Introduction

As civil engineers, we are accustomed to shaping the world around us. For centuries, our profession has been synonymous with harnessing nature’s forces and bending them to human needs. The early foundations of the Institution of Civil Engineers (ICE) reflected this ambition when it defined the civil engineer's role as “directing the great sources of power in Nature for the use and convenience of Man”. But today, we find ourselves in a rapidly changing world—one that demands we revisit and broaden this somewhat ‘egoistic’ definition, recognising that nature itself is not merely a force to be tamed, but a partner in the solutions we develop to meet our needs while respecting the need to co-exist with other species.

The environmental challenges of the 21st century, particularly the escalating climate crisis, require a paradigm shift. It's no longer enough to mitigate our impact on nature; we must actively collaborate with nature, learning from ecosystems that have evolved solutions to sustain life over millennia. Nature-based and nature-inspired solutions (NBS) represent this growing recognition: that civil engineering should not only avoid further environmental damage but should also play a role in regenerating ecosystems, protecting biodiversity, and creating sustainable systems that benefit both people and the planet.

The devastating effects of climate change—from floods and droughts to sea-level rise and extreme weather—are no longer future threats; they are present day realities. Decades of disregard for the power of nature has lead us to climatic events that we are now grappling to manage. The COP21 Paris Agreement requires world’s nations to “hold the increase in the global average temperature to well below 2°C above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels,” We are failing to meet these targets year on year, hurtling us all towards a precipice. Civil engineers have often been called upon to design systems and structures that shield human populations from these risks: levees to hold back rising seas, concrete dams to store dwindling water supplies, or impermeable barriers to control the flow of rivers. These strategies reflect a conventional mindset: one that treats nature as something to be controlled, rather than integrated, and this traditional approach to engineering is increasingly proving to be ineffective.

Today, the civil engineering profession has conceded it’s position of superiority over nature and has accepted the need to embrace a more holistic approach—one that does not merely seek to control nature but explores how we can work with natural systems to create outcomes that are not only functional but regenerative. A crucial aspect of this shift involves recognizing the interconnectedness of human with natural systems, not as ruler but as member. Civil engineers must expand their role to understand how the decisions we make ripple through ecosystems and communities, often with consequences far beyond the immediate project scope.

NBS invite us to rethink our approach, integrating natural processes into our engineering designs. Instead of building walls to keep floodwaters out, we may restore wetlands and riverside forests to absorb floodwaters and protect communities. As civil engineers we are opening our mindset to harnessing the power of ‘eco’ engineers, such as the reintroduction of the beaver, with its natural dam building skills or bison who help create habitats and wetlands. Instead of pouring more concrete to secure coastal cities, we may use mangroves or oyster reefs to buffer the effects of storm surges while enhancing marine biodiversity. These solutions are not just about softening the edges of conventional infrastructure; they represent a fundamental shift in how we approach the design process.

It’s exciting to think that biodiversity net gain (BNG) of 10% has been mandatory for major developments for nine months now. This is a planning policy that encompasses a system of incentives that are designed to reduce the impact on natural habitats. It includes a tool to calculate biodiversity value, and the creation of a market for off-site biodiversity units, for instances when a developer cannot deliver biodiversity gains on the same site as the development. BNG has four overarching aims (reference: https://defraenvironment.blog.gov.uk/2024/02/12/biodiversity-net-gain-is-live/):

1. change how development happens

2. change where development happens

3. create a high integrity market for NBS

4. contribute to nature recovery

Nine months in, and the policy has made some improvements to their tools, created the market for biodiversity units, and overall looks to be a major step towards a nature recovery, playing a role in enhancing the places where people live and work.

While NBS offer promising opportunities, implementing them at scale will require a shift in our professional culture. Civil engineers have traditionally been trained to rely on established standards and materials that prioritize efficiency, durability, and predictability. Nature, on the other hand, is inherently variable, and working with living systems introduces new uncertainties and complexities into the design process.

The need to adapt and be open to learning is more pressing than ever. As the impacts of climate change intensify, the challenges civil engineers face will only become more complex. NBS often require collaboration across disciplines—from ecologists and biologists to urban planners and community stakeholders. This demands a more integrated, cross-sector approach, where engineering expertise is blended with ecological understanding and social science insights.

Furthermore, we must learn to evaluate the outcomes of NBS differently. Traditional engineering success is often measured in terms of immediate functionality: Does a bridge withstand sufficient loading? Does a levee prevent flooding? NBS, however, may require long-term monitoring and adaptive management to assess their full benefits, including improved biodiversity, carbon sequestration, or the restoration of natural hydrological cycles. These metrics go beyond traditional engineering considerations and call for new methods of evaluation that are more dynamic and multifaceted.

As we embrace NBS, we must also be humble about what we still do not know. There may be failures along the way. Not every attempt to integrate natural systems may work as planned, and our profession must develop a tolerance for learning through trial and experience, just as ecosystems themselves evolve through adaptation. Overtime, the accumulation of NBS may assimilate sufficient case studies and empirical evidence to formulate effective guidelines which will act as vital tools to support the next generation of engineers, that may face even greater challenges than we do today. The success of NBS will rely on our ability to build on these lessons, refine our approaches, and continue to innovate in response to new challenges for the benefit of future engineers.

As stewards of the built environment, civil engineers have a critical role to play in the transition to a more sustainable and regenerative future. But to fulfil this role, we must move beyond the mindset of managing or mitigating nature’s power and instead view ourselves as collaborators with the natural world.

NBS are not a silver bullet. They will not replace all forms of traditional infrastructure, nor will they work in every context. But they represent a powerful tool in our engineering toolkit, one that holds the potential to transform how we design and build. By working with nature, rather than against it, we can create infrastructure that is more resilient, adaptable, and capable of supporting both human and ecological well-being in the face of an uncertain future.

Claire Wansbury’s briefing article (Wansbury, 2024) in the corresponding Civil Engineering general issue highlights the urgent need to move from a time of biodiversity loss to nature recovery. She discusses the definition of a nature-positive future, and urges us to avoid the risk of misusing the term such that it becomes “greenwash”. She also leaves us with the suggestion that we all need to learn, act and speak out. We hope that this issue helps inspire this.

In this issue of Civil Engineering, we showcase a diverse array of papers that explore NBS from multiple perspectives. From case studies on the implementation of green infrastructure in urban environments to evaluating the effectiveness of implemented solutions for future improvement, these contributions reflect the growing recognition within our profession of the need to rethink our relationship with the natural world.

Thank you to the authors for sharing these works, and we hope that you enjoy them and are inspired to consider how your own work can embrace NBS for a more sustainable and resilient future.