Guess where the future's most crowded cities will be

Hong Kong in 2025, artist’s impression. Image: Guzmán Lozano via Flickr.

Unless you’ve been living in a hole for the past five years, you’ll probably know that the world’s cities are getting bigger. Half the world’s population currently lives in them; by 2050, demographers predict it’ll be 70 per cent.

Some of those additional 20 per cent will live in new cities, created to meet the insatiable demand for an urban lifestyle. Sometimes, that’ll mean cities expanding; but sometimes, it’ll just mean cramming more people into existing ones.

To find out which cities will grow not just bigger, but more crowded, Bloomberg has put together a list predicting which will have the highest population density by 2025. Perhaps unsurprisingly, seven of the top 10 are in Latin America, a region whose cities are already teeming with informal slum settlements.

Here's the top ten:

(You can view the full list here.)

Hong Kong doesn’t just take the top spot: it’s predicted to be nearly twice as crowded as second ranked Salvadar’s. It doesn’t take a genius to work out why: the city-state is an island, and an rich one at that, so there are many incentives to move there, but, short of expanding onto the water (something the city is actually considering) there’s no way for the city to expand outwards. It’s a similar situation in Singapore (also an island), and in Salvador (surrounded by water on three sides).

One thing that isn’t clear is the city definition used by Bloomberg to create the predictions. It’s possible they’ve used the same urban boundaries for the 1995 figure and the 2025 figure, despite the fact these boundaries will likely change. However, examining the same urban area’s population growth over 30 years is still useful – in cities with expanding suburbs, fewer people will need to live in the packed centre. In cities with nowhere to expand, like Hong Kong, the population of that urban centre will necessasrily just keep getting higher.

Another interesting metric the list explores is the cities' percentage growth between 1995 and 2025, a period Bloomberg defines by that hazy metric, a "generation". In Hong Kong, for example, its growth over that period is predicted to be 36 per cent. This may sound like a lot, but Brasilia, which is seventh on the list, is expected to grow by a whopping 119 per cent. Two cities in Saudi Arabia, Riyadh and Jiddah, are forecasted to grow by 167 per cent and 137 per cent apiece.

Another surprise is Atlanta, Georgia. In terms of density, it takes 40th place on the list, but its population is predicted to grow by 115 per cent. Here’s the top ten cities by growth:

A report in Arab News last year claimed that Saudi Arabia’s urban populations are increasing so rapidly largely because the central government is investing in urban areas far more than smaller settlements. These cities are also relatively new, with swathes still under construction: Jeddah is currently building an entirely new transport network to deal with its terrible traffic and swelling population.

The four US cities predicted to double or nearly double by 2025 have post-recession rebounding economies to thank. Houston’s oil industry is booming, while Phoenix is becoming a slightly improbably tourist destination (we hear the golf’s lovely).

The names on this list suggest that, as rising prices make bigger global cities more inaccessible, it might be less famous cities that’ll  take the brunt of the next wave of urban migration.

 
 
 
 

What other British cities can learn from the Tyne & Wear Metro

A Metro train at Monument. Image: Callum Cape/Wikipedia.

Ask any person on the street what they know about Newcastle, and they’ll list a few things. They’ll mention the accent; they’ll mention the football; they’ll mention brown ale and Sting and Greggs. They might even mention coal or shipbuilding, and then the conversation will inevitably turn political, and you’ll wish you hadn’t stopped to ask someone about Newcastle at all.

They won’t, however, mention the Tyne and Wear Metro, because they haven’t probably heard of it – which is a shame, because the Metro is one of the best things the north-east has to offer.

Two main issues plague suburban trains. One is frequency. Suburban rail networks often run on poor frequency; to take Birmingham for an example, most of its trains operate at 30-minute intervals.

The other is simplicity. Using Birmingham again, the entire system is built around New Street, leading to a very simple network. Actually, that’s not quite true: if you’re coming from Leamington Spa, Warwick, Stourbridge, Solihull or a host of other major minor (minor major?) towns, you don’t actually connect to New Street – no, you don’t even connect to the ENTIRE SYSTEM BUILT AROUND NEW STREET except at Smethwick Galton Bridge, miles away in the western suburbs, where the physical tracks don’t even connect – they pass over each other. Plus, what on earth is the blue line to Walsall doing?

An ageing map of the West Midlands rail network: click any of the images in this article to expand them. Image: Transport for the West Midlands/Centro.

But Newcastle has long been a hub of railway activity. Tragically, the north-east has fewer active railway lines than any other region of the UK. Less tragically, this is because Tyne and Wear has the Metro.


The Metro was formed in 1980 from a somewhat eccentric collection of railways, including freight-only lines, part of the old Tyneside Electrics route, underground tunnelling through the city centre, track-sharing on the National Rail route to Sunderland, and lines closed after the Beeching axe fell in the early 1960s.

