Making cities cooler is a no brainer – so why aren’t we doing it?

Record temperatures hit New York City in 2008. Image: Getty.

You walk through a park in a city on a warm day, then cross out to a narrow street lined with tall buildings. Suddenly, it feels much hotter. Many people will have experienced this, and climate scientists have a name for it: the urban heat island effect.

Heavily urbanised areas within cities are 1-3 degrees hotter than other areas. They are contributing to global warming and damaging people’s health, and it’s set to get worse as urbanisation intensifies.

Numerous cities around the world are trying to do something about this problem. But there is a very long way to go. So what is holding us back, and what needs to happen?

Urban heat relates to how most cities have been designed. Many rows of tall buildings are organised into blocks which resist any natural breeze. Streets and roofs are clad in dark materials like asphalt and bitumen, which retain more heat than lighter materials and natural surfaces like soil.

Natural ground absorbs rain, which is evaporated by the sun’s rays on a warm day and released into the air, cooling everything down. In a city, the rain just runs into the sewer system instead.

Urban areas tend to lack trees. Trees help reduce the air temperature by blocking the sun’s rays, while cutting the levels of pollution by absorbing harmful particles.

Cities are also warmer because they are full of human activity. Everything from transport to industry to energy output makes them hotter than they otherwise would be.

Cause and effect

Urban heat has various consequences. Combined with heatwaves and global warming, both of which are also on the rise, these hotspots are producing conditions that kill and hospitalise growing numbers of people. The worst affected are the elderly and other vulnerable groups like the homeless.

The World Health Organisation (WHO) has warned that increased city temperatures lead to more pollutants in the air. These can aggravate respiratory diseases, particularly among children. As cities get bigger, more and more people will be affected by these threats to their health.

Higher city temperatures are one reason why we are using more and more air conditioning. One US study found that the urban heat island effect in Florida was responsible for over $400m (£287m) of extra aircon, for example.

Aircon feeds climate change by producing more carbon emissions through the extra electricity demand, creating a vicious circle where it gets hotter because more aircon is required. The increased energy demand means a greater risk of summer blackouts, causing both human discomfort and economic damage.

Hotter city roads and pavements also raise the temperature of storm-water runoff in sewers. This in turn makes rivers and lakes warmer, which can affect fish and other aquatic species in relation to things like feeding and reproduction.

Finally, there are major economic consequences to hotter cities. One paper from last year predicts that all the extra wear and tear caused by the excess heat would amount to between 1 per cent and 10 per cent of lost GDP in thousands of cities around the world.


How we’re reacting

The solutions to the problem are clear enough: they include using paler more reflective building materials, and wiser urban planning that incentivises more parks, tree planting and other natural open spaces.

When it comes to taking these steps, however, it’s a very mixed picture. Countries and municipal authorities have typically become very good at adopting plans to cut emissions of carbon dioxide and other greenhouse gases. They are not so good at taking steps to adapt to climate change. A study from 2014 found that most European cities had failed to introduce urban heat plans, and the situation looks little better today.

This being the case, city administrations that have gone the extra mile look particularly enlightened – even though they tend to be somewhat sporadic. Melbourne, for instance, has substituted its trademark bluestone pavements in several areas with a permeable version that absorbs rainwater, thereby increasing the amount of evaporation.

New York City’s Cool Roof Initiative has seen thousands of volunteers painting some of the city’s flat bituminous roofs with a reflective polymer material. Lately, Los Angeles has launched an initiative to paint roads white, part of a pledge by city hall to lower the temperature by 3 degrees in the next 20 years. Beijing, meanwhile, has been introducing zoning measures to reduce smog.

Other administrations have been encouraging green roofs – rooftops covered in vegetation: they are a legal requirement for big new developments in Toronto; there are floor area bonuses for developers who include them in Portland, Oregon; and Chicago had a funding scheme for a while. In Swiss cities and regions, green roofs have been a legal requirement for many buildings for years.

These are all just pockets of activity, however. Many other mayors and city administrations need to start implementing the kinds of bylaws and incentives to adapt to the reality of hotter cities.

The ConversationThe cities of the future can still be green and cool, but only if they move up the agendas of many city halls. The laggards need to follow the example of those that have been leading the way. The reality is that the social, environmental and economic costs of urban heat islands add up to a bill that is too high for humanity to pay.

Tiziana Susca, Research Fellow, Edinburgh Napier University and Francesco Pomponi, Vice Chancellor's Research Fellow, Edinburgh Napier University.

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

 
 
 
 

The media scumbag’s route of choice: A personal history of London’s C2 bus

A C2 bus at Parliament Hill. Image: David Howard/Wikimedia Commons.

