Why are cities so much hotter than the surrounding areas?

Scorchio! London. Image: pic fix/Flickr/creative commons.

In cities, the air, surface and soil temperatures are almost always warmer than in rural areas. This effect is known as the Urban Heat Island – a term which first came into use in the mid-20th century. Until the 1980s, this effect was considered to have relatively little practical significance. In fact, given that most studies were done in cities with cold winter climates, a warmer temperature was seen as a potential benefit, because it reduced the need for heating. But since then, we’ve found a number of reasons to be concerned.

For one thing, it became clear that the Urban Heat Island (UHI) effect of cities was influencing air temperature records, which are used to assess climate change. In other words, it became important to remove urban “contamination” from weather station records to ensure their accuracy.

What’s more, as populations in warm and hot cities have increased, so too has the demand for indoor cooling – typically met by air conditioning. This even applies in colder climates, where changing building uses has increased the demand for cooling; for example, in office buildings, to offset the heat generated by computers.

In these situations, the UHI adds to the heating burden: ironically, cooling buildings with air conditioners increases outdoor air temperatures.

Heatwaves have the power to kill; for example, during the 2003 heatwave in Europe, 70,000 additional deaths were recorded, making it one of the region’s deadliest natural disasters of the last 100 years. The UHI makes city dwellers more vulnerable to the dangerous effects of extreme weather events like this.


The potential medical impact is perhaps the most significant issue related to UHI, especially against the backdrop of continued climate change and global warming. For all these reasons, it’s crucial to understand how the UHI works, so that we can find ways to mitigate and adapt to its effects.

Understanding the UHI

The UHI is strongest during dry periods, when the weather is calm and skies are clear. These conditions accentuate the differences between urban and rural landscapes. Cities are distinguished from natural landscapes by their form: that is, the extent of the urban land cover, the construction materials used, and the geometry of buildings and streets. All of these factors affect the exchanges of natural energy at ground level.

Much of the urban landscape is paved and devoid of vegetation. This means that there is usually little water available for evaporation, so most available natural energy is used to warm surfaces. Construction materials are dense, and many – particularly dark-coloured surfaces like asphalt – are good at absorbing and storing solar radiation.

Urban jungle. Image: Mdalmul/Flickr/creative commons.

Meanwhile, the shape and positioning of buildings in the city slows the movement of air near the ground, creates complex patterns of shade and sunlight and limits natural energy exchanges. Urbanisation is also associated with the emission of waste heat from industry, transport and buildings, which contributes directly to the UHI.

There are, however, different types of UHIs, with different dominant causes.

Keeping our cool

“Surface UHI” refers, unsurprisingly, to warmer urban temperatures at the Earth’s surface. Typically, this type of UHI is measured using satellites with a plan view of the city, so that the temperature of roofs and roads (but not walls) can be measured. From this perspective, the surface UHI is highest during the daytime, when hard urban surfaces receive solar radiation and warm quickly.

Another type of UHI is based on observations of air temperature, which are made close to the ground; in the city, this means placing the instruments below roof height. This UHI is usually strongest at night, as street surfaces and the adjacent air cool slowly. Above the roof level, the contributions of streets and building roofs together warm the overlying urban atmosphere. In some conditions, this warming can be detected up to 1km to 2km above the surface.

The geography of the Urban Heat Island. Image: Jamie Voogt/University of Western Ontari/author provided.

The geography of the UHI is relatively simple – it’s magnitude generally increases from the urban outskirts towards the city centre. However, it also contains many micro-climates – for example, parks and green spaces appear as cool spaces.

The UHI is an inevitable outcome of the landscape changes that accompany urbanisation. But its magnitude and impacts can be managed by modifying some physical aspects of our cities. This can include increasing vegetative cover and reducing impermeable cover; using lighter coloured materials, designing urban layouts to allow for better ventilation through the streets and buildings, and managing urban energy use.

Laying a cool roof. Image: NNSANews/Flickr/creative commons.

