About 57% of the world’s population, ~4.46 billion people, currently live in cities. This number is expected to increase to 6.7 billion, or more than two-thirds of the global population, by 2050. This rapid urbanization trend is expected to result in increased climate change, nature loss, and pollution. Cities, which consume 75% of natural resources and are responsible for 80% of global GDP, hold significant political, financial, and social capital that can drive the transition to a sustainable future.
Due to rapid urbanization, cities are increasingly facing the wrath of climate change, including more frequent occurrences of natural disasters mainly caused due to changing weather patterns and the urban heat island effect. The heat island effect arises when cities exhibit significantly higher temperatures than surrounding areas and are mainly caused by anthropogenic activities through the rapid and heavy urbanization of an area. Urban heat island effect is exacerbated by heatwaves, which often result in the loss of human, animal and plant lives. Instances of urban heat island effects and flooding have specifically shown an increased trend in the recent years. Several occurrences of extensive flooding occurred globally, such as the flooding in Greece, Bulgaria, and Turkey due to Cyclone Daniel in 2023 and the severe floods affecting multiple European countries in July 2021. Furthermore, according to the World Health Organization, the population exposed to heatwaves increased by approximately 125 million between 2000 and 2016. Additionally, there is a projected annual increase of 250,000 deaths from climate-sensitive diseases from 2030 onwards.
In this context, Nature-based Solutions, often referred to as ‘NBS’ can effectively address the social, economic, and environmental issues faced by cities as a result of increased urbanization. As per the International Union for Conservation of Nature, 2016, “Nature-based solutions are defined as actions to protect, sustainably manage, and restore natural or modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits”. Nature-based Solutions or NBS not only contribute to greenhouse gas emissions reductions and help communities adapt to adverse effects of climate change but also contribute to positive impacts on ecosystems and biodiversity. The following image depicts the global challenges that NBS can tackle and the short-term/long-term advantages it provides.
The focus of Nature-based Solutions is comprehensive and incorporates different aspects of urban development, ranging from improved urban resilience to urban regeneration. It encompasses various climate actions, such as restoring natural habitats, managing water resources effectively, reducing disaster risks, and promoting green infrastructure, with the aim of addressing various socio-economic challenges.
Countries around the world are increasingly integrating NBS as an essential factor in their approaches to building sustainable and resilient cities. This trend highlights a rising awareness of the advantages that NBS offers in addressing environmental challenges and improving overall urban life.
The most appealing feature of NBS is their easy accessibility and can be implemented at both individual level at homes or at community level. Under both circumstances, eco friendly activities such as installing green roofs and green walls, initiating rainwater harvesting systems, recycling grey water from households, or encouraging grey water recycling in public buildings by municipalities can be undertaken. Additionally, reforestation efforts can be promoted within communities to help absorb pollutants, mitigate noise pollution and moderate air temperature. Similar activities in wetland areas and also rain gardens will help reduce flood risks. Green spaces like parks and gardens, further provide spiritual nourishment, encourage community interaction, and contribute to overall well-being. Below are several common examples of nature-based solutions implemented in cities worldwide. (The purpose of specifically listing examples at these levels is to encourage readers to take small steps towards implementing NBS).
- Green roofs: Also commonly referred to as ‘vegetated roofs’ or ‘living roofs’ are roofs consisting of a layer of vegetation (waterproofing membrane, soil and plants) grown on top of a traditional roof
- Green walls: In simple words, green walls or green façade consists of plants grown the exterior of the buildings. Typically, a façade consists of a supporting structure upon which plants grow vertically
- Urban green spaces: Urban Green Spaces or UGS refers to urban areas that are partially or fully covered with grass, trees, shrubs, or other forms of vegetation. Some common examples of UGS are large urban parks, pocket parks, community gardens, botanical gardens, etc.
- Permeable pavements: These refer to pavements that that are porous in nature. Rainwater falling on the surface or surface water run-off penetrates the pores and is stored in a reservoir before being infiltrated into the soil
- Constructed wetlands: Constructed wetlands are basically engineered shallow ponds, that incorporate vegetation, soil, water and microorganisms to treat sewage, greywater, stormwater runoff or industrial wastewater
- Rain gardens: Looking similar to normal gardens, rain gardens are designed to stop stormwater run-off. Planted with grasses and flowering perennials, rain gardens are built on small depressions and gathers rainwater from rooftops, driveways, or streets. In comparison to a traditional garden, rain gardens facilitate a 30% greater absorption of water into the soil
Despite the far-reaching positive effects of Nature-based Solutions, the implementation of NBS faces numerous challenges. These include a lack of awareness and understanding among the general public regarding the concept and benefits of NBS, financial constraints due to high upfront costs, limitations in land use, and inadequate support or incentives from existing policies, regulations, and zoning laws.
Addressing these challenges requires the engagement of various government and private stakeholders. Solutions involve updating land use policies to integrate NBS implementation, fostering participative co-generation stakeholder strategies, introducing financial grants, subsidies, or tax incentives to alleviate or reduce the initial costs of implementing NBS while also introducing payments for ecosystem services, and conducting awareness workshops and campaigns to highlight the benefits of NBS.
It is therefore evident that by judicious tapping of natural resources, NBS offers immense potential for addressing environmental challenges, enhancing climate resilience and promoting sustainability. Easy accessibility of NBS facilitates individuals and communities to play a greater and active role in implementing climate action goals. Whether through installing green infrastructure on rooftops, installing rain gardens, or supporting and promoting NBS-friendly policies, each one of us can contribute to creating more sustainable urban environments. Nature-based Solutions represents a transformative and participative approach to urban development while prioritizing the well-being of both people and the planet.