A brilliant new dataset produced by the European Commission JRC and CIESIN Columbia University was recently released- the Global Human Settlement Layer (GHSL). This is the first time that detailed and comprehensive population density and built-up area for the world has been available as open data. As usual, my first thought was to make an interactive map, now online at- http://luminocity3d.org/WorldPopDen/
The World Population Density map is exploratory, as the dataset is very rich and new, and I am also testing out new methods for navigating statistics at both national and city scales on this site. There are clearly many applications of this data in understanding urban geographies at different scales, urban development, sustainability and change over time. A few highlights are included here and I will post in more detail later when I have explored the dataset more fully.
The GHSL is great for exploring megaregions. Above is the northeastern seaboard of the USA, with urban settlements stretching from Washington to Boston, famously discussed by Gottman in the 1960s as a meglopolis.
Europe’s version of a megaregion is looser, but you can clearly see the corridor of higher population density stretching through the industrial heartland of the low countries and Rhine-Ruhr towards Switzerland and northern Italy, sometimes called the ‘blue banana’.
The megaregions of China are spectacularly highlighted, above the Pearl River Delta including Guangzhou, Shenzhen and Hong Kong amongst many other large cities, giving a total population of around 50 million.
The Yangtze Delta is also home to another gigantic polycentric megaregion, with Shanghai as the focus. Population estimates range from 50-70 million depending on where you draw the boundary.
The form of Beijing’s wider region is quite different, with a huge lower density corridor to the South West of mixed industry and agriculture which looks like the Chinese version of desakota (“village-city”) forms. This emerging megaregion, including Tianjin, is sometimes termed Jingjinji.
The term desakota was originally coined by McGee in relation to Java in Indonesia, which has an incredible density of settlement as shown above. There are around 147 million people living on Java.
The intense settlement of Cairo and the Nile Delta is in complete contrast to the arid and empty Sahara.
Huge rural populations surround the delta lands of West Bengal and Bangladesh, focused around the megacities of Kolkata and Dhaka.
There is a massive concentration of population along the coast in South India. This reflects rich agriculture and prospering cities, but like many urban regions is vulnerable to sea level changes.
The comprehensive nature of the GHSL data means it can be analysed and applied in many ways, including as a time series as data is available for 1975, 1990, 2000 and 2015. So far I have only visualised 2015, but have calculated statistics for all the years (turn the interactive statistics on at the top left of the website- I’ll post more about these statistics later). Change over time animations would definitely be an interesting approach to explore in the future. Also see some nice work by Alasdair Rae who has produced some excellent 3D visualisations using GHSL.
The current London mayor, Boris Johnson, has been slow to face up to the challenge. His tenure began by removing the western extension to the Congestion Charging Zone, thus increasing vehicle numbers in Inner West London, and opting out of using the Congestion Charge to tax the most polluting vehicles. This would have boosted the adoption of hybrid and electric vehicles (still only a meagre 1% of new cars) and reduced heavy emitters in Central London. Furthermore Johnson has not succeeded in comprehensively upgrading London’s bus and taxi fleet to hybrid and electric vehicles, instead embarking on an expensive new Routemaster project which still produces substantial emissions and currently makes up a minority of the overwhelmingly diesel bus fleet.
Looking to the future, London must now tackle the air pollution problem with a new mayor in the upcoming 2016 elections. The scope for change looks positive, as the main candidates on both the left and right have been openly discussing the need for change. What then could a new mayor do to address air quality and improve the health of Londoners?
Pricing Out Polluting Vehicles with the Ultra Low Emission Zone
To be fair to Boris Johnson, he did finally respond to pressure and announce a significant air pollution policy in 2013, dubbed the ‘Ultra-Low Emissions Zone‘. The ULEZ is set to come into effect in 2020 and essentially uses the Congestion Charging infrastructure to tackle the most polluting vehicles (similar to what Livingstone proposed way back in 2006). The question is whether the ULEZ goes far enough. It’s based on Euro emission standards, which measure NO2 and PM10/2.5 as well as CO2 emissions. It correctly targets diesel vehicles, requiring them to meet the Euro 6 standard, which only came into force in September 2015, so almost all current diesels on the road would have to change or pay the charge. This means that the main source of NO2 emissions will be appropriately targeted.
There are limitations however. The charge is only going to be £11.50 (except for large buses and HGVs), so it likely many diesel users will continue to drive into Central London and pay the charge. Furthermore the ULEZ will only affect Central London; the rules on diesel taxis and private hire vehicles have not been decided; and ULEZ zone residents get an overly generous exemption until 2023.