Of course, these solutions need to be tailored to the type of UHI. For example, a focus on building cool or green roofs will have an impact on the overlying air and the top floor of buildings, but may have little impact on the UHI at street level. Similarly, trees may be an effective means of providing street shade, but if the canopy encloses the street, then it can trap traffic emissions, resulting in poor air quality.

The ConversationAs a first step, many cities have completed UHI studies to identify the “hot-spots”, where design interventions could have greatest effect. But what most cities need is a coherent climate plan, which addresses interrelated environmental issues including flooding and air quality, as well as surface and air temperatures.

Gerald Mills, Senior Lecturer in Geography, University College Dublin.

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

 
 
 
 

In search of the UK’s great “city films”: the South, East Anglia and the Midlands

Beachy Head, East Sussex. Image: Wikipedia via Creative Commons.

Earlier this year, in the first blog in this series, I looked at the best city films set in London. Here the search extends outwards – to the urban metropolites of the South, East Anglia and the Midlands. The focus is on films with some combination of local stories, connections and shooting locations.

That first blog outlines the selection method in detail. If you haven’t time to read it, the key things to know are that films must have received a total IMDb score of at least 6.5 from at least 100 votes – if a film is missing from the list it is probably because it does not meet those criteria.

South East

Described by the Guardian as “one of the finest post-war British crime movies and possibly the best depiction of the seaside town on film”, Jigsaw (1962) is about a murder investigation set in and around Brighton. The producers made the film in partnership with the local police and there is extensive footage of Brighton and its surrounds. Despite similarities with the real-life Brighton Trunk Murders of the 1930s, the plot was based on a 1959 American novel.

Brighton is again the location for Smokescreen (1964), yet this time insurance fraud is the crime. In addition to scenes at locations around the city and neighbouring Hove, the rest of the filming was at Brighton Film Studios, which operated between 1949 and 1966 and was the the last of four main film studios in the area. Its closure marked the end of an era, since as early as “1912, when Hollywood was just beginning, film companies in Brighton had already produced hundreds of comedies, dramas and documentaries”.

The Chalk Garden (1964) is based on a play of the same name by Enid Bagnold and, although not a period piece, inspired by Bagnold's own inter-war life at North End House in the village of Rottingdean that borders Brighton immediately to the east. Bagnold (a remarkable woman) lived a well-healed existence and the servants – notably the governess – figure prominently in the tale. Brighton features in the film – including a scene in Preston Park that recruited background players from the Preston Lawn Tennis Club.

The storylines of a couple of 1960s Oxford films centre on that city’s ancient university. The Mind Benders (1963) is a spy thriller involving brainwashing science, while Accident (1967) is about professorial-student relationships. Accident is based on a novel of the same title by Oxford-educated Nicholas Mosley (the eldest son of Sir Oswald). Both films have numerous shots of the university; we’re talking “The Full Morse” here.

A good deal of Quadrophenia (1979) is set either in London or between London and Brighton, but it does also feature the latter’s famous seafront and beach. The film, which is about a young working-class Mod in the mid-1960s, recreates the fights between gangs of Mods and Rockers that marred Brighton and other south-coast towns over holiday weekends during the Sixties.

Fast-forward two decades and Down Terrace (2009), a “Sopranos on Sea”-type dark comedy, is Brighton to its fingertips. It has a handful of local scenes but is more a house-based play than movie. Directed and co-written by Brighton resident Ben Wheatley, it is named after the street in which it was filmed. The other co-writer, who also has a lead role, is Rob Hill, who met Wheatley at the University of Brighton. The house in which most of the filming took place was Hill’s own home in Down Terrace and Hill’s character’s father is played by his real-life father – also a Brighton resident. Wheatley and Hill self-funded the film and did interviews with “local drug dealers and ne’er-do-wells” for the initial script. Several tracks come from local folk singers, The Copper Family. I loved it (as did the British Independent Film awards).


