February 19, 2025 | UCLG ASPAC, organised an Online Learning Session: Exploring Nature-Based Solutions (NbS) for Resilient and Sustainable Cities and Regions in Asia-Pacific, one of key initiatives of the Organisation to provide a knowledge transfer platform among city and local government leaders and officials, to explore solutions based on nature for resilient and sustainable cities and communities. The on-line event brought together more than 70 participants enthusiastically engaging with experts and policymakers exploring how incorporating natural ecosystems into urban planning might help reduce climate risks, improve water management, and increase biodiversity.
Sustainable Urban Growth Through NbS
Dr. Phanith Chou, Associate Professor at the Royal University of Phnom Penh shared essential principles of NbS, highlighting that sustainable urban expansion should not be based primarily on traditional infrastructure, but rather on hybrid solutions that combine nature, technology, and human development. “The future of our cities depends on how well we integrate green and blue infrastructure into existing urban landscapes. NbS provides a cost-effective way to improve ecosystem services while addressing challenges such as flooding, heatwaves, and pollution,” Dr. Chou explained.
Innovative Applications of Nature-Based Solutions
The online learning showcased various innovative applications of Nature-Based Solutions including:
- Green roofs: vegetated roofs that lower temperatures and improve air quality.
- Rainwater harvesting: clever water collection systems that enhance consumption while reducing water scarcity.
- Permeable pavements: coverings which absorb rainfall while preventing surface drainage.
- Bioengineered riverbanks: use natural vegetation to control erosion rather than concrete barriers.
Case Studies: Cambodia, Thailand, and Beyond
The online learning showed a comparison of urban landscapes in Thailand and Cambodia demonstrating the need of implementing NbS. In Poipet, Cambodia, increased development has reduced green space to less than 5%, raising temperatures and aggravating flooding. Collaborative initiatives with the Mekong River Commission (MRC) seek to restore 103 hectares of forest, rehabilitate river systems, and replace concrete flood barriers with bioengineered alternatives. A rural water management project in Angkor Pant showed how wetland restoration and enhanced water catchment tactics increased stored water capacity from two million to three million cubic meters, assuring year-round supply during droughts. Meanwhile, a pilot project in Battambang aimed to turn congested urban streets into nature-based corridors by adding rain gardens and stormwater management technologies to reduce excessive heat and flooding.
Economic Justification for NbS
Speakers highlighted the economic advantages of NbS:
- Bioengineered riverbanks cost $6/m² against $33/m² for concrete constructions.
- Flood mitigation activities in Cambodia could result in $4.4 million in damage prevention savings.
- A nature-based school redesign with solar energy and green roofs had a benefit-cost ratio (BCR) of 1.6, indicating long-term financial feasibility.
Challenges and Future Directions
Despite its benefits, NbS adoption has challenges, such as a lack of finance, legislative opposition, and public uncertainty. Governments occasionally support conventional infrastructure due to maintenance concerns. However, the Nangang River Restoration in China and the Cheonggyecheon Stream Revitalisation in Seoul are instances of how public support and government funding may enable large-scale NbS initiatives to succeed.
- Experts advise using other funding sources like green investments and scholarships for climate adaption to get around obstacles.
- Pilot initiatives should be shown to be effective before being scaled up.
- Greater policy integration, including a requirement for NbS in urban planning laws.
- Public awareness initiatives that emphasise the long-term financial and ecological advantages.
Looking Ahead
Cities must move quickly to adopt resilient and sustainable urban planning techniques as climate change increases. Throughout Asia-Pacific, governments, urban planners, and local communities are encouraged to adopt NbS as a fundamental element of development in the future.