The next mayor will have a number of options that could be pursued if they want to be bolder than Johnson’s ULEZ proposal. These include increasing the ULEZ charge and/or Congestion Charge, bringing the ULEZ implementation forward to an earlier date, and potentially reintroducing the Congestion Charge Western Extension. All of these would make significant improvements to air quality, but would be controversial with drivers, many of whom were mis-sold diesel vehicles in the past as a supposedly environmentally benign option. The mayor may also want to re-examine the wider Low Emission Zone (LEZ) that tackles very polluting vehicles entering the whole of Greater London, as this affects the entire city and has not changed since 2012.
Banning Diesel? A more radical approach currently being proposed for Paris is to ban diesel cars all together. This would certainly make a huge improvement to air quality. The problem for London would be that the city’s bus and taxi fleet would fail this restriction, and there would likely be a backlash from thousands of car and van drivers. This would be a very confrontational approach for a new mayor.
The more pragmatic solution for London would be to work with the ULEZ framework, considering stricter measures and higher charges, and implementing the policy earlier. One very important issue for the new mayor is emerging from the current Volkswagen emissions scandal. It looks like the latest Euro 6 diesels produce significantly higher NO2 emissions in real world driving conditions compared to the misleading testing conditions. If this is the case then the proposed ULEZ will be much less effective in improving air quality (as Euro 6 diesels will be exempt from the charge). The ULEZ may have to charge all diesel vehicles, regardless of their Euro rating. This decision would need to made very early, so that there is sufficient time for car users to adjust behaviours accordingly.
Pedestrianising Streets and Upgrading the Bus Fleet Oxford Street is London’s busiest pedestrian street and has some of the worst NO2 pollution in Europe. A response that is gaining popularity is to pedestrianise the whole street. Certainly this would be an iconic change to both the image of London, and to the experience of the city for thousands of Londoners and tourists. The challenge for this measure is avoiding creating bus jams at either end of Oxford Street, and handling the extra demand levels that would be placed on the already congested Central Line. These challenges are not necessarily permanent however, as the arrival of Crossrail in 2018 (which follows the west to east Central Line route through Inner London) has been described as a ‘game changer’ that makes pedestrianising Oxford Street a realistic option. The new mayor should certainly pursue this possibility.
The wider challenge for the mayor is not to just think about Oxford Street, but to accelerate the upgrading of the entire bus and taxi fleet towards zero emission vehicles and develop wider pedestrianisation policies. This would improve air quality for all of London’s high streets. London is still at the trial stage of pure electric double-decker buses, which represents disappointingly slow progress considering how long we have known about air pollution problems. There’s been better progress on electric/hydrogen single-deckers. Considerable investment will be needed to upgrade the bus fleet, with decision-making based on real evidence and value-for-money. Johnson’s Routemaster project has failed both these criteria, and better leadership is now required.
Heathrow Third Runway All the main candidates for the London Mayor oppose the expansion of Heathrow, with air pollution alongside noise pollution amongst the most important factors. You can see how Heathrow already dramatically increases emissions in West London in the NO2 annual concentration map at the top of this article using the London Atmospheric Emissions Inventory data. This is due both to emissions for aircraft engines, and the thousands of cars driving to and from Heathrow everyday. The challenge will be how effectively the new mayor can challenge the UK government to reject the Heathrow expansion option.
Overall, the issue of air pollution has gained unprecedented prominence as we approach the 2016 mayoral elections. The main candidates need to respond accordingly in their manifesto commitments, with London having a lot of catching up to do after eight years of little change. It will be interesting to see which candidates are prepared to be bolder.
Household energy use is a key indicator for understanding urban sustainability and fuel poverty, and is a timely topic now that winter has arrived. The LuminoCity3D site maps domestic energy use in England and Wales at 1km2 scale using data from DECC. This map has also just been published as a featured graphic in Regional Studies Regional Science. The household energy use distribution is really fascinating, with large scale regional variation and fine scale intra-urban patterns identifiable-
The lowest energy use per-household is found in cities and towns in the South-West region such as Plymouth and Exeter, and also along the South coast. While the highest energy use per-household is found in commuter belt towns around London. The variation within city-regions is very high, with for example London and Manchester averages varying by up to a factor of 5, from a mere 8kWh to over 40kWh per year.
The main drivers of energy use are generally housing type (more exposed walls=more energy use; larger house=more energy use), household size, wealth and climate. Often these factors are correlated at household and neighbourhood levels- so for example wealthier households in England and Wales are more likely to live in large detached houses, and these households tend to be clustered together. These trends produce the high energy use pattern seen in London’s commuter belt, as well as in the wealthier suburbs of other large cities like Birmingham, Manchester and Leeds. South West England on the other hand benefits from the mildest climate in the UK, has a relatively high proportions of flats and generally lower average household sizes, thus resulting in the lowest energy use.
We can see how these factors play out for London in the map below. The height of the hexagons shows density, with higher density areas clearly using less energy. City centre households have considerably lower energy use, with a strong bias towards Inner East London where incomes are lower.