Emulsion (2014), a slick and clever film about a man’s search for his “missing wife”, is a Bournemouth film. Writer-director Suki Singh is a graduate of Bournemouth University’s Film School and still based locally. Despite the town council’s car park featuring heavily a good number of locations in Bournemouth and Poole are shown, including cafes, a local country house, department store, major hotel, police station, converted art deco cinema and Alum Chine suspension bridge. The film’s premiere came through a local Indie Screen scheme whereby Poole’s Lighthouse cinema guaranteed to screen good local indie films. The production company is locally based and, in addition to film-making (e.g. Bournemouth-shot feature, K-Shop), plays a key educational and networking role in the city’s film community. Even the score was by a (London-based) Bournemouth University graduate.

20,000 Days on Earth (2014) charts 24 hours in the life of Australian- born, Brighton-based singer Nick Cave. It is a curio in that, while the person is real, the day is artificial – made up of arranged but unscripted encounters with famous faces from 20,000 days-old Cave’s life. Many of the encounters take place in a car as Cave drives around the city, mostly away from the town centre and seafront. The film has been called “a great Brighton film, giving a neon noir sheen to Cave’s adopted hometown” and “as much of a love letter to the seaside city as it is to the man that inhabits it”. So, let’s include it.

South West

The film world owes a debt to the city of Bristol in that it gave the world one Archibald Alec Leach – better known by his screen name: Cary Grant. The Bristolian usually vies with the likes of Brando and Bogart for the mantle of greatest male lead in movie history. His upbringing in (and later ties with) Bristol is well captured in last year’s excellent documentary, Becoming Cary Grant.

Grant has long held a fascination for playwright Peter Nichols who, like the film star, grew up in north Bristol. Nichols converted one of his early plays into a challenging and amusing film of the same name, A Day in the Death of Joe Egg (1972). Nichols was rooted in the city, having been born there, educated at Bristol Grammar School, studied acting at the Bristol Old Vic Theatre School and had his first play staged at the Little Theatre (now part of Colston Hall). The play/film, based on Nichols' own experiences, is about how the burden of raising a very handicapped child can damage a marriage. The male lead is a teacher – just as Nichols had been. Funds to write the play came when legendary director-to-be John Boorman, then working at BBC Bristol, persuaded Nichols to write a screenplay for him – one that went on to make money. There are at least a handful of external shots filmed in the city although it remains more play than movie and you only hear a Bristol accent once – a funny department store scene.

Truly, Madly, Deeply (1990), which was also shot in London, and Paper Mask (1990) both show Bristol locations albeit without any great local rootedness. Starter for 10 (2006) is about student life and a University Challenge quiz team at the University of Bristol yet, despite a few good Bristol shots, most of the university scenes were filmed at UCL and the University of Greenwich.

East Anglia

Ipswich has The Angry Silence (1960), a film about strike-breaking and, seen more broadly, an individual opposing a group. It was shot mainly in and around a big local factory (operational as recently as 2005), neighbouring streets and a local primary school. Extras comprised of both local amateurs and many factory staff, one of whom lent their battered (ie realistic) overalls to one of the film’s stars. The lead actor, Richard Attenborough, even visited the factory beforehand to learn to use the machine he worked on in the film, and later hosted a private showing for local extras at the old Ritz Cinema in the Buttermarket. The film still holds up almost sixty years on, yet not everyone took civic pride in it – Ipswich Trades Council voted to boycott it. 

Following a successful online campaign named “Anglia Square not Leicester Square”, the world premiere of Alan Partridge: Alpha Papa (2013) was held in Norwich’s Hollywood Cinema, with Steve Coogan appearing in character as North Norfolk Digital radio station’s own Alan Partridge. Coogan/Partridge greeted fans before being helicoptered to the London premier in Leicester Square! The film has some good shots of Norwich, although many scenes were also filmed on the Norfolk coast, at Sheringham and Cromer beaches, and around London.


