Cities are warming twice as fast as the global average, and it is imperative we scale up solutions to tackle dangerous urban heat. The Nature for Cool Cities Challenge seeks to catalyze this goal by supporting a cohort of global south cities committed to developing and implementing nature-based solutions 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’s global 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 achieve the pledge, Challenge participants set a quantitative target (i.e., the area or percent of NbS to increase), a funding target (i.e., the amount of budgetary resources they will spend on NbS), and at least three implementation (policy, finance, or technical) actions.





This event, which marked the official launch of the Challenge, featured a discussion among local decision-makers, global experts and financers, which highlighted the need for support on nature for cooling, and the transformative potential of the challenge.
Partners hosted a side event at the Biodiversity COP15 in Montreal, Canada where they presented and socialized the challenge. The session underscored the role of nature as an adaptation tool, and how national and local governments can provide access to cooling while mitigating climate risks and supporting biodiversity.
The challenge winners will be profiled at the Climate COP28, which will take place in the UAE in November 2023.

The Pledge

By 2030, and with demonstrable progress by 2025, challenge participants (municipalities, groups of municipalities, or regional governments) pledge to increase or enhance the proportion of nature-based cooling solutions within built-up city surface area.


Challenge participants can include municipalities and provincial, county or state governments. In addition, eligible cities in developing countries that demonstrate high ambition will receive funding, technical assistance, partnership opportunities, and communications support. These challenge winners will receive small incubation grants to help refine pledges, and matching funding for implementation based on the value of the city’s funding target (and then scaled by country income level). 

The “ecosystem” of Challenge partners will include financial institutions and investors, creating opportunities for cities and financiers to partner for innovative finance for implementation. Winners will also receive technical assistance for implementation and monitoring, with an emphasis on comprehensive and inclusive approaches to maximize equity and environmental benefits. Finally, winners will benefit from partner-led global communications advocacy and support on the role of nature-based urban cooling solutions in support of sustainable cooling for all, highlighting the commitments of municipalities that participate in the Challenge.

The Challenge will target an initial cohort of nine cities to receive financial and technical assistance, comprising five low-income participants, three lower-middle income participants, two upper middle-income participants, and one high-income (global south) participant. Participants should be local or municipal governments, municipal/metropolitan agencies, multi-municipality groups, state and provincial governments in partnership with local governments. The focus is on secondary and tertiary cities, with populations up to 3 million, with low capacity and that have not received major assistance for cooling or nature-based solutions. Selection criteria could include:

  • Size of the quantitative urban NbS target OR the value of the placement of NbS
  • Size of the funding target, adjusted by country income group
  • Relevance of policy frameworks to support the pledge
  • Quality of NbS solutions proposed and socio-economic benefits that result
  • Demonstrated commitment to financial or technical innovation
  • Commitment to monitor implementation and verify results
  • Commitment to co-create solutions with residents

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.


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.