Energy use areas correlate strongly with the most prevalent housing type map (also on the LuminoCity3D site), with flats and terraced housing the lowest energy users, and detached and semi-detached areas the highest.
The relationship with household size is less clear cut, but it can be seen that average household sizes are smaller in the city centre. On the other hand, areas with high average household sizes such as Stratford and Wembley, do not have particularly high average energy use.
Overall domestic energy use patterns tend to mirror transport sustainability, in that higher density city centre areas perform more efficiently compared to low density suburbs. On the other hand the link to city size (which tends to be strong in transport sustainability relationships, with bigger cities reducing car use) is much weaker, and the most efficient locations are often small and medium sized towns and cities. It is not clear in this analysis whether more recent green policies (such as improved insulation or CHP schemes) are having much effect, but several cities with green reputations like Brighton and Bristol are amongst the best performing cities.
Following rapid growth and a chronic lack of new development, housing affordability has reached crisis levels in London. Median house prices are at £300k (8 times median household income) while average prices have passed half a million. London is now amongst the most expensive cities in the world, a situation with severe consequences for economic competitiveness and for inequality. Rents continue to increase faster than wages, ownership is being restricted to affluent populations and the social housing waiting list now stands at 345,000 households, nearly double the figure from 15 years ago.
Recent development figures have been very low. London needs at least 50,000 new homes per year to meet demand, yet only 21,000 were built last financial year, and this figure has been below 20,000 for all of the last five years. Nationally around 200,000 houses a year are needed, and we are building around 100,000. These figures amount to a comprehensive failure of national and mayoral policy.
Clearly substantial changes are needed. Last week the Centre for Cities outlined how this change could happen, launching their ‘Building Change: Delivering Homes Where we Need Them‘ report. It convincingly argues that we are failing to deliver homes where demand in greatest- in the vicinity of rapidly growing towns and cities- resulting in spiralling housing costs.
The report makes a range of positive recommendations for enhancing local authority capacity in relation to delivering new housing, including the streamlining and reform of compulsory purchase orders for faster development and allowing cities to benefit from uplift values in land; allowing local authorities to borrow more with longer term commitments from central government; and enabling greater cooperation between local authorities to tackle city-region challenges. Best practice examples are provided from local authorities that have successfully delivered new housing, such as Bristol and Milton Keynes. The report also provides a useful summary on brownfield capacity, with for example the potential for 350,000 homes on brownfield sites within the GLA.
Releasing Greenbelt Land for Development
By far the most politically controversial aspect of the report is the recommendation to reconsider greenbelt development restrictions. Prioritising brownfield land has been a central foundation of compact city planning over the last twenty years, directing development towards inner city regeneration and away from rural areas. Yet brownfield land can be expensive to develop, and in combination with greenbelt restrictions, land prices have soared. These spiralling land costs have significantly curtailed new housing.
Opportunities for housing on ‘Usable Greenbelt Land’ around London are mapped in the report (figure below), based on locations within 2km of rail stations. The Centre for Cities estimate that there are opportunities for 430,000 housing units on greenbelt land within the GLA, and opportunities for a massive 3 million housing units on the London greenbelt beyond the GLA boundary. This huge housing capacity could effectively solve London and the South East’s housing crisis. So is developing on the greenbelt the answer?
Usable Land and the Value of the Greenbelt The gigantic housing development capacity figures quoted in the Centre for Cities report certainly demand attention. As housing development is such a central issue for planning in the South East, I have decided to repeat the Centre for Cities spatial analysis from a sustainable urbanism perspective and assess how realistic these recommendations are, and what the environmental consequences of the greenbelt development approach are likely to be.
First of all, some details on the Centre for Cities methodology. Their Usable Land definition is a 2km crow-flies buffer of rail and underground stations, excluding several environmental protection area types (SSSIs, AONB, SAC, SPA, Ancient Woodlands). The report does not argue that all this land should be developed, rather that it could be considered for development on a case by case basis. They take a ballpark figure that, given infrastructure, services and removing highly amenable land, 60% of the remaining land could be developed for housing at an overall average of 40 dwellings per hectare (thus each hectare of usable land effectively translates to 24 homes). I have repeated this method below and I get a very similar result of 120,000 hectares / 2.87 million homes on London greenbelt land beyond the GLA boundary. I get a lower (but still substantial) figure of 12,700 hectares / 306,000 homes on greenbelt land within the GLA.
There are two main spatial analysis issues with the Centre for Cities method of identifying usable land- firstly there are significant development restrictions missing, and secondly there are problems with using rail station buffers as a proxy for sustainable travel. Regarding the first problem, the most significant restrictions that should be included are flood risk areas, and additional environmental land and habitats (principally Priority Habitat Areas). The impact of these additional restrictions is shown in the map below. Surface water and flooding risk in particular covers large areas of land in the Thames Valley west of the GLA, and north in the Lee Valley, reflecting the role of the greenbelt in flood management. Assuming these areas would not be developed, this removes nearly 40% of the usable land from the analysis, leaving 75,000 hectares. With more data and time, further restrictions could be considered, for example local site access, road congestion, airport flight paths, heritage restrictions etc.
