How can you build a city fit for a 50℃ heatwave?

It's not clear Dubai's golf courses can survive climate change. Image: Getty.

The Persian Gulf is already one of the hottest parts of the world – but by the end of the century increasing heat, combined with intense humidity, will make the region too hot for habitation, according to research published in Nature Climate Change.

Heating and air conditioning currently permit humans to live everywhere from Siberia to the Sahara. However the extreme heatwaves predicted for the Gulf, where temperatures will regularly hit 50℃ or even 60℃, will reach the limits of the thermal adaptation that buildings can provide.


Our ancestors lived without the sophisticated thermal control systems we typically use in modern buildings; they implicitly used different “bioclimatic designs”, such as natural ventilation or south-facing windows, and these skills are still valuable in many climates today. But the latest data suggest this will not be enough.

So is there a future for habitation in the hottest regions of the world? It seems mass migration is less likely than staying put and taking on the challenge.

However, figuring out how to live comfortably and sustainably while it’s hot enough to fry an egg on the sidewalk may provide a fillip for environmentally sensitive design and urban development throughout the world.

Living with intense heat

The climate is a problem but does offer some opportunities. The amount of sunshine available means there should be no shortage of solar electricity, though we need to develop efficient storage systems too. We could also take advantage of day-to-night ambient temperature variations using “thermal mass” techniques to even out temperature fluctuations.

Dino-architecture? Bahrain’s World Trade Centre is covered in glass. Image: AFP/Getty.

We will have to make significant changes to building design – highly glazed structures that soak up heat will become architectural dinosaurs. Traditional ideas from hot regions of the world will resurface: thick walls giving thermal stability (but enhanced with smarter materials such as composites with layers of insulation or perhaps embedded “phase-change” materials), used together with small windows. Building surfaces will need to be coated with smart materials that reflect heat gain – these already exist, and researchers have looked at their perfomance in the hot summers of cities such as Athens.

We’ll need to optimise where and when we occupy buildings, to seek out the coolest spots and take advantage of less intense night time conditions. We may find ourselves living partly underground in order to benefit from lower and more stable temperatures to be found a few metres below the Earth’s surface.

In intense heat, finding some shade becomes essential. Buildings, streets, services and even entire transportation systems need to be entirely shaded or even fully underground. Some of these features are already showcased in the Masdar City development in Abu Dhabi, though the project (which had significant design input from Norman Foster and partners) is not yet fully operational.

Switch on the air con industry

We can expect an air conditioning boom, too. This will cost a lot both to build and to operate, and we’ll have to come up with systems specially designed for extreme temperatures. The thermodynamics of current designs which rely on temperature differences between heat absorption and heat rejection mean it would be very difficult to achieve sufficient and efficient heat removal as these change and narrow.

In Dubai even the bus stops are air conditioned. Image: Jay Galvin, CC BY.

One opportunity would be to use the Earth or the sea/rivers as “heat sinks”, rather than the external air: these will be at lower temperatures and have the ability to absorb the heat, though perhaps with as yet unknown long term effects. It is also likely that air conditioning might most effectively be used during the night-time to pre-cool the building; night-time air temperatures will allow more efficient refrigeration.

Urban design and the ways in which cities are used at time of extreme heat will also need to be considered. Moving around outdoors without protection could become as unimaginable as walking unprotected from a polar research station in winter.

This obviously causes significant problems for those who must work outside: places of refuge may need to be constructed, and the very act of building may need to be restricted to the “winter” (or rather, slightly cooler) months. Construction products will also be obliged to change in order to cope with more extreme thermal stresses and expansion effects.

Heatwave cities

The shape of cities and the massing of their major buildings will change so that groupings offer a degree of self-protection. Streets will be designed to optimise shading and, when available, cooling air ventilation. The spaces between buildings will need to be carefully designed and uses (such as what might happen underground) considered alongside services provided to citizens. Shopping malls could be submerged and used as links between areas, just as the underground streets found in northern latitude cities like Montreal are used in winter.

Cities themselves may shift away from coastal to inland zones due to the problematic combination of high temperatures with high humidities near to water masses. In drier atmospheres, technologies such as evaporative cooling (in their simplest form, fountains and water sprays) can be used to reduce temperature.

