Cities are warming twice as fast as the global average, and it is imperative we scale up solutions to tackle dangerous urban heat. Nature- based solutions (NbS) are a powerful ally to cool cities sustainably without increasing global warming. 

The Nature for Cool Cities Challenge will support cities to increase nature-based solutions implementation in urban areas to deliver on heat resilience and cooling benefits.


Urban nature-based solutions (NbS) are a powerful tool to cool cities and reduce extreme heat risks for urban-dwellers around the world. The cooling benefits of NbS are well documented, but they need to be better recognised and leveraged to accelerate and scale up investment and implementation. The Challenge objectives are: 

  • Demonstrate urban nature-based solutions’ ability to mitigate the urban heat island effect, avoid emissions, and reduce energy demand
  • Drive finance for replication and upscaling
  • Send a demand signal to project developers and financiers

Challenge participants (municipalities, groups of municipalities, or regional governments) will pledge to increase or enhance the proportion of high-quality nature-based cooling solutions within their cities by 2030, with demonstrable progress by 2025.

To commit to the Pledge, participants will be requested to set a quantitative nature-based solutions target, a support target, and a minimum of three implementation actions.






Official launch of the Challenge at the SDG7 Pavilion, with first pledge takes from the Governor of Homa Bay County in Kenya.

The challenge winners will be profiled at the Climate COP28 in November 2023 in the UAE.
Cities can sign up to the Pledge throughout 2023.

Challenge participants can include municipalities and provincial, county or state governments. Among cities that commit to the pledge, the Challenge will identify a cohort of 8-10 ambitious cities in low to upper- middle income countries designated as Challenge winners.

Challenge winners may receive small incubation grants to help refine pledges and implementation actions, technical assistance to support implementation and financing plans, matching funding for implementation (scaled by income level), opportunities to partner with potential financiers, and communications support.


“By 2030, and with demonstrable progress by 2025, challenge participants pledge to increase or enhance the proportion of nature-based cooling solutions within built-up city surface area.”


Only eligible cities will be considered for prize money and dedicated support, but all cities wishing to demonstrate their commitment to this issue will be invited to take the pledge. In this way, the Challenge will create a community of practice for cities, partners, and financiers to exchange knowledge and accelerate action. 

COP 27 served as the official announcement of the Challenge, invitation to cities to take the pledge, and invitation to financing and implementing partners to join us. 

Commitments to the Pledge will contribute to the outcomes of the Global Cooling Pledge. Commitments to the Nature for Cool Cities Challenge will be aggregated and participants profiled at the UNFCCC Climate Conference COP28 in Dubai, UAE in December 2023.


A coalition of partners will support delivery of the Nature for Cool Cities Challenge, including UNEP, SEforALL, RMI, WWF, Mission Innovation, WRI, Durham University, the University of Oxford and Naturvation. UNEP and SEforALL will commit to in-kind support for the development and delivery of the challenge with communications, outreach and advocacy support and additional partnership will be sought for outreach, communications, and in-kind support. Further funding is required to deliver the award.

To support the project or to be kept informed on its development, please contact us here.