well tuned to the contextual needs of policymakers on the ground. Policy Briefs are a way to bridge this gap, by synthesizing the findings of research articles in a quickly digestible, actionable form for a busy generalist reader.

Pioneered by Nature Energy, Policy Briefs were designed in discussion with policymakers to address the gap in applying research results to policymaking. A decision maker would be able to reference a well-crafted page of information that synthesizes the key implications of research we publish and that foregrounds the immediate relevance to policy. This approach comes closer to making research results actionable, not only in name but also in form.

The policy problem defined in the Article by Ivanov and coauthors is that urban flooding has become more severe than expected across many cities. In a case study of flooding in Warren, Michigan, USA, the authors show that models need to better account for the underground connectivity of storm-water flows to improve the accuracy of flooding predictions. In the associated Policy Brief, the authors synthesize the implications of this research to explain to policymakers why flooding keeps being worse than expected and what can be done about it. In conjunction, we feature an I and the City by Garcia that personalizes the impacts of severe flooding on the residents and community organizations who are first responders protecting their cities.

The policy problem defined in the Article by Diezmartinez and coauthors is putting climate justice into practice in policymaking and implementation, which has risen as a priority across cities since 2020. Studying the first two years of implementing a new building-performance standard in Boston, Massachusetts, USA, the authors show that justice disputes were central to the policy process. In a Policy Brief, the authors draw lessons from this early-adopter city to guide implementation efforts as this ordinance continues to be rolled out in Boston and as other cities implement climate justice into their sustainability planning and policy efforts. In conjunction, we feature a News & Views by Thomas, who reiterates the importance of climate action and equity.

The other research papers in this issue also identify interesting policy problems and discuss important implications. Bruno and coauthors — whose Article inspired the cover of this issue — study a popular concept that motivates policymaking for sustainable, equitable cities: the 15-minute city. The authors quantify an answer to the much-debated question of how realistic it is to make all cities into 15-minute cities. As discussed in the News & Views by Ribeiro, the authors find a vast discrepancy globally, which makes this policy target much more actionable in some places than others. Sustainability policy also motivated the Article by Almulhim and coauthors, who systematically review recent publications related to SDG-11 (the UN Sustainable Development Goal focused on cities), and cover a range of policy innovations for sustainable cities around different issue areas and global geographies. In their Article, Lu and coauthors explore where low-carbon policies were implemented in China as part of COVID-19 economic recovery efforts and find that greenhouse-gas reduction combined with economic growth only occurred in 6 megacities out of 48 cities investigated. These articles demonstrate key policy challenges of implementing sustainable and equitable urban development.

The link between the physical space of cities and urban design also encompasses policy problems and solutions. In their Article, Saiz and coauthors emphasize that the policy contexts of cities are shaped in important ways by natural physical geographical barriers and that researchers need to consider this link more deeply. Chen and coauthors’ Article strikes a cautionary note for climate and urban development policy. They find that despite increasing threats from urban heat, the cloud cover from climate change — coupled with more and taller buildings — have reduced access to life-giving sunlight across cities. Last but not least, in their Article, Fairbairn and coauthors study how the design elements of public squares affect biodiversity living there, and find greenness matters but that different taxa respond differently to design elements. These articles show how policy is an important tool to mediate human interactions with nature.

Whether motivated by the need for sustainable, equitable climate action in the near and long term, or directly mediating urban residents’ relationships with the natural environments that host and make up cities, policymaking relies on the fruits of research and research investigates the outcomes of policymaking. At Nature Cities, we aim to support this linkage and publish foundational research to support policy excellence.