Originally created as the master’s project of Norwich-born, -raised and -based director, Kris Smith, who was at the time studying film at Norwich University College of the Arts, I’m Still Here (2013) focuses on a young guy diagnosed with a terminal illness and draws on Smith’s own experience of a loved one in this situation. Smith, who both wrote and directed the film, worked with three locally based actor-filmmakers, and the soundtrack includes local band National Image and locally-based rap artist C.O.L.L. The main shots of the city are at the beginning – including a trip to the Norfolk and Norwich Hospital (yet when a neighbour later drops him at “the hospital” the entrance shown is St George's in south London’s Tooting!). The premier took place at The Curve Auditorium, in Norwich’s Forum complex.

The short story that inspired the multi-award winning 45 Years (2015), which tells the tale of a retired couple, may have been set in north Wales, but the resultant film was indeed set in Norfolk. It includes a handful of scenes featuring popular Norwich locations and the nearby Norfolk Broads receive a nice profile too. The director, Andrew Haigh, has revealed that a lot of the scenes in Norwich featured genuine passers-by – lead actress Charlotte Rampling “would walk around the city and nobody even looked at her. We had the camera hidden in a van to film some of the scenes, so people wouldn’t see us”. Haigh knew the city well as he was living there at the time of filming while his partner was doing an MA in creative writing at University of East Anglia.

Blinded by the Light, at a cinema near you from 2019, is Gurinder Chadha’s film about the true story of a Bruce Springsteen-mad British Muslim growing up in Luton during the 1980s. The film is based on journalist Sarfraz Manzoor’s 2007 memoir, Greetings from Bury Park. Exact shooting locations are unclear although Manzoor, who is a co-producer and co-wrote the script, has said that “there have been moments on set when I could not stop smiling at the sight of a feature film crew in the middle of Luton”.

East Midlands

Nottingham is the focus of Saturday Night and Sunday Morning (1960), of which the screenplay, about a womanising hard-drinking young factory worker, was adapted by Alan Sillitoe, who was born and raised in the city, from his novel of the same name. The film’s anti-hero works in Raleigh bicycle factory – as Sillitoe himself had when it had been a wartime munition factory. The author’s family home was a main location for the film and his brother had a bit part. Numerous other city locations appear – from the castle to cinemas and pubs (including The White Horse – the setting for the short story that later became the novel). Although the closing scene was shot overlooking a Wembley housebuilding site, a Nottingham firm supplied one of its signs to bring “authenticity”. Not all locals welcomed the film: the then-Tory MP for Nottingham Central denounced it as a “foul libel on the respectful, clean living people of Nottingham”. The work was however deemed the 14th greatest British film in a 1999 BFI survey.

Shane Meadows, who moved to Nottingham from the eastern-most part of the West Midlands when he was 20, has shot several good films in and around his adopted home city. His first feature, TwentyFourSeven (1997), about a youth boxing club, was filmed in Nottingham suburbs and exurbs. A Room for Romeo Brass (1999), about two 12-year-old friends, was shot in Calverton – just outside the city. The relationship between the two boys is semi-autobiographical and based on the childhood relationship between Meadows and co-writer Paul Fraser. Much of Meadows’s This is England (2006), about skinhead youth in the early 1980s, was shot in residential areas of Nottingham. Meadows has used professional actors but has also drawn on local talent – notably from the Television Workshop in Nottingham – for key roles. The Workshop, now a charity, was originally set up by Central Independent Television in 1983 to act as a casting pool for young talent in their Midlands broadcasting region.

Leicester gets a look in with The Girl with Brains in Her Feet (1997), a coming-of-age tale, set in 1972, about a talented, mixed-race 13-year-old athlete at a school on the outskirts of Leicester. The screenplay was written by the late Jo Hodges who, back in 1972, had been a sporty, mixed-race 13-year-old at a school on the outskirts of …. you guessed it, Leicester.

