by Dr Jeff Vickers, Ben Fisher & Dr Barbara Nebel – thinkstep Australasia – May 2018
Energy use in buildings contributed 19% of society’s global carbon footprint in 2010, according to the Intergovernmental Panel on Climate Change. The value quoted for New Zealand is typically around 5% (Figure 1a) and sometimes as low as 2% (considering only direct combustion of fuels). These values derive from New Zealand’s Greenhouse Gas Inventory and have been popularised in recent years by the Productivity Commission and the Royal Society, among other organisations.
Taken in isolation, 2-5% seems small enough to conclude that the built environment is relatively unimportant and that other sectors are higher priorities for emissions reduction at a national level. However, there are two issues when using these figures: (1) they consider only the energy used in buildings, but not the construction of these buildings or their eventual demolition, and (2) they present the carbon footprint of everything produced in New Zealand, rather than what is actually consumed.
If we consider the full life cycle (construction, use and end-of-life), the contribution of the built environment (i.e. buildings and infrastructure) increases to approximately 13% of New Zealand’s gross carbon footprint (Figure 1b). If we then adjust for the carbon footprint embodied in our exports (dairy, meat, etc.) and our imports (cars, trucks, clothes, etc.), this share climbs to 20% (Figure 1c) – a value that highlights the built environment as a key hotspot in our national carbon footprint.
Figure 1: A breakdown of New Zealand’s carbon footprint in 2015 from (a) a production perspective, (b) a life cycle perspective, and (c) a life cycle consumption perspective.
There are two main reasons why the New Zealand figure for the carbon footprint for energy use in buildings appears to be four times smaller than the global average of 19%: (1) we use low-carbon electricity and wood for most of our building heating, and (2) the percentages are distorted by New Zealand’s large share of direct agricultural emissions, which account for roughly half of our total gross carbon footprint (Figure 1a).
The consumption-oriented view presented in this report highlights the areas in which New Zealand organisations and households can have the greatest influence on climate change through their purchasing decisions. It does not replace the production-oriented view, which is mandatory for reporting at an international level. However, if the production-oriented view is used alone, it allows nations to shift production offshore to meet their national targets. Shifting the burden will not help us to tackle climate change; instead, we should take responsibility for the emissions we are responsible for.
Given that climate change is a shared problem, it seems logical that both producers and consumers need to be part of the solution.
You might also be interested in the Press release: "Hidden Building Pollution exposed: New Report"
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