Empirical study of 113 countries shows that built-up areas and roads drive energy consumption and CO2 emissions almost as much as gross domestic product. Measures to curb land consumption are therefore a central element of promising climate protection strategies.

Built structures such as settlements and transport infrastructure are known to influence per capita energy demand and CO2 emissions in cities. It has been unknown what role built structures play at the national level because this could not be investigated so far due to a lack of suitable indicators. Discussion has focused on other potential determinants of energy demand and CO2 emissions, most notably gross domestic product (GDP). Factors such as energy prices, climatically determined heating energy demand or population density were also investigated.

In the study "Built structures influence patterns of energy demand and CO2 emissions across countries", just published in Nature Communications, researchers from the Institute for Social Ecology (SEC) at the University of Natural Resources and Life Sciences Vienna, together with colleagues from Spain and the Climate Change Center at TU Berlin, present 16 indicators to characterize patterns of built structures at the national level. They quantify these indicators for 113 countries. Using statistical methods, they investigate how strongly indicators of built structures are correlated with energy consumption and territorial CO2 emissions, and compare this with the relevance of common economic variables such as gross domestic product.

Limitation of soil consumption

Soil sealing by buildings and infrastructure continues unabated, and just a few days ago a push for an Austrian soil protection strategy failed. "We have found that built structures are about as important as gross domestic product and other conventional factors in predicting energy demand and CO2 emissions. Built-up area per capita is the most important value for making predictions, second only to GDP," said Helmut Haberl of the Institute for Social Ecology. "Limiting land consumption for new buildings and infrastructure thus turns out to be a central element of successful climate protection strategies," Haberl added.

The analysis shows that the scale and spatial patterns of built structures play an important role as determinants of resource use, in this case energy use and CO2 emissions per capita per year, in a cross-national analysis. This means that findings from studies of cities in general also apply at the national level. The indicators also have significant additional explanatory and predictive power over traditional factors. They can help develop much stronger models of energy use and CO2 emissions at the national level than has been possible in the past. This will allow researchers* to expand their scenario analysis and modeling capabilities by incorporating patterns of built structures as critical determinants of potential decoupling of energy use and emissions from GDP or societal well-being.

Population density plays a smaller role than assumed

The study also shows that the extent and pattern of built structures strongly influence differences between countries in energy demand and CO2 emissions, while population density plays a smaller role than previously thought. The indicator with the strongest and most consistent predictive power across analyses is built-up area per capita, which emerges as the second most important variable after GDP in most statistical analyses. This is also true in analyses that account for the GDP effect.

Co-author Felix Creutzig of the Climate Change Center Berlin Brandenburg and MCC Berlin says, "This is plausible because roads, highways, parking lots, and buildings require energy for their construction and use, which leads to high CO2 emissions in our fossil energy-dominated energy systems. Additional built-up area also means more heated or cooled space in buildings and longer distances between destinations, which increases energy demand in buildings and transport."

Space-saving urban and regional development central

These results confirm and extend previous analyses that used completely different models, did not capture spatial patterns, and focused mainly on temporal trends. This indicates that climate change mitigation challenges are highly dependent on the extent of building and infrastructure. "This is of concern because material stocks around the world are growing largely in step with gross domestic product," Haberl says. Creutzig adds, "Our results show that land-saving urban and regional development is central to long-term climate goals."

To the article:

Helmut Haberl, Markus Löw, Alejandro Perez-Laborda, Sarah Matej, Barbara Plank, Dominik Wiedenhofer, Felix Creutzig, Karl-Heinz Erb, and Juan Antonio Duro:

Built structures influence patterns of energy demand and CO2 emissions across countries



Scientific contact:

Univ.-Prof. Dr. Helmut Haberl
Institut für Soziale Ökologie (SEC)
Universität für Bodenkultur Wien

Prof. Dr. Felix Creutzig
Climate Change Center Berlin
Technische Universität Berlin
MCC Berlin
+49 30 314-78864