Although it didn’t include lots of Northampton scenes, Kinky Boots (2005) is based on the true story of one of the area’s shoe-making companies managing to stave off closure through switching to producing women’s boots that were large and strong enough for drag queens and male fetish footwear lovers. The company was based a few miles outside Northampton although most of the internal factory scenes were shot at the Tricker’s shoe factory in Northampton itself.

The Unloved (2009) gives a child's eye view of the UK’s government-run care system for orphans and children in danger. Filmed entirely in Nottingham, it offers a handful of shots of the city and is a semi-autobiographical account of the upbringing of the film’s director, Nottingham-born-and-raised Samantha Morton (who has twice been nominated for acting Oscars). The film also gave leading roles to two actresses – Lauren Socha and Molly Windsor – who had attended the Television Workshop.

Oranges and Sunshine (2011) depicts the true story of Margaret Humphreys, a social worker from Nottingham who, in the 1980s, uncovered the horrifying and thankfully discontinued practice of Home Children; the forcible relocation, by misguided charities, of children in care from the United Kingdom to Australia and other parts of the Commonwealth. Humphreys reunited some of the children involved – now adults living mostly in Australia – with their parents in Britain and was awarded a CBE in 2011 for her work. Several Nottingham locations were used in the film although shooting also took place in Australia. The two main young actresses were Television Workshop alumni.

Nottingham was also the location for the Weekend (2011), which was named in 2016 by a BFI survey as the second best LGBT film of all time (Carol took first place, since you ask). The plot centres upon a casual encounter that shows signs of developing. The only real connection to the area, aside from locations including the Goose Fair, is that funding came from EM Media and the region’s now-closed development agency (EMDA).

Given that we are including villages just a mile or so outside Nottingham, A Boy Called Dad (2009), about a teenage father, also merits inclusion. An East Midlands production company raised the £1m needed to start shooting – obtaining funds from the former Regional Screen Agency, EM Media. North Wales and Merseyside locations also feature however.

West Midlands

Nativity! (2009), a film about a nativity play competition, is the stand-out Coventry (and West Midlands) film. Spon Street, various city landmarks and, in particular, the bombed-out St. Michael’s Cathedral can be seen in the film, which was written, directed and produced by Coventry-based Debbie Isitt, herself a product of a two-year Coventry Performing Arts Service course, and premiered at the city’s SkyDome Arena. The multi-talented Isitt even does the music along with her long-term partner Nicky Ager. Nativity! drew on Isitt’s memories of her primary school in Birmingham, which resurfaced when her own daughter (who appears in the film) reached the same age. The other children in the film, almost none of whom had agents, were recruited from schools around Birmingham and Coventry. In 2008, BBC Coventry and Warwickshire followed the filming and, to complete the local angle, Coventry’s Belgrade Theatre even played a part in production. It’s an enjoyable feel-good Christmas film suitable for all ages.

The absence of a film from Birmingham is the elephant (not) in the room; the world is surely due a great Brum film? That said, there have certainly been good films from the city and these are outlined in the spreadsheet referred to below.

Scoring

Overall the films from the South, East Anglia and the Midlands offer some additional perspectives on England to those in the films featured last blog. Through watching them we see a nation with vibrant seaside towns, attractive provincial cities, ancient and redbrick universities, factories, and the post-industrial landscape left behind when these closed.

Anyway, once again I have used my “highly scientific” method to score those films. The full list of scores, complete with further details on all films, is available here. The top-scorers, for each region, are:

  • East – I’m Still Here (Norwich): 10.5 points
  • East Midlands – This is England and Saturday Night and Sunday Morning (both Nottingham): 9 points each
  • South East – Down Terrace (Brighton): 12 points
  • South West - A Day in the Death of Joe Egg (Bristol): 7 points
  • West Midlands – Nativity! (Coventry) 11.5 points

The next installment will look at the best city films from the three regions that make up the North of England.

The author, a Brit based in Washington DC, is founder of The New Barn-Raising a project to promote international exchange on ways to sustain parks, libraries, museums and other community and civic assets. You can find him on Twitter at @newbarnraising.