The second problem is how to consider public transport accessibility and sustainable travel. The basic principal used by Centre for Cities is sound- directing development to areas of public transport access. But locations within 2km of rail stations in the South East are often very small towns and villages, lacking local retail and services opportunities. Not surprisingly these small towns are generally highly car dependent, with around 80% of commuters driving to work, and similar patterns for other trip purposes. Building further low density housing in these locations would likely reproduce this pattern of car dependence.
Ideally the appropriate method here would be to do some accessibility modelling and network analysis (comparable to the PTAL approach used in the London Plan) to identify locations with access to local services and a range of public transport options. Unfortunately performing accessibility modelling for the whole of the South East is not trivial. The maps below shows a simpler alternative, identifying locations within an estimated local walk/bus trip of a retail and service centre (3km of a large centre, 2km of a medium centre or 1km of a small centre) based on 2010 Valuation Office data, in addition to the 2km buffer of rail stations. It is clear that a stricter definition of accessible locations greatly reduces the resulting volume of usable land, directing potential development to larger settlements with more facilities (and public transport services) like Southend, Maidstone and Hemel Hempstead. In this case it leaves 27,500 hectares of greenbelt land beyond the GLA, or 23% of the original figure. Note we also haven’t considered public transport capacity, which is a critical issue for commuters into London as many services are overcrowded.
This analysis points to the Centre for Cities figure of 3 million potential homes in the greenbelt being a big overestimate if sustainable planning guidance is going to be followed. Yet even with this stricter approach I still get a large figure of 27,500 hectares of potential development land in the greenbelt beyond the GLA, which would be about 650,000 homes at suburban densities or more at higher densities. This could go a long way to alleviating the housing crisis in the South East. The Centre for Cities report is convincing in its wider policy argument that land should be ‘evaluated on its merits’ rather than being fixed by blanket restrictions. Greenbelt development could play an important and perhaps even relatively sustainable role in addressing the housing crisis.
The question then is how any release of greenbelt land can be managed to prevent sprawl and retain the many environmental roles that the greenbelt embodies. There is also the problem of making the case to the public when the greenbelt has traditionally been a popular policy. And so we come back to the issue of local authorities cooperating to tackle regional challenges. A million commuters cross the GLA boundary every weekday, yet regional planning is almost non-existent. Any release of greenbelt land needs to be considered in its regional context and balanced against brownfield opportunities. The biggest housing opportunities are linked to new infrastructure (e.g. Crossrail both West and East of the GLA; the Varsity Line for Oxford-Milton Keynes-Cambridge), again at the regional scale. Its hard to see how the housing crisis can be tackled without much greater regional cooperation and some form of regional planning for the South East.
You know you’ve attended a good conference when the discussion leaves your head buzzing with new ideas and possibilities, and the debate continues long after the event closes. This was certainly the case at the Urban Age Electric City conference last week, where politicians, academics, designers and technologists met to share, discuss and argue urban policy and the future of cities.
Ostensibly the conference theme was smart cities and urban technology, and there were several tech business speakers extolling the virtues of electric cars, smart grids and so on. There was however widespread cynicism of techno-fixes on many fronts. Adam Greenfield used the very definitions of the smart city provided by corporate promoters to show the vacuous techno-utopian branding of what is often simply an extension of the real-estate industry. Richard Sennett articulated the ambiguous and complex nature of traditional street-based urban form, and by extension how archetypal smart-city examples from Masdar and Songdu failed to create similar spaces of social interaction that support innovation.
Yet it must be said that the urban technology debate is itself far more diverse than the strawman examples of Masdar and Songdu. Certainly the Shoreditch digital economy cluster that surrounds the conference venue illustrates thriving tech businesses in a traditional urban setting. Many of the counterexamples to smart-city utopia presented during the conference themselves involved aspects of technology, particularly in relation to communication and participation.
Urban equity, or lack of, was a key theme for many speakers. Enrique Peñalosa, former mayor of Bogotá, passionately argued for tackling social inequality as a central element of improving urban sustainability- an argument he has helped translate into reality through reforming Bogotá’s public transport networks. The politics of inequality also underlie the social movements and protests that have rocked the world, from Occupy to the Arab Spring and the London riots. In these cases social networking technology presents a highly dynamic and unpredictable force that city governments, both rich and poor, are struggling to engage with.