London’s C2 bus route, which runs from Parliament Hill, by Hampstead Heath, down to Conduit Street, just off Regent Street, is one of the bus routes recently earmarked for the chop. It has oft been noted that, of all the routes recently pencilled in for cancellation after a consultation late last year, it was the one most likely to survive, for the simple reason that it links liberal suburban north London with BBC Broadcasting House and Soho; it’s thus the route most likely to be used by people who can convince someone to let them report on its imminent demise.

So it would come as no surprise that former Guardian editor Alan Rusbridger took to the Camden New Journal when the consultation began, arguing that it would be a disservice to the local community to discontinue a route where you can always get a seat – seemingly missing the point that the fact you can always get a seat is not a great sign of the route’s usefulness.

It wasn’t always that way. When I left university in 2000, and moved from accommodation near college to up to a rented shared house in N6, the C2 was my bus. I commuted to Soho for sixteen years: for more than a decade from flats around the Swain’s Lane roundabout, and for five years from Kentish Town. While my place of work bounced around from Golden Square to Lexington Street to Great Marlborough, it was always the most convenient way to get to, and from, work; especially given the difference between bus and tube prices.

So when it comes to the C2 I’ve seen it, I’ve done it, and bought the bus pass. And by bus pass, I mean those little paper ones that still existed at the beginning of this century. Not just before contactless, but before Oyster cards.

More importantly, it was before London buses operated a single zone. There was an outer zone, and an inner zone, with different prices. To travel from one zone to another cost £1.30, meaning an all cash commute was £2.60, whereas a paper bus pass was £2.00. That made it worth your while to divert to an early opening newsagents on your way to the bus stop (GK, in my case), even if you only got two buses a day.

It’s a measure of how greatly London’s buses have improved over the last twenty years, since first brought under control of the mayoralty, that pretty much everything about this anecdotage, including the prices, seems faintly mad. But there’s more: back when I started getting that bus down to Stop N, literally at the very end of the route, the C2 used single decker buses with a single door. It’s an appalling design for use in a crowded city, which meant most of any journey was, for most passengers, spent fighting your way up and down the middle of the bus to find a seat, and then back again to get off; or – and this was more likely – fighting your way up the bus to get into standing space the driver insisted was there, before fighting your way, etc.

Such buses – and in my former life in the English Midlands I went to school on one of these buses every day – are perfectly functional where bus stops are infrequent and buses rarely standing room only. But running through Camden Town at rush hour, they’re wholly unfit for purpose.

A Citypacer. Image: RXUYDC/Wikimedia Commons.

It could have been worse. I didn’t know this at the time, but a few years before the C2 route had been run using Optare City Pacers. Those are, let us be frank, not really buses at all, but minibuses. That’s something the reveals the C2’s origins, as a hopper route to the west end largely intended for the daytime use of Gospel Oak’s pensioners in the years immediately before bus privatisation. (The C11 has a similar origin, taking the same constituency from Archway to England’s Lane.)

Once responsibility for London Buses was moved to the newly established mayoralty, things improved dramatically. Under Ken Livingstone it went double decker in 2005, and 24 hour in 2007. Under Boris Johnson it was extended from its once, and future, terminus of Conduit Street to Victoria Station, swallowing up the cancelled sections of the 8 bus; this extension was quietly disposed of a few years later, once it was clear no one would notice. (I did.)


In those years I must have taken a C2 the best part of ten thousand times; but for all the years when I wouldn’t have been able to live without the C2, times have reduced its utility, and not just for me. I’m now a 214 sort of guy: these days the top chunk of the C2 route is duplicated exactly by that other bus, which starts up in Highgate Village and, once it gets to Swain’s Lane, follows the same path until the fork of Kentish Town Road and Royal College Street, opposite the long defunct South Kentish Town tube station.

From a few hundred metres below that point, at Camden Gardens, stop C, the 88 starts. That duplicates the rest of the C2’s route, with the exception of the run down Albany Street and onto Great Portland, for much of which the C2 is the only bus.

So the C2, old friend that it is, is pretty redundant in the age of the hopper fare, which allows you to change buses without paying a second fare. That’s even more true now the C2’s otherwise un-serviced stops are being giving over to a re-routed 88, which will pick up the C2’s most northern leg, by not finishing at Camden Gardens anymore and instead going all the way to Parliament Hill Fields. Which will be nice for it.

All this, however, ignores the best reason for getting rid of the C2 (or rather for merging it with the 88, which is what’s actually happening): that first character. The letter. Who wants a bus route with a letter in front of it when even half the night buses don’t have the N anymore? It’s relic of the route’s aforementioned origins as a ‘Camdenhopper’.

That C is twenty five years past its own utility. It’s just untidy. City Metric hates that sort of thing. Get rid.