A technological alternative to this might be the use of moisture absorbing materials (regenerated desiccants) to dehumidify the atmosphere, but this would be a significant and complex task on the scale required. Moving whole cities can only be a long term plan – but it is something worth thinking about now, while there is time.

Adrian Pitts is professor of sustainable architecture at the University of Huddersfield.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Barnet council has decided a name for its new mainline station. Exciting!

Artist's impression of the new Brent Cross. Image: Hammerson.

I’ve ranted before about the horror of naming stations after the lines that they’re served by (screw you, City Thameslink). So, keeping things in perspective as ever, I’ve been quietly dreading the opening of the proposed new station in north London which has been going by the name of Brent Cross Thameslink.

I’ve been cheered, then, by the news that station wouldn’t be called that at all, but will instead go by the much better name Brent Cross West. It’s hardly the cancellation of Brexit, I’ll grant, but in 2017 I’ll take my relief wherever I can find it.

Some background on this. When the Brent Cross shopping centre opened besides the A406 North Circular Road in 1976, it was only the third large shopping mall to arrive in Britain, and the first in London. (The Elephant & Castle one was earlier, but smaller.) Four decades later, though, it’s decidedly titchy compared to newer, shinier malls such as those thrown up by Westfield – so for some years now, its owners, Hammerson, have wanted to extend the place.

That, through the vagaries of the planning process, got folded into a much bigger regeneration scheme, known as Brent Cross Cricklewood (because, basically, it extends that far). A new bigger shopping centre will be connected, via a green bridge over the A406, to another site to the south. There you’ll find a whole new town centre, 200 more shops, four parks, 4m square feet of offices space and 7,500 homes.

This is all obviously tremendously exciting, if you’re into shops and homes and offices and not into depressing, car-based industrial wastelands, which is what the area largely consists of at the moment.

The Brent Cross site. Image: Google.

One element of the new development is the new station, which’ll sit between Hendon and Cricklewood on the Thameslink route. New stations are almost as exciting as new shops/homes/offices, so on balance I'm pro.

What I’ve not been pro is the name. For a long time, the proposed station has been colloquially referred to as Brent Cross Thameslink, which annoys me for two reasons:

1) Route names make rubbish modifiers because what if the route name changes? And:

2) It’s confusing, because it’s nearly a mile from Brent Cross tube station. West Hampstead Thameslink (euch), by contrast, is right next to West Hampstead tube.

Various other names have been proposed for the station. In one newsletter, it was Brent Cross Parkway; on Wikipedia, it’s currently Brent Cross South, apparently through confusion about the name of the new town centre development.

This week, though, Barnet council quietly confirmed it’d be Brent Cross West:

Whilst the marketing and branding of BXS needs to be developed further, all parties agree that the station name should build upon the Brent Cross identity already established. Given the station is located to the west of Brent Cross, it is considered that the station should be named Brent Cross West. Network Rail have confirmed that this name is acceptable for operational purposes. Consequently, the Committee is asked to approve that the new station be named Brent Cross West.

Where the new station will appear on the map, marked by a silly red arrow. Image: TfL.

That will introduce another irritating anomaly to the map, giving the impression that the existing Brent Cross station is somehow more central than the new one, when in fact they’re either side of the development. And so:

Consideration has also been given as to whether to pursue a name change for the tube station from “Brent Cross” to “Brent Cross East”.

Which would sort of make sense, wouldn’t it? But alas:

However owing to the very high cost of changing maps and signage London-wide this is not currently being pursued.

This is probably for the best. Only a handful of tube stations have been renamed since 1950: the last was Shepherd’s Bush Market, which was until 2008 was simply Shepherd's Bush, despite being quite a long way from the Shepherd's Bush station on the Central line. That, to me, suggests that one of the two Bethnal Green stations might be a more plausible candidate for an early rename.


At any rate: it seems unlikely that TfL will be renaming its Brent Cross station to encourage more people to use the new national rail one any time soon. But at least it won’t be Brent Cross Thameslink.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and also has a Facebook page now for some reason. 

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