The climate benefits, co-benefits, and trade-offs of green infrastructure: A systematic literature review.

Climate change increases risks to natural and human systems. Green infrastructure (GI) has been increasingly recognized as a promising nature-based solution for climate change adaptation, mitigation, and other societal objectives for sustainable development. Although the climate contribution of GI has been extensively addressed in the literature, the linkages between the climate benefits and associated co-benefits and trade-offs remain unclear. We systematically reviewed the evidence from 141 papers, focusing on their climate benefits, relevant co-benefits and trade-offs, and the GI types that provide such climate (co-)benefits. This study presents a comprehensive overview of the links between climate benefits, co-benefits and types of GI, categorized along a green-grey continuum so that researchers/practitioners can find information according to their topic of interest. We further provide an analysis of trade-offs between various GI benefits. 'Bundles' of major co-benefits and trade-offs for each climate benefit can be identified with recommendations for strategies to maximize benefits and minimize trade-offs. To promote climate-resilient pathways through GI, it is crucial for decision-makers to identify opportunities to deliver multiple ecosystem services and benefits while recognizing disservices and trade-offs that need to be avoided or managed.

National Climate Change Risk Assessments to inform adaptation policy priorities and environmental sustainability outcomes: a knowledge systems perspective.

National Climate Change Risk Assessments (CCRAs) have a key role in informing priorities for adaptation policy but face significant challenges due to multiple facets of risk and adaptation. Issues are especially pronounced for meeting goals of environmental sustainability due to the complex dynamics of socio-ecological systems. In practice, a CCRA can therefore differ from its original conceptual blueprint. These challenges are explored from a knowledge systems perspective, focusing on the role of stakeholders/policymakers, risk descriptors, methods, evidence sources, and scientists. A UK case study evaluates recent developments (CCRA3) including identification of policy urgency through adaptation shortfalls and its application to the natural environment. Important science-policy issues are also highlighted regarding inclusion of opportunities, systemic risks, residual risks, and risk tolerance. A general conclusion is that CCRAs inevitably leave open questions which lead back to their evolving role in the science-policy interface. A knowledge systems perspective identifies CCRAs as open, adaptive, reflexive processes that help redefine interpretations of risk and adaptation, rather than just providing a specific policy-relevant product. This perspective identifies scope for progressive refinement of CCRAs to enhance collective science-policy adaptive capacity whilst also engaging wider society. For environmental sustainability, this open process can be used to iteratively redefine robust future pathways and system reference conditions that also better reflect evolving societal perceptions and tolerance on sustainability risk in the face of climate change.

Understanding the value and limits of nature-based solutions to climate change and other global challenges.

There is growing awareness that 'nature-based solutions' (NbS) can help to protect us from climate change impacts while slowing further warming, supporting biodiversity and securing ecosystem services. However, the potential of NbS to provide the intended benefits has not been rigorously assessed. There are concerns over their reliability and cost-effectiveness compared to engineered alternatives, and their resilience to climate change. Trade-offs can arise if climate mitigation policy encourages NbS with low biodiversity value, such as afforestation with non-native monocultures. This can result in maladaptation, especially in a rapidly changing world where biodiversity-based resilience and multi-functional landscapes are key. Here, we highlight the rise of NbS in climate policy-focusing on their potential for climate change adaptation as well as mitigation-and discuss barriers to their evidence-based implementation. We outline the major financial and governance challenges to implementing NbS at scale, highlighting avenues for further research. As climate policy turns increasingly towards greenhouse gas removal approaches such as afforestation, we stress the urgent need for natural and social scientists to engage with policy makers. They must ensure that NbS can achieve their potential to tackle both the climate and biodiversity crisis while also contributing to sustainable development. This will require systemic change in the way we conduct research and run our institutions. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.

The vulnerability of threatened species: adaptive capability and adaptation opportunity.

Global targets to halt the loss of biodiversity have not been met, and there is now an additional Aichi target for preventing the extinction of known threatened species and improving their conservation status. Climate change increasingly needs to be factored in to these, and thus there is a need to identify the extent to which it could increase species vulnerability. This paper uses the exposure, sensitivity, and adaptive capacity framework to assess the vulnerability of a selection of WWF global priority large mammals and marine species to climate change. However, it divides adaptive capacity into adaptive capability and adaptation opportunity, in order to identify whether adaptation is more constrained by the biology of the species or by its environmental setting. Lack of evidence makes it difficult to apply the framework consistently across the species, but it was found that, particularly for the terrestrial mammals, adaptation opportunities seems to be the greater constraint. This framework and analysis could be used by conservationists and those wishing to enhance the resilience of species to climate change.