On the design front, the talk that best integrated the conference themes was from Alejandro Zaera-Polo, who sought to articulate the evolution of architectural style and practice in response to digital communication. Citing modular and self-build architecture examples, he described a new aesthetic of incompleteness, and used slum developments as the model of how complex functional urban form emerges from simple building blocks. He also pointed to crowdsourcing as an increasingly key funding mechanism for development in the austerity age, requiring a new entrepreneurialism from architects to generate public support and money for ambitious projects. This spirit of architectural daring and entrepreneurialism was certainly on show from Bjarke Ingels, whose mad and wonderful “hedonistic sustainability” examples were a joy to see.
Yet as much the designers inspired, presentations tackling the global environment highlighted the gaping chasm between urban sustainability aspirations and reality. “Cities dream of Barcelona and build Los Angeles” was Greg Clark’s quick-fire summary of Joan Clos’s conclusions from the UN Human Settlements Programme. “The compact city plus global lives do not equal sustainability” correctly argued Maartin Hajer.
Intellectual heavyweight Anthony Giddens grappled with the grave implications of the 4+ degrees warming path we are set on for this century, and the high-risk high-opportunity civilisation we have created. When asked somewhat glibly by the chair whether he was an “optimist or a pessimist” he replied quite rightly that the question was irrelevant and that climate change requires scientific realism, a perspective that is currently beyond much of the public. It’s certainly appeared beyond the UK politicians on show, who enthusiastically banged the drum for sustainable London while conveniently forgetting that much of the globe’s fossil fuel industry in headquartered in London and funded by City banks.
There were also some rays of hope for a deeper understanding of urban sustainability. The former mayor of Stockholm, Carl Cederschiöld, described how sustainability progress had been achieved in his city, pointing to the vital role of both strong national support and public understanding as well as city government. Dimitri Zenghelis put forward the economic growth case for an urban green transformation. Mark Swilling presented a methodology of understanding urban sustainability through social and resource flows- exactly the kind of approach needed for considering sustainability in an age of global connectivity. Maartin Hajer described the need for forging “coalitions of the willing” in tackling global sustainability where international governance has been so ineffective.
And that’s what the Urban Age conference surely is in the end, one big coalition of the willing… or willing to discuss and debate at any rate. Thanks to all those who took part and contributed to a very engaging event. If you missed it, conference video highlights will be appearing on the website over the coming days, and you can read essays by many of these speakers in the conference newspaper.
I recently began a new job at LSE Cities and have been working for the last month on materials for the Electric City conference in London, taking place on the 6th and 7th December this week. The conference will be exploring smart cities and disruptive urban tech from a sociological slant, and includes talks from famous urbanists such as Ed Glaeser, Saskia Sassen and Deyan Sudjic. You can get a flavour of the debate from Richard Sennett’s provocative article on “Stupefying Smart Cities”.
My role, alongside the LSE Cities Research Team, has been in producing comparative urban visualisations and analysis around the theme of sustainable urbanism. These visuals and articles are now online in the conference newspaper.
Cities that achieve social and economic success without high car use generally have three things in common: high densities, good urban design, and successful planning frameworks that integrate land-use with public transport, walking and cycling networks. I’ve been working on an LSE Cities project that investigated two leading global cities in green transport- Copenhagen and Hong Kong- to better understand how their leading positions were reached. You can read the final Going Green report here.
The project required visualising the level of integration between public transport and urban density in these cities. We developed a technique where the rail network is shown as a transect through a 3D population density surface. This shows how the density of jobs and residents in these cities is clustered around major public transport nodes.
Copenhagen has a classic radial pattern, based on the famous ‘Finger Plan‘ developed over 60 years ago, where linear urban features are separated by thin green wedges. This is quite distinct to the UK greenbelt approach. Current expansion is focussed to the south of the city centre along the Orestad corridor served by the more recently developed metro links. This area sites the airport and transport links to Sweden, continuing the cross-border integration between Copenhagen and Malmö.
Hong Kong makes a very interesting comparison. It is on average 8 times(!) higher density than Copenhagen, and peak densities are around four times higher at nearly 150,000 jobs & residents per square kilometre. This is due firstly to the natural boundaries and country park designations that prevent suburban development, and secondly to the unique ‘Rail plus Property’ planning model run by the government and MTR, where extremely high development densities are pursued at rail station sites, and land value gains captured to fund public transport. The result is a polycentric pattern of jagged nodal development.
Another way to consider this relationship is to measure typical distances to rail & metro stations for these cities. As can be seen below, Copenhagen and Hong Kong compare favourably to other leading global cities like London and New York.
It would be interesting to pursue this analysis further for London. You can see that London scores relatively lower for the population within 500 metres of stations. Intensification policies at public transport nodes are a recent policy change for London. Accessibility figures are likely to change over time with several major intensification projects under way at rail stations in Inner London.
(Above figure based on metropolitan regions. Defined as Outer Met Area for London and 100 km by 100 km square centred on Manhattan for NYC).
As the costs of recent droughts spiral from USA to Australia, West Africa to India, we’re getting a taste of what a significantly warmer climate would be like. Critically as the scientific evidence mounts up that climate change is occurring, global carbon dioxide emissions are soaring. Why is this?
