Yu has been the world’s leading advocate of the Sponge City and now Sponge Planet approach. The model has three key principles:

• Absorb rainfall where it falls

• Restore water’s natural slow phases

• Adapt communities to accept more slow water on the land

Sponge Planet is part of a global “slow water movement,” which includes thousands of projects worldwide in urban, suburban, and rural areas that mimic natural systems. Together these projects are increasing “infiltration into soils, hyporheic zones, and aquifers,” and solving water, climate, biodiversity, and heath issues at the same time.

Slowing down water flow. Haikou Meishe River Greenway, Hainan, China. 2017. © Turenscape

“Climate action has focused too narrowly on carbon while neglecting the destabilized water cycle. Sponge City addresses urban flooding, extreme heat, wildfires, and biodiversity loss, but the crisis demands a planetary-scale response — Sponge Planet,” Yu told us. “We must restore Earth’s ability to absorb, store, and slowly release water — making water management the foundation of a holistic climate solution, not an afterthought or a single-goal intervention.”

Yu and his co-authors argue that Sponge Planet approaches reduce climate risks while also storing carbon and increasing biodiversity. “In absorbing high flows, Sponge Planet reduces upstream and downstream flood risk. In recharging groundwater and storing it locally, it increases the water released into streams during the dry season. Sponge Planet is also climate mitigation because ecosystems such as wetlands and mangroves store carbon at rates higher than many terrestrial forests.”

Slowing down water flow, storing carbon, and increasing biodiversity. ASLA 2014 Professional General Design Honor Award. Liupanshui Minghu Wetland Park, Guizhou Province, China. © Turenscape

Yu has been on the road, presenting 30 keynotes in two years. He was a speaker at the Vatican’s summit on climate resilience last year and is planning a Climate Design Summit in Beijing, China this October. Much of this public engagement and advocacy work is associated with the Cornelia Hahn Oberlander International Landscape Architecture Prize he received from the Cultural Landscape Foundation (TCLF).