Are nature-based solutions really helping us to adapt to climate change in cities?

To answer the question in this article’s title, we need to get a few things clear: what does it mean to be well adapted to climate change, and how will we be able to recognize it in our cities?

When it comes to helping our cities adapt to climate change, there were a few words ringing around the highest halls of global governance at both COP27 and COP15: “green and blue infrastructure,” “ecosystem-based adaptation,” and, most recently, “nature-based solutions” (NbS). These various strategies are based on leveraging ecological processes toward providing benefits not only for biodiversity but also for climate and other social challenges facing cities. While they may represent a unique way of “doing adaptation” in cities that conveniently addresses these three challenges together, their introduction does not per se clarify a lingering uncertainty at the heart of these challenges: what kind of goals and supporting information do we need to know we are successfully addressing them?

Cities have been identified as areas that can benefit the most from natural climate change adaptation strategies like NbS. These range from urban forestry that keeps cities cool during worsening heatwaves and creates natural drainage for rising flood waters, to beach revegetation and planting artificial reefs on our coasts to protect against storm surges and sea-level rise. The framing of NbS is that they are not only able to provide climate adaptation benefits but that they can also create spaces for biodiversity to thrive in otherwise sterile urban environments. Meanwhile, NbS are also seen as providing social benefits through access to green and blue spaces by encouraging more active lifestyles, improved mental health, and providing social and recreational spaces, among many other benefits. NbS are also viewed as an effective way of dealing with multiple areas covered by the Sustainable Development Goals (SDGs) simultaneously, particularly covering targets under SDGs 13 (climate action), 14 (life below water), and 15 (life on land).

Applying NbS comes with problems too

Urban NbS have begun to emerge in cities in every region of the world, though integrating and tracking the contributions has highlighted practical difficulties. Currently applied NbS appear to lack consideration of social justice concerns around their application – for example, by often lacking visible processes for designing NbS in a way that means benefits can be shared and burdens can be minimized for the most vulnerable in society. One way this often emerges is through what is termed “green gentrification.” One example is in Barcelona, where urban greening projects have been shown to displace residents in less affluent areas by driving up the cost of living due to the increased amenity and attractiveness of urban green space. This is an important missed opportunity for synergies between the targets in SDG 16 (peace, justice, and strong institutions) and those in SDGs 11 (sustainable cities and communities) and 13 through 15, especially those relating to the need to focus on the poor and vulnerable.

Our knowledge of NbS and how they are applied has also been found to be biased toward the Global North. This is yet another iteration of the power imbalance in global discussions on adaptation that underrepresent the unique challenges and vulnerabilities of cities in the Global South, at odds with the fundamental principles of the SDGs. These trends call for a stronger focus on the process of how NbS are designed and evaluated to ensure they do not serve to further exclude the already vulnerable, termed “maladaptation.”

Omissions such as these point to a much larger problem that the application of NbS shares with adaptation strategies more broadly: what it means to be “well adapted” to climate change in cities is not clearly defined, as is what information should be used to know whether we are succeeding. Not having clear definitions and goals makes it impossible to know if we are going in the right direction. The different indicators used to evaluate progress on adaptation tell different stories about how we imagine what it means to adapt to climate change. For example, some SDG targets suggest this means simply surviving climate change or minimizing its economic impact (for example, Target 11.5), or creating plans to prepare for it (for example, Target 11.b). Without a clear direction, we are already seeing that our adaptation plans are not providing us with credible pathways to knowing if anything we are doing is making a difference. Meanwhile it is becoming more and more clear that climate change has already begun to fundamentally change the way we are able to live our lives in cities.

A way forward?

As a practical way forward, we need to start expanding the range of information we track about the contribution of NbS in our cities. This requires action in communities both of research and practice (policymakers and decision-makers). As researchers, we already know that information used to evaluate urban NbS often focuses on ecological data that has a longer tradition of quantification and measurement. However, this often misses information on how we will know when adaptation strategies like NbS are helping to create just, climate-resilient societies. More research is needed into how we can develop tools to meaningfully evaluate NbS on all fronts. On the other hand, we need local policymakers to engage more seriously with their citizens about what they want their futures to look like under climate change, and how they are going to track their progress in a way that is not only supported by science but is also driven by local needs. This will require bottom-up approaches that respond to local needs and vulnerabilities, rather than applying “off the shelf” solutions like NbS encouraged from above.

All of this is underpinned by better communication and collaboration between scientists, policymakers, civil society, and citizens at a local level. Work toward setting shared goals, such as the global goal on adaptation following COP27 in Sharm El-Sheikh, must walk the line between “setting standards” and “standardization.” That is, it must ensure that goals set at the local level are done in a way that is inclusive and just, rather than applying a one-size-fits-all approach to evaluating adaptation. Adapting to climate change will not merely be a matter of surviving it. Rather, it requires that we further come together to identify and preserve the parts of our societies, cultures, and ways of living that we do not want to leave behind – and that remain possible under drastically changed climate conditions.