On 14 May 2025, the United Nations Environment Programme (UNEP) Cool Coalition hosted the fourth session of its Cool Talks webinar series, titled Cooling with Nature: Financing Nature-Based Solutions in Cities. The event brought together experts in urban heat resilience, finance, and architecture to explore how to scale nature-based solutions (NbS) for cooling in cities.
Opening the session, Dr Zhuolun Chen, Senior Advisor on Energy Efficiency and Green Finance at UNEP’s Copenhagen Climate Centre, highlighted the funding gap for urban NbS. According to UNEP’s State of Finance for Nature 2023, only 17% of global NbS finance comes from private sources, leaving a USD 700 billion annual shortfall. Chen advocated for blended finance approaches to de-risk projects and attract private capital, citing the cost-effectiveness and co-benefits of NbS such as job creation and cleaner air.
Dr Eleni Myrivili, Global Chief Heat Officer at UN-Habitat, emphasised the urgency of adapting cities to rising heat. Referring to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, she described urban greening as one of the most effective and affordable adaptation strategies. “Cities built for a 20th-century climate have become heat traps,” Myrivili said.
Dr Geronimo Gussmann, Advisor on Nature-Based Solutions at UNEP-CCC, noted that many countries’ updated Nationally Determined Contributions under the Paris Agreement mention nature-based measures, though few specify urban cooling. He called for aligning adaptation, biodiversity and health funding into integrated NbS investment pipelines and referenced UNEP-CCC’s business models to support tailored urban finance strategies.
Architect Richard Hassell, co-founder of WOHA, presented examples of incorporating greenery into high-rise buildings. He described green roofs, vegetated facades, and permeable surfaces as elements that provide environmental services including shading, cooling, and habitat creation. Hassell urged updates to building codes and incentives to make such features standard practice.
Eva Gurría, Partnerships Lead at the NBSAP Accelerator, discussed integrating urban NbS into national biodiversity strategies. She highlighted London’s natural-capital accounting, where each £1 spent on parks yields £27 in combined benefits. Gurría reported that the Accelerator is currently matching city-level cooling projects with national ministries and financiers across multiple countries.
Dr Zahra Jandaghian, Nature-Based Solutions Lead at Canada’s Construction Research Center, shared modelling results showing that combinations of reflective roofs, urban trees, and ventilated street canyons can reduce peak temperatures by up to 4 °C and cut building energy demand in Canadian cities. She pointed to potential funding mechanisms such as resilience bonds and ecosystem-service payments tied to verified outcomes.
Speakers also noted opportunities in carbon markets, public-private incentives, and outcome-based grants. According to the Climate Policy Initiative, global climate finance reached USD 1.3 trillion in 2023, indicating available capital for NbS expansion. In closing, Chen stated, “We have the science, the policy frameworks and a growing roster of success stories. What we need now is coordinated capital and political will.”