In the city, every little green space is important – the constant Kyoto – blog

Recently, much attention has been given in the scientific field to the role of cities in combating climate change. This is clearly due to the fact that an ever-increasing proportion of the world’s population is moving to urban areas and cities will play a quantitatively important role as a source of climate-changing gases.

Indeed, the role of cities in relation to climate change is twofold: they play an active role, but they also play a passive role. The active role is due to its emissions (especially carbon dioxide), which drive the climate to a rise in temperature, and the negative role to the effects it suffers from due to climate change, especially the intense heat waves, which are amplified by the phenomenon of heat islands in the city, and extreme phenomena. From violent avalanches, harbingers of disaster.

However, the effective role is not only of emissions, but also of absorption, through the green spaces present in the city. These removals have long been thought to be responsible for a small proportion of emissions, and previous studies have shown this. But now, in the international journal Environmental Research Letters One has been posted study by Dandan Wei, of Columbia University in New York, and collaborators who show how absorption values ​​are generally underestimated.

Taking what’s happening in New York City as an example, Wei and colleagues show how previous results are underestimated because only relatively low-resolution observations so far that were able to “see,” and thus are taken into account in the assimilation calculations, are only vast green areas. Now instead, using a green urban map and a high-resolution model, which also takes into account small green areas, the authors of this study show how 40% of the carbon dioxide emitted in the city is absorbed in New York on a summer afternoon. from urban areas. It remains to be understood which plants absorb more and at the same time do not produce the so-called “terpenes”, which contribute to the formation of ozone, a pollutant harmful to the airways.

In short, to plan a city, but also our small gardening business, we must understand that all green spaces are important, even those “immersed” in concrete and asphalt!

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