Cities are home to 55% of the world population and expanding. Our increasingly urban lifestyles strain ecosystems and contribute to climate change. Home to 80% of global GDP, cities are responsible for 70% of CO2 emissions and 75% of natural resource consumption. They are also increasingly vulnerable in the face of a warming world.  
 

Rising climate vulnerability in cities

The 2022 IPCC report on impacts, adaptation and vulnerability further sounds the alarm. The climate crisis affects people and nature worldwide: from droughts, fires and floods caused by extreme weather to coral reef destruction from ocean acidification. These impacts will increase as global temperatures rise. Climate change especially impacts vulnerable urban populations, many living in informal settlements. Ensuring cities are resilient is essential to absorb these stressors, while maintaining function when facing compounding threats.  
 
Cities are places of challenge and change, but also testing grounds for innovative new ideas, including how to better integrate nature-based solutions (NbS) to achieve human and ecological benefits. NbS are one tool, of many, that we can use to mitigate the impacts of climate change.  
 

Role of nature-based solutions

IUCN defines nature-based solutions as “actions to protect, sustainably manage, and restore natural or modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human wellbeing and biodiversity benefits.”  
 
WWF emphasizes that NbS should be designed to address clear societal challenges identified with and for beneficiaries: food security, climate change, water security, human health, disaster risk, natural and economic development, whilst protecting nature through monitoring of robust indicators. Examples of urban nature-based solutions include street trees, green roofs, as well as green or blue corridors connecting cities and nature areas.  
 

Nature-based solutions help improve resilience

At the landscape level, nature-based solutions contribute to climate policies, enabling enhanced Nationally Determined Contributions to ratchet up climate ambition to stay below 1.5°C of global warming. In cities, NbS can foster sustainable development, climate targets and protect urban biodiversity.  
 
Nature-based solutions improve resilience and liveability as integrating nature into cities can: reduce extreme weather impacts; mitigate urban heat; recharge aquifers and reduce urban flooding; filter air pollutants; improve health and wellbeing; and provide low-skilled and high-skilled job opportunities. Urban and peri-urban NbS have been effective in cities around the world, in developed and developing countries, in megacities and small towns, in agricultural, forestry and coastal zones.  
 

Nature-based solutions should adhere to local realities

Integrating urban nature-based solutions should adhere to local climatic and geographic realities, prioritizing native climate-resilient plants. WWF conducted a case study review of urban NbS in leading cities in several categories: (1) nature-based buildings and neighbourhoods – to integrate nature in the built environment; (2) vegetation, agriculture and forestry – with native vegetation in public spaces design and urban parks; (3) living rivers – to provide freshwater, prevent floods, improve wildlife habitats and offer a cooling effect; as well as (4) living shorelines – critical considering 40% of humanity reside near coastal zones, facing escalating threats from the climate crisis.  
 

Benefits for cities

The WWF report on urban NbS in leading cities found that investing in urban nature can result in economic and social benefits. Similarly, to tackle increasing cooling demand in a warmer and more urban climate, urban nature can reduce cooling demand and improve outdoor thermal comfort, according to the UNEP-led Cool Coalition’s Beating the Heat Guide.  
 
A similar localized study was conducted in Tshwane, South Africa, with comparable results: investing in urban nature has significant payback and extended benefits, according to WWF South Africa and IISD. 
 

Nature-based solutions must be the backbone of future development

As highlighted in the IPCC report, climate science indicates more severe consequences, including increasing vulnerability in our cities. Efforts to integrate nature in cities should be the backbone of future urban development and planning. If cities achieve this, the result will not only be more resilient cities, but also lead to improvements in quality of life, healthier cities and the creation of millions of livelihood-enhancing jobs.