From this random group of railway lines, the Metro has managed to produce a very simple network of two lines. Both take a somewhat circuitous route, the Yellow line especially, because it’s literally a circle for much of its route; but they get to most of the major population centres. And frequency is excellent – a basic 5 trains an hour, with 10 tph on the inner core, increasing at peak times (my local station sees 17 tph each way in the morning peak).

Fares are simple, too: there are only three zones, and they’re generally good value, whilst the Metro has been a national leader in pay-as-you-go technology (PAYG), with a tap-in, tap-out system. The Metro also shares many characteristics of European light rail systems – for example, it uses the metric system (although this will doubtless revert to miles and chains post-Brexit, whilst fares will be paid in shillings).

 

The Metro network. Image: Nexus.

Perhaps most importantly, the Metro has been the British pioneer for the Karlsruhe model, in which light rail trains share tracks with mainline services. This began in 2002 with the extension to Sunderland, and, with new bi-mode trains coming in the next ten years, the Metro could expand further around the northeast. The Sheffield Supertram also recently adopted this model with its expansion to Rotherham; other cities, like Manchester, are considering similar moves.

However, these cities aren’t considering what the Metro has done best – amalgamated local lines to allow people to get around a city easily. Most cities’ rail services are focused on those commuters who travel in from outside, instead of allowing travel within a city; there’s no coherent system of corridors allowing residents to travel within the limits of a city.

The Metro doesn’t only offer lessons to big cities. Oxford, for example, currently has dire public transport, focused on busy buses which share the same congested roads as private vehicles; the city currently has only two rail stations near the centre (red dots).

Image: Google.

But it doesn’t need to be this way. For a start, Oxford is a fairly lateral city, featuring lots of north-south movements, along broadly the same route the railway line follows. So, using some existing infrastructure and reinstating other parts, Oxford’s public transport could be drastically improved. With limited engineering work, new stations could be built on the current track (blue dots on the map below; with more extensive work, the Cowley branch could be reinstated, too (orange dots). Electrify this new six-station route and, hey presto, Oxford has a functioning metro system; the short length of the route also means that few trains would be necessary for a fequent service.

Image: Google.

Next up: Leeds. West Yorkshire is a densely populated area with a large number of railway lines. Perfect! I hear you cry. Imperfect! I cry in return. Waaaaaah! Cry the people of Leeds, who, after two cancelled rapid transit schemes, have had enough of imaginative public transport projects.

Here’s a map of West Yorkshire:

Image: Google.

Here’s a map of West Yorkshire’s railway network:

 ​

Image: West Yorkshire Metro.

The problem is that all of the lines go to major towns, places like Dewsbury, Halifax or Castleford, which need a mainline connection due to their size. Options for a metro service are limited.

But that’s not to say they’re non-existent. For example, the Leeds-Bradford Interchange line passes through densely populated areas; and anyway, Bradford Interchange is a terminus, so it’s poorly suited to service as a through station, as it’s currently being used.

Image: Google.

With several extra stops, this line could be converted to a higher frequency light rail operation. It would then enter an underground section just before Holbeck; trains from Halifax could now reach Leeds via the Dewsbury line. The underground section would pass underneath Leeds station, therefore freeing up capacity at the mainline station, potentially simplifying the track layout as well.

 

Image: Google.

Then you have the lines from Dewsbury and Wakefield, which nearly touch here:

Image: Google.

By building a chord, services from Morley northwards could run into Leeds via the Wakefield line, leaving the Dewsbury line north of Morley open for light rail operation, probably with an interchange at the aforementioned station.

Image: Google.

The Leeds-Micklefield section of the Leeds-York line could also be put into metro service, by building a chord west of Woodlesford over the River Aire and connecting at Neville Hill Depot (this would involve running services from York and Selby via Castleford instead):

The path of the proposed chord, in white. Image: Google.

With a section of underground track in Leeds city centre, and an underground line into the north-east of Leeds – an area completely unserved by rail transport at present – the overall map could look like this, with the pink and yellow dots representing different lines:

Et voila! Image: Google.

Leeds would then have a light-rail based public transport system, with potential for expansion using the Karlsruhe model. It wouldn’t even be too expensive, as it mainly uses existing infrastructure. (Okay, the northeastern tunnel would be pricey, but would deliver huge benefits for the area.)

Why aren’t more cities doing this? Local council leaders often talk about introducing “metro-style services” – but they avoid committing to real metro projects because they’re more expensive than piecemeal improvements to the local rail system, and they’re often more complex to deliver (with the lack of space in modern-day city centres, real metro systems need tunnels).

But metro systems can provide huge benefits to cities, with more stops, a joined-up network, and simpler fares. More cities should follow the example of the Tyne and Wear Metro.