This summer, we are registering record temperatures across the planet. Extreme heat is one of the clearest consequences of climate change. Studies show that in the future, we will experience increasingly prolonged heatwaves and a higher frequency of tropical nights — something that is already very evident in many Mediterranean cities in Spain.
The effects of this phenomenon disproportionately impact the most vulnerable populations, those with less capacity to adapt to climate change and cope with rising temperatures, due to both social factors and urban environmental conditions.
In cities, this effect is worsened by the so-called urban heat island phenomenon, caused by the design and materials of urban areas, which retain heat and lead to higher temperatures compared to natural environments.
All of this has significant consequences for both human and environmental health. Heat stress is linked to increased summer mortality in European cities and also negatively affects the wellbeing of marine ecosystems.
But how can we mitigate these effects in our urban environments?
Recently, we conducted several studies in cities of the metropolitan area of Barcelona to analyze the density and distribution of green spaces per inhabitant. While many global standards and recommendations exist, such as the WHO guideline of 10 square meters of green space per inhabitant, most cities fall far short of this target.
In our study of the city of Barcelona, we observed that most of the municipality falls below the recommended levels, reducing residents’ ability to adapt to rising temperatures.
Having green spaces close to our homes improves our surroundings by enhancing air quality, regulating temperature, preventing flooding, and supporting biodiversity. In turn, this has numerous benefits for human health by encouraging physical activity and reducing the prevalence of diseases like depression and asthma.
Figure 1: NDVI (Normalized Difference Vegetation Index)
Figure 2: Green surface per capita
The conditions of the environments we live in have a major influence on our health. Reducing urban inequalities requires integrated territorial strategies that place health and wellbeing at their core. To properly design these strategies, having an accurate diagnosis of the context is essential. In this regard, open data sources like satellite imagery allow us to analyze green infrastructure and determine where and how to intervene.
For this study, we calculated NDVI (Normalized Difference Vegetation Index) using imagery from the Sentinel-2 satellite of the European Commission’s Copernicus Earth observation program. We thank Minna-Maria Karvonen for her contribution to Healthy Cities in helping to systematize spatial analysis processes like this one.
