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Sustain to gain: November 2011 Archives

A broad literature investigates the impact of urban form and transport energy use, clearly demonstrating the benefits of compactness for lowering energy use and reducing greenhouse gas emissions. Myriad qualifications apply, of course, highlighting the importance of street accessibility and job-housing balance (e.g. Ewing and Cervero, 2010).

Ewing and Rong (2010) finally explored the other side of the story: the impact of urban form on residential energy use, relying on US data. Intuitively, sprawled residences have higher space requirement and need more energy for heating. The authors show that single-family detached housing consumes 54% more energy for heating and 26% more energy for cooling than otherwise comparable multi-family housing. With equal income, black, Hispanic and Asian household are more likely to live in multifamily housing than white households do. Multifamily housing is highly correlated with compactness.

The Urban Heat Island effect introduces another dimension. Compact neighborhoods are warmer than sprawled neighborhoods, causing less heating demand but higher cooling demand. The less-heating effect dominates in most regions in the US. The exception is the Sunbelt, where higher temperatures require higher additional cooling demand, creating an energy penalty for more compact housing. With global warming, this energy penalty is likely to increase.

Altogether the housing effect clearly dominates the energy balance. An average household in a compact neighborhood (one standard deviation above mean) consumes 20% less energy than the average household in a sprawled neighborhood (one standard deviation below mean). Let us look forward to seeing other detailed studies on this issue, also from other parts of the world. 

Amazonian deforestation is a major regional and global disaster, rapidly diminishing natural capital, contribution to mass extinction, and to climate change via land-use emissions. Evidently, the drivers of deforestation need to be closely scrutinized. Imori et al. (2011) contribute to this debate and perform an input-output analysis on Amazon deforestation in 2005. They find that cattle, soybean and to lesser degree sugar cane are main culprits of deforestation. The study does not investigate market-mediated effects. For example, the possibility that sugarcane production around Sao Paolo substitutes for cattle, which, in turn, is pushed into the Amazon region is not analyzed (Lapola et al., 2011). The authors point out that cattle and soybean provide employment in a region that otherwise offers few opportunities. Employment and economic growth targets are thus in direct conflict with forest protection. Soybean is mostly exported (e.g. for feeding industrially produced chicken in Germany). From a consumption-based perspective, importing countries of soybean are also responsible for Brazilian deforestation. A relevant CO2 tax on consumption of soybean (and cattle) in OECD countries or on production in Brazil could reduce the pressure on continued deforestation. Global efforts of forest protection are probably well advised to advance approaches that provide high employment and give ownership of forest protection to local communities.