By Associate Professor Andrew Macintosh
Who has a greater impact on the climate: a person who regularly eats beef and builds their house with bricks and mortar or a vegan with a wooden house?
Intuitively, most people would think that the bricks and mortar dwelling beef-eater has a greater impact. This is also what the vegans and forestry industry will tell you. For example, the People for the Ethical Treatment of Animals (PETA) tell us to ‘Fight Climate Change by Going Vegan’. Similarly, Planet Ark (with its partner, Forest & Wood Products Australia) tell us to ‘make it wood-do your world some good’ because ‘when sourced responsibly, wood can play a big part in helping tackle climate change by storing carbon and through reducing carbon dioxide emissions into the atmosphere’.
Some might think that the slogans of lobby groups are hardly a reliable source of information for judging the relative climate benefits of products. However, in this case, the positions of the lobby groups are supported by the results of many life-cycle analyses (LCAs).
LCA is a technique for evaluating the environmental impacts (in this case, greenhouse gas emissions) of a product, service or system. There are two broad types of LCAs: attributional and consequential. Attributional LCAs evaluate the environmental impacts associated with the production, use and disposal of a product or service at a point-in-time. Consequential LCAs evaluate the likely future environmental impacts associated with a decision to change a system.
When attributional LCAs have been carried out on food and construction materials they have tended to show that both beef and bricks and mortar are emissions-intensive relative to lentils and wood. So, if you are concerned about climate change, become a vegan and opt for wood when you are undertaking your next construction project.
But is it that simple?
What would happen if a law was passed requiring all emissions associated with beef, bricks and mortar to be offset by emission reductions from other sources? Would the lentil burger and wooden house still be the most climate friendly options?
Simple logic tells us that the answer is no. If the impacts of the law are accounted for, the net emissions associated with beef, bricks and mortar should be zero. If lentil and wood production are not subject to similar policy restrictions, the wooden house-living vegan no longer appears as climate friendly as a basic LCA would tell them they are.
In the past, LCAs have tended not to account for these types of policy effects. In a paper published in Nature Climate Change today, we (along with our colleague, Dr Heather Keith) present a framework for considering the impacts of policy institutions in LCAs and apply it to the controversial issue of whether it is better for the climate to conserve native forests or to harvest them sustainably to produce wood products.
The framework divides policy institutions into three categories for the purposes of LCAs: macro, consequential and attributional. Macro policy institutions are those concerning policy objectives and principles. Consequential policy institutions are those that affect substantive outcomes; they provide incentives (inducements, penalties or information) for policy actors to behave in ways that affect emissions and removals. Attributional policy institutions are those that assign responsibility for emissions and removals between jurisdictions and other relevant actors.
To illustrate how these different types of policy institutions affect LCAs, we undertook a consequential LCA on the Southern Forestry Region (SFR) in New South Wales, a roughly 430,000 hectare public native forest estate managed by the Forestry Corporation of NSW. The LCA compared the net emission outcomes from conserving the estate relative to a sustainable use reference case based on current practices. Eight scenario sets (conservation vs sustainable use) were devised around three groups of assumptions concerning policy institutions: basic, global and national.
The results from the analysis are shown in Figure 1. In the Figure, positive abatement represents instances when conservation reduces net emissions relative to the sustainable use reference case; negative abatement represents instances when conservation increases net emissions relative to the sustainable use reference case.
Figure 1 Cumulative abatement over the 100-year projection period in the basic, global and national scenarios, million tonnes (Mt) CO2-e
The basic scenarios assessed global net emissions outcomes from the alternative management options (conservation vs sustainable use) using `typical' forest LCA assumptions, including that policy institutions do not affect emission outcomes. Under these scenarios, conserving the native forests resulted in large reductions in global emissions over the 100-year period (57-75 MtCO2-e).
The global scenarios assessed global net emissions outcomes, having regard to applicable macro and consequential policy institutions, the most important of which are Australia’s international obligations to limit its net emissions to a prescribed target and the equivalent obligations on other nations. When these policy institutions were accounted for, the global net emissions outcomes from conserving the native forests ranged from a reduction in emissions of 1.7-3.5 MtCO2-e to an increase in emissions of 3.7-5.5 MtCO2-e. To put it bluntly, the results suggest that how the native forests of the SFR are managed should make very little difference to the global emissions outcomes, provided the international policy institutions are adhered to.
The national scenarios assessed impacts on Australia's net emissions, having regard to applicable macro, consequential and attributional policy institutions. Under these scenarios, conserving the native forests of the SFR resulted in a large reduction in national emissions over the 100-year period (79-85 MtCO2-e).
The simplest way to interpret the results of the global and national scenarios is that conserving the native forests is likely to reduce domestic emissions but not global emissions. The reason for this is that, if the native forests are not conserved, the emission reductions that would have come from stopping harvesting will have to be found elsewhere (otherwise Australia will be in breach of its international obligations).
More than anything else, our research highlights the extent to which policy institutions matter and serves as a warning about LCAs that ignore them. When policy institutions are included in the frame, as they must be, the simple dichotomies that so often characterise climate debates like ‘lentils good/beef bad’ and ‘wood good/cement bad’ become impossible to maintain.
Andrew Macintosh is the Chair of the Emissions Reduction Assurance Committee, a statutory body responsible for overseeing carbon offset methods developed for the purpose of the Australian Government's Emissions Reduction Fund. The content of this opinion piece reflects his personal views, not those of the Committee or the Australian Government.