Nature can cool cities, but proceed with caution

Abstract Increased extreme heat events draw attention to the potential of urban nature as a heat adaptation strategy for cities. This is reflected in multiple scientific perspective pieces, policy documents and science media publications advocating for urban greening as a cooling approach. Although attention to the dangers of heat and the benefits of urban nature is welcomed, it is vital that nature-based approaches to cooling are underpinned by diverse knowledge and a sound understanding of what nature in cities can and cannot do. We explain why an evidence-driven and cautious approach to heat adaptation through urban greening is so important, and propose three actions that urban actors can take towards effective and equitable long-term cooling through urban nature: enabling dialogue between different sectors with multiple remits; including diverse knowledge systems in planning and governance processes; and investing in long-term stewardship for the climatological and societal conditions of the coming decades. Policy and practice recommendation • Create fora for dialogue between governments, residents, civil society and developers from planning stage for green cooling; • Cooling through nature must be driven by expertise spanning diverse knowledge systems, combined with local knowledge and community needs; • Consider future climates and stewardship when planning urban cooling via nature. Science highlights • Understanding link between urban thermal environment and nature is an inter- and transdisciplinary task; • Critical need for evidence of how greening reduces heat impacts across different social and cultural contexts; • Evidence of how species perform under future climates required for stewardship of urban nature.