Climate change impacts people’s health in cities in many ways and urban environment influences the severity of these impacts

The new paper published within the Academy of Finland-funded project HERCULES explores the ways urban environment moderates the impacts of climate change on health in cities

The effects of direct impacts of climate change on people in cities are quite well-studied – we know what the possible health impacts of heatwaves or floods on cities’ residents are. However, climate change also influences peoples’ health through other not so well understood mechanisms.

The impacts of climate change can also be postponed in time and in space (‘deferred’). For example, heat waves not only cause direct impacts (such as e.g., cardio-vascular diseases) but also prolonged outdoor work in heat can manifest in kidney diseases in the future. Similarly, postponed impacts of floods can manifest in mental health issues related to post-traumatic stress disorder and anxiety.  

Climate change can also have indirect impacts on people’s health. These impacts occur when climate change causes disturbances in ecological systems (including water supply, air quality, soil quality), and the impacts are inflicted on people’s health through these. For example, it is known that heat will exacerbate air pollution, and thus the severity of respiratory diseases associated with poor air quality is increased with the global warming. Similarly, floods may have indirect and postponed effects on indoor air quality through damp materials, manifesting in allergies and various respiratory conditions.

The purpose of the Academy-funded project HERCULES is to understand how urban environment shapes the impacts of climate change on people’s health – how it influences their emergence and severity. Our latest paper synthesizes pathways of climate change impacts on health and explores how urban environment shapes them. When we examine urban environment, we look at the factors that relate to physical environment (landscape, local topography, built environment), social environment (access to social and health care services, social connectedness), and policy and planning.

In the study we observed that urban form influences the emergence and severity of all types of impacts from both heat- and precipitation-related hazards. For example, green infrastructure and density of built environment have a moderating effect on UHI, exacerbating or alleviating heat risk. Urban planning efforts aimed at cooling effect such as more sparsely built environment, wind corridors, increased green canopy, have co-benefits for reducing health impacts caused by heat and by worsened air quality.

Understanding the factors of urban environment influencing the severity of the impacts is helpful as it gives starting points for adaptation and for overall urban policy and planning. Mapping these factors across different mechanisms allows to explore possible options for adaptation co-benefits and to avoid possible maladaptation. Co-benefits means that policies and interventions can help achieve several positive outcomes, while maladaptation means unintended negative outcomes. Additionally, exploring adaptation options across direct, indirect and deferred pathways allows for strategic planning and better prioritizing. Thus, by preventing and minimizing direct impacts, many of the deferred and indirect risks can also be averted or minimized. For example, in the aftermath of floods and associated direct impacts, adequate disaster relief providing shelter, food, water, and sanitation helps minimize also the indirect risks through contaminated water and food.

More on how urban environment moderates the impacts of climate change on our health, and on how to approach this, can be found in the article.