Go back to nature for livable 21st century cities
By the middle of this century, two out of every three people will live in cities. This upsurge in city dwellers, coupled with the real challenges of climate change, presents us with a problem — how can our cities be places where people and ecosystems thrive?
The answer lies in nature. Following this year’s World Water Day, we reflect on the importance of nature-based solutions to solving the water challenges we face. For example, reconnecting rivers to floodplains and restoring wetlands are a sustainable and cost-effective way to help rebalance the water cycle, mitigate the effects of climate change and improve our health.
If you want healthy and productive communities, balance with nature is non-negotiable. Cities must ensure clean air and water and give citizens access to nature in order to compete in a global market for talent and growth.
At the Nature Conservancy, we work regularly with urban residents, city planners, academics and the private sector to incorporate natural solutions into cities to make them more resilient and livable. It’s encouraging to see numerous innovative projects in Hong Kong and Shenzhen that help make the case for turning to nature for sustainable urban planning solutions.
Hong Kong’s commitment to country parks has helped create a vibrant and livable city. But we can do more, as the benefits of nature go far beyond aesthetics and pay significant financial dividends. Clean water alone can add billions of dollars to a regional economy. One great example of this is the humble oyster and the positive impact that restoring Hong Kong’s historically extensive oyster reefs can have on coastal resilience and water quality.
For more than 700 years, oysters have been an important part of economic and cultural life in Hong Kong — unsurprising since oyster sauce was developed here and Hong Kong people eat four times more seafood than the global average. However, as well as being food, oysters are a critical marine habitat. With an estimated 85 percent of our global oyster reefs lost, it’s the most endangered marine habitat in the world.
Oysters have a remarkable ability to keep water clean by filtering excess nutrients and sediment from the water column and transforming them into food for small marine animals that in turn support fish production. Hong Kong oysters are world champions in filtration — each adult oyster filters more than 700 liters a day. Oyster reefs — like mangroves and seagrass — also protect coastlines from storm surges and rising waters that will come with climate change.
What can help unlock the full potential for oyster reefs in Hong Kong is official recognition of their status both as a conservation habitat and nursery for fish — like mangroves and coral reefs — and as an integral part of the government’s existing strategy to develop local sustainable fisheries for finfish and oysters themselves.
Sustainable oyster farming in Deep Bay should also be supported. Despite the long-established oyster farming industry, it isn’t recognized as an official fishery, nor are there any gazetted oyster farming locations in Hong Kong. This is a missed opportunity. When done properly, shellfish aquaculture can provide net benefits to the environment and even help accelerate restoration efforts. The majority of oyster produce in Hong Kong now comes from offshore floating racks as opposed to small quantities grown out on shoreline mudflats. Restoring shoreline oyster reef habitats has significant potential to complement offshore aquaculture and simultaneously rehabilitate marine ecosystems and local fisheries resources. The Hong Kong government has already launched artificial coral reef programs with fishery rehabilitation in mind; including oyster reefs in the bill would augment positive results.
The Pearl River Delta region, with its burgeoning economy and fast-growing cities, represents an unprecedented opportunity to build a major global center for the 21st century in the right way. By using nature-based solutions to help meet the water needs of the fast-growing PRD population, we can help protect the environment and reduce pollution.
In Shenzhen, there are plans to run a pilot “sponge city” program to test innovative ways to capture rain and runoff, prevent flooding and protect water quality in rivers, estuaries and bays. The sponge city concept is gaining traction around the world, and redevelopment in the PRD presents opportunities to put these strategies to work on a grand scale. Flood protection can prevent billions of dollars in damage, and the upfront costs are relatively small. Plazas, parking areas and even some streets can be built with permeable surfaces. This work can also create green spaces for recreation and improve air and water quality.
Going back to nature offers effective alternative engineering solutions as corporate leaders, universities and local governments increasingly take a more sustainable approach to urban planning. It’s heartening to see that so many institutions across the public and private sectors are working together to help cities and the nature and people living within them flourish. After all, it’s the natural solution.