Green Infrastructure in the cities: A Natural Shield Against CO2
In a world grappling with increasing climate change intensity, cities, as centers of population and economic activity, are at the heart of both the problem and the solution. Urban expansion and intense human activity contribute significantly to carbon dioxide () emissions, exacerbating the greenhouse effect. However, cities also possess the potential to become pioneers in the green transition, adopting innovative solutions that harness nature to combat the climate crisis. Green infrastructure is emerging as one of the most effective and sustainable ways for natural sequestration, while offering multiple benefits for the urban environment and its inhabitants.
Forms of Green Infrastructure and the CO2 Sequestration Mechanism
Green infrastructure encompasses a wide range of natural and semi-natural systems integrated into the urban landscape, with the primary goal of improving environmental quality. The most characteristic forms include:
Urban Forest Corridors: These are systems of trees and vegetation created or maintained within and around cities, acting as "lungs." Through photosynthesis, trees absorb from the atmosphere and store it in their biomass (trunk, branches, leaves) and in the soil. These corridors can connect parks, rivers, or other green areas, creating a network that enhances biodiversity and offers natural recreational spaces.
Green Roofs: These are building roofs covered with vegetation. In addition to aesthetic enhancement, green roofs contribute to sequestration through plant photosynthesis. Furthermore, they provide thermal insulation, reducing the need for air conditioning and heating, and manage stormwater, lessening the burden on drainage systems.
Moss Walls: These are vertical surfaces covered with specially cultivated mosses. Mosses are highly effective at absorbing pollutants, including , as well as particulate matter from the air. They are ideal for urban environments with limited space, offering an innovative solution for improving air quality in busy areas.
The sequestration mechanism is common: plants, through photosynthesis, convert atmospheric into organic matter, storing it and releasing oxygen. This natural process is vital for balancing the carbon cycle.
Multiple Benefits and Quantitative Impact
The impact of green infrastructure in combating climate change is significant. According to data reported by the OECD, urban forest corridors, green roofs, and moss walls can absorb up to per city. This amount, although it may seem small relative to total emissions, is crucial, especially when applied on a large scale in many cities worldwide.
Beyond sequestration, green infrastructure offers a multitude of other environmental and social benefits:
Improved Air Quality: Plants act as natural filters, absorbing not only but also other atmospheric pollutants, such as nitrogen oxides, sulfur dioxide, and particulate matter. This leads to cleaner and healthier air for city residents.
Reduction of Urban Heat Islands: Urban areas tend to be warmer than rural areas due to the absorption and release of heat from dark surfaces (asphalt, concrete) and the lack of vegetation. Green infrastructure, through shading and plant transpiration, helps reduce ambient temperatures, creating more comfortable living conditions and decreasing the need for energy-intensive cooling systems.
Enhancement of Biodiversity: Green spaces provide habitats for urban wildlife, contributing to the preservation of biodiversity within cities.
Psychological and Social Benefits: Access to green spaces improves mental health, reduces stress, and enhances social cohesion, offering spaces for recreation and interaction.
The Role of Policies and Public-Private Partnerships
Implementing large-scale green infrastructure projects requires coordinated effort and strong political will. Policies encouraging public-private partnerships are crucial for accelerating the implementation of these projects. As highlighted in OECD press releases (e.g., "Renewed momentum for ETS…"), collaboration between governments, municipalities, private companies, and local communities can unlock funding, expertise, and innovative solutions.
Governments can provide incentives, such as tax breaks, subsidies, or simplified licensing procedures, for private investments in green roofs, vertical gardens, or the development of urban forests. Private companies, in turn, can offer technological solutions, specialized services, and capital, while citizens can actively participate in planting and maintenance initiatives.
Conclusions and Prospects
Urban green infrastructure is not merely an environmental choice but a necessity for creating sustainable, resilient, and pleasant urban centers. Its ability to naturally sequester , combined with the multiple benefits for air quality, temperature, and quality of life, makes it a cornerstone of 21st-century urban development strategies.
Strengthening public-private partnerships and adopting innovative policies will accelerate the implementation of these solutions, transforming cities into green oases that actively contribute to combating climate change and building a better future for all. Investing in green infrastructure is an investment in the health, well-being, and sustainability of our urban ecosystems.