I’ve designed a new website Carbon Chart visualising current data to answer this question.
There’s no single ideal metric to determine the contribution of different countries towards global warming, and a range of different perspectives need to be considered, as well as related issues of economic development and poverty reduction. The design of Carbon Chart is intended to allow the comparison of several perspectives.
So where are the maps? I’ve gone for a graph approach to focus on change over time. See Kiln’s excellent Carbon Map website for a cartogram-based approach to understanding global warming.
Current emissions data do not make happy reading. CO2 output is increasing in the developed world in consumption terms, and is rocketing in the developing world, especially China. We’re replicating our carbon intensive economic model on an incredible scale.
Maybe the climate models are wrong, or maybe an international climate agreement with substance is just around the corner. But right now it’s difficult to see how the more extreme scenarios of 4°C+ warming are going to be avoided.
Despite the litany of sins levelled at the automobile- it’s woeful energy efficiency, harmful pollution, congestion, road casualties, damage to public space, contribution to obesity- we are still wedded to the car. In the UK the car accounts for over three quarters of trip miles. The flexibility, security and door-to-door convenience of automobile travel remains a winning combination, particularly when we spent most of the 20th century developing car-based cities with limited alternatives.
Current planning practice restricts car travel to improve sustainability and urban quality of life. Short of an outright ban however, the car is here to stay in some form or other.
For the automobile to be in any way sustainable we need to radically challenge current systems of car design, driving and ownership to effectively create a new mode of transport. This post considers whether such a revolution is possible in light of exciting recent innovations.
We now for the first time have competitive alternatives to the internal combustion engine car on the market with electric and hybrid models from the world’s biggest manufacturers. These technologies dramatically reduce or remove tail-pipe emissions. Surely then the eco-car has now arrived and city transport has been saved?
Well… as electric cars (and vans/taxis/buses) become more widespread urban air quality should improve dramatically, as should vehicle mileages. But as we generate the majority of electricity using fossil fuels (and will continue to do so for the next 20 years+), CO2 emissions from electric cars remain significant.
Furthermore several other car design issues are not solved by electrification, such as energy used in manufacture, road congestion, safety and damage to public space. There’s a danger that electric cars become merely a green-wash cover for business as usual, rather than as a step towards bigger change.
Most cars are driven for a relatively short period each day, and are parked the rest of the time occupying land (around 10% in cities). On-street parking eats up large amounts of valuable public space from pedestrians, public transport and cyclists. It’s a wasteful situation, both for the efficiency of cities and for the environment due to the vast amounts of materials and energy used to manufacture our largely idle cars.
One increasingly popular solution in cities is car-sharing, with the largest company Zipcar now up to 700,000 members. Car-sharing is a convenient and affordable option for many city residents who want regular car access without the hassles of ownership. The popularity of smartphones provides an easy way to manage car-share booking. Comparable sharing trends are also evident for ride-sharing and for urban cycling.
Is sharing the answer then to the sustainable city travel? It’s definitely an important trend. Sharing allows a much better pricing model for driving, paying by the mile and charging more at peak times, thus encouraging more efficient behaviour.
Car-sharing coverage is limited however to denser urban areas, and it is not yet clear to what extent car-sharing can significantly reduce the total number of vehicles and car parking space in cities.
Self-Drive The last trend is at a much earlier stage than electrification and car-sharing, yet it could have the most far-reaching consequences. Sat-nav and parking-assist technologies were early steps towards greater automation in cars. Now Google as well as several manufactures have working prototypes of autonomous or self-driving vehicles.
Amazing yes, but what’s the point? In its current form, the application of this technology is not immediately clear, beyond providing a luxury car gizmo that lets you read the paper while your car drives you to work. But future developments will likely involve cars built around self-drive from the ground-up.
Potentially you could have a city taxi fleet of fully autonomous electric cars, requested by smartphone, operating 24 hours a day, moving to areas of high demand, charging batteries when not in use. Whilst bad news for taxi-drivers, such a system could be highly efficient and provide a quick and flexible complement to mass transit networks.
A related concept has already been developed in a rail-pod form operating at Heathrow airport. Dubbed Personal Rapid Transit, it is intended to combine the advantages of both private and public transport. Obviously the challenges of converting such a system to operate autonomously in the ‘wild’ of the urban environment are many, yet are increasingly being tackled.
If such a system could safely and legally operate, the implications would be massive. Imagine freight and courier services operating automatically at night to minimise disruption; your car picking up your shopping on its own, or taking a nap and waking up at your destination.
Reality Check It’s easy to get carried away with the wonders of new technology. Transport challenges require political and economic solutions as much as technological brilliance. Indeed relying on car manufacturers alone to green transport is as unlikely as “Beyond Petroleum” BP and Shell delivering the renewable energy revolution. Yet there is some incredible innovation currently emerging, and the next couple of decades are certain to be very interesting times for urban transport.
