As global temperatures continue to rise, the instinctive human urge to hide indoors with the air conditioning running is having a devastating, hidden side effect: it is slowly killing the vibrancy and social diversity of our cities.
According to a new study analysing the mobile phone data of 13 million people, extreme heat drastically reshapes daily human behaviour, reducing individual mobility and actively segregating society along socio-economic lines.
Published in the journal PNAS Nexus, the research warns that as climate change accelerates, heatwaves will not only increase physical illness but also fundamentally alter the social dynamics of urban life.
The great stay-at-home
To understand exactly how temperature affects human movement at scale, researchers Andrew Renninger of University College London and Carmen Cabrera of the University of Liverpool focused on Spain, a nation where heatwaves are predicted to become significantly more intense in the coming decades.
Using aggregated, anonymous data from the Spanish Ministry for Transport and Sustainable Mobility, the team tracked the daily movements of 27 per cent of the entire Spanish population.
The authors found that on hot days, overall mobility falls by as much as 10 per cent. When temperatures peak during hot afternoons, movement plummets by a staggering 20 per cent. Physical and outdoor activities are increasingly being shifted entirely to the evening and night hours to avoid the sun.
A socially segregated society
However, the researchers discovered that the ability to escape the heat is a luxury not everyone can afford.
The data revealed that while extreme heat significantly reduces mobility among the elderly, there is a stark divide by wealth. Affluent citizens are highly likely to reduce their mobility during a heatwave, choosing to work remotely or skip social events. Conversely, lower-income individuals rarely reduce their movement, as they are financially unable or unwilling to skip work and often lack access to remote working opportunities.
As a direct result of this socio-economic divide, vital social mixing between different classes effectively collapses during hot weather.
While modern society’s default solution is to install more air conditioning, the authors warn that this approach will only further isolate people in their homes, effectively destroying urban dynamism and the bustling nature of city centres.
Instead, the researchers argue that governments must urgently invest in the heavy greening and shading of urban cores to keep public spaces liveable, attractive, and socially integrated as the planet continues to warm.
