Fire is synonymous with danger. Fire denotes the spectrum between nature and civilization, what is wild and what is captive, employed or domestic. Fire symbolizes life and death.

A ‘fire whirl’ or ‘firenado’ strikes in 2021 near Janesville, California. Credit: Justin Sullivan/Staff/Getty Images News/Getty

Fires haunt the cities of world history — from the ancient library of Alexandria to the several great fires of London, fires have wreaked irrevocable damage in urban settings. Fire has been wielded and refined as a weapon of war, yet the devastation of accidental fire or wildfire is perhaps even more terrifying. This is why fire protection has been a foundational necessity to enable cities to stand the test of time. The ability to control fire and protect people and places against uncontrolled fires has been essential for cities and urban progress throughout history, a basic necessity of policy standards for public health and safety.

To the backdrop of the recent wildfires striking Los Angeles, Anguelovski and Frumkin’s Correspondence in this issue highlights the connectedness of urban life to nature and the need to overcome political divides to address the climate crisis. Shi and coauthors’ Article provides rigorous backing to this issue, and demonstrates that fire risks in cities are increasing with a warming climate; the authors projected an increasing frequency of vehicle and outdoor fires in cities across 20 countries, which will lead to increased casualties in the future.

Flooding in cities is also rising to new levels. As indiscriminate as natural disasters can be, unequal effects reflect social disparities. In their Article, Kephart and coauthors examine over 44,000 neighborhoods in eight South American countries and find that a lower education level corresponds with increased effects of neighborhood flooding.

The context for decision-making, planning and response amid disaster and crisis is fraught with disagreement at high levels. This is playing out in anticipation of the upcoming Intergovernmental Panel on Climate Change (IPCC) Special Report on Climate Change and Cities. With this potential for a seminal commitment to climate action, Rosenzweig and coauthors argue in their Comment that key roadblocks need to be cleared — chief among them that nation states need to understand how powerful it can be to partner with cities to tackle the climate crisis. The challenge is also a fraught one for each city. In their Article, Ríos-Ocampo and Gary show that growth strategies in Sydney had negative social and environmental consequences that were considered late and in a secondary capacity to conventional growth priorities.

Decision-making under such dynamic, dangerous and uncertain conditions requires fitting tools and frameworks. Shtob and coauthors take up this conundrum in their Perspective, which grapples with how to make the process of reckoning with the complexity and interconnections of urban systems manageable. A major challenge to this is the unequal landscape of knowledge production. In their Article, Müller and coauthors show that publications from the Global North still dominate urban knowledge, and especially highlight that editorial and gatekeeping positions at journals overwhelmingly are taken by academics based in the Global North, even if content is diversifying in geographical representation.

We highlight intercity exchanges as a policy toolbox that can build resilience within the complexity of crisis and the need for multi-level action. Zhu and coauthors’ Article demonstrates that intercity personnel exchange has lowered levels of water pollution in Chinese cities. Meanwhile, Zhao and coauthors investigate the importance of intercity healthcare, and show the extent to which urban residents in China rely on cross-city services to meet basic healthcare needs.

Faced with such challenges, seeing from different vantage points can help to shape creative approaches. The thought-provoking, yet mind-settling experience of watching the bustling city below from a rooftop above is highlighted by Luca in his I and the City as general inspiration, and particularly as a way of seeing urban systems intertwine. Digital urban planner Hu’s World View highlights rooftops as a beloved feature of Old Beijing, which is balancing modernization and preservation through digital twin technology.

Cities are at the crosshairs of major challenges today. The pieces in this issue show aspects of their layered connections.