Every so often you come across a dataset that really amazes you in its richness and ability to change perspectives on understanding the world. One such dataset has been produced by academics at Stanford and Oslo tracing the global supply chain of CO2 emissions.
Traditionally emissions are attributed to countries depending on where fuels are burned- the point of production. This approach puts big industrial polluters like China at the top of the emissions pile. Yet globalisation means that we are linked into an increasingly complex web of trade that challenges a production-based understanding of emissions. A quarter of fossil fuel CO2 emissions can be considered as being embedded in manufactured goods that are consumed away from the point of production.
To address this issue Davis, Peters & Caldeira have created a database charting the global supply chain of CO2 emissions from extraction to production and finally to consumption. The database covers coal, oil, gas and secondary fuels traded by 58 industrial sectors in 112 countries for the year 2004. Even better, the entire database is available online.
Maps of the major carbon transfers included in the paper highlight firstly the massive flows from the energy rich Middle East and Russia, and secondly how production emissions from industrial countries such as China are ultimately driven by consumption in the affluent core of USA, Europe and Japan.
Being a mapping type, I feel that the flow maps in the paper miss out much of the amazing detail in the dataset, such as extraction to consumption flows within countries (half of all emissions). So I decided to put my visualisation skills to the test…
First up I produced a proportional bubble map of extraction and production, giving a good sense of the relative scale between countries. Economies with high levels of both extraction and consumption (e.g. USA and China) exploit their own energy resources and have large emission flows within their national boundaries. Other large consuming nations that lack energy resources (e.g. the EU, Japan and South Korea) must import them.
Next I mapped the transfers of CO2 embedded in trade flows, using the same black-red colour scheme to indicate flow direction. While the visualisation is not as straightforward as the simpler flow map above, it gives a strong sense of the amazing complexity in global trade relationships and highlights clear patterns and structures.
Black lines emanate from the major energy exporters of the Middle East and Russia. Indeed the degree to which all of Europe is dependent on Russian energy is highly alarming. Major industrial countries act as intermediaries, both importing and exporting emissions. For instance China and Japan import energy and materials from the Middle East, Indonesia and Australia, then export manufactured products to the USA and Europe. The USA is top predator in the emissions food chain, spectacularly drawing in goods and resources from every corner of the globe and racking up over 25% of global emissions by consumption.
The data is for 2004, so some current trends like the strong growth of South America, continued growth of China and the strengthening relationships between China and Africa are not fully captured. Hopefully an update will come in the not too distant future.
On the cartography side, I went for the Azimuthal Equidistant projection to emphasise the close North America-Europe-Asia links. This projection is recognisable as the basis of the United Nations logo. Here however it is global capitalism and environmental exploitation drawing the world together like some kind of tightening noose. After another empty environmental conference at Rio+20, burning billions of tonnes of fossil fuels is set to remain a defining characteristic of our age.
There have been some wonderful flow maps appearing online recently, such as Paul Butler’s global facebook friend’s map, and maps of global trade and flight patterns. Inspired by these, I’ve been mapping travel patterns in Great Britain using a similar “night-lights” visual style.
The above maps use data from the UK census connecting where people live to where they work, showing how transport flows form complex urban networks and extensive metropolitan regions. The data is at ward level, allowing a good level of detail:
Taking this visualisation further, a key issue for policy makers is how people travel, with private cars having greater energy, pollution and congestion impacts than alternatives. The final map below groups work trips into car, public transport and walking-cycling travel using an RGB colour scheme, creating a galactic effect (click for larger):
The aim of the visualisation is to put travel patterns in the context of the diverse urban scale and geography of Great Britain, and reveal the degree of regional variation.
The map really highlights how different London is in terms of its extensive regional public transport network, with the other major English conurbations like the West Midlands, Manchester and West Yorkshire being highly car dominant in comparison. The variation in public transport levels could be argued to relate to London’s massive size, yet the Scottish cities of Glasgow and Edinburgh perform well in public transport terms, despite being smaller than England’s northern cities.
Active travel modes of walking and cycling are generally minimal. The cities that do relatively well are the “cathedral cities” like Cambridge and York, with a few surprises like Hull.
The maps were created in ArcGIS using the XY to Line tool, then exported to Illustrator. A key aspect of such flow visualisations is that the thousands of overlapping flows add together to form denser links using a cumulative transparency effect. This is much easier to achieve using a vector graphics program such as Illustrator. Would be nice in a future post to add Northern Ireland and the Republic, and will get a data update with the 2011 census next year.
As cities expand with multiple centres spread over massive regional hinterlands, the need to better understand the geographical variation across and within cities has become more pressing. This need applies strongly to issues of travel sustainability, where urban centres differ greatly in the accessibility they facilitate for private, public and active transport.
