Cities depend on their surrounding bio-physical landscape, utilising goods and services provided to urban populations from ecosystems. These include provisioning services such as food and water; regulating services such as climate and flood control; supporting services such as nutrient cycling and crop pollination; and cultural services such as connecting urban inhabitants to natural values. The health of the ecological system within and surrounding the city influences the health of the city itself. UN Environment recognises that building the resilience of urban populations depends on how climate and non-climate drivers are tackled together. The management of urban and surrounding peri-urban ecosystems has the potential to contribute significantly to the overall resilience of the city to climate change and other pressures.
Urban Ecosystem-based approaches to Adaptation (EbA) is an adaptation approach that aims to build resilience of the ecosystems surrounding and within city boundaries, of peri-urban areas and of the broader landscape. For example, the restoration of degraded watersheds – forests, rivers and other ecosystems within a city’s ecological hinterland – to improve drinking water availability and quality; the regulation of river flows for abstraction and mitigation of flood risk; control of sediment flow and salinity; as well as providing attractive landscapes to urban populations.
Through its urban EbA programme, UN Environment provides cost-effective adaptation solutions to cities seeking to maximize ecosystem goods and services to their populations and strengthen the role of urban institutions, leaving cities more resilient to climate change impacts such as sea level rise, flooding, freshwater and food insecurity, and urban heat island effects.
The goals of the urban EbA programme are twofold:
• Reduced vulnerability of urban populations to climate change impacts by preventing critical ecosystem losses under current and future climate and socio-economic scenarios, and secure future provision of ecosystem services to urban populations.
• Strengthened governance, knowledge and capacity at national and city level to understand the socio-ecological interactions between ecosystems and cities, including the trade-offs between competing land uses; and national and city authorities and institutions able to sustainably manage urban ecosystems for current and future urban populations.
UN Environment is executing two regional urban EbA projects, funded by the Least Developed Countries Fund and the Special Climate Change Fund under the Global Environment Facility. One in Asia is working with the cities of Thimphu (Bhutan), Kep (Cambodia), Phongsaly and Oudomxay (Lao PDR) and Mandalay (Myanmar), delivering on-the-ground urban EbA activities centred on reforestation, urban agriculture and restoration of wetlands in urban areas.
The second is in the Latin America and Caribbean region. In San Salvador (El Salvador), the project is implementing climate-resilient reforestation and conservation agriculture approaches to restore the degraded Arenal-Monserrat watershed; in Kingston (Jamaica), the Hope watershed that surrounds the city will be restored to mitigate the impacts of more frequent and severe floods and droughts; and in Xalapa (Mexico), revegetation and soil conservation at the watershed scale will be undertaken along the El Palenquillo stream using native riparian species adapted to regular flooding.
In addition, UN Environment and the Government of Lao PDR are developing a large scale urban EbA project in six of the country’s most populated and climate vulnerable cities, including the capital Vientiane for funding by the Green Climate Fund. Through urban EbA interventions the project seeks to reduce the climate vulnerability of up to 820,000 people.