Contemporary challenges, such as pollution, climate change, biodiversity loss, and the escalating trend of pandemics and chronic illnesses, are deeply intertwined through an intricate web of environmental- and lifestyle-related factors. Therefore, these problems cannot be effectively addressed within disciplinary silos, and solutions must be found at a systemic level.

Mental illnesses are on the rise globally, with suicide ranking as one of the leading causes of death among young people in many countries, according to the World Health Organization. The Covid-19 pandemic exacerbated the situation, resulting in a 25 percent increase in the prevalence of depression and anxiety worldwide. Other noncommunicable diseases, like diabetes, stroke, and cancer, are also imposing significant suffering and costs on society. Following the export of Western lifestyles, these diseases are also now spreading in low- and middle-income countries, which are experiencing rapid, unstructured urbanization. Across the globe, we are replacing natural land with concrete surfaces and built-up infrastructure and, with this, humans are increasingly disconnected from nature. For a species that is, by evolutionary origin, a hunter-gatherer, would it not be strange if this disconnection did not affect both mental and physical health?

In 1984, Roger Ulrich published a pioneering study in the journal Science, demonstrating the healing power of nature. Following gallbladder surgery, patients showed faster recovery if they had views of trees from their windows compared to having views of a brick wall. Five decades later, a wealth of evidence supports nature’s role in reducing stress and improving health and well-being. This evidence needs to be proactively considered in urban planning since more than half of the world’s population resides in cities. There have been a sufficient number of well-conducted studies to assert that children grow up happier and become healthier adults if exposed to nature in early life, that people live longer in green areas, and that views of green spaces reduce the risk of depression. We even know some of the mechanisms behind these remarkable impacts. From hosting microorganisms that boost the human immune system to fighting heat-related morbidity, urban nature provides a broad range of services that promote health and well-being and prevent disease. Neuroimaging studies even prove that the structure and function of our brains are positively impacted by exposure to nature, making us less prone to rumination and better prepared to cope with daily stressors.

So, are we ready to take this evidence on board and develop healthy and green cities? Currently, voices against science-based urban greening present concerns about the need for densification, losses for local economies, and the risks of allergies and vector-borne diseases. On the other hand, it is rarely considered that modern lifestyles and disturbed biodiversity-microbiota relations are part of the explanation for the increase in allergies and other immune-system-related disorders. Equally, human-caused climate change and disturbance of natural habitats force the spread of vectors into inhabited, urban areas. Hence, we need to address the root of the problem—the anthropogenic disturbances and contemporary lifestyles—and make peace with nature instead of disconnecting even further.

The Bosco Verticale is a prime example of science put into practice while embracing nature. Acting as a home for humans, birds, butterflies, and various other species, it contributes to an unprecedented level of urban biodiversity with immediate benefits for human health. In the Bosco Verticale, human life and natural ecosystems coexist, a symbiotic relationship that fosters ecological awareness and provides health benefits across the course of life. Future cities should continue along this path to ensure a healthy and peaceful relationship with the natural world to which we belong.