You’ve probably heard that Earth is becoming an urban planet — and you’ll definitely be seeing it around the world over the next two decades. While the planet’s total urban area is projected to triple in size from 2000 levels over that period, urban populations will nearly double to 4.9 billion.
But do we really know — outside of doom-and-gloom scenarios — what that urban expansion might mean for natural resources and biodiversity?
That’s the question tackled by the new UN report “Global Urbanization, Biodiversity, and Ecosystem Services: Challenges and Opportunities,” released on Friday. The report, compiled by the UN Cities and Biodiversity Outlook project, addresses potential problems with this rapid urban expansion and offers solutions that will benefit urban populations while protecting ecosystems and maintaining biodiversity.
“This is the first global assessment of how this phenomenally fast urban growth occurring globally will affect the natural world,” says Rob McDonald, Nature Conservancy senior scientist for urban sustainability and one of the senior editors of the report, which had more than 120 contributing scientists from around the world.
“The assessment shows the ways cities depend on the natural world: forests for keeping drinking water, wetlands for mitigating the risk of flooding, urban parks to make our cities vibrant and livable,” McDonald adds. “It turns out that an urban planet needs nature more than ever.”
NATURE AND URBAN EXPANSION: KEY FINDINGS
+ Despite common belief, cities can maintain rich biodiversity. For instance, although it’s surrounded by Cape Town, South Africa’s Table Mountain National Park houses extraordinarily rich biodiversity.
+ There is added incentive to protect ecosystems when their value is quantified in economic terms. When a study revealed that it would cost $2 million a year to maintain a water-purification facility to do the same filtration work as the Nakivubo Swamps in Uganda, local officials decided to preserve the swamps instead of draining them to make way for agriculture.
+ Urban ecosystems can mitigate climate change. A good example: The Green Roof Program in Mexico City, which plans to improve air quality, regulate humidity, reduce temperatures and enhance biodiversity by building 10,000 square meters of green roofs annually.
+ Locally grown, biologically diverse foods enhance food security in urban areas. Lufa Farms, a rooftop garden in Montreal, produces more than 25 varieties of vegetables year round without using any artificial pesticides, fungicides, or herbicides.
McDonald expects that the report will provide critical information for urban planners and conservationists alike.
“There will be close to 3 billion more people in cities by 2050, and the main sponsor of the assessment — the Convention on Biological Diversity — wants to know how to do their job on an urban planet. That’s an issue the Nature Conservancy cares about too,” adds McDonald.