In the five years since we began the NATURVATION project, nature-based solutions have gone from being the concern of a small policy elite and the academically curious to becoming headline news. Across the world commitments to plant trees are piling up while the climate-saving potential of everything from mangroves to peat bogs are celebrated globally. If the urban is often absent from such promises, it is clear that nature-based solutions are rapidly acquiring hero status in both the biodiversity and climate policy arenas.

This should not really come as a surprise. The hero narrative – in this case where a protagonist is able to defeat the monster that is climate change/the loss of biodiversity/the COVID-19 pandemic and perhaps even all three at once – has dominated the sustainability policy arena over the past three decades. The next COP meeting, the introduction of a carbon tax, a new technology or individual everyday heroes are called upon to save society from impending doom. The result is, as Lesley Head has written about in her book Hope & Grief in the Anthropocene an almost ubiquitous and often relentless call for (techno) optimism and for ‘solutions’ to the problems that we have both created and now must face. For Christiana Figueres, widely credited with enabling the 2015 Paris Agreement, "you do not go at a battle or a challenge with pessimism, because by definition you will not win. So that is why I bring [a] tsunami of optimism to this whole darn thing - because we have to.”

So far, so good you might think. We have a new hero in town – nature-based solutions – and they are super-powered as not only do they offer the potential to tackle climate change, but can do so while also addressing biodiversity and a wide range of sustainability challenges. Yet if we insist on wrapping nature-based solutions in a super-hero cloak, we are already undone. Addressing climate change is a far from heroic tale. It cannot rely on single protagonists with super-powers, and will always be a flawed and incomplete endeavour. Rather than think in terms of heroes and the beasts that they slay, when it comes to our imagination of the powers of nature-based solutions we are better off following the narrative plot of the quest. Here the hero together with many allies, gifts and good fortune sets off on a journey which requires collaboration, cunning and more than a few losses along the way. This a challenging journey, with many setbacks and problems. The protagonist is far from perfect and the end of the quest unclear. It is instead the journey that matters most as through the encounters it lets the protagonist and their associates grow, gain wisdom and come to agreement about how matters can be resolved and the place they call home can thrive.

Our work in NATURVATION has shown too that nature-based solutions are far from perfect. They have the capacity to address multiple sustainability challenges, but this should not be taken for granted – the right conditions and companions are needed to grow this potential. Nature-based solutions have the possibility of addressing urban problems, of being the hero we are often told to hold out for, but at the same time they can create challenges of their own, such as exacerbating existing urban inequalities or enabling urban growth to proceed unchecked. The tidal wave of optimism that nature-based solutions have attracted in the past five years risks washing away these rather inconvenient truths as it gathers momentum in the run up to COP15 and COP26. While our work provides strong evidence that nature-based solutions can support action for both climate change and biodiversity, it is clear that there is work to be done if these outcomes are to be realised while at the same time enhancing social and environmental justice.

Indeed, our work suggests that just because we should caution against the unabated optimism that is placed in nature-based solutions, does not mean that we should be without hope. As Head (2016: 11) argues, “hope savours the life and world we have, not the world as we wish it to be.” In contrast to the ideal world of optimism, hope has to be crafted, formed and worked at, all the time knowing that things could be otherwise, that disappointment and loss are just around the corner. And in our work across six partner cities in Europe and case-studies around the world, this is how we have seen nature-based solutions take root, in the openings they offer to do and think differently about ourselves and our collective urban future. To have and make hope, even in the face of possible failure.

And as with nature-based solutions, so too with the life of research projects. NATURVATION came into this world as a half formed idea between a few colleagues who wanted a new challenge to gather around, accruing companions along the way in the unlikely settings all the way between a Swedish research panel evaluation meeting and a café in Paris. This has been a quest like no other I have taken, and certainly the journey has had its ups and downs along the way, but it has for me always been a collective project and one through which I have learnt a great deal about what it means to undertake academic leadership in a way that firmly rejects the hero narrative and instead seeks to develop a more collaborative, collective approach to a shared journey and one in which we all can thrive. I will always be grateful to everyone who came on this journey and made our project grow, gain wisdom and resolve some of the key challenges concerning how we can ensure nature-based solutions work to enable diverse and just urban futures.

Harriet Bulkeley is a Professor in the Department of Geography, Durham University and Project Co-ordinator for NATURVATION.