Planning Decisions Must be Based on Facts

While the misreporting of city population density comparisons commented on by  Wendell Cox was probably inadvertent, it is indicative of a general problem relating to contemporary planning – misrepresentation of facts.

We are repeatedly told of the wonderful results of infill high density policies in locations such as Portland, USA or Vancouver, Canada which on investigation are found to be non-existent or applicable only to a small locality instead of to the city as a whole.

Quantitative data is frequently misrepresented. To give one example, a 2008 Canadian study is often quoted as proving high-density reduces greenhouse gas emissions. Inspection and interpretation of the data provided reveals this to be negligible.  Without any evidence to the contrary, it seems reasonable to assume that the Canadian fraction of total household emissions that relate to transport is similar to that shown on the Australian Conservation Foundation's website, being 10.5%. Applying this value to the data in Chart 2 of this Canadian study one finds that for those living within 5 km of the city centre there would be a transport difference attributable to increased density of only 1% in total annual emissions per person. For people living 20 km or more from the city centre the difference would be much less at 0.2%.

We are told that high-density imposed on areas originally designed for low density is good for the environment; that it provides greater housing choice, that it reduces housing cost, that it encourages people on to public transport; that it leads to a reduction in motor vehicle use and that it saves on infrastructure costs for government. Not only do none of these claims stand up to scrutiny in any significant way, the contrary mostly prevails.

Movements advocating high-density show characteristics of an ideology, their members’ enthusiasm resulting in a less than objective approach. The desire by these individuals to be socially and environmentally responsible and to identify with a group marketing these imagined benefits is understandable. Some may even benefit professionally. However the result is policies for which no objective favorable justification can be provided and which are not wanted by the greater community who have to live with the consequences.

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Dont bet the house

If the intention is to compare overall carbon dioxide emissions the Steuterville article suffers from two problems. Firstly it only deals with emissions from vehicles which are a small portion of total emissions. Secondly it quotes emissions per household and not per person. There are usually more people living in a single-residential dwelling than in high-density.

A comprehensive study of per capita emissions in Australia based on household consumption of all products and services appears in the Australian Conservation Foundation's Consumption Atlas ( Unexpectedly, this analysis shows that greenhouse gas emissions of those living in high-density areas are greater than for those living in low-density areas. An analysis of the data (1) shows that the average carbon dioxide equivalent emission of the high-density core areas of Australian cities is 27.9 tonnes per person whereas that for the low-density outer areas is 17.5 tonnes per person. Food and goods purchased account for most of the emissions and this amounts to more for wealthier inner-city dwellers.

Surprisingly, transport emissions amount to very little (only 10.5%), household electricity and heating fuel being about twice as much at 20.0%. (2) It should also be noted that the emissions from household dwelling construction and renovations at 11.8% are greater than emissions for transport. It is clear that transport, so heavily emphasized by Smart Growth advocates, is responsible for only a small fraction of household emissions.

Interestingly, using regression analysis to attempt to isolate variables influencing household emissions, the paper on which the data is based (3) finds that density, as an isolated variable, has practically no effect on total energy requirements. The paper also finds that density has little effect on the per person energy requirement for mobility and automotive fuel consumption.

Another study which solely measures direct household energy consumption (4) (thus excluding the effect of purchases) found that annual greenhouse emissions from this source in high-rise equated to 5.4 tonnes CO2 per person per year whereas that for detached housing was only 2.9 tonnes. So even when excluding purchases associated with wealth, high-rise still comes out worst.

Yet another study, also not incorporating factors directly associated with wealth (5) finds that the total of transport, building operational and building embodied annual greenhouse gas emissions per person for city apartments is 10 tonnes whereas that for outer suburban dwellers is 7.3 tonnes – once again more for apartments.

The explanation for these findings probably partly arises from lower occupancy rates in high-rise compared to single-residential (as revealed in the above-mentioned studies) and the use of elevators, clothes dryers, air-conditioners and common lighted areas such as parking garages and foyers. Most studies do not include this latter important element, simply because they are based upon consumer bills which do not include common consumption. In addition there is the greater energy per resident required to construct high-rise.

Looking towards the future, if we are to reduce our urban energy and water footprint by individually collecting localised solar energy and rainwater it appears reasonable that this will only be practical for dwellings that have a large roof area per inhabitant. That means low density.

I would not bet the house that smart growth reduces carbon dioxide emissions.

1. Demographia, Housing Form in Australia and its Impact in Greenhouse Gas Emissions: An Analysis of Data from the Australian Conservation Foundation Conservation Atlas (2007)
2., Figure 1
3. Manfred Lenzen, Christopher Dey, Varney Foran, Energy requirements of Sydney Households, Ecological Economics, 49 (2004) 375-379. See table 4.
4. Paul Myors, EnergyAustralia, with Rachel O'Leary and Rob Helstroom, Multi-Unit Residential Building Energy & Peak Demand Study. NSW Department of Planning (October 2005), Energy News VOl 23 no 4 Dec 05
5. Perkins, Alan, Hamnett, Steve, Pullen, Stephen, Zito, Rocco and Trebilcock, David(2009), Transport, Housing and Urban Form: The Life Cycle Energy Consumption and Emissions of City Centre Apartments Compared with Suburban Dwellings, Urban Policy and Research, 27: 4, 377 — 396

not so much buddy

Sorry buy ... but Robert Steuteville just destroyed your central argument.

Better luck next time ... try posting an opinion in a field where there are less facts ... like theology.