Spatial indicators are a useful tool to summarise complicated intrametropolitan patterns, as illustrated in my new working paper mapping CO2 emissions from journey-to-work travel across the London Region. The results of this indicator show a massive range of travel emissions by workplace of up to 300%, with particular problems for airports and the specialised employment region of the Western Sector, as can be seen in the map above.
This paper was co-authored with Joan Serras at CASA, who helped with the development of the road and public transport network analysis to model realistic routing behaviour from origin and destination flows from the 2001 census. One interesting aspect to this was the inclusion of GPS data to model average road speeds in London as illustrated below:
Full paper abstract:
“This paper develops a methodology for estimating network distances and CO2 emissions for UK census ward-level journey-to-work interactions. Improvements are made on existing empirical measures by providing comprehensive intra-metropolitan analysis; increasing network routing accuracy with UK public transport timetable and GPS-based average road speed data; allowing multimodal travel; and developing metrics suitable for travel sustainability analysis. The output unit of CO2 emissions has been selected to enable the integration of mode-choice and travel distance data, and to aid compatibility with integrated assessment applications.
The methodology is applied to the case study of the London Region for the year 2001. A very high degree of intra-metropolitan variation is identified in the results. Employment sub-centres diverge in their per-capita CO2 emissions by up to 300%, with specific problems of carbon intensive commuting to major airports and the specialised employment region of the Western Sector. These findings indicate that subcentre travel variation may be intrinsic to polycentric urban structures. The paper discusses means to improve the methodology, in relation to issues of coefficient disaggregation and modelling more complicated multi-modal trips.”
With a few notable exceptions such as Cambridge, cycling in UK cities is minimal compared to continental European examples, and boosting cycling is a massive opportunity for improving travel sustainability and health in Britain. The potential is greatest in London, with its high density mixed-use form, relatively flat topography and benign climate that favour cycling; in addition to congested and expensive car and public transport networks that leave many looking for alternatives.
Planning policy at the Greater London Authority level recognises this potential and has become increasingly pro-cycling, with recent investments in the ‘Cycling Superhighways’ scheme– longer distance radial cycle routes that (almost) join up; the bike hire scheme; and modest improvements at many junctions and in cycle parking facilities. These measures have helped to increase the level of cycling in London substantially in the last decade (although beginning from a very low starting point):
So can this trend be accelerated to make London a real cycling metropolis, a larger scale version of Copenhagen or Amsterdam? I believe it’s possible, but I discuss one of the biggest obstacles here- safety and space. (Other obstacles include terrible integration with public transport, bike theft, image…).
On the 4th October a student from Korea was crushed to death by an HGV vehicle near Kings Cross, becoming the 13th fatality in London this year. Overall cycling fatalities and injuries declined in the early 2000’s, in line with pedestrian and car accidents in general, but have increased in recent years as cycling trips have increased. There were 467 serious injuries in 2010, up 8% on the previous year. Cycling in London is a hectic experience of dodging traffic and aggressive driving, with very minimal segregated lanes and many dangerous junctions to avoid.
Ultimately a serious increase in cycling use requires a serious improvement in safety, and this means the creation of many more segregated cycling routes and the redesign of many key junctions. These measures will translate into reductions in vehicle flow in London, and TfL seem largely unwilling to make this compromise when it comes to major roads. A significant culture change accepting cycling as a key part of London’s transport would have to occur to achieve a genuine cycling city.
The UK government is seeking to dramatically overhaul the English planning system, releasing the National Planning Policy Framework consultation in late July. This intends to streamline the system, reducing the array of previous planning policy frameworks into a single 50-page document. Various government ministers, including the chancellor, have been arguing this is a vital reform to ‘get Britain building’ and boost growth in a time of economic hardship.
As someone who cares deeply about the economic success and quality of life of the UK, reading this document was very alarming, as its vague pro-development language fails to get to grips with the economic and built environment challenges we face now and in the future.
The document states there should be a “presumption in favour of sustainable development” yet fails to define sustainability in any rigorous way (i.e. natural resources, energy, carbon emissions…), thus effectively making policy “a presumption in favour of development”. The previous requirement to prioritise developing brownfield land, a central policy in urban regeneration, is abandoned. The section on transport is weak, stating applications “should not be refused permission on transport grounds unless the residual impacts of development are severe”. There is no understanding of cities as the engine of the UK’s economic growth, nor of the regional relationships that are needed for urban economic competitiveness.
There is undoubtedly a need in the UK for major housing expansion and for facilitating business growth through planning. This requires a coordinated approach to development focussed on cities, urban regeneration, boosting the knowledge economy, and taking into account the severe energy constraints and carbon reduction limitations we face in coming decades (i.e. we need highly energy efficient homes and a decent life without mass car ownership). This document doesn’t even get close, and policy makers need to go back to the drawing board for a more progressive vision.