Green in the city, from climate to water increasingly a resource
Green areas reduce rising temperatures and act as reservoirs of Co2, as well as dams for water and pollution.
Key points
- - Urban parks contain rising temperatures by up to 3-5°C
- - Green areas absorb up to approximately 32.6 kg of CO₂ per square metre
- - New York, Seoul, Paris, Madrid and Valencia, the advantages in scientific studies
- - Survey on Milan's parks: one in five willing to pay to maintain them
(Il Sole 24 Ore Radiocor) - With spring, urban parks are becoming crowded again, increasingly the social heart of cities. But their economic and environmental weight is increasing with climate change, so much so that they are now an indispensable bulwark. And citizens for one are increasingly aware of this.
The benefits for climate and emissions
Every year now records record after record of rising temperatures and this is even truer for cities with urban areas seeing the thermometer rise by up to +3°C in metropolitan areas compared to surrounding areas. Well, the green areas are on average almost 1°C cooler than the rest of the city, so much so that it is estimated that increasing tree cover by 10% can reduce temperatures by as much as 3-5°C. "This is not only an environmental fact, but has direct effects on daily life, as well as on energy consumption: less heat also means less need for air conditioning. Systems such as green roofs can reduce the energy consumption of buildings by between 2% and 17%, and green walls by between 10% and 30%," says Benedetta Lucchitta of Bocconi University's Green Research Centre.
Scientific literature shows that urban green areas are no longer just 'decorative': it is estimated that they can absorb up to around 2.4 tonnes of CO₂ per hectare each year. If we look at the total stock, i.e. how much CO₂ they manage to store over time, parks and green areas can get up to around 32.6 kg of CO₂ per square metre. "Translated into more intuitive terms, this means that a single urban park can function as a true diffuse carbon sink, which on a city scale becomes comparable to that of much larger areas of forest," he explains.
Added to this is the issue of water. Green infrastructure, such as drainage beds or natural rainfall management systems, can reduce rainwater runoff by up to 26-52 per cent. "In practice, this means less water in roads and drains during intense events, and therefore less risk of flooding," Lucchitta adds.
Not to mention the economic benefits. Ecosystems are a fundamental component of the global economic system: it is estimated that over 50% of the world's GDP depends directly or indirectly on ecosystem services. Which means that cities that invest in their parks, even more so by redesigning their landscapes in the context of urban regeneration, are not just making an environmental investment, but activating a real strategic economic lever.
