Are City Buildings Making Us Hotter?
Soaring city buildings are contributing to sky-high climates leaving city-dwellers sweltering. But why?
In this blog we look at why the material the buildings are made from is having an impact, as well as their towering heights and why the time has come for things to cool down.
In 2013, the glare from a 37-floor building on Fenchurch Street in London was so powerful, it melted parked vehicles and damaged local shops. Experts put this down to a strong sun directly shining onto the building and remedied it by adding protective shading.
As our summers continue to get warmer and temperatures in general are more extreme all year round, our city environment is gradually becoming a much hotter place. Buildings absorb heat as well as letting heat out, so thought needs to be given to the spaces between buildings not just the spaces inside buildings.
Cities are said to be 10° hotter than surrounding areas. You only need to look around to see the many factors contributing to the problem. Standing traffic generating hot fumes; air conditioning units from shops and offices churning out warm air; concrete and asphalt absorbing and radiating heat; and skyscrapers trapping heat at ground level. It’s a phenomenon known as the Urban Heat Island and, apart from leaving us all feeling hot and sticky, it can be a serious risk to health.
Excessively warm temperatures can lead to an increase in heart attacks, strokes and mortality rates. In the UK, heat-related deaths are set to increase by 257% by 2050 and 535% by 2080. But, the good news is, there are ways to tackle the problem and, in doing so, we will create better places in which to live, work and play.
Cities can be made cooler through the introduction of new building materials. Urban areas tend to be dominated by dark, hard materials such as concrete, asphalt, granite and paving, most of which absorb, rather than reflect, solar radiation.
Lighter pigments in asphalt or white-coloured surfaces applied to roads, roofs and facades and known as ‘cool coatings’ would reflect more heat away from the city. It sounds simple, but the results in reducing temperatures can be significant.
Think of a way to reduce your own temperature and you immediately think of a refreshing cold drink. Water has been used as a tool to cool cities for centuries. Incorporating ponds, pools, fountains, sprinklers and misting systems into outdoor spaces would help heat-proof our cities.
If you have ever escaped the heat under a tree on a hot day, you’ll appreciate the importance of vegetation in cities. Greenery not only looks attractive and provides vital shade, but the water evaporating from plants reduces the surrounding temperature. Gardens – both high rise and ground level – should therefore become an integral part of inner city design.
As with the skyscraper in London, the importance of shading on buildings cannot be over-emphasised, especially in fully-glazed constructions. Walls of glass may afford wonderful views and lots of natural light, but they can also trap unwanted heat when temperatures rise. In Abu Dhabi, a radical example to counteract this can be seen on one towering glass building, whereby a management system operates 1,049 hexagon-shaped shades, opening and closing them like flowers, dependent on the heat.
Intuitive, forward-thinking design and versatile, resilient buildings which can resist or react to rising temperatures and climate challenges will play an important role in keeping our cities cool and comfortable in the future.